Monday, July 9, 2007

Hopkins Syndrome

Hopkins syndrome, sometimes called acute post-asthmatic amyotrophy, is an acute attack of muscle weakness that arises in a small number of patients with asthma, usually after a severe asthma episode. It is exceptionally rare, and there are not more than a few dozen cases reported in the medical literature, worldwide. The syndrome resembles poliomyelitis; it characteristically produces acute flaccid paralysis with atrophy and fasciculations, usually of one or two limbs. The illness usually arises as the patient is recovering from the asthma attack; most cases occur in children.

The cause of Hopkins syndrome has not been established, but its association with asthma exacerbations (usually with a respiratory infection as a trigger) has led to suspicion that the initial viral insult that causes the respiratory infection is also implicated in the subsequent paralysis. Herpes simplex virus type I DNA has been found in the cerebrospinal fluid of at least one patient diagnosed with Hopkins syndrome.[1] In several cases, anti-viral antibody titers for echovirus, enterovirus, coxsackievirus and poliovirus types 1, 2 and 3 were specifically sought; all were negative.[2],[3] There is one reported case in which Mycoplasma pneumoniae infection was found in the patient.[4]

The syndrome appears to involve the spinal cord: specifically, the anterior horn cells subserving the affected muscles are often damaged. The evidence for anterior horn cell involvement comes from radiological [3],[5],[6] and electromyographical studies.[4] In one case, a biopsy of an affected muscle "revealed scattered atrophic fibers, indicating lesions in the anterior horn cells of the spinal cord".[7]

As the illness is rare, no treatments have been subjected to a randomized controlled trial. Acyclovir,[1] steroids, and therapeutic plasma exchange have been tried; one report suggests that the latter is more effective than steroidal therapy.[8] The prognosis for recovery of function of the affected limbs is generally considered to be poor.

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