69-year-old male with past medical history of hyperlipidemia, gout and eczema brought in to the emergency department in early fall for altered mental status. Patient was found unresponsive on the floor with non-bloody emesis. He was just in the Dominican Republic 3 days prior to admission. Per family, patient was not complaining of any headaches, cough, back pain, arthritis, arthralgia, diarrhea, nausea, vomiting, photophobia, fever, chills. In the ED, the patient had sepsis; he was febrile to 102.8 F, disoriented, confused, tachycardic to 116, tachypneic to 40. Physical exam was remarkable for a systolic murmur 2/6 heard best at left sternal border, a macular rash on his chest associated with an area of faint erythema and warmth on the right leg below the knee extending down to the foot. Head CT and Chest X-ray were negative. Initial labs showed leukocytosis, mild thrombocytopenia and lactic acidosis. LP was negative for bacterial or viral meningitis. Infectious workup was sent including blood cultures, urine culture, CSF culture, CSF HSV PCR, RPR, HIV, NY state encephalitis, Dengue and Chikungunya serology. Patient received IV fluids, ampicillin, ceftriaxone and vancomycin.
On the medical ward, infectious disease and neurology were consulted. The differential diagnosis included meningococcemia, infective endocarditis, viral encephalitis, arboviruses such as Chikungunya and Dengue. IV fluids, ceftriaxone and vancomycin were continued and acyclovir was added. Brain MRI showed chronic micro-vascular ischemic disease but no evidence of demyelination. EEG was negative. On day 2, his mental status started to improve; his fever, leukocytosis and thrombocytopenia all resolved. Acyclovir was discontinued given negative CSF HSV PCR. On day 4, Patient’s mental status returned back to normal. His blood, urine and CSF cultures were negative as well as the blood parasite screen. CSF serology was positive for West Nile Virus. The patient was discharged with outpatient infectious disease follow up.
West Nile Virus (WNV) is most commonly transmitted to humans by mosquitoes. Most persons infected with the WNV are asymptomatic; symptoms are seen in only about 20 to 40 percent of infected patients. The two most common manifestations of WNV infection are fever and neuro-invasive disease such as encephalitis, meningitis, or an acute asymmetric flaccid paralysis. A maculo-papular rash appears in up to one-half of such patients. A diagnosis of acute infection with WNV is best made through detection of WN-specific antibodies, or in some instances by detection of viral RNA by PCR. Lumbar puncture and testing of the CSF for detection of IgM antibody as well as serum testing is recommended in patients who present with suspected meningitis, encephalitis, or acute flaccid paralysis. Treatment is always supportive care.
The differential diagnosis for a patient presenting in the late summer/early fall with a non-specific febrile illness (with or without neurologic manifestation) is broad and includes infections due to viruses, spirochetes, and other tick borne illnesses. It is important to obtain a recent travel and or exposure history to help narrow the number of possible infectious organisms. If serology is positive for West Nile virus, the treatment is supportive care with IV Fluids; pain control and antiemetic therapy should be considered for headaches and Nausea/vomiting respectively.
To cite this abstract:Abed E, Abed J, Judeh H, Gazali R, Gurunathan R. An Atypical Case of West Nile Virus. Abstract published at Hospital Medicine 2015, March 29-April 1, National Harbor, Md. Abstract 426. Journal of Hospital Medicine. 2015; 10 (suppl 2). https://www.shmabstracts.com/abstract/an-atypical-case-of-west-nile-virus/. Accessed April 4, 2020.