Encephalitis: Viral - Diagnosis

Ruling Out Other Conditions with Similar Symptoms

It is very important to differentiate viral encephalitis from other disorders that may cause similar neurological symptoms and which may be treatable.

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Other Viral Infections of the Central Nervous System. The signs and symptoms for meningitis (infection in the meninges, the membrane around the brain), for meningoencephalitis (viral infection in the brain and meninges), and for encephalomyelitis (infection in the brain and spinal cord) are very similar to encephalitis. Viral meningitis may have the following symptoms:

It is self limiting, typically causing only headache, sensitivity to light, and a stiff neck.
It also may cause fever, loss of appetite, nausea and vomiting, and fatigue.
Viral meningitis does not cause altered consciousness, confusion, or drowsiness, as encephalitis does.

Bacterial Infections in the Brain. Bacterial encephalitis may occur in Legionnaire disease or mycoplasma infection. Bacterial meningitis may cause similar symptoms and is also very serious.

Infections from Other Organisms. The parasitic infection toxoplasmosis and the tick-borne diseases Rocky Mountain spotted fever and ehrlichiosis can cause neurological symptoms. Amebic diseases that cause neurological damage include naegleria (found in soil and warm stagnant water during the summer months) and acanthamoeba (also found in soil and water as well as contaminated contact lens solution).

Stroke. Sometimes encephalitis symptoms can resemble those of stroke. (This is common with older patients with certain cases encephalitis caused by the varicella-zoster virus.) In such cases, diagnostic tests for stroke are needed.