Sir,I read with interest the article “central nervous system inflammatory demyelinating disorders of childhood” (CIDD) by Mahesh et al published in the December issue of the Journal.[1] The authors have done a commendable job in getting a good work up done in their small series of 15 patients. Acute disseminated encephalo-myelitis (ADEM) is probably the most common of the CIDD group of disorders in any hospital-based study considering the seriousness of the illness. During the initial few hours or days of the illness there is a likelihood of mistaking it for other disorders. As the authors had rightly pointed out, prompt diagnosis and immediate institution of immune-modulatory therapy is mandatory if a good outcome is to be seen in ADEM without sequeale.However, they did not explain how ‘progressive multifocal leukoencephalopathy (PML)’ was excluded in the patient who was tested positive for HIV and died ultimately of the disease. The treatment protocol for PML would be totally different from what was followed in the index case. I feel that such ambiguous cases must be excluded before one groups them as CIDD.Four of the cases were in the category of “isolated clinical syndrome.” It will be interesting to see these patients followed up for 5--10 years to find out if any of them develop features of multiple sclerosis. It is only then, that risk factors which facilitate the progression can be identified.In their study of 25 patients with ADEM, Belopitoval et al,[2] found evidence of progression to clinically definite or laboratory-supported MS in 10 patients, when followed up for 2--8 yrs.Earlier we had observed in our article in 2005,[3] that multiple sclerosis is not uncommon in children in our country. The prognosis for visual impairment is the worst in children with multiple sclerosis. Other differences have also been noted in the clinical presentation of multiple sclerosis between children and adults. The definitions of the terms have undergone change since then but the concept of “recurrent ADEM” existed earlier too.