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Aseptic Meningitis

Terminology. Subarachnoid inflammation from any cause other than pyogenic bacteria or fungi. The differential includes viruses, other microorganisms, and non-infectious causes viral meningitis. Since most cases are caused by viruses, the terms "aseptic" and "viral" are often used synonymously.

Causes of Aseptic Meningitis other than Enterovirus.

Viral Diseases with Systemic Manifestations

mumps

herpes simplex

varicella-zoster

adenoviruses

Epstein-Barr virus

parvovirus (erythema infectiosum)

lymphocytic choriomeningitis virus

Non-Viral Infections

partially treated bacterial

parameningeal infection

mastoiditis

sinusitis

brain abscess

spirochetal infections

syphilis

leptospirosis

Lyme disease

fungal

cryptococcal

coccidioidomycosis

histoplasmosis

tuberculous

toxoplasmosis

Rocky Mountain Spotted Fever

Mycoplasma pneumoniae

Bartonella henselae (cat scratch disease)

amebic meningoencephalitis

Non-Infectious Etiology

brain tumor

carcinomatous

chemical

intrathecal drugs and radiographic dyes

lead poisoning

benign intracranial hypertension

Unknown Etiology

Kawasaki disease

Etiology

may occur as part of a broader range of clinical manifestations caused by some viruses

The differential diagnosis where is the sole or dominant manifestation is more limited

Prior to the discovery of the non-polio enteroviruses (circa 1950), most cases were considered to be "non-paralytic" poliomyelitis.

Large studies conducted from 1955 to 1962 among patients of all ages (1-3), found multiple agents caused. Mumps virus and poliovirus infections are now controlled by immunization in the U.S.

Etiology Presenting with Predominately CNS

Symptoms and Signs.

Diseases Limited to Central Nervous System

enteroviruses

mumps

arboviruses

lymphocytic choriomeningitis virus (LCM)

Unknown Etiology

Mollaret's syndrome

A prospective study conducted at three Baltimore hospitals from 1986 to 1990 showed > 90% of viruses isolated from children under 2 y/o are coxsackie B viruses and echoviruses; coxsackie A viruses appear to cause < 3% of cases (4).

Seasonality. disease activity corresponds to the seasonal pattern observed with all enterovirus infections, i.e., a marked summer-fall predominance. Disease occurs at a lower incidence at other times of the year.

Rates of Disease

Based on continuous surveillance in Olmsted County, MN the overall population-based rate of physician-diagnosed was

The age-specific incidence has varied somewhat among different reported outbreaks (7-14), but most data indicate that is predominantly a disease of infants less than a year of age. A declining number of cases are

Clinical and Laboratory Features

Clinical Presentation

In the older child and adult presents with fever to 400 C, headache, meningismus, nausea and vomiting (10). Other signs of enterovirus infection, i.e., rash, are present in a minority