Poliomyelitis

Epidemics of paralytic poliomyelitis occurred regularly before the introduction of polio vaccination. Such epidemics are most problematic in the developed world. In undeveloped countries, cases are generally sporadic with few epidemics. This difference is largely the result of public health practices in the developed world. In undeveloped countries, polio is transmitted via contaminated drinking water and typically infected infants at a young age. The post-polio syndrome, which includes progressive fatigue, pain, and weakness, is present late in life in a majority of survivors of paralytic poliomyelitis. Although it is a common diagnosis, the epidemiological studies suggest that the rate of decline is modest in the majority of patients and carries a benign prognosis in most. The pathophysiology of the post-polio syndrome remains debated, but leading theories include dying-back of axonal sprouts in massively reinnervated motor units, attritional loss of affected anterior horn cells and physiological aging on a fixed neurological deficit. Treatment of the post-polio syndrome is limited to symptomatic care. Fatigue is unresponsive to multiple medication trials and responds best to energy conservation. Pain requires a thorough evaluation with treatment directed at specific etiologies. Most patients can expect years of neuromuscular stability and only a minority requires additional lifestyle modifications later in life.