A Case of Cerebellar Ataxia Associated with HIV Infection

Abstract

Cerebellar complications of HIV infection primarily manifested in ataxia, usually arise as the result of cerebellar lesions due to opportunistic infections, vasculitis or neoplastic processes. A 28 year old female known to have HIV infection for last four years, presented to our hospital with progressive unsteadiness in walking, slurring of speech and intention tremors for the last two months. There was no family history of similar complaints, and she was on Anti retroviral treatment for last one and a half years. The results of examination were notable for severe dysarthria, slow saccades, a conspicuous dysmetria and dysdiadokokinesia. She had no cognitive, sensory or motor deficits. MRI revealed diffuse cerebellar atrophy. Extensive laboratory work up failed to disclose a cause for subacute ataxia. Isolated cerebellar degeneration in an HIV patient is rare and should prompt a diagnostic work up.

Introduction

Neurocognitive impairment and polyneuropathy are common chronic neurological sequelae of HIV infection. The occurrence of ataxia in HIV-infected individuals is unusual and should prompt diagnostic workup. In the pre–highly active antiretroviral therapy (HAART) era, the most common symptomatic causes of ataxia were opportunistic infections, progressive multifocal leukoencephalopathy, lymphomas, or strokes caused by varicella zoster virus vasculitis. Furthermore, ataxia was observed in the context of HIV dementia complex. ¹ In the post-HAART era, this spectrum has changed considerably. Here, we present a case report and provide a brief discussion on HIV-associated cerebellar ataxia.

Case Report

A 28-year-old lady presented to our hospital with 2 months’ history of progressive unsteadiness while walking, slurring of speech, and tremors in both upper limbs prominent on approaching the target. HIV-1 infection was diagnosed prior to 4 years when she was worked up for chronic diarrhea. She denied any history of alcohol, prolonged drug intake, or family history of similar complaints. She also revealed that her husband, who had died about 8 years ago, was also sero-positive for HIV. Her CD4 count was 392 cells/mm³, and she had been on regular antiretroviral therapy comprising zidovudine (ZDV) 600 mg, lamivudine (3TC) 300 mg, and nevirapne (NVP) 200 mg/day for the last 1½ years. There was no history of fever, visual disturbances, headache, weakness of any limbs, sensory complaints, or cognitive decline. General and systemic examinations were normal. Neurological examination revealed normal cognition except for some minor attention deficits. Marked dysarthria was observed. Her saccades were slow, but the remainder of her cranial nerve examination was normal. No motor weakness was noted, and her sensory examination was normal. Conspicuous dysmetria and dysdiadochokinesia were evident. Rapid alternating movements were slow and poorly performed. The deep tendon reflexes were normal, and plantar response was flexor bilaterally. Her gait was broad based, and she displayed a striking inability to tandem walking. Investigations revealed Hemoglobin of 9.2 gm%, Total leukocyte count of 7500/mm³(Polymorphs 60%, Lymphocytes 35%, Monocytes 3% and Basophils 2%). Liver, renal and lipid profiles were normal. Analysis of cerebrospinal fluid revealed normal sugar, a protein level of 50 mg/dL, and no pleocytosis. Venereal Disease Research Laboratory test was nonreactive, chest skiagram was also normal. No pathological results were obtained on serum electrophoresis, and vitamin E and B12 levels were in the normal range. Magnetic resonance imaging demonstrated diffuse cerebellar atrophy without any white matter changes or abnormal signal intensity (Figures 1 and 2).

Figure 1.

Axial T1-weighted imaging showing cerebellar atrophy.

Figure 2.

Sagittal T2-weighted imaging showing diffuse cerebellar atrophy.

Discussion

HIV is known to affect the nervous system at all levels and stages of the disease. Cerebellar complications of HIV infection, primarily manifested in ataxia, usually arise as a result of cerebellar lesions due to opportunistic infections, vasculitis, or neoplastic processes. Approximately 30% of patients with HIV dementia have an ataxic syndrome at the onset of their illness before cognitive decline begins. Other authors have described isolated progressive cerebellar ataxia that does not evolve into HIV dementia in a small number of patients. ² These patients had a rapid evolution of their ataxia, leading to chair-bound status in less than a year. The diagnosis of pure cerebellar ataxia in an HIV-infected patient in stable remission with sufficient CD4 counts has to prompt a diagnostic workup. Vascular causes and compressive lesions can be readily excluded with imaging techniques. In the setting of sufficient CD4 count, classical opportunistic infections are less likely. Certain retrovirals (eg, raltegravir) and their interactions with other drugs are known to cause ataxia. ³ Finally, even in the absence of a family history, common spinocerebellar ataxias may occur in HIV-positive patients. The exact pathogenesis of ataxia in this patient was not clear. It could have been primary cerebellar degeneration caused by HIV or the other viruses detected (Epstein-Barr virus, John Cunningham virus) or autoimmune mechanisms caused by these viruses. However, HIV infection should be considered as an etiology in clinical setting of subacute ataxia, particularly in a young or immunocompromised patient.