Images in Neurology: Cortical Encephalitis in CNS Tuberculosis

A 53-year-old man who had defaulted on treatment for clinically diagnosed leprosy presented with four-month history of low-grade fever and progressive cognitive impairment. He started having left focal motor seizures with progressive left hemiparesis, followed by right focal seizures and right hemiparesis prior to hospital admission. Examination revealed axillary lymphadenopathy along with asymmetric (Left > Right) quadriparesis. Cerebrospinal fluid (CSF) evaluation did not reveal pleocytosis or hypoglycorrhachia with negative infective and inflammatory workup. Magnetic Resonance Imaging (MRI) was suggestive of abnormal signals in the cerebral cortices with swelling and a paraspinal abscess (Figure). Paraspinal tap was Culture negative with Cartridge based nucleic Acid Amplification test (CBNAAT) Positive for Mycobacterium Tuberculosis. Axillary lymph node biopsy was suggestive of caseous necrosis. He was started on Anti-Tubercular Therapy (ATT) with Multi Drug Therapy (MDT) for Leprosy and steroids along with anti-seizure medications (ASM) with significant clinical and radiological improvement in follow up. During his follow up he was ambulatory and independent in the intermediate term. Unfortunately, he contracted pneumonia in follow up and succumbed to sepsis related complications. Parenchymal involvement in the form of cortical encephalitis/cerebritis is an extremely rare presentation of CNS tuberculosis, characterised by T2/FLAIR hyperintense lesions with patchy or gyriform enhancement.