Acute Disseminated Encephalomyelitis with Measles

Acute disseminated encephalomyelitis is an inflammatory demyelinating illness usually associated with infections or antecedent immunization. Due to control of most vaccine preventable diseases in developed countries, most cases of acute disseminated encephalomyelitis occur in developing countries and are seen secondary to nonspecific upper respiratory tract infections. We report a case of acute disseminated encephalomyelitis associated with measles in a 21⁄2-year-old male child despite having measles vaccination in infancy. The diagnosis was based on clinical findings and CT scan of brain. The patient was managed with high dose corticosteroids along with supportive measures. He recovered completely and follow-up for six months revealed no neurological deterioration.

Acute disseminated encephalomyelitis (ADEM), also known as postinfectious encephalomyelitis, is an acute widespread demyelinating disease of the central nervous system that typically presents as a monophasic disorder associated with multifocal neurologic symptoms and encephalopathy. 1The incidence of ADEM is about 0.4 per 100000 people per year. 2 Although ADEM occurs in all ages, most reported cases are in children and adolescents, with the average age around 5 to 8 years. 3It usually occurs following a viral infection but may appear following vaccination and bacterial or parasitic infection. 2inical manifestations like abrupt development of irritability, fever, headache, myalgia, and drowsiness often precede the neurological symptoms of ADEM.The hallmark of clinical features of ADEM is the development of a focal or multifocal neurological disorder.Initial neurological features include encephalopathy ranging from lethargy to coma, hemiparesis, cranial nerve palsies, and paraparesis. 4lthough initially the symptoms are usually mild, they worsen rapidly over the course of hours to days, with the average time to maximum severity being about four and a half days. 5 controlled clinical trials have been conducted on ADEM treatment.The widely accepted first-line treatment is high dose intravenous corticosteroids such as methylprednisolone or dexamethasone, followed by oral doses of prednisolone tapering within 3-6 weeks.Patients treated with methylprednisolone have shown better outcomes than those treated with dexamethasone.

Case Report
Ishrat Jahan 1 , Shaheen Akter 2 , Sharmin Akhtar Rupa 3 vomiting followed by unconsciousness for 2 days.He had history of measles 10 days back.He was vaccinated according to EPI schedule.On examination, he was febrile, mildly pale, non-icteric and had no lymphadenopathy.There was brownish discoloration with fine desquamation of skin all over the body (Fig 1).The Glasgow coma scale was 8/15.There were no signs of meningeal irritation and cranial nerves were intact.There were hypotonia, hyporeflexia and quadriplegia.Other systemic examinations revealed no abnormalities.The child progressively deteriorated in the first 2 days, was comatosed (GCS 5/15) and remained in this condition for 4 days.Complete blood count, renal and liver function tests, arterial blood gas analyses and electrolyte reports were normal.Chest radiography and ultrasonography of abdomen showed normal findings.Cerebrospinal fluid (CSF) was clear with 4 WBC/cmm of which all were lymphocytes.Protein and sugar values were normal.CSF culture revealed no growth.However, CSF antigen or antibodies for measles could not be assessed.CT scan revealed diffuse hypodensity in the subcortical white matter, periventricular white matter, centrum semiovale, corona radiata, thalamus and brain stem without perilesional edema (Fig 2).All these findings were suggestive of ADEM.The patient was treated with intravenous methylprednisolone 30 mg/kg/day, which had been given for 5 days followed by oral prednisolone (1 mg/kg/day) for another 7 days.The child showed dramatic improvement and recovered completely.Follow up for six months revealed no neurological deterioration.

Discussion
Acute disseminated encephalomyelitis is an acute demyelinating disorder of central nervous system characterized by diffuse neurological signs and multiple white matter lesions on neuroimaging. 6stinfectious encephalomyelitis is associated with concomitant or antecedent infection, usually viral.Most notoriously, measles virus infection is followed by ADEM in approximately 1 in 1000 unvaccinated children and tends to produce more serious phenotype. 8In developing a n d poor countries, because of poor implementation of immunization programs, measles and other viral infections are still widely prevalent and account for frequent occurrences of postinfectious demyelinating diseases.ADEM in developing countries is much more frequent than reported. 9inical features including fever, irritability, rapid neurological deterioration with history of measles, CT finding and subsequent improvement with high dose corticosteriod led us to the diagnosis of ADEM associated with measles.However, it is difficult to differentiate from subacute sclerosing panencephalitis (SSPE) presenting as ADEM, but presence of myoclonic convulsions, latent period and no improvement with steroids can differentiate it from SSPE. 10 In myelitic form of ADEM, partial or complete paraplegia or quadriplegia and diminished or loss of reflexes also occur, which is consistent with our findings. 11EM produces multiple inflammatory lesions in the brain and spinal cord, particularly in the white matter.Usually these are found in the subcortical and central white matter and cortical gray-white junction of both cerebral hemispheres, cerebellum, brainstem, and spinal cord but periventricular white matter and gray matter of the cortex, thalami and basal ganglia may also be involved. 12This is consistent with our findings. 12EM was associated with a mortality rate of 25% after measles infection with major residual neurologic sequel in 25 to 40% of survivors. 13More recent data from two retrospective reviews of children diagnosed with ADEM found 100% survival, with more than 80% of children were neurologically normal in follow up. 2 O u r case showed complete recovery.F o llow up for six months revealed no neurological deterioration.

Conclusion
Acute disseminated encephalomyelitis is an acute yet treatable inflammatory and demyelinating disease with varying clinical presentation that responds well to immunomodulating therapy and the clinical outcome is favorable.Despite achieving and sustaining global measles vaccination coverage of about 80% over the past decade, measles remains the fifth leading cause of mortality among children aged <5 years worldwide.Because of contagiousness of measles, even sustained high coverage vaccination with single-dose strategy does not prevent large outbreaks of measles with significant morbidity and mortality.So, a second dose of measles immunization is essential for effective control of measles and prevention of neurological complications which is practiced in England and Wales, Albania, Romania, Oman, Shandong and Henan provinces of China and USA. 8

Fig 1 .
Fig 1. Brownish discoloration with fine desquamation of skin all over the body