My worst nightmare: A case of granulomatous encephalitis

Inspired by past case presentations? Now it’s your turn to take the stage! The upcoming Young Talents in Internal Medicine World Contest 2025 invites young health professionals to showcase their diagnostic skills and discuss compelling reports from their own practice. Read more at youngtalents.one and submit by February 20, 2025.

Case description

A 74-year-old Caucasian woman from Canada was admitted due to a 2-week history of a rapidly evolving cerebellar syndrome. She had no history of immunosuppression and no prior exposure to significant infections. The physical examination showed bilateral horizontal nystagmus and slight right upper limb dysmetria, and was otherwise unremarkable. Routine bloodwork was normal except for slightly elevated C-reactive protein levels (15.4 mg/L). Initial cerebral computed tomography scan and magnetic resonance imaging (MRI) showed nonspecific cystic lesions in the right cerebellar hemisphere and vermis with surrounding edema and leptomeningeal involvement. Primary extracerebral neoplasia workup was negative. Control MRI conducted 5 days later showed progression of the lesions into the left cerebellum.

Lumbar puncture was performed and was not contributory. Brain biopsy was performed 3 weeks after the onset of initial symptoms and histopathology showed numerous granulomatous inflammatory infiltrates and foci of acute inflammation with focal necrosis. No microorganisms were initially identified with immunohistochemistry. Extensive serological and cerebrospinal fluid (CSF) workups for infectious (eg, Mycobacterium tuberculosis, Toxoplasma gondii), inflammatory, and IgG4 diseases were all negative.

In addition to dexamethasone, the patient was empirically started on rifampin, isoniazid, pyrazinamide, and ethambutol for presumed central nervous system tuberculosis. The treatment was complicated by drug-induced hepatitis. Since all final tests for M tuberculosis were negative, all drugs were discontinued after 10 weeks. Three months after initial presentation, the patient was asymptomatic and MRI showed marked regression of cerebral lesions.

The patient was readmitted 4 months after initial presentation for acute onset aphasia, dysarthria, ataxia, and right hemiparesis. Cerebral MRI demonstrated multiple new cerebral and brainstem masses associated with surrounding vasogenic edema. Second brain biopsy was performed, following a rapid deterioration of the patient’s state of consciousness. This time amoebic trophozoites were identified. With the help of the Centers for Disease Control and Prevention, a diagnosis of granulomatous amoebic encephalitis (GAE) caused by Acanthamoeba spp was confirmed. The patient was started on combination therapy of IV pentamidine, trimethoprimsulfamethoxazole, flucytosine, fluconazole, miltefosine, and azithromycin. Unfortunately, the patient’s clinical status deteriorated 4 days after starting therapy. Considering the poor prognosis, palliative care was initiated and the patient died shortly thereafter.

About Best Case Report Contest 2024

Young Talents in Internal Medicine World Contest—previously Best Case Report Contest—is a contest for internal medicine specialists or trainees in internal medicine up to 35 years of age. Every year the most engaging submissions from around the world are presented by authors during a special session at the McMaster International Review Conference of Internal Medicine (MIRCIM). Visit youngtalents.one to learn more.

To browse all abstracts from Best Case Report Contest 2024, visit Polish Archives of Internal Medicine.