What is Acute Disseminated Encephalomyelitis (ADEM)?

From the Guidelines

Acute Disseminated Encephalomyelitis (ADEM) is a rare inflammatory condition that affects the brain and spinal cord, typically occurring following a viral infection or vaccination, and is treated with high-dose corticosteroids, such as methylprednisolone, as the first line of treatment, as recommended by the Infectious Diseases Society of America 1.

Definition and Pathophysiology

ADEM is characterized by widespread inflammation in the central nervous system, resulting from an abnormal immune response that mistakenly attacks the myelin sheath of nerve fibers, causing neurological symptoms.

Treatment

The treatment of ADEM usually involves:

• High-dose corticosteroids, such as methylprednisolone, which are recommended by the Infectious Diseases Society of America 1
• Alternatives, such as plasma exchange and intravenous immunoglobulin, may be considered in severe cases unresponsive to steroids 1 ### Management and Prognosis Supportive care is essential, including:
• Management of increased intracranial pressure
• Seizure control
• Rehabilitation therapy Most patients with ADEM recover well with prompt treatment, though some may experience residual neurological deficits.

Key Considerations

It is crucial to initiate treatment promptly to minimize the risk of long-term neurological damage and improve outcomes, as emphasized by the clinical practice guidelines by the Infectious Diseases Society of America 1.

From the Research

Definition and Characteristics of Acute Disseminated Encephalomyelitis (ADEM)

• ADEM is an inflammatory demyelinating disease of the central nervous system (CNS) characterized by an acute onset of polyfocal CNS deficits, including encephalopathy, and demonstrating multifocal lesions on MRI 2, 3, 4.
• It is typically a monophasic disorder, but recurrent and multiphasic courses have been described 2, 3.
• ADEM can be difficult to distinguish from other conditions such as multiple sclerosis (MS) or neuromyelitis optica (NMO), especially in adults 2, 3.

Clinical Presentation and Diagnosis

• Clinical presentation of ADEM includes encephalopathy and multifocal neurological deficits 3.
• There are no established reliable criteria for diagnosis of ADEM, and diagnosis is based on clinical, radiological, and laboratory findings 2, 3.
• A broad workup including infectious, immunologic, and metabolic tests, as well as a systematic follow-up including MRI, is indicated to establish an accurate diagnosis 2.

Treatment Options

• Treatment of ADEM is based on supportive therapy, corticosteroids, and intravenous immunoglobulin, and in selected cases, with therapeutic plasma exchange (TPE) 2, 5, 6.
• High doses of intravenous methylprednisolone, intravenous immunoglobulin (IVIG), and plasma exchange (PLEX) treatments comprise the first-line therapy 4.
• In case of insufficient response or contraindications to corticosteroids, intravenous immunoglobulin G (IVIG) at a dosage of 2 g/kg divided over 2 to 5 days is a therapeutic option 2.
• Plasmapheresis should be considered early in the disease course for severe or life-threatening cases of ADEM 2, 5, 6.