ISONIAZID-INDUCED CEREBELLITIS: A CASE REPORT

Introduction: Tuberculosis is a curable disease with low morbidity potential when treatment is appropriately conducted. Most patients’ complete treatment without significant adverse reactions. However, neurological alterations may be associated with the main drugs, except pyrazinamide. This study reports a case of acute cerebellitis following initiation of antituberculosis drugs. Case Report: A 48-year-old female patient with insulin-dependent type 2 diabetes mellitus, originally from Northeastern Brazil, diagnosed with pulmonary tuberculosis and receiving RHZE therapy (rifampicin, isoniazid, pyrazinamide, and ethambutol). Five days after starting treatment, she developed paresthesia and involuntary movements in the left upper limb, as well as vertigo, diplopia, and headache. Physical examination revealed multidirectional rotary nystagmus, mild left appendicular dysmetria, and a wide-based gait, without other neurological abnormalities. Cerebrospinal fluid analysis showed only hyperproteinorrachia, and brain MRI revealed asymmetric T1 hyperintensity in the cerebellar tonsils with mild paramagnetic contrast enhancement. Vascular, autoimmune, and infectious causes were excluded, attributing the clinical picture to a possible adverse effect of isoniazid. Anticonvulsant therapy and pyridoxine were initiated, and isoniazid was maintained, considering the benefit greater than the severity of neurological symptoms. Comments: Acute cerebellitis is a rare entity in adults, with multiple etiologies; among antituberculosis drugs, only isoniazid is described in the literature as associated, with mechanisms yet to be clarified. Despite the rarity of these findings, Brazil is an endemic region where a large number of individuals undergo prolonged RHZE treatment. Therefore, attention must be paid to the differential diagnosis of this neurological manifestation to ensure appropriate management.