Neurological Symptoms in Danes with a History of Poliomyelitis: Lifelong Follow-Up of Late Symptoms, their Association with Initial Symptoms of Polio, and Presence of Postpolio Syndrome

Abstract

Background: Previous studies suggest that patients with a history of poliomyelitis (PM) later in life experience a variety of symptoms. These studies were carried out in patients who later in life were admitted to hospital or became members of polio societies and may therefore not be representative of all polio patients. Little data have been published concerning patients actually discharged from hospital with a diagnosis of acute paralytic PM.

Objectives: The aim of this study was to compare the prevalence of late symptoms in individuals with a history of paralytic PM with that of controls, and to study whether late symptoms in individuals with a history of PM were associated with symptoms at the acute stage of polio, and finally to compare the prevalence of symptoms in polio patients with postpolio syndrome (PPS) with the prevalence of symptoms in polio patients without PPS.

Methods: A questionnaire concerning various symptoms was sent to a previously established cohort of patients, who during the polio epidemics were discharged from the Department of Infectious Disease at Blegdamshospitalet, Copenhagen, with a diagnosis of paralytic PM, and to age- and gender-matched controls without PM. Information about symptoms at the acute stage of disease was obtained from hospital records. Logistic regression analysis with adjustment for age and gender was applied to compare the occurrence of late symptoms in cases and controls and within the above-mentioned groups of individuals with a history of PM.

Results: (i) Compared with controls, individuals with a history of polio significantly more often reported muscle symptoms, pain, neuropathic sensory symptoms, and bulbar symptoms; (ii) the occurrence of symptoms did not seem to be related to symptoms of the initial PM; and (iii) symptom prevalence was significantly higher in individuals with a history of polio who reported PPS as compared with those who did not.

Conclusion: Our data indicate that individuals with a history of PM late in life experience a variety of symptoms that cannot be attributed to lesions of the anterior horn. Furthermore, late symptoms do not seem to be related to initial symptoms of the acute stage of PM but to reported PPS. The last finding supports the perception that the cause of PPS is not just normal ageing.

Keywords: Acute polio; Follow-up; Neurological symptoms; Poliomyelitis; Postpolio syndrome.