Respirology Flashcards
What is the diagnostic criteria for BRUE?
BRUE: a sudden, brief, and now resolved episode in a child <1 year of age, including ≥ 1 of the following:
1. Cyanosis or pallor 2. Absent, decreased, or irregular breathing 3. Marked change in tone (hyper- or hypotonia) 4. Altered level of responsiveness
Which areas of the lung are the “dependent areas” of the lung?
- R and LUL
- Apical segment of the RLL
What antibiotics should be used in empiric treatment of lung abscess?
• 2-3 wks IV antibiotics for uncomplicated cases
• Follow with 4-6 wks of PO antibiotics
• Guide Abx choice with Gram stain results
• Empiric treatment: Penicillinase-resistant agent + aerobic coverage
i.e. Cloxacillin + Clindamycin/Clavulanic acid)
What is the definition for ARDS (Berlin definition)?
- Acute onset (<7 days)
- Severe hypoxemia (PaO2/FiO2 <300 for acute lung injury, or <200 for ARDS)
- Diffuse bilateral pulmonary infiltrates consistent with pulmonary edema (can be patchy and asymmetric, and pleural effusions can be present)
- Absence of L atrial hypertension (pulmonary artery wedge pressure <18 mm Hg if measured)
In what situations is pulse oximetry unreliable?
- In highly deoxygenated states
- In the presence of carboxyhemoglobin (overestimates as in cases of carbon monoxide poisoning)
- In the presence of methemoglobin (over-/underestimates)
What are the diagnostic criteria to confirm asthma?
- Change in 12% in FEV1 following use of bronchodilator
- Positive methacholine challenge (PC20 < 4 mg/mL) or exercise stress test (> 10-15% decrease in FEV1 post-exercise)
- FEV1/FVC ratio <0.8 of predicted
- Increase of at least 20% in peak expiratory flow after use of bronchodilator
What are the Canadian Thoracic Association’s guidelines for GOOD control of asthma symtoms?
- Daytime symptoms <4 days/wk
- Night time symptoms <1 night/wk
- Physical activity - normal
- Exacerbations - mild/infrequent
- No absences from work or school due to asthma
- Need for a fast-acting beta2 agonist <4 doses/week
- FEV1 or PEF ≥90% personal best
- Sputum eosinophils < 2-3%
What are common allergenic triggers for children with asthma?
- Indoor: Animal dander, dust mite, cockroach, molds
- Seasonal aeroallergens: Pollens (trees, grass, weeds), seasonal molds
- Air pollutants: Environmental tobacco smoke, ozone, N2O2, sulfur dioxide, particulate matter, wood/coal burning smoke, mycotoxins, endotoxins, dust
- Strong/noxious odours/fumes: Perfumes, hairspray, cleaning agents
- Occupational: Farm/barn exposures, formaldehydes, cedar, pain fumes, cold dry air, exercise, crying/laughter/hypeventilation
What side effects of chronic inhaled steroid use should be discussed with families?
• Most common:
- oral candidiasis (thrush) –> propellant induced mucosal irritation and local immunosuppresion
- dysphonia (hoarse voice) –> vocal cord myopathy
• Long-term, prospective NIH-sponsored CAMP study - slight height reduction of 1 cm in final adult height
What is generally a medium dose of ICS?
200-400 mcg/day
How does the treatment algorithm for asthma change based on age?
- In children > 12 yoa, start with SABA, add low dose ICS and then consider LABA first before either medium dose ICS or leukotriene receptor inhibitor, then steroids or anti-IgE
- In children 6-12 yoa, start with SABA, add low dose ICS then move to medium dose ICS before considering either LABA or leukotriene receptor inhibitor, then steroids or anti-IgE
What is the criteria for diagnosing asthma in a preschooler?
- Documented or reliable history of wheeze or obstructive airflow by health care provider (or parent)
- Documented response to inhaled SABA or oral steroids
- Does not meet criteria for any other illness
What considerations should be made for asthmatic children preparing for elective surgery?
- Asthma should be well controlled prior to surgery
* Caution should be used when using volatile inhalants for induction, particularly desflurane
What are some potential complications with chest tubes?
- Injury on insertion (diaphragm, nerves, blood vessels)
- Pneumothorax
- Dislodgement
- Malposition
- Occlusion
- Pain
- Pulmonary re-expansion pulmonary edema
Causes of chylothorax
• Post cardiothoracic surgery
- Chest injury, ECMO
• Primary or metastatic intrathoracic malignancy (i.e. Lymphoma)
• Thoracic duct rupture during delivery
• Lymphangiomatosis
• Thrombosis of the duct, SVC or subclavian vein
• Infection: TB, histoplasmosis
• Congenital anomalies of the lymphatic system
- Missense mutation in integrin aα9 gene
• Trauma/Child abuse
• Idiopathic
How to manage a child with chylothorax?
- Enteral feedings with a low fat or MCT, high-protein diet or TPN
- Thoracentesis (repeated)
- Pleuroperitoneal shunt, thoracic duct ligation or application of fibrin glue
- Parenteral octreotide (0.5 - 1 µg/kg/hr to a maximum of 10 µg/kg/day) can be used
- PPV with PEEP
What condition is associated with PHOX2B mutations?
Congenital central hypoventilation syndrome
may also see a subset with Hirshsprung’s Disease
What clinical manifestations are seen in cases of OSA?
- Sleep related: Loud, frequent and disruptive snoring, Breathing pauses, Choking or gasping arousals, Restless sleep, More frequent partial arousal parasomnias (i.e. Sleepwalking and sleep terrors), Hyperextension of neck to maintain airway patency
- Daytime: Mouth breathing, Dry mouth, Chronic nasal congestion/rhinorrhea, Hyponasal speech, Morning headaches, Difficulty swallowing, Poor appetite, Secondary enuresis, Daytime sleepiness with drowsiness, Increased irritability, mood instability and emotional dysregulation, Low frustration tolerance, Anxiety/depression, Aggression, impulsivity, hyperactivity, oppositional behaviour, conduct problems
What is the gold standard test for OSA?
Polysomnogram
What does the CPS recommend with respect to empiric treatment of pneumonia?
- If uncomplicated, first line is amoxicillin
- If requires hospitalization, ampicillin (IV)
- If hospitalized and in resp distress, 3rd generation cephalosporin such as ceftriaxone
- May add vancomycin if there is concern for MRSA
Standard treatment duration in Canada is 7-10 days (5 days if as outpatient)
What are the most common pathogens in the case of pneumonia (immunocompetent host)?
- Strep pneumo
- S. aureus
- Strep pyogenes (GAS)
- MRSA
What does the CPS recommend in the case of complicated pneumonia?
Cefotaxime/ceftriaxone +/- clindamycin (anaerobic infections/CA MRSA) OR vancomycin (MRSA)
No consensus on duration, typically 3-4 weeks
What are the most common causes of pleurisy (inflammation of pleura)?
Bacterial pneumonia!!!
• Next most common causes:
○ Heart failure
○ Rheumatologic causes
○ Metastatic intrathoracic malignancy
What is the genetic inheritance pattern of Kartagener Syndrome?
Heterogeneous group of disorders; generally AR but there are AD, X-linked conditions
What is the classic Kartagener triad?
- Situs inversus totalis
- Chronic sinusitis
- Bronchiectasis
How is diagnosis of primary ciliary dyskinesia made?
• Nasal/tracheal mucosa biopsy & electronic microscopy (AbN ciliary structure; will not defect function defects in PCD)
• Electron microscopic analysis as the gold standard
□ Identifies abnormal structure i.e. Absence of inner/outer dynein arms, radial spokes or of the central microtubular pair
□ Normal - 9 outer doublets in a circular pattern surrounding a central pair of microtubles, maintained by radial spikes and intertubular linkage
• Genetics: 2 dz causing mutations in trans (DNAH5, DNAI1, DNAI2, DNAH11)
• High speed videomicroscopy & ciliary beat frequency (technically difficult, hard to do reliably)
What clinical findings are suggestive of PCD?
- Hx of neonatal respiratory distress, tachypnea, hypoxemia or respiratory failure
- Chronic, daily nasal drainage that is non-seasonal, may be purulent, and may be present as early as the first weeks after birth
- Chronic wet or productive cough, often worse in the early morning
- Chronic otitis media or otorrhea, often requiring tympanostomy tube placement; complications include regional spread of chronic middle ear infection (e.g. Mastoiditis) and hearing loss
- Recurrent or chronic bronchitis or pneumonia
- Bronchiectasis
- Male infertility
What is the most common fatal AR inherited gene disorder among Caucasians?
CFTR (responsible for cystic fibrosis)
The most common CF gene mutation is Delta F508
How many classes of Cystic Fibrosis are there and what are the associated defects?
- Class I: defective protein production, complete absence of CFTR protein
- Class II: defective protein processing which prevents the protein from going to the right location. This includes delta F508
- Class III: defective regulation which means diminished activity in response to ATP
- Class IV: defective conductance which means the rate of ion flow and duration of channel opening is reduced
- Class V: reduced number of active CFTR
What is the diagnostic criteria for children with cystic fibrosis?
• Must have clinical symptoms + evidence of CFTR dysfunction
○ Sweat chloride > 60mmol/L on 2 occasions
○ Presence of 2 disease causing mutations
○ Abnormal nasal potential difference
• Clinical symptoms not required if identified by newborn screening
What are some potential causes for a false positive sweat chloride test?
- Eczema
- Ectodermal dysplasia
- Malnutrition
- Hypoparathyroidism
- Adrenal insufficiency
- CAH
- Pseudohypoaldosteronism
- Hypothyroidism
- Nephrogenic DI
- Pancreatitis
- Hypogammaglobulinemia
What are some potential causes for a false negative sweat chloride test?
- Edema
- Done too early (<48 hrs)
- Wt <7 lbs (3.1 kg)
- Poor technique
- Meconium ileus
- Hyponatremia
What nutritional deficiencies are expected in children with CF?
- Fat soluable vitamins: ADEK
- Iron
- Zinc
What organisms are commonly seen in CF patients? Which are more concerning for long term prognosis?
- Staph aureus and Haemophilus influenzae (will also see stenotrophomonas and achromobacter)
- Pseudomonas (biofilm makes eradication almost impossible)
- Burkholderia cepacia can cause rapid decline in lung function
How do you diagnosis allergic bronchopulmonary aspergillosis?
- Patients may present with rust coloured sputum that is non-responsive to antibiotics
- Confirm with blood work and investigations
- ↑ total IgE levels, specific aspergillus IgE and IgG
- Positive sputum culture
- CT showing central bronchiectasis and mucous plugging
At what point should a lung transplant be considered for a patient with CF?
An FEV1 < 30 is often an indication for transplant
What antibiotics should be used to treat CF exacerbations?
- Ceftazidime and tobramycin
* (oral steroid and itraconazole for ABPA)
What interventions should be done to treat a CF exacerbation?
- Bronchodilators
- Hypertonic saline (7%)
- DNase/pulmozyme
- Chest physiotherapy
- Azithromycin for anti-inflammatory properties
- GI support via enzyme replacement, PPI, PEG3350 as required
