Upper Respiratory Tract Infections - Medical Microbiology - PDF

Jerome Walker 2018 DR. JEROME WALKER MBBS DM MEDICAL MICROBIOLOGY FOR PHYSIOTHERAPISTS MARCH 27 2023 10:00 AM Jerome Walker 2018 Upper Respiratory Tract Infections Objectives Appreciate List Describe Define upper respiratory tract infection(s) (URTI) Appreciate the relevant anatomy of the upper resp...

Jerome Walker 2018 DR. JEROME WALKER MBBS DM MEDICAL MICROBIOLOGY FOR PHYSIOTHERAPISTS MARCH 27 2023 10:00 AM Jerome Walker 2018 Upper Respiratory Tract Infections Objectives Appreciate List Describe Define upper respiratory tract infection(s) (URTI) Appreciate the relevant anatomy of the upper respiratory tract List the common respiratory tract infections Describe the epidemiology, pathophysiology, management, prevention and control of URTIs Jerome Walker 2018 Define Introduction infections that affect the nose, paranasal sinuses, pharynx, larynx ► Among the most common infections in the outpatient setting. ► They range from mild infections – the common cold. To life-threatening infections such as epiglottitis. Jerome Walker 2018 ► Includes Jerome Walker 2018 Anatomy of the Upper Respirator y Tract Jerome Walker 2018 The Common Cold UPPER RESPIRATORY TRACT INFECTIONS The Common Cold Syndrome characterized by rhinorrhea (runny nose) and nasal congestion sore and scratchy throat are prominent symptoms Generally mild, acute and, self-limited Caused by several families of viruses Jerome Walker 2018 Upper respiratory tract infection The Common Cold: Epidemiology ► Occur 2-3 times/year in adults ► In temperate climates usually ► Transmission in early fall and late spring via direct contact, large particle aerosols, small particle aerosols. Jerome Walker 2018 ► Occur 5- 7 times/year in children Common Cold: Microbiology Coronavirus (CoV) Respiratory Syncytial Virus (RSV) Human metapneumovirus (HMPV) Other viruses (e.g. Influenza, parainfluenza, adenoviruses) but are also associated with lower respiratory tract/systemic symptoms. Jerome Walker 2018 Rhinovirus (HRV) – approx. half of all URTI The Common Cold: Diagnosis ► Lab diagnosis can be made with serology, PCR, culture, antigen detection – not usually recommend Jerome Walker 2018 ► Largely clinical Nasal dryness or irritation - May be first symptom Sore throat or throat irritation – Common and bothersome initial symptom Nasal discharge, nasal congestion, and sneezing – Intensify over 2-3 days Headache Facial and ear pressure Loss of sense of smell and taste Cough (30% of infected individuals) Hoarseness (20%) Posttussive vomiting Irritability or restlessness Fever (unusual; when present, typically low grade) Source: Jerome Walker 2018 The Common Cold: Clinical Symptoms & Signs Common Cold: Pathogenesis Jerome Walker 2018 Viral Infection Nasal epithelial destruction / acute inflammatory response Nasal Obstruction/ Rhinorrhea The Common Cold: Transmission Jerome Walker 2018 Small particle aerosols Large-particle aerosols Forms droplets that do not settle Transmitted over long distances by airflow Particles may reach lower Rapidly settle Transmitted over short distances Filtered by Upper tract, particles do not reach lower airway Physical Contact Fomites Person to Person Contact Jerome Walker 2018 The Common Cold: Treatment Jerome Walker 2018 ► No specific antiviral medication available ► Management largely symptomatic at most bothersome symptoms ► Infections are self limited with treatment geared WARNING: Antibiotics don’t work for viruses like colds and the flu. Using them for viruses will NOT make you feel better or get back to work faster. The Common Cold: Treatment for common cold. ► Influenza – Neuraminidase duration inhibitors modest effect on Jerome Walker 2018 ► No proven interventions Treatment: Supportive Measures Jerome Walker 2018 ► Bulb suction with saline drops may reduce nasal congestion and help remove secretions ► Vapor rub applied to chest and neck of children and 11 may help reduce nighttime cough between Hand Hygiene ► Exercise ► Immunization and chemoprophylaxis against Influenza, SARS-COV2 ► ► Jerome Walker 2018 The Common Cold: Prevention Zinc, Vitamins C, D and E; Echinacea, Ginseng – rigorous evaluation has not shown effectiveness Source: A special note on Influenza ► Caused by Influenza A, B, or C viruses ► Pandemics caused by Influenza A (H1N1, H3N2 etc) ► Epidemics caused by Influenza B Jerome Walker 2018 ► Influenza is a viral respiratory tract infection A special note on Coronaviruses coronaviruses 1. 229E (alpha coronavirus) 2. NL63 (alpha coronavirus) 3. OC43 (beta coronavirus) 4. HKU1 (beta coronavirus) Jerome Walker 2018 ► Common human Other human coronaviruses ► MERS-CoV (the beta coronavirus that causes Middle East Respiratory Syndrome, or MERS) ► SARS-CoV (the beta coronavirus that causes severe acute respiratory syndrome, or SARS) ► SARS-CoV-2 (the novel coronavirus that causes coronavirus disease 2019, or COVID-19) Jerome Walker 2018 ► SARS-COV2 Jerome Walker 2018 Jerome Walker 2018 UPPER RESPIRATORY TRACT INFECTIONS Jerome Walker 2018 Pharyngitis (Nasopharyngitis) Pharyngitis: Definition Pharyngeal Inflammatio n Jerome Walker 2018 Pharyngit is Fever Sore Throat Pharyngitis: Epidemiology ► Mostly young in adults and children children and young adults affected Jerome Walker 2018 ► One of the most common disorders Pharyngitis: Etiology VIRUSES ► Adenovirus (most common) ► Influenza A and B ► Rhinovirus ► Bacteria ► Group A Streptococcus (GAS) ► Fusobacterium necrophorum Jeroe Walker 2018 ► Clinical Features of Pharyngitis Features suggestive of GAS etiology Features suggestive of viral etiology Fever Headache Absence of fever Tonsillopharyngeal inflammation Conjunctivitis Tonsillopharyngeal exudate Coryza Palatal petechiae Cough Tender anterior cervical adenopathy Hoarseness Winter-early spring presentation Ulcerative mouth lesions Age 5-15 years Viral type rash Jerome Walker 2018 Sudden onset sore throat History of exposure to GAS pharyngitis There can be significant overlap between GAS and viral pharyngitis McIsaac et al. JAMA. 2004; 291:1587, Bisno et al. Clin Infect Dis. 2002; 35:113 Pharyngitis: Diagnosis ► GAS ► Acute onset of sore throat with tonsillar and pharyngeal exudates ► Tender anterior cervical adenopathy ► Fever ► Viral etiologies (conjunctivitis, oral ulcers, diarrhea) ► Do not require testing cough, coryza, oral ulcers, Jerome Walker 2018 ► Identification of TREATABLE cause: Acute Pharyngitis Diagnosis suggest a viral etiology, testing is not indicated ► In persons with findings suggestive of GAS infection, confirmation with a rapid antigen detection test (RADT) or culture is needed ► In children and adolescents a negative RADT has a low negative predictive value and should be backed up with a throat culture for GAS McIsaac et al. JAMA. 2004; 291:1587, Bisno et al. Clin Infect Dis. 2002; 35:113 Jerome Walker 2018 ► For adults and children with features that strongly ► Not routine request ► Specimen should be plated immediately ► Organism dies quickly when refrigerated ► Gram stain cannot identify it from throat specimens Jerome Walker 2018 Laboratory Diagnosis: Gonococcal pharyngitis ► The posterior nares should ► Posterior pharynx be swabbed should be swabbed ► Transport on primary agar e.g. Chocolate Tellurite agar ► Demonstration of toxin production for e.g. Elek test Jerome Walker 2018 Laboratory Diagnosis: Corynebacterium diphtheriae Pharyngitis: Therapy therapy needed for GAS to prevent postinfectious sequelae ► Penicillin – drug of choice ► Viral etiology ► Symptomatic treatment Jerome Walker 2018 ► Antibiotic Pharyngitis: Complications GAS Pharyngitis can be associated with major sequelae: ► Post streptococcal Glomerulonephritis ► Post streptococcal rheumatic heart disease ► Retropharyngeal abscess ► Peri-tonsillar abscess ► Sinusitis ► Cervical lymphadenitis ► Otitis media ► Mastoiditis. Jerome Walker 2018 ► Diphtheria pharyngitis ► Characterized by the development of adherent pseudomembranes that can cause occlusion ► Rare cause in places with robust immunization programs with diphtheria toxin ► Patients are treated with diphtheria antitoxin Jerome Walker 2018 ► Caused by Corynebacterium diphtheriae Signs and symptoms ► Nasal discharge: Profuse discharge is more characteristic of viral infections than bacterial infections; initially clear secretions typically become cloudy white, yellow, or green over several days, even in viral infections ► Foul breath ► Fever: Less common in adults but may be present in children with rhinoviral infections Jerome Walker 2018 ► Nasal mucosal erythema and edema are common Acute Laryngitis characterized by a hoarse voice with decreased phonation and voice projection, usually occurring after an upper respiratory tract infection with cough. ► 2% of individuals with acute respiratory symptoms are diagnosed with acute laryngitis Jerome Walker 2018 ► Acute laryngitis is a clinical syndrome Acute Laryngitis: Microbiology Jerome Walker 2018 Rhinovirus ► Influenza ► Parainfluenza ► Adenovirus ► Coronavirus ► Mycoplasma pneumoniae ► Chlamydia pneumoniae ► Group A beta hemolytic streptococcus ► Human metapneumovirus ► Laryngitis In voice ► Visualization of the larynx reveals edema and vascular engorgement of the mucous membranes and hyperemic vocal cords. Jerome Walker 2018 ► Diagnosis is made by the appropriate history and changes Laryngitis: Treatment ► Symptomatic treatment ► Voice rest ► Analgesics ► humidification Jerome Walker 2018 ► No specific treatment Jerome Walker 2018 Otitis Media UPPER RESPIRATORY TRACT INFECTIONS Otitis Media the presence of fluid in the middle ear and inflammation of the mucosa lining of the middle ear space. Jerome Walker 2018 ► Acute Otitis Media (AOM) is an acute illness marked by OM: Epidemiology ► Peak incidence in the first 3 years of life ► Children at risk for severe and recurrent OM are frequently: ► Male ► Genetic predisposition to ear infections ► May be in large-group daycare exposed to frequent respiratory viruses and bacterial pathogens Jerome Walker 2018 ► Occurs in all ages dysfunction: ► Seasonal allergic rhinitis ► URTI ► Mucosal disease e.g.. Inflammatory, immunologic impairment, immotile cilia ► Extrinsic compression (tumor, enlarged adenoid) Jerome Walker 2018 ► Eustachian tube Otitis Media: Microbiology Common bacterial pathogens ► Streptococcus pneumoniae ► Haemophilus influenza (not typable) ► Less common ► Moraxella catarhallis ► Group A Streptococcus ► Staphylococcus aureus ► Respiratory viruses are a frequent cause of OM (alone or with bacterial infection) Jerome Walker 2018 ► Otitis Media: Diagnosis of inflammation of the middle ear: ► Ear pain ► Ear drainage ► Hearing loss ► Fever ► Lethargy ► Irritability ► Vertigo, nystagmus, tinnitus can also occur Jerome Walker 2018 ► Rapid onset of signs and symptoms Otitis Media: Treatment are the mainstay of treatment ► High dose amoxicillin is preferred drug ► If amoxicillin fails then amoxicillin-clavulanate or ceftriaxone ► Some children may improve without antimicrobial agents Jerome Walker 2018 ► Antibiotics Otitis Media: Treatment tubes may be warranted for children with severe and recurrent AOM ► Manage pain – mild analgesic e.g. NSAIDs etc. Jerome Walker 2018 ► Tympanostomy Otitis Media: Prevention with antibiotics may be of value in prevention of episodes of AOM in children with severe and recurrent disease ► Pneumococcal conjugate vaccines have been effective in reducing episodes of AOM due to vaccine serotypes ► Influenza vaccine also helps Jerome Walker 2018 ► Chemoprophylaxis Otitis Externa: Microbiology elsewhere ► Staphylococcal species ► Anaerobic bacteria ► Swimmer’s ear and malignant OM ► Frequently Pseudomonas aeruginosa Jerome Walker 2018 ► Similar to skin infections Otitis Externa auditory canal ► Can be acute, invasive ► Acute Otitis Externa (swimmer’s ear) – occurs in hot humid weather ► Invasive (malignant) occurs in diabetics, immunocompromised, or debilitated patients Jerome Walker 2018 ► Infection and inflammation of the external Jerome Walker 2018 Rhinosinusitis (Sinusitis) UPPER RESPIRATORY TRACT INFECTIONS ► Inflammatory disorder of the paranasal sinuses and nasal cavity ► Most acute causes due to infection other causes include allergy Jerome Walker 2018 Rhinosinusitis: Definition Sinusitis: Epidemiology ► Usually resolves in 7 to 10 is viral days ► Bacterial infection of the sinusitis occurs in 0.5% to 2% cases of viral upper respiratory tract infections in adult ► 6% -13% children Jerome Walker 2018 ► Most common cause of acute rhinosinusitis Sinusitis: Microbiology ► Haemophilus influenzae ► Moraxella catarhallis ► Staphylococcus aureus – not a significant cause may play a role in complicated disease Jerome Walker 2018 ► Streptococcus pneumoniae most frequently isolated Sinusitis: Diagnosis Jerome Walker 2018 May present in one of three ways: 1 2 3 Onset of persistent signs or symptoms lasting for at least 10 days without evidence of clinical improvement Onset with severe symptoms or signs of high fever (≥39 C) and purulent nasal discharge lasting for 3 to 4 consecutive days Worsening symptoms or signs characterized by the new development of fever, headache, or increased nasal discharge after a typical viral URI and lasted 5 to 6 days with initial improvement Sinusitis Adjuncts include antihistamines, decongestants, nasal steroids and nasal washes ► Surgical drainage in complicated cases ► Jerome Walker 2018 Amoxicillin or amoxicillin-clavulanate – first line ► Cefuroxime ► Or clindamycin ► (fluoroquinolones) ► Duration usually 7 days after patient becomes symptom free ► Jerome Walker 2018 Croup (Acute Laryngotracheobronchitis) UPPER RESPIRATORY TRACT INFECTIONS Croup: Definition and Epidemiology presenting as stridor and a brassy cough ► Most children will develop croup only once ► Some recur called: Spasmodic croup ► Usually occurs in epidemics, but can be sporadic ► Occurs in children 6 moths -3years Jerome Walker 2018 ► Croup is an acute viral infection of the upper airway Croup: Microbiology ► Other viruses: ► Other parainfluenza virus, RSV, ► Bacterial infections adenovirus, measles of the airway are medical emergencies and should rapidly discriminated from croup Jerome Walker 2018 ► Parainfluenza virus 1 (most common etiology) Croup: Diagnosis Clinical: ► Hoarseness ► Stridor ► Coughing ► Radiographs may be helpful ► Children with bacterial tracheitis or epiglottis are typically toxic Jerome Walker 2018 ► with croup are rarely toxic ► Recurrent croup is common reflux disease in children with atopy and Jerome Walker 2018 ► Children Treatment to decrease severity and duration ► Nebulized epinephrine can be used ► Mist therapy with steam also shown to help ► HelOx may be used but benefit not shown Jerome Walker 2018 ► Single dose of steroid shown Epiglottitis UPPER RESPIRATORY TRACT INFECTION Jerome Walker 2018 Epiglottitis: Definition A localized, invasive Haemophilus influenzae type b infection of the supra glottis area, including the epiglottitis that can be associated with bacteremia (60-90%) Adult epiglottitis involves more of the proglottic area and when a causative agent is identified usually S. pneumoniae, S. pyogenes or Jerome Walker 2018 Epiglottitis: Diagnosis be promptly evaluated ► Labs and radiologic should be delayed until airway is evaluated in a safe environment (e.g. Operating theatre, emergency department, ICU) because of propensity to develop airway obstruction ► Peripheral leukocytosis is common ► Radiographs may show characteristic thumb sign ► Direct or indirect laryngoscopy is definitive diagnosis Jerome Walker 2018 ► Airway management should Thumb Sign Jerome Walker 2018 Epiglottitis: Clinical Manifestations Abrupt illness in a febrile child with a toxic appearance ► Dysphagia ► Sore throat ► Muffled or hoarse voice ► Stridor ► Drooling ► Tripod position Jerome Walker 2018 ► Epiglottitis: Therapy Diagnosis is made at the time of intubation by direct visualization of the larynx ► Complete Blood Count ► Blood culture ► Emergency tracheostomy and cricothyroidotomy is rarely needed ► Empiric therapy is with Ceftriaxone or Ampicillin/sulbactam to cover: ► Streptococci ► Pneumococci ► H. influenza ► Meningococci Jerome Walker 2018 ► Epiglottitis: Prevention Chemoprophylaxis of household contacts of persons with H. influenza type b ► For those unimmunized under the age of 4years Jerome Walker 2018 ► Severe Acute Respiratory Virus 2 (SARS-COV2 Caused by a beta coronavirus called SARS-COV2 ► ► Pandemic started at the end of 2019 believed to have originated in Seafood market in Wuhan. China. ► 21 MARCH 2023 – ► 761, 071,826 confirmed cases of COVID-19 ► Over 6.8 million deaths reported to the WHO ► These numbers significantly underestimate the global burden of the disease Jerome Walker 2018 Jerome Walker 2018 https://covid19.who.int/ SARS-COV2: Symptoms Ageusia or other taste abnormalities Myalgias ► Rhinorrhea and or nasal congetion ► Headache ► Chills/rigors ► Dyspnea (new or worsening of baseline) ► Fatigue ► Confusion ► Sore throat ► Chest pain or pressure ► Diarrhea ► Nausea/ Vomiting ► Anosmia or other smell abnormalities Cough ► Fever ► Jerome Walker 2018 ► ► Variants of Concern Omicron Sublineages and the effectiveness of therapeutics Jerome Walker 2018 SARS-COV2 Person to person through respiratory droplets when someone coughs, sneezes or talks ► May occur if hands contaminated with secretions ► Can travel both by airborne and droplet spread Jerome Walker 2018 ► Transmission: SARS-COV2: PREVENTION setting ► Personal preventive measures ► Hand washing ► Vaccination ► Ensure adequate ventilation in indoor spaces Jerome Walker 2018 ► Infection control in hospital Jerome Walker 2018 Summary/Closing UPPER RESPIRATORY TRACT INFECTIONS Upper Respiratory Tract Infections ► Usually non-life-threatening Jerome Walker 2018 ► Common infections worldwide and self- limiting ► Most infections are caused by viruses and hence require no specific antibiotic ► Some are however, bacterial and may require antibiotic therapy – these causes usually need to be identified early to prevent sequelae References Jerome Walker 2018 References & Works Cited (RV) Infection (Common Cold).” Practice Essentials, Background, Pathophysiology, 11 Sept. 2017, emedicine.medscape.com/article/227820-overview. Jerome Walker 2018 ► “Rhinovirus References Jerome Walker 2018