West Nile Virus Encephalitis: A Case Study

Rhonda Morgan

Disclosures

J Neurosci Nurs. 2004;36(4) 

In This Article

Abstract and Introduction

West Nile virus (WNV) has recently emerged as a significant and increasingly frequent etiology of encephalitis in this country. Even though WNV has been in the limelight of the national news media and in the public arena, recognition of WNV encephalitis is frequently not overtly apparent. The reason for this is that WNV infection can present a variety of symptoms along a continuum of severity. Awareness of the symptoms of WNV infection and the measures to prevent disease spread are important factors that will shape future management of the disease, as well as the extent of outbreaks facing the population.

Ted is a 67-year-old male with no significant past medical history, except for occasional migraine headaches. He is married, has two grown children, and is retired from the Air Force. He does not smoke and does not use alcohol. He has no regular exercise program, but does try to eat healthy. On July 15, Ted awoke with pain in his chin and jaw that radiated to his left ear. The next day, he visited his physician, as the pain had become more intense. He described the pain as severe, sharp, and constant. His physician could find no etiology for the facial pain, and convinced it was likely a dental problem, he advised Ted to see his dentist.

Since the pain remained constant with unremitting intensity, Ted saw his dentist the next day. He was prescribed amoxycillin for a likely developing dental abscess and was to return in 1 week for definitive treatment. When he returned to his dentist 1 week later, the pain had somewhat subsided, and no evidence of a dental abscess could be found either radiographically or clinically.

Two days later Ted embarked upon a 1,500-mile car trip across the country to attend a family reunion. His condition worsened while traveling, and he presented to an emergency department en route with a fever of 104.2°F and worsening pain in the left side of his face and jaw. He was diagnosed with strep throat and prescribed antibiotics. After resting for 1 day in a hotel, Ted felt well enough to continue the trip to his destination, even though the pain and fever persisted, and now Ted complained of overall weakness.

Upon arriving at his destination, the home of relatives, Ted was not improved. He continued to have fever, and he described shooting pains in his face, accompanied by pain in his back and legs. He was brought to the emergency room by family members for the fever, pain, and dizziness. He was treated for viral syndrome and discharged with amitriptyline, oxycodone, and meclizine. Throughout the following evening, Ted developed nausea, the fever increased, and his mental status declined. His family noticed mild confusion, particularly with timing of events and short-term memory. He also developed a rash on his lower legs, both axillae and over his shoulders. Ted's family brought him back to the emergency department because of persistent fever, worsening mental status, and the inability to keep down his food.

Upon this third visit to an emergency department, Ted was found to be in obvious discomfort, mildly confused, but oriented to person and place. He had no history of trauma or seizures and demonstrated no photophobia. He had no nuchal rigidity, but did experience left-sided neck pain upon rotation. Pupils were equal and briskly reactive to light. Tympanic membranes were clear bilaterally, and his oropharynx and nasopharynx were dry without erythema and exudates. He had coarse basilar crackles in the right lung, but the left lung was clear. Neurological exam revealed cranial nerves II-XII were grossly intact; sensation was equal bilaterally in upper and lower extremities. Muscle strength was 5/5 in all extremities. Deep tendon reflexes were 2+ in both upper and lower extremities. Vital signs were as follows: temperature 102.8°F, pulse 98 bpm, normal sinus rhythm, blood pressure 136/79 mm Hg, respiratory rate 24/min, and weight 96 kg.

Laboratory studies were as follows: urine: protein 30, ketones 15; WBC 5.4 with 18% bands, 16% lymphs, platelets 141,000; Hgb/Hct:14.1gm/dL/42.3%, ALT = 122U/L; and AST = 89U/L. His chest X ray showed bilateral basilar focal atelectasis.

During the 2 hours in the emergency department, while awaiting laboratory and X-ray results, Ted became more confused, failed to recognize family members, and ceased to follow commands. A computed tomography (CT) scan of the brain was done, which was normal. A lumbar puncture was performed with the following results: protein 101, glucose 89, nucleated cells 960, segs 78. The cerebrospinal fluid (CSF) was slightly cloudy, but colorless.

Ted was admitted with the medical diagnosis of meningitis and dehydration. With the hospital being at high census, Ted was kept in the emergency department for the night awaiting a monitored bed in a respiratory isolation room. He was started on intravenous (IV) normal saline at 150 ml/hr, clear liquids as tolerated, vancomycin 2 grams IV q 12 hours, ceftriaxone 2 grams IV q 12 hours, and metoclopramide 10 mg q 3 hours as needed for nausea.

Upon further questioning about recent history, Ted's wife recalled he had a large mosquito bite on his left ear before leaving home 2 weeks earlier. Based on this information, blood was drawn for West Nile Virus (WNV) studies and sent for analysis.

Ted was received in the medical intensive care unit (ICU) the following morning. Upon admission to the ICU, Ted was moving all extremities spontaneously, did not open his eyes to voice or pain, and did not follow commands or recognize family members. Vital signs were as follows: temperature 102.6°F, pulse 116 bpm, respiratory rate 36/min, and blood pressure 118/67 mm Hg. A fine red rash was noted on both lower extremities, upper chest, axillae, and shoulders. His breathing was rapid, shallow, and labored. An arterial blood gas sample yielded the following results: pH 7.47, paO2 64 mm Hg, paCO2 29 mm Hg, HCO3 23 mEq. He experienced increasing respiratory distress with crackles and wheezing in both lung fields. A repeat chest X ray revealed bilateral pulmonary edema. A pulmonary consult was ordered, and Ted was electively intubated and placed on mechanical ventilation due to clinical respiratory failure and inability to control his airway. Positive pressure volume limited mechanical ventilation in assist-control mode with a rate of 20/min, fraction of inspired oxygen (FIO2) of 50%, tidal volume (VT) of 650 ml, and positive end-expiratory pressure (PEEP) of +8 cm H2O were employed to manage his respiratory failure. Ted's pulmonary status continued to worsen over the next 3 days, with increased airway pressures, decreased pulmonary compliance, and increased oxygen requirements. His chest X ray, as well as clinical evidence, indicated adult respiratory distress syndrome (ARDS). The oxygen concentration were increased to 65% and PEEP was increased to +12 cm H2O.

Over the next 7 days, Ted remained neurologically unresponsive, mechanically ventilated, and received sedation with lorazepam and morphine to achieve comfort and maintain ventilator synchrony. His mental status did not improve even during short periods of time off sedation. Supportive care consisted of enteral feedings via gastric tube, kinetic therapy, prophylaxis for deep vein thrombosis, and fever management. Family members were present most of the time and were involved in Ted's care. His wife and sister assisted in turning, positioning, bathing, and massaging his hands and feet. His family members were offered frequent updates and counseled about measures for self-care.

By day 10, Ted had made significant improvement and was responsive to voice and able to follow simple commands. His ARDS was improving, with decreasing airway pressures and adequate oxygenation on an FIO2 of 30%, as well as an improved chest X ray. Continuous positive airway pressure (CPAP) trials were begun with the goal of extubation within the next 24 hours. Lab studies of serum IgM, IgG, and titers for WNV, which were drawn 8 days earlier, returned positive.

On day 11, Ted was sleepy but arousable, followed commands, and had tolerated daytime CPAP trials well. He had periods of agitation and self-extubated on the evening of day 11, but maintained appropriate oxygen saturation levels and denied dyspnea.

On day 12, Ted's pulmonary status was stable, with a forceful cough and oxygen saturation of 98% on 3L of oxygen by nasal cannula. He was moderately confused and lethargic, but followed commands. He was transferred to a step-down unit. Ted's gastric tube was removed, and clear liquids by mouth were begun and tolerated well. Even though he experienced periods of agitation, restlessness, and profound muscle weakness, Ted was able to stand and move to a chair with assistance.

On day 13, Ted was transferred to a medical floor for a 2-day stay before being discharged to a rehabilitation hospital for convalescence. At the time of discharge to a rehabilitation facility, Ted experienced significant muscle weakness and periods of restlessness and agitation, but was oriented to person and place. After spending 2 weeks in the rehabilitation facility, he was discharged to the home of relatives for several weeks before returning to his own home.

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