Week 4 Pulmonary System PDF

Structure & Function of the Pulmonary System Chapter 26 Learning Objectives 1. Discuss common disorders related to altered respiratory functioning 2. Discuss the pathophysiology of the upper, lower, restrictive and obstructive respiratory disease. 3. Identify clinical manifestat...

Structure & Function of the Pulmonary System Chapter 26 Learning Objectives 1. Discuss common disorders related to altered respiratory functioning 2. Discuss the pathophysiology of the upper, lower, restrictive and obstructive respiratory disease. 3. Identify clinical manifestations of respiratory disease. 4. Discuss environmental factors that influence the development of respiratory disease. 5. Discuss differences between restrictive, obstructive, and vascular disorders of the respiratory system. 6. Describe long term effects of a respiratory disease. 7. Describe medical treatment for common respiratory disorders. Function of the Pulmonary System PRIMARY FUNCTION is the exchange of gases between the environmental air and the blood. There are 3 steps in this process: 1. VENTILATION: the movement of air into and out of the lungs 2. DIFFUSION: the movement of gases between air spaces in the lungs and the bloodstream 3. PERFUSION: the movement of blood into and out of the capillary beds of the lungs to the body organs and tissues Let's talk about what we know… What is the primary organ in the respiratory system? How many lobes per lung? Can anyone name more structures of the pulmonary system? What is the mediastinum? Structures of the Pulmonary System Conducting Airways: allows air into and out of the gas-exchange structures of the lungs Gas Exchange Airways: participate in gas exchange Pulmonary and Bronchial Circulation: gas exchange, delivering nutrients to lung tissues and providing oxygen-rich blood to the heart Control of the Pulmonary Circulation: important for matching ventilation and perfusion Chest Wall and Pleura: protects the lungs from injury Conducting Airways Upper Airway: - Nasopharynx & oropharynx: lined with mucosa that warms and humidifies air and removes foreign particles from it Larynx: - Connects the upper and lower airways - “Voicebox”; supported by cartilage, contains vocal cords Lower Airway: - Trachea: connects larynx to bronchi, supported by U-shaped cartilage - Bronchi: brings air into the lung at the hilum, then further branch - The lining of the bronchi contains exocrine glands called goblet cells (mucous secretion) Gas-Exchange Airways trachea → bronchi → bronchioles → alveolar ducts →alveoli ALVEOLI - Primary gas-exchange units of the lung, where oxygen (O2) enters the blood and carbon dioxide (CO2) is removed - Epithelial cells - Type I maintain structure - Type II secrete surfactant - Alveolar Macrophages immune protection; ingests foreign material that reaches the alveolus Pulmonary & Bronchial Circulation Pulmonary circulation carries deoxygenated blood away from the heart, to the lungs, and returns oxygenated blood back to the heart. Pulmonary & Bronchial Circulation Alveolocapillary membrane - Formed by the shared alveolar and capillary walls - Gas exchange occurs across this membrane Pulmonary artery - Divides and enters the lung at the hilus - Deoxygenated blood from the heart Pulmonary veins - Drains several pulmonary capillaries & dispersed randomly throughout the lung - Leave the lung at the hila and enter the left atrium - Oxygenated blood to the heart Control of the Pulmonary Circulation Calibre (internal diameter) of pulmonary artery decreases as smooth muscle in the arterial walls contracts. Contraction (vasoconstriction) and relaxation (vasodilation) occur in response to local humoral (hormone) conditions & acidemia - Most important cause of pulmonary artery constriction is a low alveolar partial pressure of oxygen (PO2) - Constriction can affect only one portion of the lung (ex. one lobe is obstructed, decreasing its partial pressure of oxygen) - The arterioles to the segment constrict, shunting blood to other well-ventilated portions of the lung (improves the lung efficiency by matching ventilation and perfusion) - If all segments of the lung are affected, pulmonary hypertension can occur; and if not treated can lead to right-sided heart failure (cor pulmonale) Chest Wall & Pleura Chest Wall: skin, ribs, and intercostal muscles - The intercostal muscles, as well as the diaphragm, accessory muscles and abdominal muscles do the muscular work of breathing Thoracic Cavity: contained by the chest wall and encases the lungs Pleura: adheres to the lungs (visceral), folds over itself, and attaches to chest wall (parietal) - The area between the two pleura is called the pleural space (cavity) - Normally, a thin layer of fluid is secreted by the pleura called pleural fluid, which lubricates the surfaces Quick Review Which is TRUE regarding the pulmonary system? A. Each lobe is divided into bronchi. B. Left lobe is divided into three lobes. C. Mediastinum contains the lungs and heart. D. Larynx connects the upper and lower airways. Function of the Pulmonary System PRIMARY FUNCTION is the exchange of gases between the environmental air and the blood. There are 3 steps in this process: 1. VENTILATION: of the alveoli 2. DIFFUSION: of gases into and out of the blood 3. PERFUSION: of the lungs so that organs and tissues of the body receive blood that is rich in oxygen Ventilation The mechanical movement of gas into and out of the lungs - “Respiratory rate” is actually the ventilatory rate, or the # of times gas is inspired and expired per minute… what is our normal range for this? Neurochemical Control → the respiratory center in the brainstem controls respirations by sending impulses to the respiratory muscles, causing them to contract and relax → the lung is innervated by the autonomic nervous system (ANS), and the sympathetic & parasympathetic divisions control the calibre of the airway - Parasympathetic contracts smooth muscle (ex. when there is an irritant) - Sympathetic relaxes Chemoreceptors monitor the pH, PaCO2, and PaO2 of arterial blood & sends signals to maintain homeostasis Mechanics of Breathing 1/3 Major muscles: - Diaphragm - External intercostals Accessory muscles: - Sternocleidomastoid muscle - Scalene muscles - Abdominal muscles - Internal intercostals Mechanics of Breathing 2/3 Alveolar Surface Tension & Ventilation: - Function of surfactant; decreases surface tension on the alveoli, allowing the alveoli to ventilate effectively - If surfactant is not produced, surface tension increases causing alveolar collapse (↑WOB, ↓lung expansion, severe gas-exchange abnormalities) Elastic Properties of the Lung and Chest Wall: - Elastic recoil: return to resting state after inspiration - Compliance: opposite of elasticity; see how much they can be stretched - INCREASED compliance indicates that the lungs or chest wall is abnormally easy to inflate and has LOST some elastic recoil (ex. aging, emphysema) - DECREASED compliance indicates that the lungs or chest wall is abnormally stiff or difficult to inflate (ex. pneumonia, pulmonary fibrosis) Mechanics of Breathing 3/3 Airway Resistance: - Determined by length, diameter, and airway obstructions (mucus, tumors, or foreign bodies) - Pulmonary Function Tests (PFTs) measure lung volumes and flow rates and can be used to diagnose lung disease Work of Breathing: - Determined by muscular effort required for ventilation - WOB may increase in diseases that disrupt the equilibrium between forces exerted by the lung and chest wall - More muscular effort is required when compliance decreases, or airways are obstructed Quick Review A patient has a history of emphysema and has hyperinflated lungs. Which would be TRUE regarding this patient? A. Increased compliance B. Decreased surfactant C. Increased elastic recoil D. Increased airway resistance Gas Transport 1. Ventilation of the lungs 2. Diffusion of oxygen from the alveoli into the capillary blood 3. Perfusion of systemic capillaries with oxygenated blood 4. Diffusion of oxygen from systemic capillaries into the cells *Diffusion of CO2 occurs in reverse order Ventilation-Perfusion Ratio (V/Q) & V/Q mismatch https://www.youtube.com/watch?v=UKsOLb5XWa0&ab_channel=RespiratoryTher apyZone Oxygen & Carbon Dioxide Transport Oxygen Transport - Diffusion across the alveolocapillary membrane - Determinants of arterial oxygenation: Hemoglobin binding & Oxygen saturation - Oxygen saturation (SaO2) id the percentage of the hemoglobin that is bound to oxygen, and can be measured using an oximeter Carbon Dioxide Transport Carried in 3 ways - Dissolved in plasma - As bicarbonate (HCO3) - Carbamino compounds Geriatric Considerations Decreased chest wall compliance and elastic recoil of the lungs - Reduces ventilatory reserve Decreased surface area for gas exchange as well as capillary perfusion Decreased exercise capacity  Alterations of the Pulmonary System Chapter 27 Signs & Symptoms of Pulmonary Disease (1/4) Dyspnea: a subjective experience of breathing discomfort; often described as breathlessness, air hunger, shortness of breath, laboured breathing and preoccupation with breathing Orthopnea: dyspnea that occurs during heart failure when the individual lies flat; the abdominal contents puts pressure on the diaphragm Paroxysmal Nocturnal Dyspnea (PND): occurs when individuals with pulmonary or cardiac disease awake at night gasping for air; usually have to stand up to catch their breath Signs & Symptoms of Pulmonary Disease (2/4) Cough: protective reflex that clears the airways; inhaled particles, mucus, inflammation, or the presence of a foreign body will cause a cough reflex. Cough can be acute (resolve in 2-3 weeks), where as a chronic cough is persistent in individuals who do not smoke Abnormal Sputum: changes in the amount, colour, and consistency of sputum provides information about progression of disease; sputum sample can provide identification of microorganisms & influence the care plan Hemoptysis: coughing up blood or bloody secretions, usually bright red & mixed with “frothy” sputum; bronchoscopy and a chest CT is used to confirm the site of bleeding Signs & Symptoms of Pulmonary Disease (3/4) Abnormal Breathing Patterns: change in rate, depth, and regularity of breaths; - Kussmaul respirations (increased RR, large tidal volume & no expiratory pause) is caused by metabolic acidosis or strenuous exercise - Laboured breathing occurs when there is increased WOB, usually due to obstruction - Restricted breathing result of “stiffening” lungs (pulmonary fibrosis, cystic fibrosis), results in decreased compliance, small tidal volumes and rapid RR (tachypnea) - Cheyne-Stokes respiration alternating periods of deep and shallow breathing; apnea lasting 15-60 seconds followed by ventilations (results from decreased blood flow to brain stem) Signs & Symptoms of Pulmonary Disease (4/4) Hypoventilation: inadequate alveolar ventilation in relation to metabolic demands; can result in respiratory acidosis (hypercapnia). RR and breathing pattern may look normal. Diagnosed by ABG. Hyperventilation: alveolar ventilation exceeding metabolic demands; can result in respiratory alkalosis (hypocapnia). Increased RR, usually seen in severe anxiety, head injury, and pain. Diagnosed by ABG. Cyanosis: bluish discolouration of the skin and mucous membranes; usually not present in adults until severe hypoxemia is present Clubbing of the Fingers: bulbous enlargement of the end of a digit; usually seen in cystic fibrosis, lung abscess, congenital heart disease Pain: usually localized to a portion of the chest cavity - Chest wall; infection and inflammation of the parietal pleura→ can auscultate pleural friction rub. Seen in people with pulmonary infarction caused by pulmonary embolism. Other causes include broken ribs, or muscle pain - Central; infection & inflammation of the trachea and pain is prominent after coughing **ALWAYS ensure we assessing for cardiac events if your patient presents with this** Hypercapnia - Conditions Caused by Pulmonary Disease or Injury Hypercapnia: hypoventilation of the alveoli, leading to increased CO2 concentration in the arterial blood (increased PaCO2) → respiratory acidosis! Causes (*decreased drive to breathe or inadequate ability to respond to ventilatory stimulation*) - Depression of the respiratory centre by medications - Changes to the central nervous system - Thoracic cage abnormalities (chest injury or congenital deformity) - Airway obstruction - Increased WOB, or dead space as seen in emphysema Treatment: correct the underlying cause of hypoventilation  Hypoxemia - Conditions Caused by Pulmonary Disease or Injury Hypoxemia: reduced oxygenation of arterial blood Different from hypoxia (ischemia); which is the reduced oxygenation of cells in tissues, but hypoxemia can eventually lead to tissue hypoxia Causes (problem with one or more major mechanisms of oxygenation) 1. O2 delivery to the alveoli (O2 content of air breathed in or ventilation of alveoli) 2. Diffusion of O2 from alveoli into the blood (V/Q match) a. V/Q mismatch = abnormal distribution of ventilation and perfusion b. Inadequate ventilation of well-perfused areas will cause SHUNTING (atelectasis, pneumonia) c. Inadequate perfusion of well-ventilated is termed alveolar DEAD SPACE (pulmonary embolism) 3. Perfusion of pulmonary capillaries V/Q mismatch = abnormal distribution of ventilation and perfusion VERY LOW V/Q = Inadequate ventilation of well-perfused areas will cause SHUNTING (atelectasis, pneumonia) HIGH V/Q = Inadequate perfusion of well-ventilated is termed alveolar DEAD SPACE (pulmonary embolism) Acute Respiratory Failure - Conditions Caused by Pulmonary Disease or Injury Respiratory Failure: inadequate gas exchange Causes - Direct injury to the lungs, airway or chest wall - Indirectly due to spinal cord injury, or brain injury - Surgery - Opioid overdose Treatment - If due to hypercapnia (inadequate alveolar ventilation) → ventilatory support - If due to hypoxemia (inadequate exchange of O2 between alveoli & capillaries) → supplemental O2 - Narcan/Naloxone for overdose Postoperative Respiratory Failure Respiratory failure is an important potential complication of any major surgical procedure! Post-Op Pulmonary Problems: - Atelectasis - Pneumonia - Pulmonary edema - Pulmonary emboli PREVENTION IS KEY! - Frequent turning and repositioning - Deep-breathing exercises (incentive spirometer) - Early ambulation (decreases accumulation of secretions) Chest Wall Restriction Compromised chest wall due to deformity, trauma, immobilization, or obesity - Increased WOB, decreased tidal volume - Muscle weakness can result in hypoventilation, inability to remove secretions, and hypoxemia Flail Chest results from the fracture of several consecutive ribs, resulting in instability of a portion of the chest wall, causing opposite movement of the chest with breathing. Chest wall restrictions result in a decrease in tidal volume, increased RR to compensate, but eventually will progress to hypercapnic respiratory failure. PFT, ABD, and X-rays used to diagnose Treatment is to correct underlying cause but otherwise supportive of symptoms; mechanical ventilation if severe  Pneumothorax - Pleural Abnormality Pneumothorax: the presence of air or gas in the pleural space caused by a rupture in the visceral pleura (which surrounds the lungs) or the parietal pleura and chest wall; negative pressure is lost & the lung collapses Primary (Spontaneous) Pneumothorax: sudden onset without any apparent cause Secondary Pneumothorax: caused by an underlying condition (ex. chest trauma) Open Pneumothorax: occurs when air accumulates between the chest wall and the lung due to open chest wound Tension Pneumothorax: severe condition that results when air is trapped in the pleural space under positive pressure, displacing mediastinal structures (including the heart, great vessels, and trachea (tracheal deviation)) Pneumothorax - Clinical Manifestations, Diagnosis & Treatment Clinical Manifestations Diagnosis - Sudden pleural pain - Chest X-Ray, ultrasound, and CT - Tachypnea - Dyspnea Treatment - Decrease or absence of breath sounds (depending on size) - Aspiration, usually with insertion - Hyperresonance to percussion on of a chest tube that is attached to a affected side water-seal drainage system with - Severe hypoxemia (tension) suction - Tracheal deviation away from affected lung (tension) - The chest tube is removed after - Hypotension (tension) the pneumothorax is resolved & the plural rupture has healed Pleural Effusion - Pleural Abnormality Pleural Effusion: the presence of fluid in the pleural space; usually coming from blood vessels or lymphatic vessels. Presence of pus = empyema, presence of blood = hemothorax, presence of chyle = chylothorax Clinical Manifestations - Dyspnea - Pleural pain - Decreased breath sounds or pleural friction rub over inflamed pleura Diagnostic Tests - Chest X-ray - Thoracentesis (needle aspiration); fluid can be tested by lab Treatment - Drainage by chest tube if large - Symptom management (dyspnea, pain) Empyema - Pleural Abnormality Empyema (infected pleural effusion): presence of pus in the pleural space; common infectious organisms include Staphylococcus aureus, Escherichia coli, anaerobic bacteria, and Klebsiella pneumoniae Usually develops as a complication of pneumonia, surgery, trauma, or obstruction from a tumour. Clinical Manifestations Diagnostic Tests - Cyanosis - Chest X-ray - Fever - Thoracentesis - Tachycardia - Sputum culture - Cough Treatment - Pleural pain - Decreased breath sounds - Antibiotics & drainage Restrictive Lung Diseases Characterized by: - Decreased compliance of lung tissue - It takes MORE EFFORT to expand the lungs during inspiration which increases work of breathing (WOB) - Individuals will have dyspnea, increased respiratory rate, and decreased tidal volume - Can cause V/Q mismatch Aspiration - Restrictive Lung Disease Aspiration: the passage of fluid and solid particles into the lungs - Tends to affect individuals whose normal swallowing mechanism and cough reflex are impaired by central or peripheral nervous system abnormalities (stroke, sedation, etc). Causes inflammation and infection (aspiration pneumonia) Clinical Manifestations Treatment - Choking & coughing - Prevention!!!! - Fever - Aspiration pneumonia; O2, corticosteroids, - Dyspnea & wheezing antibiotics Atelectasis - Restrictive Lung Disease Atelectasis: the collapse of lung tissue 1. Compression: caused by external pressure by a tumour, fluid or abdo distention 2. Absorption: removal of air from alveoli 3. Surfactant Impairment: decreased surfactant compromises surface tension and results in collapse Usually occurs after surgery! Clinical Manifestations: - Dyspnea, cough, fever, leukocytosis Treatment: - Prevention!!! - Deep breathing exercises Pulmonary Fibrosis - Restrictive Lung Disease Pulmonary Fibrosis: excessive amount of fibrous or connective tissue in the lung; formation of scar tissue after active pulmonary disease, chronic inflammation, and inhalation of harmful substances can lead to pulmonary fibrosis Idiopathic Pulmonary Fibrosis (IPF): no specific cause Clinical Manifestations Treatment - Dyspnea on exertion - O2 - Inspiratory crackles - Corticosteroids - Cytotoxic medications Diagnostic Tests - Lung transplant - PFT, CT, lung biopsy Pulmonary Edema - Restrictive Lung Disease Pulmonary Edema: excess fluid in the lung (normal lung is kept DRY by lymphatic drainage and a balance between our hydrostatic and oncotic pressures) Most common predisposing factor is left-sided heart disease Clinical Manifestations Treatment - Dependant on cause - Dyspnea - HF caused: diuretics, - Hypoxemia vasodilators, medication to help - Increased WOB heart contraction - Inspiratory crackles (rales) - Oxygen usually in all cases - Frothy sputum (severe cases) Acute Lung Injury (ALI)/ Acute Respiratory Distress Syndrome (ARDS) - Restrictive Lung Disease (1/2) Spectrum of acute lung inflammation and diffuse alveolocapillary injury; most commonly caused by sepsis or multiple trauma Phases of ALI/ARDS include inflammation, resolution of edema and proliferation, then remodelling and fibrosis of lung tissues Clinical Manifestations (progressive!) 1. Dyspnea and hypoxia with poor response to O2 supplementation 2. Hyperventilation and respiratory alkalosis 3. Decreased tissue perfusion, metabolic acidosis, and organ dysfunction 4. Increased WOB, decreased tidal volume, and hypoventilation 5. Hypercapnia, respiratory acidosis, and worsening hypoxemia 6. Respiratory failure, decreased cardiac output, hypotension, and death Acute Lung Injury (ALI)/ Acute Respiratory Distress Syndrome (ARDS) - Restrictive Lung Disease (2/2) Diagnosis is based on - History of the lung injury - Physical examination - ABG analysis - Chest X-ray Treatment - Supportive therapy (maintaining oxygenation and ventilation while preventing infection) - Prevention of complications Restrictive Lung Diseases (More Examples) Bronchiectasis: persistent abnormal dilation of the bronchi; chronic inflammation leads to destruction of elastic and muscular components of their walls. Primary symptom is chronic productive cough. Bronchiolitis: inflammatory obstruction of the small airways of bronchioles (most common in children). S/S: fever, increased RR, dry cough, hyperinflated chest Treatment for the above two: antibiotics, corticosteroids, chest physio, O2 Pneumoconiosis: change in the lung caused by the inhalation of inorganic particles (silica, asbestos, coal); leads to fibrosis of the lung tissue Treatment: usually palliative & focuses on preventing further exposure and managing symptoms Obstructive Lung Disease Characterized by - Airway obstruction that is worse with expiration - More force is required to expire a given volume of air and emptying of the lungs is slowed - Common signs & symptoms include dyspnea and wheezing, increased WOB - Can cause V/Q mismatch Common obstructive disorders include asthma, chronic bronchitis, emphysema Individuals with both chronic bronchitis & emphysema have chronic obstructive pulmonary disease (COPD) Asthma - Obstructive Lung Disease Asthma: chronic inflammatory disorder of the bronchial mucosa that causes bronchial hyper-responsiveness, constriction of the airways, and variable airflow obstruction that is reversible - Risk Factors: familial hx, exposures to allergens during childhood Pathophysiology: inflammation → smooth muscle constriction & mucous production → impaired expiration & air trapping → V/Q mismatch → hyperventilation → hypoxemia → respiratory acidosis → respiratory failure Symptoms: expiratory wheezing, dyspnea, tachypnea, bronchospasm Diagnosis: hx of allergies & recurrent episodes of wheezing, dyspnea, and cough or exercise intolerance, and spirometry Treatment: avoidance of allergens, inhalers (corticosteroids & beta agonists), using peak flow meters Chronic Obstructive Pulmonary Disease (COPD) - Obstructive Lung Disease COPD: defined as persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response; exacerbations and co-morbidities contribute to the overall severity of the disease - Risk factors: tobacco smoke, air pollution, any factor that affects lung growth in childhood Consists of both chronic bronchitis and emphysema Eventually leading to airway obstruction, air trapping, loss of surface area for gas exchange, frequent exacerbations (infections, bronchospasms), and further worsening dyspnea, cough, hypoxemia, hypercapnia and cor pulmonale  Chronic Bronchitis & Emphysema Chronic Bronchitis: hypersecretion of mucus and chronic productive cough for at least 3 months of the year for at least 2 consecutive years. Bronchial inflammation & mucus production. Emphysema: abnormal permanent enlargement of gas-exchange airways accompanied by destruction of alveolar walls without obvious fibrosis Clinical Manifestations of COPD: productive cough, dyspnea, wheezing, barrel chest, prolonged expiration (pursed lip breathing), cyanosis, chronic hypoventilation Treatment - Bronchodilators, mucolytics, anti-inflammatory medications are prescribed to control cough and reduce dyspnea - Exacerbations; antibiotics and steroids - Eventual home oxygen; **chronic elevation of PaCO2 diminishes the sensitivity of central chemoreceptors and they no longer act as the primary stimulus for breathing; maintain SpO2 88-92% - Teaching; nutritional counselling, recognition of early signs of infection, techniques that relieve dyspnea (pursed-lip breathing ) Respiratory Tract Infections Split into Upper respiratory tract infections (URTI): common cold, pharyngitis (sore throat), laryngitis Lower respiratory tract infections (LRTI): pneumonia; usually affects very young or very old or immunocompromised individuals Acute Bronchitis - Respiratory Tract Infections Acute Bronchitis: acute infection or inflammation of the airways or bronchi and is usually self-limiting (usually caused by viruses) Clinical manifestations similar to those of pneumonia (fever, cough, chills, malaise); but physical examination/ x-rays do not demonstrate pulmonary consolidation - Individuals usually have non-productive cough that occurs in paroxysms & is aggravated by cold, dry or dusty air; chest pain often develops from the effort of coughing Treatment: - Rest, aspirin, humidity, and cough suppressants - If BACTERIAL, rest, antipyretics, humidity, and antibiotics Pneumonia - Respiratory Tract Infections (1/2) Pneumonia: infection of the lower respiratory tract caused by bacteria, viruses, fungi, protozoa or parasites Categorized as healthcare associated pneumonia (HCAP), community acquired (CAP), hospital acquired (HAP), ventilator associated (VAP); different microorganisms are seen in each & these infections can be difficult to treat Cause is usually due to aspiration of oropharyngeal secretions Viral pneumonia is usually seasonal & self limiting Pneumonia - Respiratory Tract Infections (2/2) Clinical Manifestations - Usually preceded by a viral URTI - Fever, chills, productive or dry cough, malaise, pleural pain, and sometimes dyspnea and hemoptysis - Inspiratory crackles Diagnosis - WBC count, chest x-ray, sputum culture, blood cultures Treatment - Prevention! Of aspiration - Establishing adequate ventilation and oxygenation (supplemental O2) - Pulmonary hygiene (deep breathing & coughing, chest physio) - Antibiotics if bacterial Tuberculosis - Respiratory Tract Infections (1/2) Tuberculosis (TB): an infection caused by Mycobacterium tuberculosis. Usually affects the lungs but can invade other body systems. Pathophysiology: TB is highly contagious and is transmitted via airborne droplets. Usually, TB is contained by inflammatory and immune response systems, resulting in latent TB infection (LTBI)… meaning present in their body but no clinical evidence of the disease Once the bacilli (the microorganism) is inhaled, it lodges into the lung periphery; usually on the upper lobe & causes non-specific inflammation; our immune system attacks and once infected tissues die, scar tissue grows around and isolates the bacilli. Once this happens, TB may stay dormant for life; although, there is one great risk for reactivation and that is developing HIV infection - Other risk factors include cancer, immunosuppressive medications, poor nutrition and renal failure Tuberculosis - Respiratory Tract Infections (2/2) Clinical Manifestations - LTBI is asymptomatic - Other symptoms are slow & usually not noticed until disease has advanced, this includes: fatigue, weight loss, lethargy, anorexia (loss of appetite), low-grade fever, cough with purulent sputum, night sweats, general anxiety Diagnosis - Positive tuberculin skin test (bleb injection), sputum cultures, and chest x-rays Treatment - Combination antibiotic therapy Pulmonary Vascular Disease Blood flow through the lungs can be disrupted by disorders that occlude vessels, increase pulmonary vascular resistance, or destroy the vascular bed This may lead to life-threatening changes in ventilation-perfusion ratios Major disorders include Pulmonary Embolism (PE), pulmonary hypertension, and cor pulmonale Pulmonary Embolism - Pulmonary Vascular Disease (1/3) Pulmonary Embolism: occlusion of a portion of the pulmonary vascular bed by an embolus; most commonly from embolization of a clot from deep venous thrombosis in the lower leg (other emboli can be tissue fragments, lipids, or an air bubble) - Risk factors include conditions and disorders that promote blood clotting… VIRCHOW’S TRIAD (venous stasis, hypercoagulability, or injury to the endothelial cells that line the vessels) **no matter its source, a blood clot (thrombus) becomes an embolus when all or part of it detaches from the site of formation and travels in the bloodstream** Pulmonary Embolism - Pulmonary Vascular Disease (2/3) Pathophysiology: the effect of the PE depends on the extent of pulmonary blood flow obstruction - With infarction = causes tissue death to a portion of the lung - Without infarction = no permanent injury - Massive occlusion = major portion of circulation occluded - Multiple PE = multiple at once, may be chronic or recurrent *if the embolus does not cause infarction, the clot is dissolved & function returns to normal… if there is infarction shrinking and scarring will occur Pulmonary Embolism - Pulmonary Vascular Disease (3/3) Clinical Manifestations - Sudden onset of chest pain, dyspnea, tachypnea, tachycardia, and unexplained anxiety Diagnostic Tests - Elevated D-dimer in the blood (product of thrombus degradation) - CT scan (with contrast) Treatment - Prevention of clot formation; mobilization, repositioning, and pneumatic calf compression - Anticoagulant therapy is the primary treatment for PE’s, and then continued for several months afterwards Pulmonary Artery Hypertension - Pulmonary Vascular Disease Pulmonary Artery Hypertension (PAH): mean pulmonary artery pressure >25 mmHg at rest Causes are usually other diseases of the respiratory system (COPD) and hypoxemia. Idiopathic pulmonary arterial hypertension (IPAH) - caused by unclear multifactorial mechanisms Clinical Manifestations: enlarged right heart border (on xray), fatigue, chest discomfort, dyspnea on exertion, peripheral edema, and jugular vein distention (JVD) Diagnosis: with right heart catheterization to measure pressure Treatment: O2, diuretics, anticoagulants, and avoidance of contributing factors Cor Pulmonale - Pulmonary Vascular Disease Cor Pulmonale: right ventricular enlargement of the heart caused by PAH Pathophysiology: cor pulmonale develops as PAH exerts chronic pressure into the right ventricle → hypertrophy (enlargement) of the heart muscle →dilation → failure of the ventricle Clinical Manifestations: ECG changes, dyspnea on excretion, extra heart sounds, JVD, peripheral edema, hepatosplenomegaly Diagnosis: ECG, x-ray, physical exam of manifestations Treatment: goal is to decrease the workload of the right ventricle! Diuretics, avoidance of contributing factors Quick Review A patient has right ventricular enlargement secondary to pulmonary hypertension. Which would be the most likely diagnosis? A. Cor pulmonale B. Acute bronchitis C. Pulmonary embolism D. Pulmonary thromboembolism Developmental Alterations of Pulmonary Function Chapter 28 Disorders of the Upper Airways Can cause significant obstruction to airflow Common causes of upper airway obstruction in children include: - Infections - Foreign body aspiration - Obstructive sleep apnea - Trauma Croup - Infection of the Upper Airway Croup: is an acute laryngotracheitis occuring in children ages 6 months - 5 years; most commonly caused by a virus (parainfluenza) Pathophysiology: subglottic inflammation and edema → increased resistance to airflow → increased WOB →collapse of upper airway → respiratory failure Clinical Manifestations: runny nose, sore throat, low-grade fever, harsh (seal-like) barking cough, inspiratory stridor, hoarse voice Treatment: dependant on degree of symptoms, usually no treatment needed - Glucocorticoids (symptom management) - For acute respiratory distress, epinepherine is nebulized to decrease edema and secretions Acute Epiglottitis - Infection of the Upper Airway Acute Epiglottitis: severe, rapidly progressive, life-threatening infection of the epiglottis and surrounding area. Historically caused by Haemophilus influenzae type B, but overall incidence of acute epiglottitis has been reduced due to Hib vaccination Clinical Manifestations: fever, irritability, sore throat, inspiratory stridor, muffled voice, respiratory distress, drooling, dysphagia, tripod position to improve breathing Treatment: life-threatening emergency, keep the child calm, no throat exams, emergency airway and antibiotics Tonsillar Infections & Abscesses - Infection of the Upper Airway Tonsillitis: inflammation of the tonsils; occasionally severe enough to cause upper airway obstruction Tonsillar Abscess: complicates tonsillitis & further can contribute to obstruction Peritonsillar Abscess: usually unilateral and is a complication of acute tonsillitis; abscess must be drained and there must be administration of antibiotics Aspiration of Foreign Bodies Foreign body aspiration in children occurs frequently between the ages of 1 and 4 Clinical Manifestations *symptoms depend on foreign body size* - Coughing - Choking - Gagging - Wheezing Aspirated foreign bodies can be removed by bronchoscopy Obstructive Sleep Apnea Syndrome (OSAS) Obstructive Sleep Apnea Syndrome (OSAS): partial or intermittent complete upper airway obstruction during sleep Obstructive sleep apnea disrupts normal ventilation and sleep patterns One of the most common causes for childhood obstructive sleep apnea is adenotonsillar hypertrophy Clinical Manifestations - Snoring and labored breathing during sleep - Daytime sleepiness - Chronic mouth breathing Diagnosis: sleep study Treatment: tonsillectomy and adenoidectomy or CPAP Disorders of the Lower Airways Lower airway disease is one of the leading causes of morbidity in the first year of life Disorders include respiratory distress syndrome of the newborn, bronchopulmonary dysplasia, infections, asthma, cystic fibrosis, and acute respiratory distress syndrome Respiratory Distress Syndrome of Newborn Primarily a disease of preterm infants Poor lung structure and surfactant deficiency →causes widespread atelectasis resulting in significant hypoxemia → pulmonary hypertension causes continued shunting of blood away from the lungs Symptoms: Tachypnea, expiratory grunting, nasal flaring and retractions, cyanosis Diagnosis: based on premature birth, chest x-rays, and pulse oximetry measurements Treatment: exogenous surfactant nebulized or CPAP ventilation beginning within 15-30 minutes of birth Most infants survive this; complete recovery within 10-14 days Bronchopulmonary Dysplasia Bronchopulmonary Dysplasia: associated with premature birth, the need for prolonged perinatal supplemental oxygen, and positive pressure ventilation Poor formation of the alveolar structure with fewer and larger alveoli and decreased surface area for gas exchange Clinical Manifestations - Hypoxemia - Hypercapnia - Elevated work of breathing - Bronchospasm - Mucus plugging - Pulmonary hypertension *Bronchopulmonary dysplasia is not as common because of the availability of exogenous surfactant and antenatal glucocorticoids* Bronchiolitis - Respiratory Tract Infections Bronchiolitis: most common associated pathogen is RSV, major reason for hospitalization Clinical Manifestations - Runny nose - Cough - Decreased appetite, lethargy, fever - Wheezing, tachypnea Diagnosis: history & signs/symptoms Treatment: supportive; suctioning secretions, IVF for hydration, supplemental O2 & pulse ox monitoring Pneumonia - Respiratory Tract Infections Can be bacterial or viral Atypical (Mycoplasma pneumoniae) - Most common cause of community-acquired pneumonia for school-age and young adults - Onset is usually gradual, resembling a typical upper respiratory infection but with low-grade fever and cough - Usually not severe and self-limiting Diagnosis: chest x-ray Treatment: usually outpatient, but at times require supplemental O2, antibiotics, prevention (vaccines against influenza & pneumococcus) Asthma Characterized by bronchial hyper-reactivity and reversible airflow obstruction, usually in response to an allergen Most prevalent chronic childhood disease that results from a complex interaction between genetic susceptibility and environmental factors Clinical Manifestations Treatment - Cough - Education (preventing asthma - Expiratory wheeze attacks) - Shortness of breath, tachypnea - Use of peak flow meters - Nasal flaring - Inhalers (steroids & bronchodilators) - Accessory muscle use - Exercise intolerance Cystic Fibrosis (CF) Cystic Fibrosis: autosomal recessive inherited disease It is a multiorgan disease that affects the lungs, GI tract and reproductive system Clinical Manifestations: - Mucus plugging, chronic inflammation, and chronic infection of the small airways - Persistent cough or wheeze - Barrel chest, digital clubbing Diagnosis: sweat test; sweat chloride concentration >60mmol/L Treatment: focused on pulmonary health and nutrition - Chest physio to clear secretions, bronchodilators - Antibiotics if infection occurs - Lung transplantation (end stage lung disease) Sudden Unexpected Infant Death (SUID) Defined as “sudden death of an infant under 1 year of age that remains unexplained” Incidence: Lower during the first month of life, increases in the second month, and peaks at 2 to 4 months & is more common in male infants Seasonal variation; possible relationship to respiratory infections Usually occurs at night Wide range of risk factors: prone & side-lying sleeping, sleeping on soft bedding, lack of prenatal care, preterm birth Etiology unknown - Vulnerable infant - Environmental stressors Quick Review A child is born prematurely and requires respiratory support. The child experiences neonatal lung injury and several weeks later develops hypoxemia and hypercapnia. Which is the most likely diagnosis? A. Pneumonia B. Bronchiolitis C. Aspiration pneumonitis D. Bronchopulmonary dysplasia