A 43-year-old non-smoking male presented to the Chest Clinic with chief complaints of cough and breathlessness on exertion for 2 weeks. There was no history of sore throat, fever, weight loss, or loss of appetite. He reported that he had been on anti-epileptics for focal seizures with secondary generalization since the age of 12. He was initially treated with carbamazepine and was shifted to VA (500 mg twice daily) 2 years back. He was not on any other medications. He was not a diabetic or hypertensive and had no past history of pulmonary tuberculosis. There was no history of joint pains, difficulty in swallowing, dry eyes, or skin changes. His bowel and bladder habits were normal. There was no history of trauma, surgical intervention, prolonged immobilization, or occupational exposure to asbestos or other toxic substances.
Clinical examination revealed that he was afebrile with normal vitals. Baseline blood investigations were unremarkable with a normal total leucocyte count (7,000/muL; eosinophils 2%). A chest radiograph showed right-sided moderate pleural effusion without parenchymal infiltrates [Figure 1a]. A diagnostic thoracentesis was carried out revealing a pale, exudative (protein: 5 g/dL) effusion with eosinophilia (42%), and low adenosine deaminase (18 U/L). Other pleural fluid findings are depicted in Table 1. The ultrasound abdomen was unremarkable. His real-time polymerase chain reaction test of nasopharyngeal swab for SARS-CoV-2 was negative. Sputum for gram stain, acid fast bacilli, and cartridge-based nucleic acid amplification test (CBNAAT) for mycobacteria were also negative. The tuberculin skin test was negative. Further laboratory tests, including thyroid hormones, Rheumatoid factor (RA), and Antinuclear antibodies (ANA) were negative. Blood absolute eosinophil count in blood was 140 cells/muL. The echinococcus IgG antibodies were undetectable. There was no evidence of parasites or parasite eggs in stool or pleural fluid. Based on the above findings, a diagnosis of VA-induced pleural effusion was made. On application of Naranjo criteria, the probable cause of pleural effusion with a score of 7 was drug induced.
The drug (VA) was discontinued, and the patient was shifted to alternative anti-epileptic (levetiracetam 500 mg once daily). On follow-up at 3 weeks, his symptoms had improved and pleural effusion had resolved [Figures 1a and b]. The patient remained asymptomatic with no evidence of refilling on either side at repeat follow-up after 1 month.