Differential Diagnosis for Chronic Cough with Clear Phlegm and Acute Fever
Single Most Likely Diagnosis
- Chronic Bronchitis: This condition is characterized by a persistent cough with clear phlegm, often associated with chronic sinus congestion. The elevated CRP suggests an inflammatory component, which is consistent with chronic bronchitis. The recent fever could be a superimposed infection.
Other Likely Diagnoses
- Pneumonia: Although the patient is currently afebrile, the recent fever and elevated CRP could indicate a recent pneumonia that has partially resolved. The chronic cough and clear phlegm could be residual symptoms.
- Asthma: Asthma can cause a chronic cough with clear phlegm, and the presence of chronic sinus congestion suggests allergic rhinitis, which often co-exists with asthma.
- Chronic Sinusitis: This condition can cause chronic cough due to postnasal drip, and the elevated CRP could indicate an inflammatory component.
Do Not Miss Diagnoses
- Lung Cancer: Although less likely, lung cancer can cause a chronic cough and should be considered, especially if the patient has a history of smoking or other risk factors.
- Tuberculosis (TB): TB can cause a chronic cough with clear phlegm, and the recent fever could be a symptom of active disease. The elevated CRP is also consistent with TB.
- Pulmonary Embolism: Although the patient is afebrile, a pulmonary embolism can cause a chronic cough and should be considered, especially if there are other risk factors such as recent travel or immobility.
Rare Diagnoses
- Sarcoidosis: This condition can cause a chronic cough with clear phlegm, and the elevated CRP could indicate an inflammatory component. However, it is a less common condition and would require further testing to diagnose.
- Cystic Fibrosis: Although typically diagnosed in childhood, cystic fibrosis can cause a chronic cough with clear phlegm and should be considered in patients with recurrent respiratory infections.
- Bronchiectasis: This condition can cause a chronic cough with clear phlegm, and the elevated CRP could indicate an inflammatory component. However, it is a less common condition and would require further testing to diagnose.