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Empyema Biochemistry Recognition — SCE Palliative Medicine MCQ

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ModerateRespiratory SymptomsEmpyema Biochemistry RecognitionSCE Palliative Medicine

A 65‑year‑old woman with advanced ovarian cancer has a malignant pleural effusion. A diagnostic tap reveals a pH of 6.8, glucose <1.5 mmol/L and LDH >1000 IU/L. She has fever and chest wall tenderness. What does this biochemistry suggest?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Complicated parapneumonic effusion or empyema; low pH, very low glucose, and very high LDH indicate infected/inflammatory fluid requiring drainage and antibiotics

Explanation lettering: B = shown as A · D = shown as B · A = shown as D

The pH of 6.8 (well below the BTS guideline threshold of ≤7.2), very low glucose, and high LDH are classic markers of a complicated parapneumonic effusion or empyema in adults. In the context of fever and chest wall tenderness, this confirms an infected pleural collection. BTS guidelines recommend chest drainage and antibiotics in such cases. Other options are excluded: transudates (A) don’t have these biochemistry changes; chylothorax (C) presents with high triglycerides and milky fluid; simple or malignant effusions (D and E) do not show such severe acidotic, low‑glucose profile.

Reference: British Thoracic Society Guideline for pleural disease, Thorax 2023 and Whittington NHS Initial Management guideline, 2013