1000 Section - Isoniazid-induced peripheral neuropathy in the treatment and prophylaxis of tuberculosis: a scoping review of incidence, risk factors, diagnostics, and outcomes

Objectives : Peripheral neuropathy is a well-recognized adverse effect of isoniazid (INH), a key agent in tuberculosis (TB) treatment and prevention. However, the extent, variability, and clinical implications of INH-induced peripheral neuropathy (INH-PN) remain poorly characterized across different populations. This scoping review aimed to synthesize existing literature on INH-PN to describe its incidence, risk factors, diagnostic approaches, clinical presentation, and outcomes, and to identify knowledge gaps that can inform future clinical practice and research priorities.

Design: A scoping review was conducted using the PRISMA-ScR framework. A comprehensive search of four electronic databases was performed to identify original studies involving individuals receiving INH for TB treatment or prophylaxis. Eligible studies included case reports, observational studies, and clinical trials that described the incidence, risk factors, diagnosis, prevention, or outcomes of INH-PN. Studies were excluded if they were non-English, non-retrievable, review articles, animal studies, grey literature, or if INH could not be clearly implicated in neuropathy. Two reviewers independently charted data and synthesized findings thematically across five domains.

Results: A total of 797 records were identified through the database search. After removing duplicates and applying eligibility criteria, 18 studies were included in the final review. Reported prevalence and incidence of INH-PN ranged from 0.21% to 56%, influenced by patient population, dosage, and comorbidities. High-risk groups included those with HIV co-infection, diabetes, malnutrition, and slow acetylator genotypes. Presentations ranged from mild distal paresthesias to disabling motor deficits. Diagnosis was primarily clinical, with variable use of nerve conduction studies. Preventive pyridoxine supplementation practices differed widely. Management included drug modification, vitamin therapy, and rehabilitation, with outcomes dependent on early recognition and intervention.

Conclusion: INH-PN presents a heterogeneous burden with gaps in diagnosis, prevention, and outcome assessment. Improved risk stratification, standardization of diagnostic criteria, and context-specific preventive strategies are essential to mitigate its impact, particularly in high-risk and underserved populations.