Week 2 Flashcards
Would you expect the following values to be increased, normal, or decreased in a patient presenting with interstitial lung disease?
Residual volume, FEV1, FEV1/FVC, DLCO
The characteristic pulmonary function abnormality in ILD is a restrictive defect (although some cases of hypersensitivity pneumonitis and sarcoidosis can have a mixed defect) with concomitant decrease in diffusing capacity. So: RV decreases, FEV1 decreases, FEV1/FVC is normal or increased (FVC decreases with FEV1), and DLCO decreases.
A patient with a cough, fever, and fatigue gets a chest X ray. You notice that the left heart border is obscured in the radiograph. What, do you suspect, is wrong with the patient? Be specific!
Pneumonia in the lingula (mass also possible – but much less likely with clinical suspicion for pneumonia). This radiologic finding is called the “silhouette sign” – where two structures that have a similar density will obscure the borders of each structure. Here, the consolidation abuts the left heart border, which indicates a density in the lingula (right atrium borders the right middle lobe, basilar lower lobes touch the diaphragm)
A young woman presents with exertional dyspnea and signs/sx of right heart failure. You are concerned for pulmonary hypertension. How do you confirm this diagnosis? Why might serologies (antibodies) also be ordered in the workup?
The diagnosis of pulmonary hypertension requires a right heart catheterization in which the mPAP is > 25 mmHg. Serologic testing for connective tissue disease (e.g. lupus, systemic sclerosis, mixed CT disease) and HIV are recommended at time of dx to screen for conditions associated with the development of group 1 PH
An infant born earlier in the day is examined further due to excessive drooling and choking when attempting to feed. What is the most likely anatomic basis for this presentation?
Tracheoesophageal fistula – most commonly esophageal atresia with distal tracheoesophageal fistula. Other anatomic variants can lead to the same presentation, but they converge on failure of the esophagus to pass into the stomach. Radiology and failure to pass a tube from mouth to stomach confirm the diagnosis and are an indication for surgical repair.
What does the term “obstructive” in obstructive lung disease really mean, i.e. which part of the respiratory cycle is obstructed? What spirometry measurement most directly assesses this obstruction to flow?
Obstruction to expiratory flow. On the other hand, restrictive lung disease can be through of as “restricting” inspiration, a difficulty to expand and fill the lungs fully. The “obstruction” in obstructive lung disease is assessed by the FEV1/FVC ratio. In obstructive lung disease, FVC is more or less normal, but the amount of air that can be expired in one second is lower.
You have a patient with chronic and worsening restrictive lung disease and are concerned that they may have an idiopathic interstitial pneumonia. What other causes of DPLD/ILD must you rule out, and how can you rule out these disorders?
DPLD can be considered idiopathic only if known triggers are ruled out, i.e. connective tissue disease (history and serology), exposure to certain drugs (history and pneumotox.com) or common environmental triggers (history). Sarcoidosis also must be ruled out with a history (other organ involvement), exam (lymphadenopathy), and biopsy if questionable. Finally, other factors such as eosinophilia on the CBC could point toward diseases such as lymphangioleiomyomatosis, which can be investigated further with BAL.
Risk factors for venous thromboembolism can be thought of in the three pathways of Virchow’s triad. What are these pathways, and what are two examples of conditions/states which alter each of them?
Venous stasis (immobility, casting, CHF, afib). Alterations in coagulation (hereditary thrombophilia, antiphospholipid syndrome, nephrotic syndrome, estrogen therapy, malignancy). Vascular injury (surgery, trauma, post-partum, indwelling vascular access)
What is the function of the CFTR gene? How do mutations in this gene cause airway disease in CF?
Anion channel (chloride and bicarbonate). By not being able to secrete chloride and bicarbonate, the pH and osmolarity of the secretions is altered (reducing the amount of water which follows solute), in turn causing abnormal and viscous secretions which impair clearance and may facilitate chronic infection. This causes a chronic cycle of infection, tissue damage, inflammation, and altered secretions which persist and worsen over the lifetime.
What do you need in order to make the diagnosis of occupational lung disease?
Medical and occupational history PLUS an abnormality detected in chest imaging, lung function testing, laboratory testing, or lung pathology. Note that chest imaging, laboratory testing, and lung function testing are standard in the work up and lung pathology is often not required if an abnormality is detected elsewhere.
