16. Respirology Flashcards
Define: Asthma (3)
- inflammatory disorder of the airwarys characterized by recurrent episodes of reversible small airway obstruction, resulting from airway hyperresponsiveness to endogenous and exogenous stimuli
- very common, presents most often in early childhood
- associated with other atopic diseases such as allergic rhinitis or atopic dermatitis
Describe clinical features: Asthma (3)
- episodic bouts of wheezing, dyspnea, tachypnea, cough (usually at night/early morning, with activity,or cold exposure)
- physical exam may reveal hyper-resonant chest, prolonged expiration, wheeze
- symptoms may be exacerbated by “triggers”: URTI (viral or Mycoplasma), weather (cold exposure, humidity changes), allergens (pets), irritants (cigarette smoke), exercise, emotional stress, drugs (ASA, β-blockers)
Describe classification: Asthma (3)
- mild: occasional attacks of wheezing or coughing (<2/wk); symptoms respond quickly to inhaled bronchodilator; never needs systemic corticosteroids
- moderate: more frequent episodes with symptoms persisting and chronic cough; decreased exercise tolerance; sometimes needs systemic corticosteroids
- severe: daily and nocturnal symptoms; frequent ED visits and hospitalizations; usually needs systemic corticosteroidsa
Describe management: Acute Asthma (6)
- O2 (keep O2 saturation >94%) and fluids if dehydrated
- β2-agonists: salbutamol (Ventolin®) MDI + spacer (nebulized or IV in very severe episodes with impending respiratory failure), 5 puffs (<20 kg) or 10 puffs q20min for first h (>20 kg)
- ipratropium bromide (Atrovent®) if severe: MDI + spacer, 3 puffs (<20 kg) or 6 puffs (>20 kg) q20min with salbutamol, or add to first 3 salbutamol masks (0.25 mg if <20 kg, 0.5mg if >20 kg)
- steroids: prednisone (1-2 mg/kg x 5 d) or dexamethasone (0.3 mg/kg/d x 5 d or 0.6 mg/kg/d x 2 d); in severe disease, use IV steroids
- if no response, add magnesium sulphate
- continue to observe; can discharge patient if asymptomatic for 2-4 h after last dose
Describe management: Chronic Asthma (10)
- education, emotional support, avoid allergens or irritants, develop an “action plan”
- exercise program (e.g. swimming)
- monitor respiratory function with peak flow metre (improves self-awareness of status)
- PFTs for children >6 yr
- reliever therapy: short acting β2-agonists (e.g. salbutamol)
- controller therapy (first line therapy for all children): low dose daily inhaled corticosteroids
- second line therapy for children <12 yr: moderate dose of daily inhaled corticosteoroids
- ■ second line therapy for children >12 yr: leukotriene receptor antagonist OR long acting β2-agonist in conjunction with low dose inhaled corticosteroids; leukotriene receptor antagonist monotherapy may be considered an alternative second line therapy
- severe asthma unresponsive to first and second line treatments: injection immunotherapy
- aerochamber for children using daily inhaled corticosteroids
Name: Indications for hospitalization for asthma (4)
- ongoing need for supplemental O2
- persistently increased work of breathing
- β2-agonists are needed more often than q4h after 4-8 h of conventional treatment
- patient deteriorates while on systemic steroids
Name: Canadian Pediatric Asthma Consensus Guidelines for Assessing Adequate Control of Asthma (8)
- Daytime symptoms <4d/wk
- Night time symptoms <1 night/wk
- Normal physical activity
- Mild and infrequent exacerbations
- No work/school absenteeism
- Need for β-agonist <4 doses/wk
- FEV1 or peak expiratory flow ≥ 90% of personal best
- Peak expiratory flow diurnal variation <10-15%
Describe: Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection (6)
- Palivizumab prophylaxis is recommended for the first year of life for infants born before 29 wk gestation, and preterm infants with chronic lung disease of maturity (born at <32 wk gestation and requiring >21% oxygen for at least 28 d after birth).
- Such prophylaxis may be administered in the first yr of life to infants with hemodynamically significant heart disease, and a maximum of 5 monthly 15 mg/kg doses may be administered during the RSV season to infants requiring it; infants born during the RSV season may need fewer doses.
- Prophylaxis may be considered in the first yr of life for children with pulmonary abnormalities or neuromuscular disease impairing the ability to clear secretions from the upper airway, and may be considered for children younger than 24 mo who are profoundly immunocompromised during the RSV season.
- Palivizumab prophylaxis is only recommended in the second year of life for children who required at least 28 d of supplemental oxygen after birth with ongoing medical intervention needs.
- Monthly prophylaxis should be discontinued in children experiencing breakthrough RSV hospitalizations.
- Insufficient evidence exists to support the use of prophylaxis for children with cystic fibrosis or Down’s syndrome
Define: Bronchiolitis (3)
- LRTI
- usually in children < 2yr,
- that has wheezing and signs of respiratory distress
Describe epidemiology: Bronchiolitis (4)
- the most common LRTI in infants
- affects 50% of children in first 2 yr of life
- peak incidence at 6mo, winter or early spring
- increased incidence of asthma in later life
Describe etiology: Bronchiolitis (6)
- RSV (>50%)
- parainfluenza
- influenza
- rhinovirus
- adenovirus
- M.pneumoniae (rare)
Describe clinical feature: Bronchiolitis (4)
- prodrome of URTI with cough and/orrhinorrhea, possible fever
- feeding difficulties, irritability
- wheezing, crackles, respiratory distress, tachypnea, tachycardia, retractions, poor air entry;
- symptoms often peak at 3-4 d
Describe investigations: Bronchiolitis (3)
- routine investigations are not required when bronchiolitis is suspected (Choosing Wisely)
- CXR (only in poor response to therapy or atypical disease): air trapping, peribronchial thickening,
- atelectasis, increased linear markings
Symptoms of bronchiolitis last how long? (1)
self-limiting disease with peak symptoms usually lasting 2-3wk
Describe management of bronchiolitis: mild to moderate distress (3)
supportive:
- PO or IV hydration
- antipyretics for fever
- regular or humidified high flow O2
Describe management of bronchiolitis: severe distress (2)
- as above ± intubation and ventilation as needed
- consider rebetol (Ribavirin®) in high risk groups: bronchopulmonary dysplasia, CHD, congenital lung disease, immunodeficient
What can help protect from bronchiolitis in high risk groups? (1)
monthly RSV-Igorpalivizumab (monoclonal antibody against the F-glycoprotein of RSV) is protective against severe disease in high risk groups; case fatality rate <1%
What’s the use of bronchodilators, corticosteroids and antibiotics in bronchiolitis? (1)
have not herapeutic value (unless there is secondary bacterial pneumonia)
Name indications for hospitalization in bronchiolitis (6)
- hypoxia: O2 saturation <92% on initial presentation
- persistent resting tachypnea >60/min and retractions after several salbutamol masks
- past history of chronic lung disease, hemodynamically significant cardiac disease, neuromuscular problem, immunocompromised
- young infants <6 mo old (unless extremely mild)
- significant feeding problems
- social problem (e.g. inadequate care at home)
Define: Choanal Atresia (1)
obliteration or blockage of the posterior nasal aperture, associated with bony abnormalities of the pterygoid plates and midfacial growth abnormalities
Describe epidemiology: Choanal Atresia (2)
- 1/7000 live births
- associated with bony abnormalities of the pterygoid plates and midfacial growth abnormalities
Describe diagnosis: Choanal Atresia (1)
By CT with intra nasal contrast
Describe tx: Choanal Atresia (2)
depends on extent
- immediate treatment of bilateral choanal atresia: placement of an oral airway and initiation of gavage feedings
- long term treatment: surgery
Describe etiology: Cystic Fibrosis (3)
- 1 per 3000 live births, mostly Caucasians
- autosomal recessive, CFTR gene found on chromosome 7 (ΔF508 mutationin 70%, but > 1600 different mutations identified) resulting in a dysfunctional chloride channel on the apical membrane of cells
- leads to relative dehydration of airway secretions, resulting in impaired mucociliary transport and airway obstruction
Describe clinical feature in neonatal: Cystic Fibrosis (3)
- meconium ileus
- prolonged jaundice
- antenatal bowel perforation
Describe clinical feature in infancy: Cystic Fibrosis (4)
- pancreatic insufficiency with steatorrhea and FTT (despite voracious appetite)
- anemia
- hypoproteinemia
- hyponatremia
Describe clinical feature in childhood: Cystic Fibrosis (8)
- heat intolerance
- wheezing or chronic cough
- recurrent chest infections (S.aureus, P. aeruginosa, H. influenzae)
- hemoptysis
- nasal polyps
- distal intestinal obstruction syndrome
- rectal prolapse
- clubbing of fingers
Describe clinical feature in older patients: Cystic Fibrosis (3)
- COPD
- infertility (males)
- decreased fertility (female)
Describe investigation: Cystic Fibrosis (3)
- sweat chloride test x2 (>60mEq/L)
- false positive tests: malnutrition, atopic dermatitis, hypothyroidism, hypoparathyroidism, GSD, adrenal insufficiency, G6PD, Klinefelter syndrome, technical issues, autonomic dysfunction, familial cholestasis syndrome
- false negative tests: technical problem with test, malnutrition, skin edema, mineralocorticoids
- CFTR gene mutation analysis
- disease often detected during new born genetic screening; positive result requires DNA testing and subsequent sweat choride testing
Describe complications: Cystic Fibrosis (2)
- respiratory failure, pneumothorax (poor prognostic sign), cor pulmonale (late), pancreatic fibrosis with DM, gallstones, cirrhosis with portal HTN, infertility (male)
- early death (current median survival in Canada is 46.6yr)
Describe: Approach to Dyspnea (4)
- determine if patient is sick or not sick; ABCs
- history: onset, previous episodes, precipitating events, associated symptoms, past medical/familyhistory of respiratory disease
- physical exam: vitals, SpO2, evidence of cyanosis, respiratory, cardiovascular
- investigations: CBC and differential, electrolytes, BUN, Cr, NP swab, ABG, CXR, ECG (based on clinical findings)
Name ddx: Dyspnea (20)
Describe etiology: Pneumonia (1)
inflammation of pulmonary tissue, associated with consolidation of alveolar spaces
Describe clinical features: Pneumonia (4)
- incidence is greatest in first year of life with viral causes being most common in children <5yr
- fever, cough, tachypnea
- CXR: diffuse, streaky infiltrates bilaterally
- bacterial causes may present with cough, fever, chills, dyspnea, more dramatic CXR changes (e.g.lobar consolidation, pleural effusion)
Describe management: Pneumonia (3)
supportive therapy:
- hydration
- antipyretics
- humidified O2
Name: Common Causes and Treatment of Pneumonia at NEONATES
Name: Common Causes and Treatment of Pneumonia at 1-3 months
- Bacterial
- Viral
- Atypical bacteria
- Treatment
Name: Common Causes and Treatment of Pneumonia at 3 mo-5yr
- Bacterial
- Viral
- Atypical bacteria
- Treatment
Name: Common Causes and Treatment of Pneumonia at > 5yr
- Bacterial
- Viral
- Atypical bacteria
- Treatment
Describe: Lower respiratory tract disease (2)
- obstruction of airways below thoracic inlet, produces more expiratory sounds
- classics ymptom: wheezing
Name common ddx of wheezing (4)
- asthma (recurrent wheezing episodes, identifiable triggers, typically over 6yr)
- bronchiolitis (first episode of wheezing, usually under 1 yr)
- recurrent aspiration (often neurological impairment)
- pneumonia (fever, cough, malaise)
Name uncommon ddx of wheezing (3)
- foreign body (acute unilateral wheezing and coughing)
- CF (prolonged wheezing, unresponsive to therapy)
- bronchopulmonary dysplasia (often develops after prolonged ventilation in the newborn)
Name rare ddx of wheezing (4)
- CHF
- mediastinal mass
- bronchiolitis obliterans
- tracheobronchial anomalies
Describe: Upper respiratory tract disease (2)
- diseases above the thoracic inlet characterized by inspiratory stridor, hoarseness, and suprasternal retractions
- ddx of stridor: croup, bacterial tracheitis, epiglottitis, foreign body aspiration, subglottic stenosis (congenital or iatrogenic), laryngomalacia/tracheomalacia (collapse of airway cartilage on inspiration), retropharyngeal abscess
Describe anatomy: Croup (Laryngotracheobronchitis) (1)
Subglottic laryngitis
Describe epidemiology: Croup (Laryngotracheobronchitis) (3)
- Common in children <6 yr
- with peak incidence between 7-36 mo
- Common in fall and early winter
Describe etiology: Croup (Laryngotracheobronchitis) (4)
- Parainfluenza (75%)
- Influenza A and B
- RSV
- Adenovirus
Describe clinical presentation: Croup (Laryngotracheobronchitis) (5)
- Common prodrome: rhinorrhea, pharyngitis, cough ± low-grade fever
- Hoarse voice
- Barking cough
- Stridor
- Worse at night
Describe investigations: Croup (Laryngotracheobronchitis) (2)
- Clinical diagnosis
- CXR in atypical presentation: “steeple sign” from subglottic narrowing
Describe tx: Croup (Laryngotracheobronchitis) (3)
- Stridor at rest is an EMERGENCY
- No evidence for humidified O2
- Dexamethasone: PO 1 dose Racemic epinephrine: nebulized, 1-3 doses, q1-2h Intubation if unresponsive to treatment
Describe anatomy: Bacterial Tracheitis (1)
Subglottic tracheitis
Describe epidemiology: Bacterial Tracheitis (2)
- Rare
- All age groups
Describe etiology: Bacterial Tracheitis (2)
- S. aureus
- H. influenzae α-hemolytic strep
- Pneumococcus
- M. catarrhalis
Describe Clinical Presentation: Bacterial Tracheitis (3)
- Similar symptoms as croup, but more rapid deterioration with high fever
- Toxic appearance
- Does not respond to croup treatments
Describe investigations: Bacterial Tracheitis (2)
- Clinical diagnosis
- Endoscopy: definitive diagnosis
Describe tx: Bacterial Tracheitis (2)
- Usually requires intubation
- IV antibiotics
Describe anatomy: Epiglottitis (1)
Supraglottic laryngitis
Describe epidemiology: Epiglottitis (2)
- Very rare – due to Hib vaccination
- Usually older (2-6 yr)
Describe etiology: Epiglottitis (2)
- H. influenzae
- β-hemolytic strep
Describe clinical presentation: Epiglottitis (7)
- Toxic appearance
- Rapid progression
- 4 Ds – drooling, dysphagia, dysphonia, distress Stridor
- Tripod position
- Sternal recession
- Anxious
- Fever (>39oC)
Describe investigation: Epiglottitis (2)
- Clinical diagnosis
- Avoid examining the throat to prevent further respiratory exacerbation
Describe tx: Epiglottitis (3)
- Intubation
- Antibiotics
- Prevented with Hib vaccine
