Study Illuminates Differences Between Autoimmune Encephalitis and Acute Encephalomyelitis

A recent study has documented the differences between two rare forms of childhood brain inflammation. The two similarly presenting conditions are often confused for one another. A better understanding of what differentiates these conditions could lead to better individualized therapies and a better understanding of the prognosis for patients and their families. This study was completed by Molly McGetrick from UTSW and her colleagues and published in Pediatric Neurology.

The Conditions

There are two primary forms of encephalitis (brain inflammation) caused by the immune system overreacting and inappropriately attacking the body’s own healthy cells in the brain. These forms comprise about half of all cases. The other half of encephalitis cases arise from infection.

The two types caused by an overactive immune system are autoimmune encephalitis (AE) and acute encephalomyelitis (ADEM).

Both conditions present very similarly in terms of symptoms. These include-

  • Disorientation
  • Altered mental status
  • Seizures
  • Motor abnormalities
  • Sensory abnormalities

The similarity in these symptoms makes accurate diagnosis difficult. Unfortunately, the treatment for these conditions differs. Although the types of therapies that are used are generally the same (corticosteroids, intravenous immunoglobulins, plasmapheresis, etc.), they are used in different doses and for different periods of time. Those with AE typically necessitate a greater number of therapies due to prolonged and protracted condition.

The Study

To better differentiate between AE and ADEM, researchers studied a decade of medical records (up until December of 2019). All records were from pediatric patients at the University of Texas Southwestern. In total, 75 individuals had a form of encephalomyelitis related to the immune system. Of these, 52 had AE and 23 had ADEM.

Analyzing the records, the team assessed-

  • Patient history
  • Lab results
  • Imaging results

As a whole, the differences found between the two conditions were slight. ADEM patients had-

  • Shorter period of time until diagnosis
  • Abnormal magnetic resonance imaging (100% vs 61% for AE)
  • Lower chance than AE patients to have a longer hospital stay (13 days vs 21)
  • Lower chance than AE patients to have a neurological disability upon leaving the hospital that required significant PT or OT

As aforementioned, treatment typically takes longer for AE patients, however, symptoms improve with the same treatments for both groups.

The more we can understand about each condition and what makes each unique, the better we will be able to serve these patient populations.  

You can read more about this study here.

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