[Clinical, electrophysiological, and sural nerve pathological features of patients developing peripheral neuropathy during tuberculosis treatment].

Objective: To summarize the clinical, electrophysiological, and sural nerve pathological features of patients who developed peripheral neuropathy during tuberculosis treatment, and to explore the pathological patterns of nerve injury and their value in differential diagnosis. Methods: The clinical data, neuroelectrophysiological findings, sural nerve pathological features, and follow-up outcomes of 10 patients who developed peripheral neuropathy during tuberculosis treatment and underwent sural nerve biopsy at the Eighth Medical Center of Chinese PLA General Hospital between February 2022 and May 2024 were retrospectively analyzed. Results: Among the 10 patients, 4 were male and 6 were female, with an age at onset ranging from 23 to 69 years. Peripheral neuropathy usually developed several weeks to several months after the initiation of anti-tuberculosis treatment. The main clinical manifestations were distal numbness, pain, and weakness of the limbs, and 7 patients had grade 3-4 peripheral neuropathy according to the National Cancer Institute Common Terminology Criteria for Adverse Events. Neuroelectrophysiological studies showed sensorimotor mixed peripheral nerve involvement in all patients, predominantly characterized by axonal injury, with conduction slowing and late-response abnormalities in some cases. Sural nerve biopsy revealed varying degrees of myelinated fiber loss and axonal degeneration in all cases, with regeneration, myelin abnormalities, microvascular changes, or mild inflammatory cell infiltration in some cases. No typical tuberculous granuloma, caseous necrosis, or positive acid-fast staining was observed. Mycobacterium tuberculosis nucleic acid testing was positive in 1 case. Most patients showed limited neurological recovery during follow-up. Conclusions: Peripheral neuropathy occurring during tuberculosis treatment is pathologically characterized predominantly by axonal injury, with variable myelin changes, microvascular abnormalities, and mild inflammatory cell infiltration. Most cases showed no pathological evidence of typical direct tuberculous invasion of the peripheral nerve, suggesting that this condition may represent a heterogeneous injury process involving multiple factors in the context of tuberculosis infection. Sural nerve biopsy is useful for identifying pathological injury patterns and provides evidence for differential diagnosis in complex etiological settings.