Clinical Geriatrics

Case Presentation
Mr. D is a 75-year-old Caucasian man who sought care after experiencing a one-day history of fever and generalized weakness. He stated that he began to feel unwell after a day of gardening. He reported mild intermittent headache and generalized malaise with no stiff neck. He denied having a sore throat, with no cough and no dyspnea. He had no urinary symptoms earlier, but the morning of his visit he reported having some dysuria. There was no pertinent travel history of environmental exposure.

The patient, a WWII veteran, has lived with his long-term girlfriend in southern Louisiana for the past 30 years. He has a medical history that is significant for coronary artery disease with myocardial infarction and had a prior coronary artery bypass graft in 1996. He had a mild cerebrovascular accident in 1999 with no significant residual symptoms. Subsequently, he had an episode of seizure in 2000, which was well controlled with felbamate. He also has a history of hypertension, hyperlipidemia, and benign prostate hypertrophy. He does not smoke or use alcohol. Vital signs were taken, indicating the following: blood pressure 123/76 mm Hg; pulse 90 beats per minute; respiratory rate 22; and temperature 103.1 degrees F. Additional physical examination revealed coarse breath sounds from both lung fields.

Laboratory results indicated normal electrolytes, liver enzymes, coagulation studies, and urinalysis. Blood urea nitrogen (BUN) and creatinine levels were slightly elevated at 32 mg/dL and 1.5 mg/dL, respectively. A complete blood count showed normal hemoglobin and hemocrit with a white cell count of 5.3x10³/µL with 89% neutrophils, 9% lymphocytes, and 2% monocytes. Platelet count was 130x10³/µL. Erythrocyte sedimentation rate was 22 mm/h. C-reactive protein was 2.5 mg/L. Cardiac enzymes were negative. Thyroid function tests were normal. Chest x-ray showed no acute pulmonary infiltrates, and electrocardiogram revealed normal sinus rhythm of 100 beats per minute with left ventricular hypertrophy. Blood/urine/sputum cultures were obtained, as well as additional tests for West Nile virus (WNV).

Mr. D was treated empirically with broad-spectrum antibiotics, intravenous fluid, and an antipyogenic. The next hospital day, the patient’s high fever persisted at 102 degrees F with rigor, and he developed shortness of breath. A computed tomographic angiography of the chest was performed and ruled out pulmonary embolism. An ultrasound of the bilateral lower extremities revealed no deep venous thrombosis. Tests for rheumatoid factor, ehrlichiosis, HIV, and antistreptolysin O were negative, as was a skin test for tuberculosis.

The patient’s fever persisted daily, with a maximal temperature of 103 degrees F for the next few days with fluctuating mental status. He became drowsier and more lethargic with minimal response to commands. A magnetic resonance imaging of the brain showed some enhancement in the meninges of the brain, with otherwise unremarkable findings. A lumbar puncture was performed. Mr. D had normal open pressure with elevated protein and normal glucose from cerebrospinal fluid (CSF). There was predominantly lymphocytic pleocytosis in the CSF, and testing for herpes simplex and WNV from the CSF were submitted. Acyclovir was added to cover for possible herpes encephalitis. All of the blood and urine cultures were negative. The initial serum WNV serology on day 5 was negative, but was positive with repeat testing from CSF and blood on day 20.

Discussion
West Nile virus is an emerging mosquito-transmitted encephalitis virus, with its first North American case recognized in 1999.¹ The virus spread rapidly, with initial cases reported along the Atlantic seaboard. The highest concentration of cases was in the upper Midwest and the South, such as in Louisiana, where the case presented here occurred.