West Nile virus infection presenting as cerebellar ataxia and fever: case report. (Case Report).

Abstract

Evidence of West Nile encephalitis virus infection has been documented in most states of the continental United States within a short period of its first introduction in 1999. Health care providers are mostly aware of the usual presentations of this disease, eg, aseptic meningitis, encephalitis and Guillain-Barre syndrome. We present a patient whose only manifestations were cerebellar ataxia and fever.

Key Words: cerebellar ataxia, West Nile virus infection

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West Nile encephalitis virus (WNV) has spread rapidly to most of the states in the United States. The typical features of WNV infection include fever, headache, neck stiffness, vomiting, confusion, disorientation, and generalized muscle weakness. (1-3) Health care authorities are continuously reminding physicians to report any suspected case of WNV encephalitis, aseptic meningitis, and acute Guillain-Barre syndrome (New York City Department of Health: 2002 Alert, July 1, 2002).. However, not all cases present with the above manifestations. Here we report a patient with WNV infection who presented with cerebellar ataxia and fever.

Discussion

Clinical features of the WNV infection can be variable, ranging from asymptomatic infection to severe central nervous system disease. (2) Of the first eight symptomatic patients diagnosed in New York in 1999, six presented with encephalitis and the other two presented with meningitis. (1) Features of encephalitis in these patients were fever, general muscle weakness, and confusion. Those with meningitis presented with high fever, nausea, vomiting, headache, weakness, and skin rash. Involvement of the cerebellum is less frequent in the U.S. epidemic of WNV infection? The autopsy findings of the first four fatal cases in New York City documented that the thalamus, cerebellum, and cortex were not frequently or intensely involved. (4) However, the involvement of the cerebellum has been reported in other parts of the world. (2,5) In the Romanian outbreak, ataxia and extrapyramidal signs were recorded in 17% of patients. (2) There is a case report from Israel in which a 55-year-old woman presented with meningoence phalitis, optic neuritis, vertigo, and cerebellar ataxia along with wide base gait. (5) Without a strong index of suspicion the presence of only ataxia in our patient would have led to an alternative diagnosis. There are few case reports of other unusual presentations of WNV infection, such as meningoencephalitis complicated by motor aphasia, (6) myelitis, (7) and Guillain-Barre syndrome. (8) Involvement of the skin is less common in WNV infection. In one case of WNY meningitis, skin rash is described as macular. However, rash can be roseola-like or maculopapular and nonpruritic. Other extraneurologic infections include myocarditis, pancreatitis, and hepatitis. (1)

WNV infection carries a high rate of morbidity and mortality; 14% mortality occurred in the 2001 outbreak in the United States. (9) Identification of new patients is essential in the control and prevention of this potentially fatal disease. Our patient and the other cases in the literature suggest that the presentation of this disease can be quiet variable. Knowledge of these atypical presentations will assist physicians in increasing their index of suspicion for WNV infection. Current guidelines to test and report WNV infection do not include these atypical features. We suggest that the association of cerebellar ataxia, fever, and a history of mosquito bite should prompt the physician to consider WNV infection.

Accepted September 19,2002.

References

(1.) Asnis DS, Conctia R, Teixeira AA, Waidman G, Sampson BA. The West Nile virus outbreak of 1999 in New York: The Flushing Hospital experience. Clin Infect Dis 2000;30:413-4l8.

(2.) Tsai TF, Popovici F, Cernescu C, Campbell GL, Nedelcu NI. West Nile encephalitis epidemic in southeastern Romania. Lancet 1998;352:767-771.

(3.) Weiss D, Gaff D, Kellachan J, Tan C, Phillips M, Bresnitz E,. et al. Clinical findings of West Nile virus infection in hospitalized patients, New York and New Jersey, 2000. Emerg Infect Dis 2001;7:654-658.

(4.) Sampson BA, Ambrosi C, Charlot A, Reiber K, Veress IF, Armbrustmacher V. The pathology of human West Nile virus infection. Hum Pathol 2000;31:527-531.

(5.) Vaispapir V, Blum A, Soboh S, Ashkenazi H. West Nile virus meningoencephalitis with optic neuritis. Arch Intern Med 2002;162:606-607.

(6.) Spiegel R, Miron D, Gavriel H, Horovitz Y. West Nile virus meningoencephalitis complicated by motor aphasia in Hodgkin's lymphoma. Arch Dis Chid 2002;86:441-442.

(7.) Ohry A, Karpin H, Yoeli D, Lazari A, Lerman Y. West Nile virus myelitis. Spinal Cord 2001;39:662-663.

(8.) Ahmed S, Libman R, Wesson K, Ahmed F, Einberg K. Guillain-Barre syndrome: An unusual presentation of West Nile virus infection. Neuralogy 2000;55:144-146.

(9.) Centers for Disease Control and Prevention. West Nile virus activity: United States, 2001. MMWR Marl, Mortal Wkly Rep 2002;51:497-501.

RELATED ARTICLE: Key Points

* West Nile virus infection usually presents with meningitis, meningoencephalitis, and Guillain-Barre syndrome. Involvement of cerebellum has been rarely reported.

* Presentation of our patient with only ataxia is unusual.

Case Report

The patient was a 69-year-old Russian woman with a past medical history of hypertension who was hospitalized in autumn 2001. She came with a 5-day history of occipital headache, mild vertigo, and tendency to fall when walking. Ten days before admission she had a low-grade fever and a pink rash over her upper body. The rash improved in a few days, but the headache and tendency to fall persisted. She had nausea but denied any vomiting as well as weakness in any of her extremities. The patient denied any recent travel outside Brooklyn. In the month before her admission, the patient played with her grandchildren in the courtyard of her Brooklyn apartment building, and she remembered a few mosquito bites. Her only home medication was fosinopril, and she denied any recent antibiotic usage.

On physical examination her vital signs were stable except for a temperature of 101 [degrees]F (38.3 [degrees]C). Skin showed a few pink macular lesions over her left thigh. Her neck was supple, and her chest was clear. Cardiovascular and abdominal examinations were essentially normal. Neurologic examination showed an alert, awake, and a fully oriented woman with normal cognitive ability and speech. She had severe truncal and gait ataxia, and she had mild intention tremors in both upper limbs. Her muscle power was 5/5 in all four limbs, and sensory examination was normal. Laboratory studies showed white blood cell count of 14,000/ul with 78% neutrophils and 15% lymphocytes. Her blood chemistry profile and liver function tests were normal. Her chest x-ray, computed tomographic scan, and electrocardiogram were normal. Lumbar puncture revealed clear cerebrospinal fluid (CSF) with white blood cell of 204/ul (90% lymphocyte), protein 58 mg/dl, and glucose of 49 mg/dl. CSF was negative for herpes simplex virus by polymerase chain reaction. In view of her history of mosquito bite and CSF picture consistent with aseptic meningitis, a diagnosis of WNV infection was considered.

Enough CSF was not available to test for WNV antibody. Hence, serum was sent for WNV antibody. The test revealed presence of immunoglobulin M in serum by antibody-capture enzyme-linked immunosorbent assay and was confirmed by a positive plaque reduction and neutralization test for WNV and a negative plaque reduction and neutralization test for other flaviviruses. Magnetic resonance imaging of the brain was done and reported to be normal. Her symptom of ataxia resolved within a week, and she was discharged home in good health. On a 2-month follow-up visit, she was completely asymptomatic.

From the Department of Medicine and the Division of Infectious Diseases, Coney Island Hospital and State University of New York Health Science Center at Brooklyn, Brooklyn, NY.

Reprint requests to Muhammad M. Zaman, MD, Department of Medicine, Coney Island Hospital, 2601 Ocean Parkway, Brooklyn, NY 11235. Email: [e-mail]

Copyright (c) 2003 by The Southern Medical Association 0038/4348/03/9606-0600