First Aid for the USMLE Step 2 CK: Pulmonary Flashcards
List the four obstructive lung diseases.
ABCO •Asthma •Bronchiectasis •Cystic fibrosis / COPD • Obstruction (tracheal or bronchial)
Obstructive lung diseases primarily affect which part of the lungs?
The airways
Restrictive lung diseases, meanwhile, affect the alveoli and interstitium.
An FEV/FVC ratio less than _________ is suggestive of obstructive lung disease.
0.7
List Samter’s triad.
Samter’s triad (of asthma):
•Asthma
•Nasal polyps
•Aspirin/NSAID sensitivity
True or false: those having moderate asthma attacks usually have mild respiratory acidosis.
False
Initially, asthma leads to respiratory alkalosis from hyperventilation. Respiratory acidosis is a sign of severe respiratory failure in asthma.
List the four lung volumes.
- Inspiratory reserve volume (IRV): volume after inhaling
- Tidal volume (TV): volume from end of resting expiration to end of resting inspiration
- Expiratory reserve volume (ERV): volume from end of normal expiration to end of forced expiration
- Residual volume (RV): volume in lung at the end of a forced expiration
RV __________ in obstructive lung diseases.
increases
Which spirometry value is best for gauging the severity of restrictive lung diseases?
FVC
Inspiratory capacity (IC) is _____________.
IRV plus tidal volume
IRV + TV + ERV = _____________.
VC
FRC is equal to what two values _______________.
ERV + RV
FEV is best at marking the severity of _____________ lung disorders.
obstructive
___________ is caused by repeat infection/irritation that leads to widening of the airways.
Bronchiectasis
Bronchiectasis can present with what auscultation findings?
- Wheezes
- Rales
- Rhonchi
How is bronchiectasis diagnosed?
- First, CXR
* Second, CT (definitive)
How is the DLCO affected by emphysema?
Decreased
Review First Aid’s mnemonic for restrictive lung diseases.
When you’re lungs AIN’T compliant, it’s likely:
•Alveolar: edema, hemorrhage, pus
•Interstitial (IIP), Idiopathic (pulmonary fibrosis), Inflammatory (sarcoidosis)
• Neuromuscular (myasthenia gravis, phrenic nerve palsy)
•Thoracic wall (scoliosis, ankylosing spondylitis)
List five medications that can cause pulmonary fibrosis.
- Methotrexate
- Amiodarone
- Nitrofurantoin
- Busulfan
- Bleomycin
Review the history, exam, and diagnostic workup of pulmonary fibrosis.
- History: chronic, non-productive cough; dyspnea
- Exam: diffuse crackles; cyanosis; clubbing; signs of right-heart failure
- Diagnostic workup: CXR showing ground-glass opacity; spirometry showing decreased TLC, decreased FVC, and a normal FEV/FVC ratio; surgical biopsy
Describe three treatment approaches to interstitial lung disease.
- Prevention: avoid further exposure to causative agent
- Treat fibrosis: antifibrotic agents for some disease
- Transplant for severe disease
Go over First Aid’s mnemonic for sarcoidosis.
GRUELING •Granulomas • aRthritis •Uveitis • Erythema nodosum •Lymphadenopathy •Interstitial lung disease (fibrosis) • Negative TB test •Gammaglobulinemia
A person has dyspnea, fever, cough, and shivering 4-6 hours after being exposed to a cockatiel. What is this syndrome?
Hypersensitivity pneumonitis –can also present with noncaseating granulomas
What occupations predispose people to asbestosis?
- Brake repair
- Shipbuilding
- Insulation
- Demolition
Coal worker’s lung and silicosis present with ___________ on x-ray.
small nodular opacities
How are berylliosis and sarcoidosis similar?
They both present with a restrictive lung disease and hilar lymphadenopathy, and both require steroid treatment.
NSAID use, aspergillosis, and Löffler syndrome all share what commonality?
They are eosinophilic lung disorders.
List the five causes of hypoxemia.
- V/Q mismatch
- Cardiac shunt
- Decreased partial pressure of inhaled O2
- Hypoventilation
- Diffusion impairment
The pathogenesis of acute respiratory distress syndrome (ARDS) is thought to be due to ______________.
endothelial injury in the pulmonary vasculature
How is ARDS diagnosed?
- Hypoxemia refractory to oxygenation
- Noncardiogenic pulmonary edema
- PaO2/FiO2 less than 300
How do you calculate PaO2/FiO2 ratio?
- PaO2 is given in mm Hg: ~ 90 mm Hg
- FiO2 is given in decimal fraction: ~ 0.21
Thus, a normal PaO2/FiO2 is 90/0.21 = ~ 425.
Once you know that a person’s PaO2 is decreased (that is, that they have hypoxemia), then you should check their _______________.
A-a gradient
- If the A-a gradient is normal, then the cause of hypoxemia is either decreased FiO2 or hypoventilation (which PaCO2 can distinguish).
- If the A-a gradient is increased, then the cause is either V/Q mismatch, diffusion problems, or shunt (which administration of FiO2 can help distinguish, as FiO2 will not correct shunts).
One of the key caveats in diagnosing ARDS is that their respiratory failure has to not be explainable by _______________.
CHF
Review the management of ARDS.
- Treat the underlying cause (e.g., pneumonia)
- Use minimal tidal volume ventilation to prevent ventilator-associated injury
- Use PEEP to open atelectatic alveoli
- Titrate FiO2 to maintain PaO2 above 55 mm Hg
- Wean from ventilation as tolerated
Pulmonary hypertension is defined as ______________.
pulmonary pressure greater than 25 mm Hg
There are five causes of pulmonary hypertension: ________________.
- Chronic lung disease leading to vasoconstriction
- Thromboembolic disease
- Left-sided heart failure leading to pulmonary congestion
- Pulmonary arterial hypertension (which I think is idiopathic)
The best predictor of successful extubation is _____________.
a frequency / tidal volume ratio less than 105
Review the diagnosis of pulmonary hypertension.
- History: SOB, lethargy, syncope, symptoms of right-sided HF (edema, abdominal distention)
- PE: loud split S2, JVD
- Workup: CXR shows increased pulmonary vasculature; ECG shows RV hypertrophy; right-heart catheterization shows PHTN
List Virchow’s triad and some common examples of each.
- Venous stasis: CHF, immobility, obesity
- Endothelial injury: trauma, surgery, catheterization
- Hypercoagulability: cigarettes, OCPs, pregnancy, coagulopathy, malignancy, burns
Describe the workup of PE.
- History: SOB, pleuritic chest pain, Virchow’s risk factors
- Labs: D-dimer
- Imaging: CT angiogram, V/Q scan
- ECG: S1Q3T3
Why does the S1Q3T3 ECG finding present in PE?
Right heart strain
Review the treatment of PEs.
- Acute: heparin
- Chronic: warfarin (INR 2-3)
For PE that causes acute right-heart failure (with hypotension), give tPA.
___________ lung cancer is neuroendocrine in origin.
Small cell lung
Review the characteristics that make a pulmonary nodule low risk.
- Age of person younger than 35
- Size of nodule less than 2 cm
- Smooth borders
- No calcification (or calcification that is central and uniform)
- Person not a smoker
Review the lung cancers by prevalence.
1) Metastases
2) Adenocarcinoma
3) Small cell, squamous cell, and large cell
Which lung cancer presents with cavitations?
Squamous cell carcinoma
Gynecomastia can be seen in what lung cancer?
Large cell
Hypertrophic pulmonary osteoarthropathy is a feature of which lung cancer?
Adenocarcinoma
All of the neuromuscular conditions are seen in which kind of lung cancer?
Small cell
Although dermatomyositis can be caused by any lung cancer.
What hematologic abnormalities can be seen in lung cancer?
- Anemia
- Eosinophilia
- Thrombocytosis
- Hypercoagulability
How should you work up suspected pulmonary embolus?
It depends on the initial clinical suspicion:
- High suspicion, given by multiple symptoms and a history suspicious for PE: give heparin immediately and then do a CTA to confirm.
- Low suspicion, given by only one or two symptoms and a history without features of PE: do CTA first.
The triad of Horner syndrome is ________________.
ptosis, miosis, and anhidrosis
How should you work up a pulmonary effusion?
You need to determine if it is a transudate or an exudate. To do this, tap the fluid:
- Transudate: low in protein; caused by CHF, liver disease, or nephrotic syndrome
- Exudate: high in protein; caused by infection, malignancy, pancreatitis, or embolism
The best initial test for diagnosing pleural effusion is ______________.
lateral decubitus x-ray
Go through the mnemonic for the presentation of pneumothorax.
P-THORAX •Pleuritic chest pain •Tracheal deviation (if tension) •Hyperresonance •Onset sudden •Reduced breath sounds •Asymmetric chest wall •X-ray showing absent lung fields
These don’t fit into the mnemonic, but tachypnea and JVD can be present, too.
Review the three types of pneumothorax.
- Spontaneous
- Secondary (to COPD, pneumonia, or iatrogenic factors)
- Tension (traumatic)
Tension pneumothoraces require what treatment?
Immediate needle decompression in the second intercostal space, midclavicular line