Poliomyelitis--new problems with an old disease

Mechanisms and strategies for prevention in diabetic retinopathy

Evidence converges from multiple directions to indicate that prevention or very early intervention is the correct approach to diabetic retinopathy. Preclinical studies are identifying promising drugs or classes of drugs to be added to antidiabetic treatment. Recent clinical trials were still initiated at such late stages of retinopathy that the results are not readily interpretable. The challenge for the next few years is to find ways faster than clinical trials to ascertain the relevance to human diabetic retinopathy of adjunct drugs successful in animal studies.

Prevalence and risk factors of post-polio syndrome in a cohort of polio survivors

OBJECTIVE

To investigate frequency and associated factors of post polio syndrome (PPS) in an Italian cohort of people with prior poliomyelitis.

METHODS

We screened subjects admitted for poliomyelitis at the paediatric hospital of the University of Palermo during the time frame 1945-1960. Patients who developed PPS were identified through a structured questionnaire and a neurologic examination. PPS diagnosis was made according to specified diagnostic criteria. Frequency of PPS was calculated in the selected cohort of polio survivors. The association with the investigated risk factors (sex, age at onset of polio, extension and severity of polio, education, associated diseases, cigarette smoking, trauma, polio vaccination) was analysed by the calculation of the odds ratio.

RESULTS

Forty-eight participants met the adopted diagnostic criteria for PPS, giving a prevalence of 31.0%. The prevalence rate was significantly higher in women than in men (p=0.02). Logistic regression analyses revealed a significant inverse association with onset of poliomyelitis at over 12 months of age (OR 0.33; CI 0.14-0.79) a higher degree of education (OR 0.20; CI 0.07-0.79), and a significant association with the presence of other diseases (OR 9.86; CI 3.69-26.34).

CONCLUSIONS

In our survey one-third of patients with prior poliomyelitis had PPS. Higher age at onset of poliomyelitis is inversely associated with PPS. The association with other diseases may indicate that a chronic physical stress, particularly in already weak motor units, can contribute to the development of signs and symptoms of PPS. Our results also suggest the impact of socio-economic conditions on the risk of PPS.

Varied clinical patterns, physical activities, muscle enzymes, electromyographic and histologic findings in patients with post-polio syndrome in Taiwan

STUDY DESIGN

A study of the clinical features, physical activity, muscle enzyme, electromyography and histopathological alternations of muscles in patients with post-polio syndrome (PPS).

OBJECTIVE

To assess the varied patterns of PPS in Taiwan.

SETTING

Taiwan.

METHODS

Thirty-one patients who fulfill the inclusion criteria of PPS were selected for study. Clinical features, physical activity scale, serum concentrations of creatine kinase, electromyography and histopathological alterations of muscles were assessed and correlated to the causes of PPS patients.

RESULTS

Patients with PPS in Taiwan are relatively young, with a mean age of 39.3 years. Elevated concentration of creatine kinase was found predominantly in male patients with higher physical activities. Electromyographic examinations as well as histological tests of affected muscles revealed prominent evidence of chronic and active denervation with reinnervation in PPS patients.

CONCLUSION

Patients with PPS in Taiwan are young. Thus, PPS should not be attributed to aging. Physical attrition with degradation of nerve terminals is considered the main cause of this disease.

SPONSORSHIP

This study was supported by the National Science Council, Republic of China under grant no. NSC-83-0412-B002-302.

A pilot study to determine the efficiency of lightweight carbon fibre orthoses in the management of patients suffering from post-poliomyelitis syndrome

OBJECTIVES

To assess the usage of carbon fibre orthoses in assisting post-polio syndrome patients who reported advancing weakness and difficulty in maintaining their independent ambulatory status.

DESIGN AND INTERVENTIONS

Carbon fibre orthoses that are 30% lighter than metal braces were constructed.

SUBJECTS

Thirty patients who complained of difficulty in maintaining their ambulation using long-leg braces were provided with lightweight orthoses.

RESULTS

Seventy per cent of the patients reported satisfaction with their braces. There were, however, problems in construction and use.

CONCLUSIONS

Ambulation can be preserved in some patients who report advancing weakness because of post-polio syndrome.

The post-polio syndrome as an evolved clinical entity. Definition and clinical description

Post-polio syndrome (PPS) refers to the new neuromuscular symptoms that occur at least 15 years after stability in patients with prior acute paralytic polio-myelitis. They include: (1) new muscle weakness and atrophy in the limbs, the bulbar or the respiratory muscles [post-poliomyelitis muscular atrophy (PPMA)] and (2) excessive muscle fatigue and diminished physical endurance. PPS is a clinical diagnosis that requires exclusion of all other medical, neurological, orthopedic or psychiatric diseases that could explain the cause of the new symptoms. Routine electromyography is useful to confirm chronic and ongoing denervation and exclude neuropathies. Muscle biopsy, single fiber electromyography (EMG), macro-EMG, serum antibody titers to polio virus, and spinal fluid studies are very useful research tools but they are rarely needed to establish the clinical diagnosis. PPS is a slowly progressive phenomenon with periods of stability that vary from 3 to 10 years. Current evidence indicates that PPS is the evolution of a subclinically ongoing motor neuron dysfunction that begins after the time of the acute polio. It is clinically manifested as PPS when the well-compensated reinnervating process crosses a critical threshold beyond which the remaining motor neurons cannot maintain the innervation to all the muscle fibers within their motor unit territory.

The polio survivor as expert: implications for rehabilitation nursing research

Clients' personal experiences with illness or tragedy can uniquely qualify them as experts in many research-relevant content areas. Nurse researchers can benefit from this expertise by involving such clients in important decision-making aspects of research planning. The advantages of consulting with client-experts in the early and subsequent stages of research are discussed in this article, which uses as an example the way such consultation has worked in the development of a study of coping in polio survivors. Consultation with client-experts is especially appropriate when research involves sensitive issues or the measurement of subjects at vulnerable periods in their lives. It is advocated as a means of helping to ensure that participants are questioned in the most ethical, sensitive way possible and that the research will address the needs and concerns of the target population.

Fractures in an aging population of poliomyelitis survivors: a community-based study in Olmsted County, Minnesota

OBJECTIVE

To determine the incidence of fractures in a cohort of survivors of paralytic poliomyelitis ("polio").

DESIGN

We conducted a population-based retrospective cohort study of residents of Olmsted County, Minnesota, who had an initial diagnosis of polio between 1935 and 1959 and survived the acute illness.

MATERIALS AND METHODS

A comprehensive medical records-linkage system was used to retrieve all diagnoses of poliomyelitis in residents of the county for the specified 25-year period. For the 277 study subjects, the medical records were searched for the occurrence of fracture from the time of initial diagnosis of polio until death or the most recent clinical contact. All fractures were classified on the basis of type of associated injury and skeletal site of involvement. The influence of polio on the incidence of fractures was evaluated by estimating the cumulative incidence of new fractures after the diagnosis of polio and the standardized morbidity ratio. The relative influence of various factors on the risk of fracture was determined.

RESULTS

Of the 277 Olmsted County residents with polio, 87 experienced 161 fractures, and the estimated cumulative incidence of any fracture after 40 years was 48%. The cumulative incidence of any limb fracture was 41% and was less than the expected value of 44% (P = 0.001). Only the risk of distal femoral and proximal humeral fractures was significantly higher than that among Olmsted County residents in general. The increased risk seemed to be associated with weakness and disuse of the involved limbs rather than with generalized osteoporosis. Theoretically, a greater capacity for bone remodeling in response to changes in muscle use might have protected patients with polio in childhood, but such persons were as likely to sustain a fracture as those with adult-onset poliomyelitis.

CONCLUSION

These data indicate that survivors of paralytic poliomyelitis do not have an unusual risk of fracture except in affected limbs.

Lack of serum neutralizing antibody against poliovirus in patients with juvenile distal spinal muscular atrophy of upper extremities

Serum neutralizing antibodies for type 1, 2 and 3 poliovirus were studied in 15 Chinese patients in Taiwan with juvenile distal spinal muscular atrophy of the upper extremities and 15 age-matched normal subjects. Significantly lower serum antibody titers were found in the study group, suggesting that patients with this chronic focal form of acquired motor neuron disease are, to some degree, immunologically unresponsive to the neutralizing epitope of poliovirus.

The postpolio syndrome: no evidence for poliovirus persistence

To investigate the possibility of poliovirus persistence in patients with the postpolio syndrome, we examined skeletal muscle biopsy specimens, cerebrospinal fluid specimens, and sera for the presence of poliovirus RNA by the polymerase chain reaction, and for IgM antibodies by a poliovirus type-specific IgM antibody-capture enzyme-linked immunosorbent assay. In none of these specimens was poliovirus RNA or a poliovirus type-specific IgM response detected. These results argue against the hypothesis that poliovirus persists in patients with the postpolio syndrome and plays a role in the pathogenesis of the postpolio syndrome.

Circulatory autonomic failure 50 years after acute poliomyelitis

A 59-year old woman who presented with postural dizziness 50 years after an acute episode of poliomyelitis is described. There were no new neurological signs and no evidence of motor neuron disease. She had postural hypotension with an abnormal Valsalva. Investigations led to a diagnosis of hypo-adrenergic orthostatic hypotension, with a predominantly preganglionic sympathetic lesion and intact vagal baroreflex pathways. Although pure autonomic failure and multiple system atrophy are possible causes of circulatory autonomic failure, no other new neurological or autonomic features have developed during a 2 year follow-up. We propose that hypo-adrenergic orthostatic hypotension may be a late complication of poliomyelitis. Deterioration in ambulatory ability in a patient with previous poliomyelitis should additionally include assessment of cardiovascular autonomic function.