Respirology Flashcards
What is CF (genetics, mechanism, clinical features)?
How do you diagnose it?
Management?
Genetics: gene that codes for the CFTR protein (majority are ΔF508) Inheritance: Autosomal Recessive
- Mechanism:
- CFTR dysfunction = ↓Cl secretion and ↑Na absorption → dehydrated/viscous mucus
- Clinical Features (I’m CF Pancreas)
- Infertility
- Meconium ileus
- Cough
- Failure to thrive
- Pancreatic insufficiency
- Asthma (refractory)
- Nasal polyps
- Clubbing
- Rectal prolapse
- Electrolyte abnormalities (metabolic alkalosis, ↓Na, ↓Cl, ↓K)
- Atypical organisms from sputum
- Sludge (cholelithiasis/cystitis, pancreatitis, sinusitis)
- Respiratory*: bronchiectasis, pneumothorax, respiratory failure
- Gastrointestional*: DIOS, intussusception, biliary cirrhosis, hepatic steatosis, GERD, inguinal hernia, steatorrhea, fat-soluble vitamin deficiency (A, D, E, K)
Delayed puberty, hypertrophic osteoarthropathy/arthritis, amyloidosis, aquagenic palmoplantar keratoderma (skin wrinkling), hypoproteinemia
Diagnosis:
- Requires either (1 of):
- Clinical features
- Sibling with CF
- positive NBS
- AND (1 of):
- Elevated sweat chloride
- Abnormal nasal potential difference
- Identification of 2 disease-causing CF mutations
Management:
- Suppressive antibiotic therapy
- Mucociliary clearance (chest PT)
- Inhaled mucolytics (DNase if >6yo)
- Bronchodilators
- Inhaled 3%NaCl
- Antiinflammatory: NSAIDs and macrolides (3x/wk)
- Nutrition: enzyme replacement, vitamin supplements, high-fat, high protein diet, MCTs added
- Insulin PRN
- Ursodiol to prevent/treat liver disease
- CFTR modulators
- Lung transplant
List 2 features that would make you concerned for a diagnosis of Primary Ciliary Dyskinesia.
What is the diagnostic test for PCD?
Having ≥2 of the following should prompt investigations for PCD:
- Unexplained neonatal respiratory distress in a term infant
- Year-round daily cough starting <6mo
- Year-round daily nasal congestion starting <6mo
- Organ laterality defect
Diagnostic test:
- Electron microscopy of ciliary ultrastructure → Recognized ciliary ultrastructural defect
- Genetic testing → biallellic pathogenic variants in PCD-associated gene
- Contributory: Nasal nitric oxide measurement (must be available in centre, cooperative patient ≥5yo [capable of performing maneuver] and if CF is excluded) → Low nNo level
Define Asthma
Asthma is:
- paroxysmal or persistent symptoms (SOB, chest tightness, wheeze, sputum production and cough) associated with variable airflow limitation and airway hyperresponsiveness (endo/exogenous stimuli)
- Inflammation and it’s effects on airway structure are the mechanisms for development and persistence of asthma.
List 5 alternative diagnoses to a child you suspect has asthma.
- Cystic fibrosis
- Foreign body aspiration
- Chronic aspiration
- Primary Ciliary Dyskinesia
- Infectious adenopathy (TB, fungal)
- Pulmonary infections (viral bronchiolitis, pneumonia)
- CLD of prematurity
- Rare interstitial lung disease
- Congestive Heart Failure (CHF)
- GERD
- Allergic reaction
- Large airway obstruction
- Extrinsic - tumour (mediastinal mass), vascular ring
- Intrinsic - laryngeal web, tracheoesophageal fistula (TEF)
- Wall abnormality - CNS disorder
List 5 indications of asthma control in school-aged children
Describe the differences in monitoring control for “preschool” children (1-5yo)
- Daytime symptoms <4 days/week
- Nighttime symptoms <1 night/week
- Normal physical activity
- Mild, infrequent exacerbations
- No absence from school/work
- Requiring <4 doses/week of SABA (no longer excludes pre-exercise beta-agonist use)
- FEV1 or PEF is ≥90% personal best
Differences
- Persistent symptoms:
- Daytime symptoms ≥8 days/month
- SABA use ≥8 days/month
- ≥1 night awakening due to symptoms/month
- Severe exacerbations (requiring rescue corticosteroids or hospital admission
Same
- Absence from usual activities due to asthma symptoms
- No exercise limitation
What is your initial management for a preschool child (1-5yo)?
Describe the progression for escalation of management.
Initial
- Start management if:
- No red flags for alternative diagnosis AND
- ≥1 document asthma-like exacerbation OR
- ≥2 episodes asthma-like symptoms AND no documented signs of obstruction or improvement to therapy
- Asthma education (environmental control + action plan)
- Current signs of obstruction (wheeze, initial ↓AEBB→↑RR→ prolonged expiration→accessory muscle use→hypoxemia →altered LOC)
- Mild intermittent symptoms
- SABA PRN
- Persistent symptoms OR moderate/severe exacerbations (hospital or requiring corticosteroids)
- Low-dose ICS + SABA PRN
- Mild intermittent symptoms
- No signs of obstruction
- Monitor and reassess when symptomatic
- +/- SABA PRN x 3mos,
- If documented signs of airflow obstruction AND convincing response to SABA = ASTHMA
- If unclear, stop trial, if deterioration = ASTHMA
- +/- SABA PRN x 3mos,
- Monitor and reassess when symptomatic
- If frequent symptoms OR ≥1 moderate/severe exacerbation
- MEDIUM dose ICS x 3 mos + R/A at 6wks AND 3 mos, if clear improvement = ASTHMA
- If unclear improvement, stop challenge - if deteriorates = ASTHMA
- MEDIUM dose ICS x 3 mos + R/A at 6wks AND 3 mos, if clear improvement = ASTHMA
GET INFLUENZA VACCINATION
Escalation
If initially mild → low dose ICS → Medium dose ICS → asthma specialist (add LABA/LTRA)
How do you diagnose asthma in preschoolers (1-5yo) vs school-aged children/teenagers?
Preschool
- Documentation of signs/symptoms of airflow obstruction
- Reversibility of obstruction (improvement of these symptoms with asthma therapy [SABA +/-)
- No clinical suspicion of an alternative diagnosis
Recurrent (≥2) asthma-like exacerbations
School-aged/Teens
- Clinical symptoms + Objective evidence (below)
- Spirometry: obstruction (↓FEV1/FVC) + bronchodilator response (↑FEV1 by ≥12%)
- Peak flow: ↑≥20% following SABA
- Methacholine
- +ve = <4mg/mL
- Borderline = 4-16mg/mL
- Negative = >16mg/mL
List 3 reasons for referring a preschool (1-5yo) asthmatic to a respirologist or specialist
- Diagnostic uncertainty or suspicion of comorbidity
- ≥2 exacerbations needing rescue PO CS or hospitalization or frequent symptoms (≥8 days/month) despite moderate (200 -250µg) daily doses ICS
- Life-threatening event (ICU admission)
- Need for allergy testing
- Other considerations
- Parental anxiety
- Need for Reassurance
- Additional education
What is the most frequent cause of Recurrent Cough?
Recurrent URTIs with postnasal drip
List 4 causes of stridor
- Infection*: Tracheitis, croup
- Intrinsic:* Laryngomalacia, Tracheal Stenosis
- Extrinsic:* Vascular Ring, Tumour
Other: Foreign body
What type of spacer is indicated for 1-3yo, 4-5yo
Describe the pyramidal progression of asthma management for school aged children.
- Confirm diagnosis
- Environmental Controls, Education and Written Action Plan
6-11yo: SABA PRN→Low ICS→↑Med ICS→add LABA/LTRA
≥12yo: SARA PRN→Low ICS→add LABA →Add LTRA→Med ICS +LTRA+LABA
What are indications that a child may have asthma later in life?
Modified Asthma Predictive Index (mAPI)
- For patients ≤3yo
- MUST HAVE
- ≥3 episodes of wheezing/year
- 1 MAJOR or 2 MINOR criteria
MAJOR
- Parental Asthma (dx by MD)
- Eczema (dx by MD at 2 or 3)
MINOR
- Allergic rhinitis (dx by MD at 2 or 3)
- Wheezing apart from colds
- Eosinophilia (≥4%)
What are the most common organisms seen in a baby, toddler and school-aged child with cystic fibrosis?
Baby: Staphylococcus aureus
Toddler: Haemophilus influenzae
School-aged child: Pseudomonas aeruginosa, Klebsiella pneumoniae, Stenotrophomonas maltophilia, Burkholderia cepacia
How can parents minimize transmission of RV to their infants?
- Hand hygiene
- Avoid contact of high-risk children with people with respiratory tract infections
- Breastfeeding
- Avoidance of cigarette smoke
What are the indications for RSV prophylaxis?
<6mo at start of season
- <30wks GA WITHOUT CLD
- <36wks GA in remote communities
- Term Inuit infants living in communities with documented persistent high rates of RSV hospitalization
<12mo at start of season
- HD-significant CHD or CLD (need for O2 at 36wks GA)
- Consider for those <24mo on home O2, severely immunocompromised or prolonged hospitalization for severe pulmonary disease
If they get an RSV infection, stop the immunizations.
If being discharged home for first time during RSV season, give first dose before discharge.
What are 2 risk factors for severe RSV?
Describe features of vocal cord dysfunction
Intermittent stridor (with wheezing) that accompanies physical activity and is not responsive to asthma therapies.
Investigated with laryngoscopy during exercise challenge test if symptoms are successfully elicited. (would cause a truncated loop on spirometry)
Management: SLP and behaviour modification can be therapeutic
List 4 indications for hospitalization of a child with RSV infection
- Risk for progression to severe disease
- Respiratory status - tachypnea (RR>70), ↑WOB, O2 required, cyanosis or history of apnea
- Ability to maintain adequate hydration
- Family’s ability to cope at home
- Infant at risk of severe disease
- Prematurity <35wks
- Age <3mo
- HD-CHD
- Immunodeficiency
List 2 indications for discharge from hospital with bronchiolitis.
- Improvement of breathing and tachypnea
- Maintaining SpO2 >90% without O2 or stable for home oxygen therapy
- Adequate PO feeding
- Education provided and appropriate follow-up arranged
What 2 treatments for bronchiolitis are recommended by CPS?
Which have equivocal evidence?
What treatments should be considered if there is no improvement?
Recommended: Hydration, oxygen
Equivocal: Epi nebs, nasal suctiniong, combined Epi/dex
No improvement: humidified, heated, high-flow nasal oxygen (HHHFN), nebulized epinephrine
If high-risk in acute phase of illness, place continuous SpO2 on. Low-risk children to have intermittent monitoring or spot checks.
When is a CXR indicated with bronchiolitis?
- Diagnosis of bronchiolitis is unclear
- Rate of improvement is not as expected
- Severity of disease raises other diagnostic possibilities, such as pneumonia