Isoniazid-Induced Psychosis & Peripheral Neuropathy in a Middle-Aged Male with Pulmonary Tuberculosis: A Rare Case Report

Abstract

Introduction: Isoniazid (INH) is a first-line antitubercular drug widely used in the treatment of tuberculosis. Although generally safe and effective, it may rarely cause neuropsychiatric adverse effects, including psychosis and peripheral neuropathy. The concurrent occurrence of both complications in a single patient is uncommon and may result in substantial psychological distress and functional impairment if not identified promptly.

Aim & Objective: To highlight the rare occurrence of isoniazid-induced psychosis and peripheral neuropathy in the same patient and emphasize the importance of early recognition and multidisciplinary management of these adverse drug reactions.

Case Presentation: A 53-year-old male receiving antitubercular therapy for pulmonary tuberculosis developed paranoid delusions, auditory hallucinations, agitation, and somatic preoccupation within two months of treatment initiation. Following completion of therapy, psychotic symptoms resolved spontaneously. Subsequently, he experienced persistent tingling, numbness, burning sensations in the limbs, sleep disturbances, and marked impairment in daily functioning. Due to severe psychological distress and persistent neuropathic symptoms, he attempted suicide on three occasions. Neurological examination revealed sensory deficits involving fine touch sensation. Routine laboratory investigations were largely normal except for vitamin D insufficiency, while MRI brain showed insignificant chronic small-vessel ischemic changes.

Result: Based on the temporal association with antitubercular therapy, a diagnosis of isoniazid-induced psychosis (in remission) with peripheral neuropathy was made. Treatment with pyridoxine, vitamin B12, GABAergic agents, selective serotonin reuptake inhibitors, benzodiazepines, vitamin D supplementation, and transcutaneous electrical nerve stimulation (TENS) resulted in significant clinical improvement within one month.

Conclusion: Early recognition and comprehensive management of isoniazid-related neuropsychiatric complications are essential to reduce morbidity, improve quality of life, and optimize treatment outcomes in patients receiving antitubercular therapy.