The electroclinical characteristics of 5 children (ages 4-13 years) with subacute inflammatory demyelinating polyneuropathy (SIDP) are reported from the Royal Children’s Hospital, Victoria, Australia. Onset followed 2-13 days after a nonspecific infection with fever, upper respiratory tract symptoms or gastroenteritis in 3 patients; one had recent cytomegalovirus infection; none had Campylobacter jejuni. All had leg weakness (with pain in 3) at presentation, and upper limb involvement followed. All remained ambulant. Neurologic findings included areflexia in 5, ataxia in 4, and bilateral facial weakness in 1. CSF protein was elevated (0.75-1.5 g/L) in 3, and leukocytes were absent or 1/mm3. Nerve conduction studies were abnormal. Period from onset of symptoms to treatment was 4-8 weeks. All received oral prednisolone for 1.5-6 months, and all showed improved muscle strength within 1 week. Three had returned to normal within 6 months and one within 8 months, and none showed relapse at 6-20 years follow-up. One was normal when last seen at 10 months follow-up. 
COMMENT. The authors have differentiated this series of SIDP patients with a benign, subacute illness and monophasic course of 4-8 weeks from the acute form of inflammatory demyelinating polyneuropathy (Guillain-Barrc syndrome [GBS]) with a 4 week course, and a chronic form (CIDP) with progression over 8 weeks and frequent relapse. SIDP characteristics that differ from GBS include 1) longer period of progression; 2) lack of respiratory, cranial nerve, or autonomic involvement; 3) more abnormal nerve conduction in initial stages; and 4) rapid and sustained response to corticosteroids. The monophasic and nonrelapsing course of SIDP differentiates it from CIDP. The response of CIDP to steroids is reviewed in Ped Neur Briefs 2005; 19:19).