Clinical scenario: low grade fever with breathlessness | pleural effusion
A 13-year-old boy presents with a 4-week history of low-grade fever, fatigue, reduced appetite, and progressive breathlessness. He has lost 4 kg of weight during this period. There is no history of acute onset cough or aspiration. Examination reveals reduced air entry and stony dullness over the right lower chest.
Chest X-ray shows a moderate right-sided pleural effusion. Diagnostic thoracentesis reveals straw-coloured pleural fluid with:
- Exudative characteristics
- Lymphocyte predominance
- Raised ESR (85 mm/hour)
- Negative bacterial culture
What is the most likely diagnosis?
A. Parapneumonic effusion
B. Tuberculous pleural effusion
C. Chylothorax
D. Empyema thoracis
E. Congestive heart failure-related effusion
Correct answer & Explanation:
Correct answer: B. Tuberculous pleural effusion
Explanation:
The combination of:
- Subacute illness
- Constitutional symptoms (fever, weight loss, fatigue)
- Lymphocyte-predominant exudative effusion
- Straw-coloured pleural fluid
- Raised ESR
is highly suggestive of tuberculous pleural effusion.
Tuberculous pleural effusion occurs due to a delayed hypersensitivity reaction to Mycobacterium tuberculosis antigens in the pleural space. The pleural fluid usually contains predominantly lymphocytes and has high protein content.
Why other options are incorrect:
- A. Parapneumonic effusion: Usually associated with acute bacterial pneumonia, neutrophil predominance, and higher inflammatory markers.
- C. Chylothorax: Produces milky pleural fluid with high triglycerides.
- D. Empyema thoracis: Usually purulent fluid with neutrophil predominance.
- E. Heart failure effusion: Usually bilateral, transudative, and associated with cardiac signs.
