The diagnosis of Acute Disseminated Encephalomyelitis (ADEM) needs to be considered whenever a close relationship appears between an infection and the development of neurological symptoms accompanied by headache, fever, and an altered mental state. Once the symptoms begin, they tend to worsen and a serious problem becomes apparent.
MRI scanning is an important part of the diagnosis. In ADEM, there are usually widespread, multiple changes deep in the brain in areas known as the white matter. There are also sometimes lesions in the grey matter deep in the brain as well. Often the affected areas can be more than half of the total volume of the white matter.
While these changes are characteristic, they are not specific for ADEM. Physicians caring for such patients have to consider other diagnoses, including multiple sclerosis, direct brain infections, and sometimes tumors.
Over months these changes on MRI should gradually improve and even disappear.
Spinal fluid testing
A lumbar puncture is typically needed in patients with ADEM. This is partially to rule out direct infections or other processes that can look like ADEM. The lumbar puncture allows the neurological team to test the cerebrospinal fluid for many different things that assist in the diagnostic process.
In ADEM, the spinal fluid often shows an increase in white cells. The type of which cell increased is usually lymphocytes, which are an active part of the immune system. Occasionally doctors can culture or measure a reaction to a specific virus or bacteria in the spinal fluid that may have triggered ADEM.
In ADEM, there are often no oligoclonal bands. Oligoclonal bands are commonly found in MS, and this difference may help to distinguish the two diseases.