Pediatric Respiratory System PDF

1 Respiratory System Pediatric inflammatory multisystem syndrome temporarily associated with COVID-19 (PIMS-TS) A small number of children develop a severe systemic inflammatory response associated with 900s COVID-19 infec6on. It shares a number of features in common with Kawasaki disease, q staphylococcal and streptococcal toxic shock syndromes, bacterial sepsis and macrophage ac6va6on syndromes. ha Those who have cardiac disease may present with shock, typically 3-4 weeks after suspected or proven COVID- 19 infection. On echocardiography they have may severe cardiac W.231 dysfunc6on or coronary artery is aneurysms a k al M Zones 1. Conduc6ng zone: no gas exchange 2. Respiratory zone: Gas exchange Alveolus - A Sac surrounded by capillaries. - Its wall consists of 2 types of pneumocytes. a) Type 1: 97% & thin for gas exchange. b) Type 2: produce surfactant & Regenera6on. - Surfactant i. Consist of proteins, lipid & CHO ii. Prevent collapse of the lung by decreasing surface tension. iii. Production begins at 24wks: 28wks. iv. Lungs are mature when enough surfactant is produced at 34 weeks. Types of Respiration 1. Quiet Respiration 2 Inspiration -> Diaphragm contracts Expiration -> Passive 2. Forced Respira6on Inspira6on Expira6on Abnormal Sounds of Respiration q ha Upper Airway Obstruc6on -> inspiratory sound -> stridor. Lower Airway Obstruc6on -> Expiratory Sound -> Wheezes. is Sever upper of lower Obstruc6on -> biphasic sound. Risk factors for respiratory disease in children or young people: a k al Parental - gene6c predisposi6on, maternal smoking during pregnancy M In the child or young person - prematurity or low birthweight, especially with bronchopulmonary dysplasia, congenital heart disease, disorders causing muscle weakness, reduced immune function, lack or incomplete immuniza6on or cigarette use or vaping Environmental - household or air pollution, number of siblings, allergens, low socio-economic status, cigarette smoke, and vaping. Presentation of respiratory disorders in children: 1. Upper respiratory tract: coryza, sore throat, earache, sinusitis, cough, or stridor. 2. Lower respiratory tract: 3 Cough - The character and nature of the cough may suggest a particular diagnosis. In general, wet or moist cough suggests that there are extra secretions. Increased rate of breathing: tachypnea is one of the most sensitive signs of illness. However, this is not specific to respiratory problems and occurs in heart failure, metabolic disorders, and sepsis. Increased work (effort) of breathing - An increase in resistance in the airways or lungs will result in an increase in the effort required to achieve adequate gas exchange. A conscious child will try to keep blood carbon dioxide and oxygen levels normal. If the resistance is increased in the upper airway, then effort is increased in inspira6on. If the resistance is increased in the lower airway, then effort is increased in expira6on. This is a specific indicator of respiratory illness. q Chest recession - In infants and young children, chest recession is an important indicator of increased work of breathing, ha Extra respiratory noises—The flow of air against a resistance will lead to the generation of sounds. A stethoscope makes lower airway sounds easier to hear. Musical noises, e.g., wheeze, suggest partial obstruction. Coarser is sounds, e.g., crackles, suggest increased secretions. low in children with cardiac conditions a k Reduced oxygen saturation - In air, this is a sensitive marker of respiratory illness. Oxygen satura6on can also be al 3. Impending respiratory failure Cyanosis persistent grun6ng M Reduced oxygen satura6on despite oxygen therapy Rising pCO2 on blood gas Exhaustion, confusion, reduced conscious level-bue Respiratory distress syndrome (RDS, also called hyaline membrane disease), there is a deficiency of surfactant, which lowers surface tension. Causes: 4 Infants born before 28 weeks' gestation and tends to be more severe in boys than girls. NB: The more preterm the infant, the higher the incidence of RDS Surfactant deficiency is rare at term but may occur in infants of 1) Diabetic mothers 2) Genetic mutations in the surfactant genes. very rarely Surfactant deficiency leads to widespread alveolar collapse and inadequate gas exchange. Clinical signs Tachypnea over 60 breaths/minute q ha Increased work of breathing, with chest wall recession (particularly sternal and subcostal indrawing) and nasal flaring is Expiratory grun6ng in order to try to create positive airway pressure during expiration and maintain functional residual capacity. Cyanosis if severe. a k Diagnosis al Chest X-ray: characteristic appearance. M A proteinaceous exudate (forming a hyaline membrane) may be seen in the airways on histology. Management Glucocorticoids, given antenatally to the mother, stimulate fetal surfactant production and are given if preterm delivery is anticipated. Initially, with supplemental oxygen and non-invasive respiratory support (con6nuous positive nominal airway pressure (CPAP) or high-flow nasal cannula therapy). Surfactant therapy may be required. It is given by injecting surfactant directly into the lungs via a tracheal tube or a fine catheter inserted directly between the vocal cords into the trachea. Mechanical ventilation is initiated if there is an inadequate response. Respiratory distress in term infants Newborn infants with respiratory problems develop the following signs of respiratory distress: Tachypnea (>60 breaths/min) Increased work of breathing, with chest wall recession (par6cularly sternal and subcostal indrawing) and nasal flaring - Expiratory grunting 5 q Cyanosis if severe. ha Affected infants should be admitted to the neonatal unit for monitoring of heart and respiratory rates, oxygen saturation, and circulation. is A chest X-ray will be required to help identify the cause, especially the causes that may need immediate treatment, e.g., pneumothorax or diaphragmatic hernia. a k Additional ambient oxygen, respiratory support that may be noninvasive, e.g., CPAP or high-flow nasal cannula therapy, or mechanical ventilation and circulatory support are given as required. al If infec6on is a cause, inves6ga6ons will need to be performed and empiric an6bio6cs started and con6nued M un6l the results of the infec6on screen are available. Transient tachypnoea of the newborn This is by far the most common cause of respiratory distress in term infants. It is caused by delay in the resorp6on of lung liquid and is more common after birth by caesarean sec6on. Diagnosis The chest X-ray may show fluid in the horizontal fissure. Treatment If the neonate is unable to feed normally, supplemental oxygen may be required in addition to feeding support with nasogastric feeds or IV fluids. The condition usually settles within the first day of life but can take several days to resolve completely. This is a diagnosis made after consideration and exclusion of other causes such as infec6on. Meconium aspira8on Meconium is passed before birth by 8%-20% of babies. It is rarely passed by preterm infants, and occurs increasingly the greater the gesta6onal od ysbro 92 90 YEM DAS 90 affec6ng 20%-25% of deliveries by 42 weeks. 6 It may be passed in response to fetal hypoxia. Asphyxiated infants may start gasping and aspirate meconium before or at delivery. Meconium is a lung irritant and results in Mechanical obstruc6on. Chemical pneumoni6s. Predisposing to infec6on. q ha is k In meconium aspira6on the lungs are overinflated, accompanied by patches of collapse and consolida6on. a There is a high incidence of air leak, leading to pneumothorax and pneumomedias6num. Mechanical ven6la6on al is often required. M Complications Infants with meconium aspira6on may develop persistent pulmonary hypertension of the newborn, which may make it difficult to achieve adequate oxygenation despite high-pressure ven6la6on. Severe meconium aspira6on is associated with significant morbidity and mortality. NB: There is no evidence that aspiration of meconium from an infant's oropharynx immediately after delivery of the head or removal of meconium by intubation and tracheal suc6oning of the infant after birth reduces the incidence or severity of meconium aspiration. Oxygen therapy should be provided to correct hypoxemia. However: - Excess oxygen leading to hyperoxia is damaging to the lungs and brain and other organs from excess free radicals. - for neonatal resuscitation, it is now recommended to start with 21%-30% oxygen in preterm infants, avoiding oxygen saturation over 95%; increased risk of re6nopathy of prematurity. Upper respiratory tract infections Children have an average of five upper respiratory tract infec6ons (URTIs) per year in the first few years of life, but some infants and primary school-age children have as many as 10-12 per year. Approximately 80% of all respiratory infec6ons are URTIS - Common cold (coryza) - Sore throat (pharyngi6s, including tonsilli6s) - Acute otitis media 7 - Sinusitis (relatively uncommon). The child may have a combina6on of these condi6ons. Cough may be troublesome and may be secondary to attempt to clear upper airway secre6ons or a postnasal drip. URTIS may cause: Difficulty in feeding in infants as their noses are blocked and this obstructs breathing Febrile seizures. Hospital admission may be required if feeding and fluid intake is inadequate. The common cold (coryza) q This is the most common infec6on of childhood. ha Symptoms is Clear or mucopurulent nasal discharge and nasal blockage. Pain Pathogens a k al Viruses rhinoviruses (M/C), coronaviruses, and respiratory syncy6al virus (RSV). M Treatment Colds are self-limiting, and there is no specific curative treatment that may reduce anxiety and save unnecessary visits to doctors. Pain is best treated with paracetamol or ibuprofen. An6bio6cs are of no benefit as the common cold is viral in origin, and secondary bacterial infection is very uncommon. Cough may persist for up to 4 weeks after a common cold. Sore throat (pharyngitis and tonsillitis) Inflammation of the pharynx and so\ palate with variably enlarged and tender local lymph nodes. Tonsilli6s is a form of pharyngi6s causing intense inflamma6on of the tonsils Pathogens 1. Viruses (adenovirus, enterovirus or rhinovirus) 2. Epstein-Barr virus (infec6ous mononucleosis or glandular fever) 3. Bacteria: group A beta-haemoly6c streptococci (The last 2 ass with purulent discharge) NB: The tonsilli6s of group A beta-hemolytic streptococci may produce a toxin responsible for the rash of scarlet fever 8 Clinical picture: Dysphagia Cons6tu6onal disturbance, such as headache, apathy and abdominal pain is more common 164 with bacterial infec6on. NB: it is not possible to dis6nguish clinically between viral and bacterial causes, and less than a third of cases of tonsilli6s are caused by bacteria. q ha is a k al Management: M Medical: Antibiotics such as penicillin V or erythromycin hasten recovery from streptococcal tonsilli6s on average by only 16 hours. However, an6bio6cs may be indicated to eradicate beta haemolytic streptococci to prevent rheumatic fever in high incidence countries or in children at increased risk of severe infection. This requires 10 days of oral an6bio6cs. and to children may require hospital admission for intravenous fluid administra6on and analgesia o if they are unable to swallow solids or liquids. Amoxicillin is best avoided as it may cause a widespread maculopapular rash if the tonsillitis is due to infec6ous mononucleosis. Surgical: Tonsillectomy and/or adenoidectomy In Children with recurrent tonsilli6s or its complica6ons (e.g. peritonsillar abscess - quinsy) and those with sleep disordered breathing (e.g. obstructive sleep apnoea) Indications: a) Child has had either seven or more episodes of significant sore throat in the preceding 12months b) Five or more episodes in each of the two previous years, c) Three or more episodes in each of the previous three years. NB: Tonsils and adenoids increase in size un6l about 8 years of age and then gradually regress. 9 In young children, the adenoids grow proportionately faster than their airway. Narrowing the airway is therefore greatest between 2 and 8 years. Acute otitis media Infants and young children are prone to acute ots media because Their Eustachian tubes are short, horizontal, and function poorly. Most children will have at least one episode of acute otitis media and up to 20% will have three or more episodes q Clinical picture ha It is most common at 6-12 months of age. It causes earache and fever. is NB: Every child with a fever should have their tympanic membranes examined. The tympanic dam membrane is bright red and bulging with loss of the normal light reflection. k Occasionally, there is acute perfora6on of the eardrum with pus visible in the external canal. a al M Pathogens RSV, rhinovirus, pneumococcus, Haemophilus influenzae and Moraxella catarrhalis. Complicatons (rare) Mastoidits, Meningitis Treatment Pain should be treated with regular analgesia and may be required for up to a week. Otitis media usually resolves spontaneously. An6bio6cs marginally shortens the duration of pain but has not been shown to reduce the risk of hearing loss. Neither decongestants nor an6histamines are beneficial. 10 Otitis media with effusion (glue ear) Condi6on in which there is fluid in the middle ear, but no signs of acute infection. Due to Recurrent ear infec6ons Presentation Children are usually asymptoma6c Possible decreased hearing. q The eardrum is dull and retracted, often with a visible fluid level. ha Otitis media with effusion is very common between the ages of 2 and 7 years. It usually resolves spontaneously, may cause conductive hearing loss, and interfere with normal speech is development. Treatment a k There is no evidence of long-term benefit from the use of an6bio6cs, steroids, or decongestants. Nasal al infla6on, where the child breaths out through a nostril to inflate a small balloon, may help by opening the eustachian tube, but the child usually needs to be school-aged to perform it. M If hearing does not improve, surgery may be considered, with insertion of tympanostomy tubes (grommets) with or without the removal of adenoids but benefits often do not last more than 12 months. Croup laryngotracheobronchitis, is a type of respiratory infection that is usually caused by a virus. The infection leads to swelling inside the trachea. Viral croup accounts for over 95% of laryngotracheal infections in children. It typically occurs from 6 months to 6 years of age, but the peak incidence is in the second year of life. It is most common in the autumn. Pathogens 11 Parainfluenza viruses are the most common cause It may be triggered by rhinovirus, RSV and influenza. Clinical picture Coryza Fever Hoarseness due to inflamma6on of the vocal cords q ha A barking cough, like a sea lion, due to tracheal oedema and collapse Harsh stridor is Variable degree of difficulty breathing with chest recession k The symptoms often start, and being worse, at night. a al M Treatment: When the upper airway obstruction is mild, the stridor and chest recession disappear when the child is at rest and the child can usually be managed at home. Parents should be advised to observe the child closely for signs of increasing severity. The decision to manage the child at home or in hospital is inﬂuenced. by the severity of the illness the time of day, ease of access to hospital 12 The child's age (with a lower threshold for admission for those less than 12 m because their narrow airway caliber. Those parental understanding and conﬁdence about the disorder. Oral dexamethasone, oral prednisolone, or nebulized steroids (budesonide) reduce the severity and duration of croup, and either one is ﬁrst-line therapy for croup causing chest recession at rest. They have been shown to reduce the need for hospitalization. If the upper airways obstruction is severe, nebulized epinephrine (adrenaline) with oxygen by face mask provides rapid but transient improvement. q The child must continue to be observed closely for 2-3hours after administration as its beneﬁt is ha temporary, but the therapy is useful whilst waiting for the corticosteroids to take eKect. Intubation for viral croup has become extremely unusual since the introduction of steroid therapy. is NB Inhalation of warm moist air is a traditional and widely used therapy, but it has not been proven to be beneﬁcial a k Some children have a pattern of recurrent croup, which may be related to atopy. al Bacterial tracheitis M Tracheitis is an inﬂammation of the trachea. Although the trachea is usually considered part of the lower respiratory tract, in ICD- 10 tracheitis is classiﬁed under "acute upper respiratory infections" Bacterial tracheitis and acute epiglottitis have similar clinical features. The most common pathogen is Staphylococcus aureus. Clinical picture A very ill-looking child High fever Drooling saliva as they are unable to swallow it. Stridor is soft. Copious, thick airway secretions. They have rapidly progressive airways obstruction. Treatment Urgent hospital admission and treatment are required. Calm administration of oxygen with nebulized adrenaline will usually oKer some temporary beneﬁt. Treatment must be initiated without delay. 13 A senior anesthetist, pediatrician, and ear, nose, and throat (ENT) surgeon should supervise the maintenance of the airway, and the child should be intubated under controlled conditions with a general anesthetic. Rarely, this is impossible and urgent tracheostomy is required. Only after the airway is secured should blood be taken for culture and intravenous antibiotics started. Acute epiglottitis Epiglottitis is inﬂammation and swelling of the epiglottis. q The most common pathogens is H. inﬂuenza type b. ha NB: Its very rare since children in most countries are immunized against H. inﬂuenza type b (Hib). Clinical picture is A very ill-looking child High fever a k Drooling saliva as they are unable to swallow it. al Stridor is soft. M MuKled voic e. Treatment Urgent hospital admission and treatment are required. Calm administration of oxygen with nebulized adrenaline will usually oKer some temporary beneﬁt. Treatment must be initiated without delay. A senior anesthetist, pediatrician, and ear, nose, and throat (ENT) surgeon should supervise maintenance of the airway, and the child should be intubated under controlled conditions with a general anesthetic. Rarely, this is impossible and urgent tracheostomy is required. Only after the airway is secured should blood be taken for culture and intravenous antibiotics started. Causes of acute stridor (upper airway obstruction) Common causes - Viral laryngotracheobronchitis ('croup') Foreign body Rare causes Laryngeal edema (anaphylaxis and recurrent croup) Inhalation of smoke and hot fumes in ﬁres 14 Trauma to the throat. Retropharyngeal abscess - Bacterial tracheitis or epiglottitis Severe lymph node swelling (malignancy, tuberculosis, infectious mononucleosis, measles) Hypocalcemia Vocal cord dysfunction Diphtheria (exceedingly rare) q NB: If a child has an abrupt onset of stridor without infection, consider anaphylaxis or inhaled foreign body. ha Causes of chronic stridor (upper airway obstruction) Usually due to a structural problem, either from is Intrinsic narrowing or collapse of the laryngotracheal airway. - laryngomalacia (ﬂoppy larynx). subglottic stenosis. a k al External compression M Investigations are sometimes required to determine the cause. Laryngomalacia Is common and is due to the soft, immature cartilage of the upper larynx Clinical picture Collapsing on inspiration, causing airwa y obstruction. Although it is a congenital anomaly, it usually presents at about 4 weeks of age when inspiratory ﬂow rates are suKicient to generate the stridor. worsens when the in fant is agitated, feeding, or lying on his/her back. Treatment If the child is thriving, no treatment or further investigation is required. It resolves by 2 years. Lower respiratory tract infections Lower respiratory tract infections (LRTI) are common in children. About half of all cases are viral in origin. 15 They include: bronchiolitis, bronchitis - pneumonia Bronchiolitis Bronchiolitis is the most common serious respiratory infection of infancy, resulting in admission to q hospital of 2% -3% of all infants during annual winter epidemics. ha 90% are aged 1-9 months. Pathogens is RSV, the pathogen in 80%. The remainder are accounted f or by parainﬂuenza virus, rhinovirus, a k adenovirus, inﬂuenza virus, and human metapneumovirus. There is evidence that co-infection with more than one virus, al particularly RSV and human metapneumovirus, may lead to a more severe illness. M Clinical picture Coryzal symptoms precede a cough and breathlessness.. Feeding diKiculty due to dyspnoea is often the reason for admission to hospital. Recurrent apnea is a serious complication, especially in young infants. NB: Infants born prematurely who develop bronchopulmonary dysplasia, those with other underlying lung disease, such as cystic ﬁbrosis, or those who have congenital heart disease are most at risk from severe bronchiolitis. Investigations Pulse oximetry should be performed on all children with suspected bronchiolitis. No other investigations are routinely recommended. Chest X-ray or capillary blood gases are only indicated if respiratory failure is suspected. Management Hospital admission is indicated if any of the following are present: Apnea (observed or reported) Persistent oxygen saturation of less than 92 % when breathing air Inadequate oral ﬂuid intake less than 70% of usual volume) Severe respiratory distress - grunting, marked chest recession, or a respiratory rate over 70 breaths/minute. 16 Treatment is supportive. Humidiﬁed oxygen is delivered via nasal cannula at a concentration adjusted according to swol pulse oximetry. The infant is monitored for apnea Fluids may need to be given by nasogastric tube or intravenously. If the infant remains hypoxic despite standard nasal cannula oxygen, heated, humidiﬁed high ﬂow nasal cannula oxygen (HHFNCO) may be beneﬁcial by allowing higher ﬂows of oxygen to be delivered comfortably, although its role in bronchiolitis has not been determined. q In some infants, non-invasive respiratory support with continuous positive airway pressure (CPAP), bi-level ha positive airway pressure (BIPAP) or mechanical ventilation is required. NB is There is no evidence of beneﬁt from the use of mist, nebulized hypertonic saline, antibiotics, corticosteroids or bronchodilators such as salbutamol or ipratropium. - Good hand hygiene, a k ✓RSV is highly infectious, and infection control measures, al - Gowns and gloves, have been shown to prevent cross infection to other infants in hospital. M Outcome: Most infants recover from the acute infection within 2 weeks. As many as half will have recurrent episodes of cough and wheeze Rarely, following adenovirus infection, the illness may result in permanent damage to the airways (bronchiolitis obliterans). Prevention of bronchiolitis A monoclonal antibody to RSV (palivizumab) given monthly by intramuscular injection reduces the number of hospital admissions in high-risk preterm infants. Its use is limited by cost and the need for multiple injections. Pneumonia Pneumonia is an inﬂammatory condition of the lung primarily aKecting the small air sac is known as alveoli The incidence of pneumonia peaks in infancy and old age, but is relatively high in childhood. It is a major cause of childhood mortality in lo w- and middle-income countries Pathogens Viruses are the most common cause in young children beyond the neonatal period. 17 Bacteria are more common in neonates and older children. In clinical practice, it is diKicult to distinguish between viral and bacterial pneumonia In more than half of cases no causative pathogen is identiﬁed. The likely pathogen varies according to age: Newborn - organisms from the mother's genital tract, particularly group B streptococcus, but also Gram- negative enterococci and bacilli. - Infants and young children: q > Respiratory viruses such as RSV are commonest. ha Bacterial infections include Streptococcus pneumonia, H. inﬂuenzae and Staphylococcus aureus. Bordetella pertussis and Chlamydia trachomatis can also cause pneumonia at this age. is Children over 5 years - Mycoplasma pneumoniae, Streptococcus pneumoniae, and Chlamydia pneumoniae are the main causes. a k - At all ages Mycobacterium tuberculosis should be considered. Immunization with Hib and pneumococcal vaccines has markedly reduced the incidence of pneumonia from Haemophilus inﬂuenzae and invasive Streptococcus pneumoniae. al Types M 1. Lobar pneumonia: aKects one or more sections (lobes) of the lungs. old on 2. Bronchial pneumonia (also known as bronchopneumonia): aKects patches throughout both lungs, patchy consolidation involving one or more lobes. The neutrophilic exudate is centered in bronchi and bronchioles, with centrifugal spread to the adjacent alveoli. 3. Interstitial pneumonia: patchy or diKuse inﬂammation involving the interstitium while the alveoli do not contain a signiﬁcant exudate, but hyaline membranes may line the alveolar spaces. NB: Bacterial superinfection of viral pneumonia can also produce a mixed pattern of interstitial and alveolar airspace inﬂammation Clinical features The most common presenting symptoms Usually preceded by a URTI. Fever Cough Shortness of breath. Other symptoms include Lethargy. Poor feeding. Appearing 'unwell'. Some children do not have a cough during presentation. 18 Localized chest, abdominal, or neck pain is a feature of pleural irritation. Examination Tachypnea Increased work of breathing. NB: The most sensitive clinical sign of pneumonia is raised respiratory rate so this must always be measured in a febrile child. The classic signs of consolidation are localized dullness on percussion, The percussion note will be 'stony q dull' if there is an accompanying eKusion or empyema. ha Decreased breath sounds, Bronchial breathing the BESTS is End-inspiratory coarse crackles, NB: these signs are often absent in young children. Investigation a k Oxygen saturation may be decreased. al A chest X-ray is only necessary if there is doubt about the diagnosis M NB ✓ Neither a chest X-ray nor blood tests, including full blood count and acute-phase reactants, can reliably diKerentiate between a viral and bacterial cause. ✓ When pneumonia is associated with a pleural eKusion, this is initially sterile (para-pneumonic eKusion) but can become infected (empyema) When this happens, the ﬂuid becomes increasingly viscous, and ﬁbrin strands form, leading to septations. Management Most aKected children can be managed at home but indications for admission are: - Oxygen saturation less than 92%, Recurrent apnoea, Grunting And/or an inability to maintain adequate ﬂuid/feed intake. General supportive care for children requiring admission should include Oxygen for hypoxia Analgesia for pain. - Intravenous ﬂuids should be given if necessary to correct dehydration and maintain adequate hydration and sodium balance. The choice of antibiotic is determined by the child's age and the severity of the illness. Newborns require broad-spectrum intravenous antibiotics. 19 Most older infants can be managed with oral amoxicillin, with broader spectrum antibiotics such as co-amoxiclav reserved for complicated or unresponsive pneumonia. - For children over 5 years of age, either amoxicillin or an oral macrolide such as clarithromycin is the treatment of choice. NB: the choice of antibiotic agent may vary based on local resistance rates. In areas where resistance is very high (>25% of strains being non- susceptible), a third-generation cephalosporin might be indicated. Olde r children, in addition, may receive a macrolide to q cover for atypical infections. ha Children who are toxic appearing should receive antibiotic therapy that includes vancomycin (particularly in areas where penicillin- resistant pneumococci and methicillin-resistant S aureus [MRSA] is are prevalent) along with a second- or third-generation cephalosporin. a k There is no advantage in giving intravenous rather than oral treatment in mild/moderate pneumonia unless the child is vomiting. al Small sterile parapneumonic eKusions occur in up to one-third M of children with pneumonia and usually resolve once the pneumonia is treated. Persistent fever despite 48hours of antibiotics in a child with an eKusion suggests it has become infected. This is a pleural empyema; the ﬂuid becomes increasingly viscous, and ﬁbrin strands form, leading to septations, Drainage may be required. - The percutaneous placement of a small-bore chest drain under ultrasound guidance Regular instillation of a ﬁbrinolytic agent to break down the ﬁbrin strands is usually eKective. Video-assisted thoracoscopic surgery or even thoracotomy and decortication is sometimes necessary in refractory cases. Outcome Prognosis and follow-up is not required for a child with simple pneumonia who makes a full clinical recovery. Those with a lobar collapse or persistent symptoms should have a repeat chest X-ray after 4-6 weeks to conﬁrm resolution. Virtually all children with pneumonia, even those with empyema, make a full recovery in high- income countries. Causes of recurrent or persistent childhood wheeze Viral episodic wheeze Multiple trigger wheeze Asthma Recurrent anaphylaxis (e.g. in food allergy) 20 - Chronic aspiration - Cystic ﬁbrosis Bronchopulmonary dysplasia Bronchiolitis obliterans - Tracheo-bronchomalacia (a) Consolidation of the right upper lobe with loss of volume of this lobe. The horizontal ﬁssure has been shifted upwards. q (b) Left upper lobe consolidation. ha (c) Right lower lobe consolidation with volume loss on the right. The heart silhouette is clearly seen but the right hemidiaphragm is raised and partially obscured. is (d) A normal right hemidiaphragm but partial loss of the right heart border typical of right middle lobe consolidation. a k (e) Left lower lobe consolidation. The diaphragm is not clearly seen behind the cardiac silhouette. (f) Lingular consolidation with obvious loss of the left heart border. al Pathogens M This highly contagious respiratory infection is caused by Bordetella pertussis, which produces pertussis toxin. A related organism, Bordatella pertussis, causes a similar illness but it does not produce pertussis toxin and the illness is usually milder and shorter. Pertussis is endemic, with epidemics every few years.. Clinical picture Catarrhal phase a week of coryza Paroxysmal phase characteristic paroxysmal or spasmodic cough followed by a characteristic inspiratory whoop - The spasms of cough are often worse at night and may culminate in vomiting (tussive vomiting). During a paroxysm, the child goes red or blue in the face, and mucus ﬂows from the nose and mouth. The whoop may be absent in infants, but apnea is common at this age. Epistaxis and subconjunctival hemorrhage can occur due to vigorous coughing. The paroxysmal phase lasts up to 3 months. Convalescent phase: The symptoms gradually decrease (but may persist for many months and Complications pneumonia, seizures and bronchiectasis are uncommon 21 There is still a signiﬁcant mortality, particularly in infants who have not yet completed their primary vaccinations at 4 months. Infants and young children suKering severe spasms of cough or cyanotic attacks should be admitted to hospital and isolated from other children. Diagnosis The organism can be identiﬁed early in the disease from culture of a paranasal swab, PCR (polymerase chain reaction) is more sensitive. q Characteristically, there is a marked lymphocytosis (>15 x 109 /L) on a blood count. ha Treatment Although macrolide antibiotics eradicate the organism, they decrease symptoms only if started during the catarrhal phase. is Siblings, parents, and school contacts are at risk and close contacts should receive macrolide prophylaxis. Unimmunized infant contacts should be vaccinated. guarantee protection. a k Immunization reduces the risk of developing pertussis and the severity of disease if aKected but does not al The level of protection declines steadily during childhood and most cases are now in young people over 15 years old. M Reimmunization of mothers during pregnancy as it reduces the risk of pertussis in the ﬁrst few months of the infant's life, when it is most dangerous. Asthma Asthma is a long-term inﬂammatory disease of the airways of the lungs, It is characterized by variable and recurring symptoms, reversible air ﬂow obstruction, and easily triggered bronchospasms. Asthma is the most common chronic respiratory disorder in childhood. Although the symptoms of asthma can be readily controlled in most children, it is an important cause of school absence, restricted activity, and anxiety for the child and family. Pathophysiology Ag->mast cell -> Leukotriene & Histamine -> Bronchoconstriction Clinical features Wheezing on more than one occasion, particularly if this persists between viral illnesses (interval symptoms). 22 Ideally, the presence of wheeze is conﬁrmed on auscultation during an acute episode to distinguish it from transmitted upper respiratory noises, which are often loud and easy to hear in children. Asthmatic wheeze is a polyphonic (multiple pitch) noise as multiple airways of diKerent sizes are aKected. A chronic dry cough is common in children with asthma but is rarely the only symptom. Key features associated with asthma in the history include: Wheeze, cough and breathlessness worse at night and in the early morning Wheeze and breathlessness with non-viral triggers q Interval symptoms, i.e. symptoms between acute exacerbations ha Personal or family history of an atopic disease Positive response to asthma therapy. is Once suspected, the pattern or phenotype should be further explored by asking: How frequent are the symptoms? k The depressions at the base of the thorax associated with the muscular insertion of the diaphragm are a called Harrison sulci, and are associated with chronic obstructive airways disease such as asthma during al childhood from chronic increased work of breathing. M - What triggers the symptoms? Speciﬁcally, are sport and general activities aKected by the asthma? - How often is sleep disturbed by asthma? How severe are the interval symptoms between exacerbations? - How much school has been missed due to asthma? Examination: Usually normal between attacks. In long-standing asthma there may be hyperinﬂation of the chest, On auscultation a prolonged expiratory phase and generalized polyphonic (musical) expiratory wheeze. Onset of the disease in early childhood may result in Harrison sulci Evidence of atopy should be sought, by examination of the nasal mucosa for allergic rhinitis and the skin for eczema. Growth should be plotted, but is usually normal. The presence of a wet cough productive of sputum, ﬁnger clubbing or growth faltering suggests a condition characterized by chronic infection such as cystic ﬁbrosis rather than asthma. The preschool child Diagnosing asthma in preschool children is often diKicult. Approximately half of all children wheeze at some time 23 Multiple trigger wheeze and asthma Multiple-trigger wheeze is used to describe wheezy episodes triggered by many stimuli which can include viral infections, cold air, dust, animal dander and exercise. A signiﬁcant proportion have asthma. The presence of asthma risk factors increases thenő likelihood the child has asthma and will beneﬁt from asthma treatment, e.g. salbutamol during acute events and inhaled steroids over longer periods. Risk factors are q More than 3 episodes a year of cough and wheeze for more than 10 days with viral ha infections, cough and wheeze between episodes, Laughing or excitement causing wheeze, is Allergic sensitization, eczema, food allergy or family history of asthma. DiHerential diagnosis: Viral episodic wheeze a k al Most wheezy preschool children have viral episodic wheeze, triggered by viral upper respiratory M tract infections, with no interval symptoms between episodes. It is thought to result from an abnormal immune response to viral infection causing inﬂammation and obstruction of the small airways. Risk factors include Maternal smoking during and/or after pregnancy, Prematurity Male sex. A family history of asthma or allergy is not a risk factor, but a family history of early viral wheezing is common. It usually resolves by 5 years of age, presumably from increased airway size. Investigations of asthma: In children less than 5 years old, the diagnosis of asthma is based on nottalanobodanon trovans History, Examination Response to treatment. Speciﬁc investigations such as skin prick testing to identify sensitization to inhaled allergens may help determine the precise phenotype and determine whether changes to the child's environment might improve symptoms. A chest X-ray is not necessary unless other conditions need to be excluded. In children >5 years old, if diagnosis is uncertain, investigations may include: 24 Peak expiratory ﬂow rate (PEFR) - measured with peak ﬂow meters, which are simple to use, portable and useful for serial measurements. The child should fully inhale bef ore placing the mouthpiece between their teeth and sealing tightly with their lips. A sharp, fast exhalation will provide an estimate of the maximum rate of exhalation, and this is achieved very early in exhalation (usually the ﬁrst 0.2seconds). Poorly controlled asthma leads to increased variability in peak ﬂow rate, with both diurnal variability (morning usually lower than evening) and day-to-day variability. -Spirometry a non-invasive measure of ﬂow through the airways larger than the q bronchioles It involves blowing out as hard and fast as possible for as long as possible. ha To generate reliable results children must be able to fully expire whilst completing each test. This provides a measurement of the volume expired in is the ﬁrst second (forced expiratory volume in 1second - FEV1) and the total volume of expired air (forced vital capacity - FVC). Asthma classically produces obstructive spirometry in which FEV1 is reduced but FVC remains normal (resulting in a FEV1:FVC ratio less than 80%). a k - Children with mild to moderate asthma may have normal spirometry when well. al Bronchodilator reversibility - identiﬁed by showing an improvement before and after a dose of inhaled M bronchodilator (by ≥20% in PEFR or ≥12% in FEV1). Exhaled nitric oxide concentration (FeNO, fractional exhaled nitric oxide) - if available, is a marker of airway inﬂammation, and is elevated in untreated asthma and allergic rhinitis. It is recommended in diagnosis of asthma in children if there is diagnostic uncertainty. Management of asthma: 1. B2-Agonist Bronchodilator & smooth muscle relaxant M/C used & most eKective. Short Acting (SABA) - Used in acute Rapid onset (10:15min) Short Acting (24h) Used in 21wk of age Permanent needed Long Acting (LABA) Not used as monotherapy so used with CST - First choice in children > 5y 25 2. Muscarinic Antagonist - Prevent Bronchoconstriction Short Acting (Ipratropium) & Long Acting (Tiotropium) Used if sever acute asthma & if the other bronchodilators are ineKective. 3. Steroids - Decrease inﬂammation & decrease expression of many ILs Inhaled (preventors) q - The most eKective prophylactic therapy if taken regularly. ha No SE if taken in low dose Oral is Used if sever acute asthma & if the other bronchodilators are ineKective 4. LTRA k Montelukast & add on therapy if child < 5ys with CST. a 5. Omalizumab -> decrease IgE binding & is used in severe asthma. al 6. Cromolyn -> stop mast cell degradation M 7. Theophylline -> Bronchodilators & has many SEs so limited to used for children Asthma Management uses a stepwise approach, starting treatment with the step most appropriate to the severity of the asthma and aiming for optimal control of symptoms. Complete control is deﬁned as the absence of - Daytime or night-time symptoms, No limit on activities (including exercise), No need for reliever use, normal lung function, No exacerbations (need for hospitalization or oral steroids) in the previous 6 months. Once a diagnosis has been established all children should be on a regular preventer. Treatment is stepped up when asthma control is poor and stepped down when control is good. Older children should follow adult protocols and guidance which typically use higher doses of ICS and a greater range of biologicals. Acute Asthma Assessment With each acute attack, duration of symptoms, treatment already given, and the course of previous attacks should be noted. The severity of an attack needs to be classiﬁed as: - Mild Moderate - Severe 26 - Life-threatening. Criteria for admission to hospital Children require hospital admission if, after high-dose inhaled bronchodilator therapy, they: Have not responded adequately clinically, i.e. there is persisting breathlessness or tachypnoea Becoming exhausted Still have a marked reduction in their predicted (or usual best) peak ﬂow rate or FEV1 (less than 50%) Have a reduced oxygen saturation less than 92% in air). q - A chest X-ray is indicated only if there are unusual features ha a) (e.g. asymmetry of chest signs suggesting pneumothorax, lobar collapse) or b) signs of severe infection. is In children, blood gases are only indicated in life-threatening or refractory cases and are often normal until the child is in extremis. Management a k Acute breathlessness is frightening for both the child and the parents. al Calm and skillful management is the key to their reassurance. M Oxygen, Inhaled bronchodilators Steroids form As soon as the diagnosis has been made, if the oxygen saturation is less than 92%, oxygen therapy should be given. All children should be given a ẞ2-bronchodilator; the dose and frequency is varied according to severity of the attack, the child's age and response to therapy. The addition of nebulized ipratropium and/or nebulized magnesium to the initial therapy in severe asthma is probably beneﬁcial. A short course (3-5 days) of oral prednisolone expedites recovery in moderate or severe acute asthma. Inhaled therapies may not be delivered in therapeutic concentrations to severely aKected areas of the lung that are under-ventilated, so intravenous therapy has a role in the few children who fail to respond adequately to inhaled bronchodilator therapy. Magnesium sulphate, salbutamol and aminophylline are all potentially beneﬁcial. 1) Magnesium sulphate is usually the ﬁrst-line intravenous agent, but can cause profound hypotension. 2) Intravenous salbutamol can cause tachycardia and lactic acidosis 3) Nausea and vomiting are common with aminophylline. For both intravenous salbutamol and aminophylline, a loading dose is given over 20 minutes, followed by continuous infusion during which ECG and blood electrolytes should be monitored. 27 - Antibiotics are only given if there are clinical features of bacterial infection. Occasionally, these measures are insuKicient and mechanical ventilation is required. Patient education Prior to discharge from hospital after an acute admission, the following should be reviewed with the child and family: When drugs should be used (regularly or 'as required'). How to use the drug (inhaler technique) What each drug does (relief vs prevention) q How often and how much can be used (frequency and dosage). ha What to do if asthma worsens (a written personalized asthma action plan should be completed The child and parents need to be aware that increasing symptoms is Cough, wheeze and breathlessness Reduced ability to participate in activities and increased use of bronchodilator a k All indicate poorly controlled asthma. al Children and young people with diKicult asthma may be given an emergency supply of oral steroids M to keep at home and use for acute exacerbations as detailed in their asthma action plan. Outcomes are better for children with asthma who have a package of educational measures, but no single component has been shown to be beneﬁcial in isolation. Periodic assessment and review by a healthcare professional is required Choosing the correct inhaler Inhaled drugs may be administered via a variety of devices, chosen according to the child's age and preference. Pressurized metered dose inhaler and spacer. Appropriate for all age groups - 0-2 years, spacer with face mask; 23 years, spacer with mouthpiece. A spacer is recommended for all children as it increases drug deposition to the lungs and reduces oropharyngeal deposition and therefore systemic side- eKects. Useful for acute asthma attacks when poor inspiratory eKort may impair the use of inhalers direct to the mouth. Breath-actuated metered dose inhalers (e.g. Autohaler, Easi-Breathe) - from 6 years. Less coordination needed than a pressurized metered dose inhaler without spacer. Useful for delivering B-agonists when 'out and about' in older children. Dry powder inhaler - from 4 years (Fig. 17.16). Needs a good inspiratory ﬂow, therefore less good in severe asthma and during an asthma attack. Also easy to use when 'out and about' in older children. 28 Nebulizer—any age (Fig. 17.17). Due to variation in droplet size, it is a far less eKicient method of drug delivery than metered-dose inhalers (MDI) plus spacers. It should always be administered using high-ﬂow oxygen, not air. It is only used in acute asthma where oxygen is needed. Many children fail to respond to treatment because their inhaler is not appropriate for their age or they have poor inhaler technique. Inhaler technique should be taught and then assessed at every review. Chronic cough By far the most common reason for this is that the child has had a series of respiratory tract infections in rapid succession. q This often happens when a child enters school or nursery for the ﬁrst time and is much more common if ha there are older siblings. However, some infections, such as pertussis and RSV and Mycoplasma, can cause a cough that persists for weeks or months but eventually remits spontaneously. These coughs are typically dry. is Chronic wet cough (i.e. sounding like there is excess sputum in the airways) or a productive cough after an acute infection may indicate k Unresolved lobar changes following pneumonia, persistent bacterial bronchitis Suppurative lung disease. a al If the cough is 'wet' further investigation is required. 118 to grub 10:00 60 31 M Children rarely expectorate and therefore sputum is not commonly seen, Causes of chronic or recurrent cough: Recurrent respiratory infections Persistent bacterial bronchitis (will be persistently wet) Following speciﬁc respiratory infections (e.g. pertussis, respiratory syncytial virus, Mycoplasma) Asthma (only if accompanied by wheezing) Persistent lobar collapse following pneumonia Suppurative lung diseases (e.g. cystic ﬁbrosis, ciliary dyskinesia or immune deﬁciency) 2010 * Recurrent aspiration (+ gastro-oesophageal reﬂux) Inhaled foreign body Cigarette smoking (active or passive) Tuberculosis Habit cough Airway anomalies (e.g. tracheo-b ronchomalacia, tracheo-oesophageal ﬁstula) 29 Protracted bacterial bronchitis (PBB) It is caused by bacterial infection of the conducting airways (the trachea, bronchi and bronchioles), PBB is the leading cause of chronic wet cough in young children (less than 8 years) in high- income countries. Children are otherwise well, but often miss school and have disturbed sleep. Pathogens q Haemophilus inﬂuenzae, ha Streptococcus pneumoniae, Moraxella catarrhalis is Staphylococcus aureus. Clinical diagnosis Chronic wet cough, a k The absence of symptoms or signs suggesting another cause such as bronchiectasis al Resolution of cough following antibiotic treatment. M Although improvement with treatment is part of the diagnostic criteria, relapse of cough is common. Frequent relapse (recurrent PBB) is associated with a subsequent diagnosis of bronchiectasis Aspiration of feeds Clinical picture: Cough, wheeze Recurrent lower respiratory tract infections. It can occur during or after feeding due to gastro-oesophageal reﬂux disease or swallowing disorders. Aspiration is more common in children with cerebral palsy. Rarely it is due to an anatomical anomaly, e.g. H- type tracheo-oesophageal ﬁstula. Foreign body aspiration Inhaled foreign body needs to be considered in any Cough with acute onset respiratory symptoms, Unilateral respiratory signs or Chronic cough with a persistent radiological abnormality. 30 It occurs most commonly in children aged 6 months to 3 years. The aspirated material is most often food, but can be bits oK toys, or coins. A history of choking is present in >80%, but only when speciﬁcally asked about. Diagnosis: Radio-opaque foreign bodies can be readily identiﬁed on plain chest X-ray A radiolucent foreign body such as a peanut is more diKicult to diagnose (o inspiratory ﬁlm is normal whereas expiratory ﬁlm shows hyperinﬂation of right lung and mediastinal shift. q Treatment: ha Removal is using a rigid bronchoscope. In any child with a severe, persistent cough, tuberculosis should be considered. is Allergy A hypersensitivity reaction initiated by speciﬁc immunological mechanisms. This can be IgE-mediated (e.g. k peanut allergy) or non-IgE mediated (e.g. coeliac disease) a Hypersensitivity al Symptoms & signs following exposure to a deﬁned stimulus at dose usually tolerated by most people. M An abnormal immune system may result in: Allergic diseases Immune deﬁciencies - Autoimmune disorders - either organ-speciﬁc (e.g. type I diabetes mellitus) or systemic (e.g. systemic lupus erythematosus). Immune tolerance The absence of an active immune response against a particular antigen, e.g. the absence of an allergic immune response to peanut or house dust mite Sensitization A positive test to an allergen, either by skin prick test, or speciﬁc IgE. Does not equate to allergy unless a clinical reaction is initiated on exposure. However, the ibm-391 higher the number of positive tests, the more likely the person is going to be "allergic" Type 1 Hypersensitivity Immediate reaction to an Ag (1ry exposure of this Ag) -> IgE Abs -> attached to mast cells -> Degranulation -> Histamine & Interleukins: - Increase permeability -> swelling edema. SM contract 31 Histamine -> itching Risk factors Inhalant allergens, e.g. house-dust mite, plant pollens, pet dander and moulds Ingestant allergens, e.g. egg, cow's milk, nuts, wheat, seeds, legumes, seafood and fruits insect stings/bites, drugs, and natural rubber latex Alterations in the ﬁlaggrin gene are associated with increased risk of eczema and food allergy q C/P ha » Skin -> Urticaria Respiratory system -> As thma / Rhinitis is Eye -> Allergic conjunctivitis GIT-> Diarrhea Atopy a k al A personal and/or familial tendency to produce IgE antibodies in response to ordinary exposures to potential allergens, usually proteins. Strongly associated with asthma, allergic rhinitis and conjunctivitis, eczema, M and food allergy Anaphylaxis A serious type 1 hypersensitivity reaction with bronchial, laryngeal, or cardiovascular involvement that is rapid in onset and may cause death. Itching & Erythema Urticaria & Angioedema Respiratory distress -> stridor cyanosis Laryngeal edema -> hoarseness of voice Vomiting - Shock & death Rx - Acute: IM adrenaline - Additional: Fluids/ antihistamine/CST/salbutamol IgE-mediated allergic reactions have a characteristic clinical course: An early phase, occurring within minutes of exposure to the allergen, caused by release of tergirl histamine and other mediators from mast cells. Causes urticaria, angioedema, sneezing, vomiting, bronchospasm and/or cardiovascular shock 32 A late phase response may also occur after 4-6hours, especially in reactions to inhalant allergens. This causes nasal congestion in the upper airway, and cough and bronchospasm in the lower airway. A potential late phase response in food allergy is why children need to be dalumage0 observed in hospital for several hours after a moderate or severe food allergy reaction. Most severe life-threatening allergic reactions are IgE mediated Clinical evaluation 1. History and examination An allergy-focused history is the cornerstone to a correct diagnosis. q The child and family may not volunteer a history of allergic disease as they have come to s consider the ha symptoms as normal, e.g. the child who coughs most nights or has a blocked nose most of the time may not perceive this as abnormal. As allergic diseases are a 1291 sn multisystem, in addition to the signs of individual allergic diseases, examination may reveal: Mouth breathing Children who habitually breathe with is their mouth open may have an eq obstructed nasal airway from rhinitis, and there may also be a history of snoring or obstructive sleep apnea Allergic salute from rubbing an itchy nose a k Pale and swollen inferior nasal turbinates from rhinitis al Hyperinﬂated chest or Harrison sulci from chronic undertreated asthma M Atopic eczema aKecting the limb ﬂexures Allergic conjunctivitis; may be accompanied by be prominent creases (Dennie-Morgan folds) and blue grey discoloration below the lower eyelids. Growth needs to be checked, especially in those with food allergy, where dietary restrictions or malabsorption can lead to nutritional deﬁciencies or compromise, and in those treated with high-dose inhaled/nasal/topical corticosteroids. 2. Investigations a) Skin prick tests Skin prick testing is performed for food and inhaled allergens, and sometimes for at angrells investigating drug or insect sting allergies. A drop of allergen (either an extract or the fresh food) is placed on the skin, the site is ento marked and the skin is pricked with a lancet After 15 minutes any wheals are measured to determine if positive. Providing antihistamines have been stopped 48-72 hours before testing, negative tests suggest that allergy is unlikely. Test results can only be interpreted in the context of a detailed history. b) IgE blood tests Raised total IgE is an indication of atopy in a child. For investigating food or inhaled allergy, such as to milk, grass pollen, etc, speciﬁc IgE tests are required. Food that the child is already eating without symptoms should not be tested as it may yield a false positive result. The greater the response, the more likely the child is to be allergic. Negative results make IgE-mediated allergy unlikely. 33 More recently developed 'component' blood tests to speciﬁc components of the allergen can provide more speciﬁc information. c) Spirometry and other lung function tests May be performed to provide information about lung function to diagnose or monitor asthma or lung inﬂammation. d) Allergen challenge If results from the history and investigations are not clear, or if the child is thought to have grown out of an allergy, an allergen challenge may be performed. This is usually a food A challenge for food allergy. The child is given increasing quantities of the food, starting with a tiny amount, until a full portion is reached. q The test should be performed in a hospital with full resuscitation facilities available, with on close ha monitoring for signs of anaphylaxis. Similarly, drug challenges are also sometimes um performed. Age of onset of allergic conditions is Allergic children develop individual allergic disorders at diKerent Eczema and food allergy usually develop in infancy. k Allergic rhinitis, conjunctivitis and asthma begin most often in preschool and primary school years. Allergic a disorders often coexist; for example, most children with food allergy have a history of early onset eczema al and most children with asthma have some degree of allergic rhinitis M Allergic march The progression from eczema to later developing food allergies, allergic rhinitis and asthma is called the allergic march. The allergic march is also called the atopic march. Prevention of allergic diseases Induction of 'immune tolerance' by feeding common food allergens such as egg and peanut to young infants to reduce their risk of developing egg or peanut allergy when multiple food allergens havev been introduced together, the eKect is limited due to diKiculty feeding infants suKicient food allergens for long enough to prevent all food allergy. Thus, the impact of using immune tolerance to prevent food allergy is limited. Other approaches tried without success include probiotics (live bacteria such as lactobacillus), prebiotics (non-digestible oligosaccharides), nutritional supplements (e.g. omega-3 fatty acids, vitamin D, antioxidants, trace elements), medications (e.g. antihistamines, immunotherapy), and skin moisturizers. House dust avoidance Food allergy and food intolerance In infants -> the most common causes are egg, cow's milk and nuts In children -> peanut, tree nut, ﬁsh, shellﬁsh and sesame. Classiﬁed into 1ry -> 1st exposure - 2ry -> cross reaction between proteins e.g., pollen food allergy 34 Clinical features Food allergy occurs when a pathological immune response is mounted against a speciﬁc food protein. 1. It is usually IgE-mediated With a history of allergic symptoms varying from urticaria to facial swelling to anaphylaxis, usually 10- 15minutes (up to 2hours) after ingestion of a food. - Over 80% of children with food allergy present in the ﬁrst year of life; many have atopic eczema. 1692 bins tiun of verellis bʊot q 2. Non IgE-mediated: ha - food allergy typically occurs hours after ingestion and usually involves the gastrointestinal tract, with diarrhoea, vomiting, abdominal pain and sometimes faltering growth It sometimes presents in an infant with blood in the stools in the ﬁrst few weeks of life from proctitis, or is rarely with severe repetitive vomiting in an infant following milk or rice which can result in shock (food protein induced enterocolitis syndrome). Eosinophilic esophagitis presents with persistent vomiting and food in the oesophagus. a k diKiculty swallowing in young children; and in older children with diKiculty swallowing, and impaction of 3. A non-immunological hypersensitivity reaction to a speciﬁc food is called food intolerance. al Diagnosis M The clinical history is key in food allergy diagnosis. Food allergy should be suspected if typical symptoms occur following exposure to a particular food. For IgE-mediated food allergy, the most helpful conﬁrmatory tests are skin prick tests and measurement of speciﬁc IgE antibodies in blood as described above. Management Avoidance of the relevant food(s). This can be very diKicult as the most common food allergens are common ingredients in the diet and may be present in small quantities in many foods. - Food labelling legislation requires all common food allergens to be clearly disclosed. The advice of a paediatric dietitian can help patients avoid foods to which they are allergic, ﬁnd appropriate alternatives, and avoid nutritional deﬁciencies. If a child is diagnosed with one allergy, related allergies need to be considered; 20% of children with egg allergy have peanut sensitization and may be peanut allergic and children with peanut allergy will often have a tree nut allergy. - Proteins with an unstable tertiary structure may be rendered non-allergenic by heat degradation or other forms of processing because high temperatures makes the food less allergenic. Mild reactions (rash, swelling of lips/face/eyes) are treated with non-sedating antihistamines. Severe reactions (i.e. with cardiovascular, laryngeal or bronchial involvement) are treated with adrenaline given intramuscularly by autoinjector (e.g. EpiPen), which the child or parent should carry with them at all times. 35 Immunotherapy for food allergy involves giving the child minute amounts of the food they boos are allergic to, and building up that amount over time. There is a substantial risk of signiﬁcant allergic reaction during this treatment, and it is highly resource intensive Food allergy to cow's milk and egg often resolves in early childhood, and gradual reintroduction under supervision of a pediatric dietician may be possible for these foods. Food allergy to nuts and seafood usually persists through to adulthood. NB: The diagnosis of food allergy should not be made lightly - dietary restrictions and fear of accidental reactions make a major impact on family life. almabds.gritmov q Urticaria and angioedema ha Urticaria: Presents as hives or redness and results from local vasodilation and is increased permeability of capillaries and venules due to activation of skin mast cells, which release a range of mediators including histamine. It is itchy. k Papular urticaria is a delayed hypersensitivity reaction most seen on a the legs, following a bite from a ﬂea, bedbug, animal, or bird mite. al Irritation, vesicles, papules and wheals appear and secondary infection due to scratching is common. It may last for wee ks or M months and may be recurrent. Angioedema: When Urticaria may involve deeper tissues to produce swelling (especially of the lips and soft tissues around the eyes. While hives and angioedema can be a symptom of an IgE-mediated allergic reaction, not all hives are due to allergy. Hives and angioedema due to IgE-mediated allergy will occur very shortly after exposure, they are reproducible, i.e. they happen whenever the child is exposed to the allergen, and resolve within 2-4hours of allergen removal to the potential allergen Chronic urticaria (6 weeks) is usually no allergic. Treatment second-generation non-seda ting antihistamines, which may need to be increased up to four times the standard dose. In refractory cases anti-IgE antibody (omalizumab) may be used. Insan nidolgamsed or did JA Angioedema without urticaria is a feature of C1 esterase inhibitor deﬁciency, which results in 103 hereditary angioedema. This very rare condition is due to an inability to control the ubs of sub stil complement cascade. Drug allergy Drug allergies occur in children but are not common. Only a minority who are labelled 'drug allergic' are truly allergic; usually the label of drug allergy arises because a viral illness, for which the child has been prescribed antibiotics, causes a skin rash. 36 A detailed history is required of the nature and timing of the rash in relation to taking the antibiotics. Any mucous membrane, widespread skin or systemic involvement may suggest a more severe drug allergy such as Stevens-Johnson syndrome. Allergy skin and blood tests may be used to support a diagnosis of drug allergy. A drug challenge may be the only way to conclusively conﬁrm or refute the diagnosis. Drug challenge is not safe after a severe drug reaction - an alternative drug should be sought instead of re- exposing the patient to the same drug(s) Hematology q ha Hematological values at birth and the ﬁrst few weeks of life is At birth, the hemoglobin concentration (Hb) in both term and preterm infants is high, 140g/L to 215g/L, to compensate for the low oxygen concentration in the fetus. The Hb falls naturally a over the ﬁrst few weeks of life due to reduced red k al cell production, reaching a nadir of around 100g/L at 2 months of age. M Preterm babies have a steeper fall in Hb to a mean of 65g/L to 90g/L at 4 weeks to 8 weeks chronological age; this is mainly due to reduced red blood cell production and lifespan. The main hemoglobin at birth (~60%), both in term and preterm babies, is HbF (fetal hemoglobin). Almost all the remaining hemoglobin at birth is HbA (adult hemoglobin). In healthy babies HbF gradually falls to around 1% at the age of 12 months at the same time as HbA gradually rises. HbF has a higher aKinity for oxygen than HbA and is therefore better able to hold on to oxygen,ino an advantage in the relatively hypoxic environment of the fetus (Fig. 23.2). 58 520Dad 292.15 V219116 Normal blood volume at birth varies with gestational age. It is increased by delayed clamping of sa the umbilical cord. In healthy term infants the average blood volume is 80ml/kg; in preterm infants the average blood volume is 100ml/kg.ie Stores of iron, folic acid, and vitamin B12 in term and preterm babies are adequate at birth. However, in preterm infants, stores of iron and folic acid are lower and are depleted more quickly, leading to deﬁciency after 2 months to 4 months if the recommended daily intakes are not maintained by supplements. White blood cell counts in neonates are higher than in older children (10-25 x 109/L). Platelet counts at birth are within the normal adult range (150-400 x 109/L). 37 Hematopoiesis the formation of blood cellular components - occurs during embryonic development and throughout adulthood to produce and replenish the blood system. From pluripotent stem cells 1- In fetal life 2- Post natal medulla of BM Hemoglobin is formed of q 1- Heam ha 2- Globin Anaemia is Anaemia is deﬁned as a Hb below the normal range. The normal range varies with age, so anaemia can be deﬁned as: - Neonate: Hb less than 140g/L a k al - 1 month to 12 months of age: Hb less than 100g/L 1 year to 12 years of age: Hb less than 110g/L. M Anaemia results from one or more of the following mechanisms: Reduced red cell production: either due to red cell aplasia or qualitatively abnormal erythropoiesis (e.g. iron deﬁciency, the most common cause of anaemia) - Increased red cell destruction (haemolysis) - Blood loss: relatively uncommon cause in children. Clinical deﬁnition: tissue hypoxia due to decreased 02 carrying capacity. Compensation: (accor ding to the type and severity) 1. Extramedullary hematopoiesis 2. Expansion of BM-> thinning of cortex-> bonny changes & pathological fractures. 3. Hyperdynamic circulation-> tachycardia/ murmurs/ dyspnea 1. Iron deﬁciency The main causes of iron deﬁciency are: Inadequate intake Malabsorption - Blood loss. 38 Inadequate intake of iron is common in infants because additional iron is required for the increase in blood volume accompanying growth and to build up the child's iron stores (Fig. 23.5). A 1-year-old infant requires an intake of iron which is about the same as an adult male but only half that of an adult female. Iron may come from: breast milk (low iron content but 50% of the iron is absorbed) infant formula (supplemented with adequate amounts of iron) cow's milk (low iron content and poor bioavailability, so poor source of iron) q solids introduced at weaning, e.g., cereals (cereals are supplemented with iron but only 1% is absorbed). ha Iron stores in infants are increased by delayed cord clamping at birth, from increased transfusion of placental blood. is Iron deﬁciency may develop because of a delay in the introduction of mixed feeding beyond 6 months of age in fully a k breast-fed infants or to a diet with insuKicient iron-rich foods, especially if it contains a large amount of cow's milk. Iron absorption is increased when eaten with food rich in vitamin C al (fresh fruit and vegetables) and is inhibited by tannin in tea. M Clinical features Most infants and children are asymptomatic until the Hb drops below 60g/L to 70g/L. As the anaemia worsens, children tire easily and young infants feed more slowly than usual. The history should include asking about blood loss and symptoms or signs suggesting malabsorption. (They may appear pale but pallor is an unreliable sign unless conﬁrmed by pallor of the conjunctivae, tongue or palmar creases. Some children have 'pica', a term which describes the inappropriate eating of non-food materials such as soil, chalk, gravel, or foam rubber There is evidence that iron deﬁciency anaemia may be detrimental to behaviour and intellectual function. Diagnosis The diagnostic clues are: a) Microcytic, hypochromic anaemia, with low MCV (Mean Cell Volume), and MCH (Mean Cell Haemoglobin) b) Low serum ferritin. The other main causes of microcytic anaemia are: a) ẞ-thalassaemia trait (usually children of Asian, Arab or Mediterranean origin) b) Anaemia of chronic disease (e.g. due to chronic kidney disease). iad.chine Children with a-thalassaemia trait (usually children of African or Far Eastern ethnicity) also have a microcytic/hypochromic blood picture but most of these children are not anaemic. 39 Management For most children, management involves dietary advice and supplementation with oral iron. The abu best tolerated preparations are Sytron (sodium iron edetate) or Niferex (polysaccharide iron complex) unlike some other preparations these do not stain the teeth. Iron supplementation should be continued until the Hb is normal and then for a minimum of a togni further 3 months to replenish the iron stores. With good compliance, the Hb will rise by about 10g/L per week. Failure to respond to oral iron usually means the child is not getting the treatment. However, investigation for other causes, in particular malabsorption (e.g. due to coeliac disease) or q chronic blood loss (e.g. due to Meckel diverticulum), is advisable if the history or examination suggests a non-dietary cause or if there is failure to respond to therapy in compliant families. ha Blood transfusion should never be necessary for dietary iron deﬁciency. is Even children with a Hb as low as 20g/L to 30g/L due to iron deﬁciency have arrived at this low level over a prolonged period and can tolerate it. Treatment of iron deﬁciency with normal Hb a k Some children have biochemical evidence of iron deﬁciency (e.g., low serum ferritin) but have not yet developed anemia. Whether these children should be treated with oral iron is controversial. al In favor of treatment is the knowledge that iron is required for normal brain development, and there is M evidence that iron deﬁciency anemia is associated with behavioral and intellectual impairment, which may be reversible with iron therapy. However, it is not yet clear whether treatment of subclinical iron deﬁciency confers signiﬁcant beneﬁt. Treatment also carries a risk of accidental poisoning with oral iron, which is very toxic. A simple strategy is to provide dietary advice to increase oral iron and its absorption in all children with subclinical deﬁciency and to oKer parents the option of additional treatment with oral iron supplements. 2. Red cell aplasia There are three main causes of red cell aplasia in children: Congenital red cell aplasia ('Diamond-Blackfan anaemia') Transient erythroblastopenia of childhood Parvovirus B19 infection (this infection causes red cell aplasia in children with inherited haemolyticanaemias and not in healthy children). The diagnostic clues to red cell aplasia are: Low reticulocyte count despite low Hb normal bilirubin Negative direct antiglobulin test (Coombs test) absent red cell precursors on bone marrow examination. 40 Diamond-Blackfan anaemia (DBA) is a rare (5-7 cases/million live births) cause of severe, lifelong anaemia usually presenting at 2-3 months of age. Most cases are caused by genetic mutations in one of the ribosomal proteins (RP) genes. There is a family history of DBA in 20% of cases; the remaining 80% are sporadic. Some children with DBA have other congenital anomalies, such as short stature or abnormal thumbs, which are a clue to the diagnosis. Treatment is by oral steroids, monthly red blood cell transfusions or, in very severe cases, stem cell transplantation. Unlike DBA, transient erythroblastopenia of childhood (TEC) is triggered by viral infection and always q recovers, usually within several weeks. These children have no family history and no congenital anomalies. ha 3. Bone marrow failure syndromes is Bone marrow failure (also known as aplastic anaemia) is a rare condition characterized by a reduction or absence of all three main blood cell lineages in the bone marrow (red cell lineage, white blood cell lineages, and megakaryocyte/platelet lineage) leading to peripheral blood pancytopenia. It may be inherited or a k acquired. The acquired cases may be due to viruses (especially hepatitis viruses), drugs (such as sulphonamides, chemotherapy), or toxins (such as benzene, glue); however, many cases are labelled as 'idiopathic' because a speciﬁc cause cannot be identiﬁed. al Bone marrow failure may be partial or complete. It may start as failure of a single lineage but progress to M involve all three cell lines. The clinical presentation is with: · Anaemia due to reduced red cell numbers Infection due to reduced white cell numbers (especially neutrophils) Bruising and bleeding due to thrombocytopenia. 4. Fanconi anaemia This is the most common of the rare inherited aplastic anaemias. It is an autosomal recessive condition caused by mutations in one of the many FANC genes, most commonly FANCA. The majority of children have congenital anomalies, including short stature, abnormal radii and thumbs, renal malformations, microphthalmia, and pigmented skin lesions. Children may present with one or more of these anomalies as the signs of bone marrow failure do not usually become apparent until the age of 5-6 years. The diagnosis is made by demonstrating increased chromosomal breakage of peripheral blood lymphocytes and/or by genetic analysis of the FANC genes to identify the causative mutations. 41 This test can be used to identify aKected family members or for prenatal diagnosis. AKected children are at high risk of death from bone marrow failure or transformation to acute leukaemia. The recommended treatment is bone marrow transplantation using normal donor marrow from an unaKected sibling or matched unrelated marrow donor. 5. Shwachman-Diamond syndrome This rare autosomal recessive disorder is characterized by bone marrow failure, together with signs of pancreatic exocrine failure and skeletal abnormalities. q Most are caused by mutations in the SBDS gene, which can be used for identifying unusual cases or ha prenatal diagnosis. Most aKected children have an isolated neutropenia or mild pancytopenia. Like Fanconi anaemia, there is an increased risk of transforming to acute leukaemia. is Increased red cell destruction (haemolytic anaemia) k a Hemolytic anemia is caused by increased red blood cell destruction either in the circulation (intravascular hemolysis) or in the liver or spleen (extravascular hemolysis). al While the lifespan of a normal red cell is 120 days, in haemolysis, red cell survival may be reduced to a M In mild hemolysis, the bone marrow compensates by producing more red cells. This means that hemolysis only leads to anemia when the bone marrow is no longer able to fully compensate. The main cause of hemolysis in children is intrinsic abnormalities of the red blood cells which lead to their premature destruction: Red cell membrane disorders (e.g. hereditary spherocytosis) Red cell enzyme disorders (e.g. glucose-6-phosphate dehydrogenase deﬁciency) Hemoglobinopathies (abnormal hemoglobins, e.g., B-thalassaemia major, sickle cell disease). The diagnostic clues to hemolysis are: - Anaemia with a normal white cell count and platelet count The spleen and/or liver may be moderately enlarged (due to extramedullary haemopoiesis) - Raised reticulocyte count (on the blood ﬁlm this is called 'polychromasia' as the reticulocytes have a characteristic lilac colour on a stained blood ﬁlm) Unconjugated bilirubinaemia and increased urinary urobilinogen - Abnormal appearance of the red cells on a blood ﬁlm (e.g. spherocytes, sickle shaped or very hypochromic) Positive direct antiglobulin test (only if an immune cause, as this test identiﬁes antibody- coated red blood cells) - increased red blood cell precursors in the bone marrow. 42 1. Hereditary spherocytosis Hereditary spherocytosis (HS) occurs in 1 in 5000 births in Caucasians. It usually has an autosomal dominant inheritance, but in 25% there is no family history. The disease is caused by mutations in genes which encode important red cell membrane proteins, such as spectrin or ankyrin. In HS the red blood cells become spherical in shape (spherocytes) because the red cell loses part of its membrane each time it passes through the spleen. Spherocytes are less deformable than normal red blood cells and are, therefore, destroyed prematurely in the spleen. q Clinical features ha The disorder is often suspected because of family history. a) Jaundice: usually develops during childhood but may be intermittent; may cause severe haemolytic jaundice in the ﬁrst is few days of life b) Anaemia: presents in childhood with mild anaemia (Hb 90- a k 110g/L), but the Hb may transiently fall during infections mild to moderate splenomegaly - depends on the rate of haemolysis al c)Aplastic crisis: uncommon, transient (2-4 weeks), caused by parvovirus B19 infection M d) Gallstones: due to increased bilirubin excretion. Some children are completely asymptomatic and HS may be identiﬁed during a routine blood test. Diagnosis and management The blood ﬁlm is usually diagnostic but more speciﬁc tests are available (e.g. dye binding assay or genetic testing). Autoimmune haemolytic anaemia is also associated with spherocytes, but a positive direct antibody test can exclude this. Most children have mild chronic haemolytic anaemia and the only treatment they require is oral folic acid as they have a raised folic acid requirement secondary to their increased red blood cell production. Splenectomy is beneﬁcial but is only indicated for poor growth or troublesome symptoms of anaemia (e.g. severe tiredness, loss of vigour) or needing blood transfusions. It is usually deferred until after 7 years of age because of the risks of post-splenectomy sepsis. Prior to splenectomy all patients should be vaccinated against Haemophilus inﬂuenzae(Hib), meningitis ACWY, meningitis B and Streptococcus pneumoniae, and lifelong daily oral penicillin prophylaxis is advised. Aplastic crisis due to parvovirus B19 infection is treated by red cell transfusions over the 3- week to 4-week period when no red blood cells are produced. If gallstones are symptomatic, cholecystectomy may be necessary 43 2. Glucose-6-phosphate dehydrogenase deﬁciency Glucose-6-phosphate dehydrogenase (G6PD) deﬁciency is the most common red cellphinh enzymopathy aKecting over 100 million people worldwide. It has a high prevalence (10%-20%) in individuals originating from central Africa, the Mediterranean, the Middle East, and the Far East. Many diKerent mutations of the gene have been described, leading to diKerent clinical features in diKerent populations. q G6PD is the rate-limiting enzyme in the pentose phosphate pathway and is essential for preventing oxidative damage to red cells. ha Red cells lacking G6PD are susceptible to oxidant-induced haemolysis (usually caused by certain drugs G6PD deﬁciency is X-linked and therefore mainly causes symptoms in males. is Females who are heterozygotes are usually clinically normal as they have about half the normal G6PD activity. Clinical manifestations a k Children usually present clinically with: al Neonatal jaundice: onset is typically in the ﬁrst 3 days of life. Worldwide it is the most common cause of M severe neonatal jaundice requiring exchange transfusion - Acute haemolysis: precipitated by: - G6PD deﬁciency is associated with fever, malaise, abdominal pain, and the passage of dark 12.8 urine, as it contains haemoglobin as well as urobilinogen as the haemolysis is mainly intravascular. The Hb often alls rapidly and may drop below 50g/L over 24-48hours. Diagnosis and management Between episodes, almost all patients have a completely normal blood picture and no jaundice or anaemia. The diagnosis is made by identifying a low level of G6PD activity in red blood cells.ǝris During a haemolytic crisis, G6PD levels may be misleadingly elevated to a normal level due to 12 the higher enzyme concentration in reticulocytes, which are produced in increased numbers dis during the crisis. A repeat assay is then required once the haemolytic episode is over to conﬁrm the diagnosis.abbi Parents should be given advice about the signs of acute haemolysis to look out for (jaundice, pallor, and dark urine) and provided with

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