Acute disseminated encephalomyelitis (ADEM) is an immune-mediated, inflammatory demyelinating disease of the central nervous system with predominant white matter involvement. It is more common in children and usually occurs after infection or vaccination. Disease is characterized by a non-specific clinical presentation which includes sudden onset of encephalopathy and multifocal neurological symptoms. It usually has a monophasic course, but it can also occur in recurrent or multiphasic form when the differential diagnosis of multiple sclerosis needs to be considered. Acute hemorrhagic leukoencephalitis (AHL) is a fulminant ADEM variant characterized by rapid disease progression and severely impaired consciousness, usually leading to fatal outcome. Due to the absence of pathognomonic biological markers and great similarity to other inflammatory demyelinating disorders (MS, NMO), a definitive diagnosis is difficult to establish. Diagnosis is based on medical history, clinical status, MRI of the central nervous system and cerebrospinal fluid analysis. Magnetic resonance image shows multiple demyelinating lesions most commonly located in the subcortical and central white matter of the CNS and sometimes in the gray matter. CSF analysis may show a mild to moderate pleocytosis, elevated protein and usually negative oligoclonal bands. Often, prolonged clinical and neuroimaging follow-up of the patient is required to confirm the diagnosis. High dose intravenous corticosteroids are most commonly used in treatment, whereas in more severe forms of the disease, intravenous immunoglobulins (IVIg) or plasmapheresis are used. Most patients recover completely, but some are left with neurological deficits.