West Nile encephalitis (WNE) is one of the illnesses caused by West Nile virus (WNV) infection. Most individuals infected with WNV are asymptomatic, some develop West Nile fever, and a small percentage develop neuroinvasive disease. WNV is transmitted to humans mainly via mosquito bites. The incubation period ranges from 2 days to 2 weeks [1]. WNE can present in a number of ways, albeit similar to other types of viral encephalitis. Patients usually have a fever, headache, and altered mental status.

Initial symptoms and signs of illness may include myalgia, arthralgia, or pharyngitis and are often nonspecific. Those at the extremes of age have more pronounced symptoms. Aseptic meningitis may occur simultaneously with encephalitis, resulting in signs of meningism. The severity of illness is proportional to the extent of viral invasion. Changes in the mental status range from acute confusion to coma.

Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described [2]. Less frequently reported are seizures and cerebral edema [3]. Parkinsonism, extrapyramidal manifestations, myoclonus, and muscle weakness mimicking lower motor neuron lesions, also form part of the clinical picture [4].

WNE could present with acute flaccid paralysis, which is also directly caused by WNV infection. The presence of muscle weakness distinguishes WNE from other encephalitides. Facial nerve palsies present acutely or over the course of a few weeks [5]. Elderly individuals are at an increased risk [6].

Further presenting features of WNE are ophthalmologic manifestations, lymphadenopathy (especially of the submental nodes), and a maculopapular rash on the trunk [5].

• Fever

  We report the case of a 46-year-old woman who presented with fever, altered mental status, and maculopapular rash, who was diagnosed with locally acquired WNV encephalitis. [ncbi.nlm.nih.gov]

  fever, WN - West Nile fever, West Nile fever (diagnosis), West Nile virus infection, West Nile fever NOS, West Nile Fever [Disease/Finding], west nile fever, West Nile fever (disorder), West nile virus infection, West Nile; fever, fever; West Nile, West [fpnotebook.com]

  (inanition) (of unknown origin) (persistent) (with chills) (with rigor) R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with [icd10data.com]

• Fatigue

  Localized Stage (early) Early symptoms of Lyme disease include fever, fatigue, and muscle and joint aches, which can also be associated with a variety of other illnesses. [navicenthealth.org]

  The most common symptom observed in these patients was fatigue (25.93%). Other symptoms included dizziness (7.4%), decreased sense of hearing (7.4%) and decreased sense of smell (7.4%). Reduced power in limbs was found in 33.33% of the cases. [ncbi.nlm.nih.gov]

  Supportive therapy Respiratory support; airway management Increased fluid intake As tolerated Rest periods when fatigued Antipyretics such as acetaminophen Interferon alfa-2b Nursing Considerations-Nursing Diagnoses Acute pain Decreased cardiac output [quizlet.com]

  Re: Modafinil for treatment of fatigue in post-polio syndrome: a randomized controlled trial. Neurology. 2008 Feb 26;70(9):736-7; author reply 737-8. No abstract available. [rarediseases.org]

• High Fever

  See a doctor if you develop symptoms such as high fever, confusion, muscle weakness, severe headache, or stiff neck. Spread West Nile virus is spread to people and animals through the bite of infected mosquitoes. [bchu.org]

  This illness can cause confusion, a high fever, and a severe headache. Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. [myhealth.alberta.ca]

  In a severe infection, symptoms are headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and on rare occasions, death. [infoplease.com]

  The symptoms of meningitis or encephalitis can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. [drsfostersmith.com]

• Chills

  (with rigor) R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with rigors Hyperpyrexia NOS Persistent fever Pyrexia NOS West [icd10data.com]

  Early symptoms are nonspecific and include fever, chills, malaise, headache, ocular pain or photophobia, myalgia, and occasionally a maculopapular rash (more common in children) and gastrointestinal upset. [medical-dictionary.thefreedictionary.com]

  When symptoms develop, West Nile virus infection typically begins with the abrupt onset of fever, chills, muscle aches, headache, and flu-like symptoms. Headache is particularly common and may be severe. [emedicinehealth.com]

• Rigor

  R50.9 ICD-10-CM Diagnosis Code R50.9 Fever, unspecified 2016 2017 2018 2019 Billable/Specific Code Applicable To Fever NOS Fever of unknown origin [FUO] Fever with chills Fever with rigors Hyperpyrexia NOS Persistent fever Pyrexia NOS West Nile (viral [icd10data.com]

  However, even with rigorous surveillance, spraying, and larvaciding, the virus may still infect people. What About “Larvicides” and “Adulticides”? Larvicides are products used to kill immature mosquitoes. [onhealth.com]

• Vomiting

  A 57-year-old Caucasian woman presented with fever, dizziness, balance difficulties, vomiting, dancing eye, altered speech, tremor, generalized myoclonus and failure to rise or stand. [ncbi.nlm.nih.gov]

  Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. Almost all cases are from mosquito bites. Most people with this illness get better after treatment. [myhealth.alberta.ca]

  Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  Neurologic impairment Seizures Bronchial pneumonia Myocarditis Pancreatitis Hepatitis Death Headache Myalgia Fever Fatigue Neck stiffness Possible recent exposure to bodies of water or to dead birds Recent mosquito bites Decreased appetite Nausea Vomiting [quizlet.com]

  Other symptoms and signs variably reported include vomiting, diarrhea, cough, and sore throat. [clinicaladvisor.com]

• Nausea

  Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  Signs and symptoms include the sudden onset of drowsiness, headache and nausea due to encephalitis, pain in the abdomen, a rash, and swollen glands (lymphadenopathy). These features are usually but not always mild. [medicinenet.com]

  Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. Almost all cases are from mosquito bites. Most people with this illness get better after treatment. [myhealth.alberta.ca]

  In adults and older children, symptoms include: fever drowsiness bad headache and stiff neck nausea muscle tremors dizziness. In young children the symptoms include: fever floppiness irritability drowsiness fits. [ww2.health.wa.gov.au]

  It may be of sudden onset, and symptoms may include drowsiness, severe frontal headache, maculopapular rash, abdominal pain, loss of appetite, nausea, and generalized lymphadenopathy. [medical-dictionary.thefreedictionary.com]

• Hypertension

  Other chronic medical problems included a history of prostate cancer in remission, dyslipidemia, and hypertension. He also had a history of “visual seizures” for which he was taking daily antiepileptic medication. [hindawi.com]

  […] infections are more likely to develop in the following category of individuals: Adults, older than 50 years of age Individuals with weakened immune systems, such as after receiving an organ transplant, major surgeries, those suffering from cancer, diabetes, hypertension [dovemed.com]

  People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk. Recovery from severe illness might take several weeks or months. [cdc.gov]

• Maculopapular Rash

  We report the case of a 46-year-old woman who presented with fever, altered mental status, and maculopapular rash, who was diagnosed with locally acquired WNV encephalitis. [ncbi.nlm.nih.gov]

  Further presenting features of WNE are ophthalmologic manifestations, lymphadenopathy (especially of the submental nodes), and a maculopapular rash on the trunk. [symptoma.com]

  It may be of sudden onset, and symptoms may include drowsiness, severe frontal headache, maculopapular rash, abdominal pain, loss of appetite, nausea, and generalized lymphadenopathy. [medical-dictionary.thefreedictionary.com]

  Common clinical features include HEADACHE; FEVER; maculopapular rash; gastrointestinal symptoms; and lymphadenopathy. MENINGITIS; ENCEPHALITIS; and MYELITIS may also occur. [fpnotebook.com]

• Photophobia

  Early symptoms are nonspecific and include fever, chills, malaise, headache, ocular pain or photophobia, myalgia, and occasionally a maculopapular rash (more common in children) and gastrointestinal upset. [medical-dictionary.thefreedictionary.com]

  There was no evidence of tongue biting, urinary incontinence, photophobia, or nuchal rigidity. Muscle strength, tone, and deep tendon reflexes were normal and symmetric. Babinski signs were absent. Sensory examination was normal. [hindawi.com]

  The signs and symptoms of WNE may include: Fever, headache Nausea and vomiting Mental changes such as confusion, hallucination, or decreased consciousness Sensitivity to light (photophobia) Stiff neck (nuchal rigidity) Lesser known symptoms also include [dovemed.com]

  A meningeal-type infection may manifest as typical meningeal symptoms (eg, neck stiffness, photophobia, headache). [13, 20] Encephalitis may be more varied, possibly featuring mental status changes, confusion, lethargy, seizures, local paresthesia, and [emedicine.medscape.com]

• Diplopia

  […] patients 23 64 59 16 162 General Headache 48% 27% 47% 94% 44% Altered mental status 74% 75% 46% 56% 62% Weakness 48% 41% 56% 47% 48% Central Nervous System Dysfunction Facial palsy 17% 11% — — 13% Dysphagia — 34% — 25% 33% Dysarthria — 17% 8% — 13% Diplopia [clevelandclinicmeded.com]

• Headache

  A 58-yr-old Korean man was admitted with headache and cognitive dysfunction. The patient had been on a business trip in Guinea. Cerebrospinal fluid (CSF) showed pleocytosis. [ncbi.nlm.nih.gov]

  Symptoms are flu-like and may include fever, headache, body aches, and/or a skin rash. The elderly and people with weak immune systems are more likely to have severe cases. [bchu.org]

  Your child has a severe headache. Your child has a stiff neck. Your child is nauseated or is vomiting. Your child is confused or cannot think clearly. [myhealth.alberta.ca]

  In adults and older children, symptoms include: fever drowsiness bad headache and stiff neck nausea muscle tremors dizziness. In young children the symptoms include: fever floppiness irritability drowsiness fits. [ww2.health.wa.gov.au]

  Patients usually have a fever, headache, and altered mental status. Initial symptoms and signs of illness may include myalgia, arthralgia, or pharyngitis and are often nonspecific. Those at the extremes of age have more pronounced symptoms. [symptoma.com]

• Tremor

  A 57-year-old Caucasian woman presented with fever, dizziness, balance difficulties, vomiting, dancing eye, altered speech, tremor, generalized myoclonus and failure to rise or stand. [ncbi.nlm.nih.gov]

  Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  […] majority of cases but that can present in rare occasions with mild flulike symptoms such as low-grade fever, arthralgia, myalgia, and/or rash, or with neurologic manifestations including meningitis, encephalitis with mental confusion or disorientation, tremors [orpha.net]

  Over a period of several days, his mental status improved completely to baseline and his fever and tremors subsided. [hindawi.com]

• Confusion

  This illness can cause confusion, a high fever, and a severe headache. Other symptoms include nausea, vomiting, and a stiff neck and back. West Nile virus is not spread by touching a person who has the virus. [myhealth.alberta.ca]

  Changes in the mental status range from acute confusion to coma. Gastrointestinal upset (nausea and vomiting) is common. Gait instability, coarse tremor, and bulbar palsy have been described. Less frequently reported are seizures and cerebral edema. [symptoma.com]

  An 89-year-old man presented to a community hospital in October 2001 with fever and confusion. Except for recurrent hematuria, he had been in good health until the day before admission. [nejm.org]

  More than one third of adult survivors of WNV infection continue to experience muscular weakness, cognitive impairment (for example, confusion, difficulty concentrating), or both after 12 months. [medical-dictionary.thefreedictionary.com]

  […] that is asymptomatic in the majority of cases but that can present in rare occasions with mild flulike symptoms such as low-grade fever, arthralgia, myalgia, and/or rash, or with neurologic manifestations including meningitis, encephalitis with mental confusion [orpha.net]

• Neck Stiffness

  In a severe infection, symptoms are headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and on rare occasions, death. [infoplease.com]

  The symptoms of meningitis or encephalitis can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. [drsfostersmith.com]

  Neurologic impairment Seizures Bronchial pneumonia Myocarditis Pancreatitis Hepatitis Death Headache Myalgia Fever Fatigue Neck stiffness Possible recent exposure to bodies of water or to dead birds Recent mosquito bites Decreased appetite Nausea Vomiting [quizlet.com]

• Seizure

  Occipital lobe seizures, often mimicking other primary seizure types due to extra-occipital spread, is uncommon in adults and especially so from an infectious origin. [ncbi.nlm.nih.gov]

  Institute safety and seizure precautions as indicated by the patient's neurologic status. Reorient the patient as necessary. Observe for signs and symptoms of increased intracranial pressure (ICP). [quizlet.com]

  Less frequently reported are seizures and cerebral edema. Parkinsonism, extrapyramidal manifestations, myoclonus, and muscle weakness mimicking lower motor neuron lesions, also form part of the clinical picture. [symptoma.com]

  The transient nature of his encephalopathy raised suspicion of a generalized seizure as the inciting event with resultant temporary postictal state. [hindawi.com]

  The patient remained in a coma with occasional partial seizure activity that manifested as rhythmic clonic movements. This partial seizure activity diminished and ceased after repeated intravenous injections of diazepam. [jamanetwork.com]

The main diagnostic test for WNV infection is the IgM antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA) [7]. IgM antibodies may be detected in serum, however, when they are present in cerebrospinal fluid (CSF) this indicates central nervous system (CNS) invasion by the virus (as IgM does not cross the blood-brain barrier). Eventually, this confirms the diagnosis of West Nile encephalitis. The majority of patients will test positive at the time of presentation [8]. Moreover, nearly all patients are MAC-ELISA positive after a week of symptomatic illness.

Immunological assays may be supplemented by the use of nucleic acid amplification test (NAAT), thus improving the detection rate to over 90%. One advantage that NAAT has over immunology is that it can detect viral infection even in immunosuppressed patients who may produce a scarce amount of antibodies.

Raised white blood cell count may be a feature of WNE, although it is not always present. Increased leukocytes, either neutrophils or lymphocytes, and elevated protein level are some of the CSF findings [9]. T2-weighted magnetic resonance imaging (MRI) may sometimes reveal brainstem and periventricular lesions [10] [11].

• Hyponatremia

  Blood work to follow up on any remaining abnormalities noted while under acute care (e. g. sodium level in cases associated with hyponatremia). E. Placement Considerations. [clinicaladvisor.com]

  Laboratory evaluation was significant only for mild hyponatremia (132 mmol/L) and elevated creatinine kinase (236 mmol/L). Tests for liver function, complete blood count, and urinalysis were unremarkable. [hindawi.com]

  […] been described. 10–13 Back to Top Diagnosis Laboratory Findings Complete blood counts on admission usually show no major abnormalities, although there may be absolute or relative lymphopenia. 10,21 Up to one third of the patients develop significant hyponatremia [clevelandclinicmeded.com]

  Elevated creatinine kinase and hyponatremia, and elevated serum ferritin late in the course of illness, have also been reported. [ncbi.nlm.nih.gov]

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