WHEN THE DIAGNOSIS AND THE DRUG CHART DISAGREE: AN ADENOSINE DEAMINASE-RICH PLEURAL EFFUSION LABELLED AS PULMONARY EMBOLISM IN AN ELDERLY DIABETIC SMOKER – A CLINICAL PHARMACIST-LED CASE ANALYSIS

A pleural effusion in a comorbid patient attracts a diagnostic label early, and once written that label can survive unchallenged even when the fluid, the imaging and the prescription point elsewhere. We describe a 70-year-old man, a thirty-year bidi smoker with type 2 diabetes, hypertension and a myocardial infarction eighteen years earlier, admitted with eight days of breathlessness and productive cough. Computed tomography showed a gross left pleural effusion with collapse of the underlying lung and mediastinal shift to the right. The pleural fluid was an exudate with a protein of 5.2 g/dL, a glucose of 26.4 mg/dL and an adenosine deaminase of 53 IU/L; the erythrocyte sedimentation rate was 90 mm/hour and glycated haemoglobin 10.2%. The recorded provisional and final diagnosis was left-sided pulmonary embolism. No anticoagulant was prescribed at any point, no confirmatory imaging was documented, and no antitubercular therapy or microbiology followed the adenosine deaminase result. A structured medication review using the Pharmaceutical Care Network Europe classification identified eleven drug-related problems, among them metformin delivered twice through two fixed-dose combinations, a sodium-glucose co-transporter-2 inhibitor and a sulfonylurea continued through acute infection, metronidazole added to piperacillin-tazobactam, and withdrawal of statin and antiplatelet therapy at discharge in a man with established ischaemic heart disease. The patient improved symptomatically and went home on three medicines. The case shows how a diagnostic label that never reaches the prescription can coexist with a pleural fluid result that never reaches a diagnosis, and what a pharmacist reading the whole chart can recover.