Differential Diagnosis for Chronic Cough and Difficulty Breathing
Single Most Likely Diagnosis
- Restrictive Lung Disease: The patient's lung function tests show a normal FEV1/FVC ratio (91%), which suggests that there is no significant airway obstruction. The FEV1 and FVC are both reduced, but the ratio is normal, indicating a restrictive pattern. The RV (residual volume) is also within normal limits, which further supports a restrictive pattern.
Other Likely Diagnoses
- Asthma: Although the FEV1/FVC ratio is normal, asthma can present with a normal ratio if the patient is not having an acute exacerbation. The chronic cough and difficulty breathing could be symptoms of asthma.
- Chronic Bronchitis (non-smoker): Although the patient has no history of smoking, chronic bronchitis can occur in non-smokers, especially if they have been exposed to other irritants.
Do Not Miss Diagnoses
- Interstitial Lung Disease (ILD): ILD can present with a restrictive pattern on lung function tests and can be deadly if missed. It is essential to consider ILD, especially if the patient has a history of exposure to certain substances or has systemic symptoms.
- Lymphangitic Carcinomatosis: This is a rare but deadly condition that can cause respiratory symptoms and a restrictive pattern on lung function tests.
Rare Diagnoses
- Neuromuscular Disease: Certain neuromuscular diseases, such as muscular dystrophy, can cause respiratory symptoms and a restrictive pattern on lung function tests.
- Sarcoidosis: Sarcoidosis is a rare disease that can cause respiratory symptoms and a restrictive pattern on lung function tests.
- Eosinophilic Pneumonia: This is a rare condition that can cause respiratory symptoms and a restrictive pattern on lung function tests.