A 54–year–old Caucasian male with medical history of alcohol dependence presented to our hospital with 3 weeks of worsening gait, behavioral changes and slurred speech, as observed by his friends. Exam revealed normal vital signs, and a neurological exam remarkable for attention deficit, disorientation to time, dysarthria, 4/5 strength in his right upper and lower extremities, right sided dysmetria, 2+ reflexes and normal planter reflexes. He had truncal ataxia. A brain CT revealed extensive predominant white matter disease. Due to his confusion and claustrophobia, the patient unfortunately could not undergo a brain MRI and lumbar puncture (LP) on the day of admission. He became increasingly agitated and disoriented over the ensuing days, which was thought to be due to alcohol withdrawal. On day 3, the patient’s psychomotor agitation was controlled enough to obtain a partially complete MRI, which was remarkable for bihemispheric abnormalities involving large areas of the subcortical and deep white matter suspicious for ADEM. On day 4, a repeat LP was performed. CSF revealed 265 mg% protein, 60 mg% glucose, and 0 nucleated cells. With a low suspicion for infectious etiology on LP, the patient was started on intravenous steroids for suspected ADEM. His mental status and neurological exam markedly improved over the next 2 days. He was finally able to tolerate a complete brain MRI on day 7, which showed multiple T1 hypointense, T2/FLAIR hyperintense, smoothly marginated ring–enhancing lesions throughout the bilateral periventricular and subcortical white matter consistent with ADEM. Patient was discharged on hospital day 9 on a steriod tapering regimen.
ADEM is an immune mediated disorder of the central nervous system. This phenomenon is triggered by infectious (viral and bacterial) illnesses or vaccinations. ADEM is a clinically diagnosis which manifests with a spectrum of neurologic deficits, and delirium. The altered sensorium which is unique to this disorder distinguishing it from multiple sclerosis which may present with similar neurological and radiological findings. CSF may show pleocytosis and usually shows no oligoclonal bands. Neuroimaging aids in diagnosis and typically reveals multifocal and/or diffuse subcortial white matter lesions, with MRI more sensitive than CT. ADEM is more common in children, but is more serious in adults and can lead to permanent neurologic deficits if left untreated; death can result from complications of neurologic deficits due to cerebral edema. Neurological symptoms in ADEM can be completely reversible; high–dose glucocorticoid therapy is the mainstay of therapy. IVIG and plasmapheresis may reportedly provide additional benefits.
ADEM must be considered as a possible diagnosis in adults presenting with features of encephalopathy, ataxia and abnormal MRI findings.
Figure 1T2/FLAIR post–gadolinium sequence: Multiple hyperintense, smoothly marginated ring–enhancing lesions throughout the bilateral periventricular and subcortical white matter.
Figure 2T2/FLAIR post–gadolinium sequence: Multiple hyperintense, smoothly marginated ring–enhancing lesions throughout the bilateral periventricular and subcortical white matter.