Postpolio syndrome: Clinical and epidemiological studies

Poliomyelitis anterior acuta (polio) is a viral disease with an asymptomatic or mild course in most of the affected patients. In a minority of the patients the virus invades the nervous system. When this results in muscle weakness the term paralytic poliomyelitis is used. Paralytic poliomyelitis has a characteristic course. Acute onset with subsequent muscle weakness is followed by a two-year period of recovery of muscle strength. When maximal recovery is reached, some patients are still left with residual paresis. Usually a period of relative stability of several decades follows, whereafter some patients may experience new neuromuscular complaints. When other causes of progressive neuromuscular symptoms have been excluded, this complex of symptoms is called "postpolio syndrome". The complaints mainly concern new or increasing muscle weakness, decrease in muscle size, muscle cramps, muscle and joint pains, involuntary 'twitches' of muscles, fatigue, diminished stamina and increase of disabilities.
This thesis focusses on several aspects of the postpolio syndrome that are still a matter of debate. We investigated: (1) the clinical features of the postpolio syndrome, i.e., the occurrence of the new neuromuscular complaints and the extent of progression of new muscle weakness; (2) the diagnostic means to distinguish postpolio patients from polio survivors with stable neuromuscular conditions; (3) the prevalence of new neuromuscular complaints resulting in an impaired function in Dutch polio survivors.