Review of 23 patients affected by the stiff man syndrome: clinical subdivision into stiff trunk (man) syndrome, stiff limb syndrome, and progressive encephalomyelitis with rigidity

摘要

OBJECTIVE—To investigate whether the stiff limbsyndrome may be separated from the stiff man syndrome and progressiveencephalomyelitis with rigidity on simple clinical grounds, and whethersuch a distinction has implications for aetiology, treatment, and prognosis.
METHODS— Twenty three patients referred over a 10 year period with rigidity and spasms in association with continuousmotor unit activity, but without evidence of neuromyotonia,extrapyramidal or pyramidal dysfunction or focal lesions of the spinalcord were reviewed. The patients were divided into those with an acuteor subacute illness, leading to death within 1 year, and those with achronic course. The latter were divided into those in whom rigidity and spasms dominated in the axial muscles, or in one or more distal limbs,at the time of their first assessment.
RESULTS—This simple division identified threedistinct groups of patients. (1) Progressive encephalomyelitis withrigidity: two patients had a rapidly progressive conditioncharacterised by widespread rigidity which resulted in death within 6 and 16 weeks. One patient had negative anti-GAD and anti-neuronalantibodies, but had markedly abnormal CSF and widespread denervation.The principal pathological findings in this case were a subacuteencephalomyelitis which primarily affected the grey matter. In theremaining patient anti-GAD antibodies were not tested, and postmortemwas refused. (2) Stiff man syndrome: eight patients had rigidity andpainful spasms of the lumbar paraspinal, abdominal, and occasionallyproximal leg muscles associated with a lumbar hyperlordosis. There wasno involvement of the upper limbs, distal lower limbs, sphincters orcranial nerves. Seven had anti-GAD antibodies and most had additional evidence of autoimmune disease. Neurophysiologically there was continuous motor unit activity with abnormal exteroceptivereflexes, but a normal interference pattern during spasms. The patients all responded to baclofen/diazepam and remained ambulant. (3) Stifflimb syndrome: thirteen patients had rigidity, painful spasm, andabnormal postures of the distal limb, usually the leg. About half wenton to develop sphincter or brainstem involvement. Generalised myoclonicjerks were not a feature. Only two had truncal rigidity, and anothertwo had anti-GAD antibodies. Most had no evidence of autoimmunedisease. Neurophysiologically they had continuous motorunit activity in the affected limb, abnormal exteroceptive reflexes,and abnormally segmented EMG activity during spasms. The disease ran aprotracted course, and most patients had only a partial response tobaclofen or diazepam. About half became wheelchair bound.
CONCLUSIONS—The stiff limb syndrome seems distinctfrom the stiff man syndrome or progressive encephalomyelitis withrigidity, and is an important cause of rigidity and spasm in thesetting of continuous motor unit activity.