What are the diagnostic criteria for acute disseminated encephalomyelitis

What is the Diagnosis of Acute Disseminated Encephalomyelitis

What is the Diagnosis of Acute Disseminated Encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) is defined by a transient yet extensive bout of inflammation in the brain and spinal cord, leading to myelin damage, the protective sheath around nerve fibers. Typically, ADEM occurs after viral or bacterial infections, and occasionally, following vaccination for diseases like measles, mumps, or rubella. Clinically and pathologically, ADEM shares notable similarities with multiple sclerosis (MS).

Diagnosis of ADEM

ADEM should be considered as a diagnosis when there’s a close temporal relationship between an infection and the onset of multiple neurological symptoms, often accompanied by headache, fever, and changes in mental status. Symptoms typically worsen over several days, indicating a serious issue.

MRI scanning is crucial for diagnosis. In ADEM, widespread changes are typically observed deep in the brain’s white matter, which contains nerve fibers. These changes may also affect grey matter regions. Although these findings are characteristic of ADEM, they’re not specific, necessitating consideration of other conditions like multiple sclerosis, brain infections, or tumors.

Over time, MRI changes in ADEM should gradually improve or disappear entirely.

Spinal fluid testing via lumbar puncture is often necessary. This helps rule out infections or other conditions mimicking ADEM. Analysis of cerebrospinal fluid, which circulates around the brain and spinal cord, may reveal elevated white cell count, primarily lymphocytes, indicating immune system activation. Additionally, absence of oligoclonal bands, abnormal proteins indicating immune activity, helps differentiate ADEM from multiple sclerosis.