From the Guidelines
St. Louis encephalitis (SLE) typically presents with fever, headache, nausea, vomiting, and altered mental status, which can progress to seizures, tremors, and coma in severe cases, and the management includes supportive care with intravenous fluids, antipyretics, and anticonvulsants as needed, with the prognosis varying by age and severity. The incubation period of SLE ranges from 5-15 days after a mosquito bite, with symptoms developing gradually.
Presentation
- The presentation of SLE can include fever, headache, nausea, vomiting, and altered mental status, which can progress to seizures, tremors, and coma in severe cases 1.
- The median age at presentation can vary, with some studies reporting a median age of 25 years and a male to female ratio of 1:2, while others report a median age of 65 years and a male to female ratio of 2:1 1.
Treatment
- Treatment of SLE is primarily supportive, as no specific antiviral therapy exists, and includes intravenous fluids, antipyretics like acetaminophen (500-1000mg every 4-6 hours), and anticonvulsants such as levetiracetam (500-1500mg twice daily) for seizures, and respiratory support if needed 1.
- Patients often require hospitalization, with severe cases needing intensive care monitoring.
Prognosis
- The prognosis of SLE varies by age and severity, with most patients recovering completely, but the case fatality rate ranges from 5-20%, with higher mortality in elderly patients 1.
- Approximately 30-50% of survivors, particularly older adults, may experience long-term neurological sequelae including cognitive impairment, memory problems, and movement disorders.
Prevention
- Prevention through mosquito control measures and personal protection is crucial since no vaccine is available, and early recognition and supportive care remain the cornerstones of management 1.
From the Research
Presentation of St. Louis Encephalitis (SLE)
- The clinical presentation of SLE is variable and may range from inapparent infection to a severe illness with diverse neurologic signs 2
- Patients with SLE may exhibit signs of brain stem dysfunction or acute cerebellar ataxia 2
- The virus is transmitted by a mosquito vector and is an annual public health concern during the late summer and early fall in much of the midwest and southeast 3
Treatment of St. Louis Encephalitis (SLE)
- Although no specific antiviral agents are yet available, patients will benefit from close monitoring during the initial phase of illness, supportive critical care, and appropriate rehabilitation 3
- Supportive care of patients on mechanical ventilation is crucial, with a focus on pain, anxiety, and sleep deprivation management, as well as early mobilization and avoidance of physical restraint 4
- Pharmacotherapy plays an essential role in Emergency Neurological Life Support (ENLS), with considerations including organ function, medication allergies, and potential adverse drug effects 5
Prognosis of St. Louis Encephalitis (SLE)
- The prognosis of SLE depends on various factors, including the severity of the illness and the patient's overall health 3
- Early diagnosis and treatment are crucial to improve outcomes, with serologic identification facilitating early vector control 2
- The epidemic features of SLE, coupled with public health surveillance and vector monitoring programs, have made diagnosis readily accessible during the past decade 3