A 40 years old man presents with a recurrent hemoptysis and purulent cough. X-ray was found to be normal. The next investigation done to aid in diagnosis is –
**Core Concept**
The patient's presentation of recurrent hemoptysis and purulent cough suggests a possible pulmonary infection or inflammatory condition. The normal X-ray result indicates that the condition may not be easily visible on imaging, necessitating further diagnostic testing.
**Why the Correct Answer is Right**
Given the clinical presentation, the most likely diagnosis is a pulmonary infection, such as bronchiectasis or bronchitis. The correct investigation to aid in diagnosis is a **High-Resolution Computed Tomography (HRCT) scan of the chest**, which can provide detailed images of the lung parenchyma and help identify any abnormalities that may not be visible on a standard X-ray. HRCT can also help identify bronchiectasis, which is a condition characterized by irreversible dilatation of bronchi and is a common cause of recurrent hemoptysis and purulent cough.
**Why Each Wrong Option is Incorrect**
* **Option A:** Sputum culture would be useful in identifying the causative organism of the infection, but it would not provide information about the underlying anatomy or pathology of the lung.
* **Option B:** Pulmonary function tests (PFTs) would be useful in assessing the lung function, but they would not provide information about the specific pathology or anatomy of the lung.
* **Option C:** Bronchoscopy would be useful in visualizing the airways and obtaining samples for culture, but it would not provide information about the lung parenchyma or the underlying anatomy.
**Clinical Pearl / High-Yield Fact**
HRCT of the chest is essential in diagnosing conditions such as bronchiectasis, which can be a cause of recurrent hemoptysis and purulent cough.
**Correct Answer:** C. HRCT scan of the chest.