Acute Disseminated Encephalomyelitis vs. MS: What's the Difference?
ADEM and MS: How They’re the Same
Acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) are inflammatory autoimmune disorders. Our immune system protects us by attacking foreign invaders that enter the body. Sometimes, the immune system mistakenly attacks healthy tissue.
In ADEM and MS, the target of the attack is myelin, which is the protective insulation that covers nerve fibers throughout the central nervous system. Damage to myelin makes it difficult for signals from the brain to get through to other parts of the body. This can cause a wide variety of symptoms, depending on the area(s) damaged.
In both ADEM and MS, symptoms include vision loss, weakness, and numbness. Problems with balance and coordination or difficulty walking are common. In severe cases, paralysis is possible. Symptoms vary according to the location of the damage within the central nervous system.
Symptoms of ADEM come on suddenly and, unlike MS, can include confusion, fever, nausea, and vomiting. Most of the time, an episode of ADEM is a single occurrence. MS lasts a lifetime. In relapsing-remitting forms of MS, symptoms come and go. People with progressive forms of MS experience steady deterioration.
Who Gets It?
According to the MS Society UK, you can develop ADEM at any age, but it’s more likely to occur in children under the age of age 10.
MS can also develop at any age. However, it’s usually diagnosed between the ages of 20 and 50. MS strikes women at twice the rate of men, according to the Mayo Clinic. Incidence is higher in Caucasians than in people of other ethnic backgrounds.
MS isn’t hereditary, but researchers believe there is a genetic predisposition toward developing MS. Having a first-degree relative—such as a sibling or parent—with MS slightly increases your risk.
Due to similar symptoms and the appearance of lesions on the brain, initially ADEM can easily be misdiagnosed as an MS attack. ADEM generally consists of a single attack, while MS involves multiple attacks. In this instance, an MRI of the brain can help.
MRI can differentiate between older and newer lesions. The presence of older lesions is more consistent with MS. The absence of older lesions could indicate either condition.
However, several key factors in ADEM distinguish it from MS, including sudden fever, confusion, and possibly even coma, which are rare in MS patients. Similar symptoms in children are more likely to be ADEM.
The causes of ADEM and MS aren’t entirely clear, though neither condition is contagious.
ADEM often develops within months of an infection. In rare cases, ADEM may be triggered by an immunization. Doctors aren’t always able to identify the triggering event.
Most researchers believe that MS is caused by a genetic predisposition to develop the disease combined with a viral or environmental trigger.
The goal of treatment for ADEM is to stop inflammation in the brain. Intravenous and oral corticosteroids can usually control ADEM. In more difficult cases, intravenous immunoglobulin therapy may be recommended. Long-term medications aren’t necessary.
MS currently has no cure. Disease-modifying drugs are used to treat relapsing-remitting MS in the long term. However, these drugs have no benefit for people with progressive MS. Targeted treatments can help manage individual symptoms and improve quality of life.
About 80 percent of patients have a single episode of ADEM, according to the MS Society UK. Most make a complete recovery within months following the illness. In a small number of cases, a second attack of ADEM occurs within the first few months.
More severe cases that can result in lasting impairment are rare. According to National Institute of Neurological Disorders and Stroke, “a small fraction” of people diagnosed with ADEM eventually develop MS.
There is no cure for MS and treatment may be ongoing. MS worsen over time.
- Acute Disseminated Encephalomyelitis (ADEM). (n.d.). Boston Children’s Hospital. Retrieved December 5, 2013 from http://www.childrenshospital.org/health-topics/conditions/acute-disseminated-encephalomyelitis-adem
- Acute Disseminated Encephalomyelitis (ADEM). (n.d.). National MS Society. Retrieved December 5, 2013 from http://www.nationalmssociety.org/about-multiple-sclerosis/do-i-have-ms/other-conditions-your-doctor-needs-to-rule-out/adem/index.aspx
- MS Essentials Factsheet. ADEM (Acute disseminated encephalomyelitis. (2012, March). MS Society U.K. Retrieved December 5, 2013 from http://www.mssociety.org.uk/sites/default/files/Documents/Factsheets/ADEM factsheet 0312.pdf
- Multiple sclerosis. Definition. (2012, December 15). Mayo Clinic staff. Mayo Clinic. Retrieved December 5, 2013 from http://www.mayoclinic.com/health/multiple-sclerosis/DS00188
- Multiple sclerosis. Risk factors. (2012, December 15). Mayo Clinic staff. Mayo Clinic. Retrieved December 5, 2013 from http://www.mayoclinic.com/health/multiple-sclerosis/DS00188/DSECTION=risk-factors
- NINDS Acute Disseminated Encephalomyelitis Information Page. (2012, October 5). National Institute of Neurological Disorders and Stroke, National Institutes of Health. Retrieved December 5, 2013 from http://www.ninds.nih.gov/disorders/acute_encephalomyelitis/acute_encephalomyelitis.htm