Medline ® Abstracts for References 3,4

Seven cases of subacute idiopathic demyelinating polyradiculoneuropathy had a monophasic illness characterized by progressive weakness of all four limbs that evolved during 4 to 8 weeks. Neurophysiological investigations implied demyelination in all seven cases. In two patients, sural nerve biopsy specimens that were taken showed macrophage-associated demyelination. All patients made substantial or complete recoveries with oral prednisolone (four cases) or without treatment (three cases). None of the patients required ventilation or had autonomic complications. These cases provide a link between the acute idiopathic demyelinating form of Guillain-Barrésyndrome and chronic idiopathic demyelinating polyradiculoneuropathy.

OBJECTIVE: To report the clinical, electrophysiologic, and histologic characteristics of subacute inflammatory demyelinating polyneuropathy (SIDP) and to present the diagnostic criteria of this disease.

METHODS: For a diagnosis of "definite SIDP," there were four mandatory criteria: 1) progressive motor and/or sensory dysfunction consistent with neuropathy in more than one limb with time to nadir between 4 and 8 weeks, 2) electrophysiologic evidence of demyelination in at least two nerves, 3) no other etiology of neuropathy, and 4) no relapse on adequate follow-up. Supportive criteria included high spinal fluid protein level (>55 mg/dL) and inflammatory cells in the nerve biopsy. A diagnosis of "probable SIDP" required progression of demyelinating neuropathy over a 4- to 8-week period.

RESULTS: Sixteen definite SIDP patients were identified among 29 probable SIDP patients. An antecedent infection was found in 38% of cases. The two most common neuropathy types were a symmetric motor-sensory neuropathy and a pure motor neuropathy. Cranial nerve deficits and respiratory failure were rare. Spinal fluid protein was high in 93% of cases. Demyelination was documented by the motor nerve conduction in 88% of cases and by the near-nerve needle sensory nerve conduction in two cases. Almost all patients were treated with prednisone and some with additional immunotherapies. Complete recovery was achieved in 69% of cases and partial recovery in others. Definite SIDP had all the characteristics of CIDP with three exceptions: a higher rate of antecedent infection, no relapse rate, and a high rate of recovery to normal.

CONCLUSION: Subacute inflammatory demyelinating polyneuropathy is a definite entity bridging the gap between Guillain-Barrésyndrome and chronic inflammatory demyelinating polyneuropathy.