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[Postpolio late progressive muscular atrophy--clinical and epidemiologic analyses in 4 Japanese cases]
T Nagashima1, H Karashima, R Takahashi
1Department of Neurology, Tokyo Metropolitan Neurological Hospital.
Abstract:
Four Japanese cases of postpolio progressive muscular atrophy (PPMA) of late onset were clinically studied to characterize their clinical features and discussed upon the epidemiologic viewpoint. Four male patients were included with mean age of 43.5 (30-59) years on examination, diagnosed as PPMA after the criteria by Alter (1982) and Dalakas (1986). All suffered from polio at age 10 month to 8 years (mean: 3y) between 1931 and 1957 with residual motor paresis in one limb or two. Twenty-eight to 55 (mean: 40.3) years later, subsequent muscle weakness and atrophy appeared in the limb seemingly unaffected by the initial polio attack. Marked fasciculations and occasional myalgias were noticed without sensory disturbance and bulbar as well as upper motor neuron signs. Laboratory examinations revealed moderate elevations of serum CK and protein content in SCF. No significant elevation of polio virus antibody titers was found in both serum and CSF. Electromyography showed neurogenic changes of various degrees by muscle tested. Muscle CT disclosed patchy distribution of atrophied muscles with fatty replacement in all extremities. Spinal cord MRI images were unremarkable. Scatters of small grouped atrophy and fiber type grouping were noticed on muscle biopsy specimens. These findings summarized in our cases are generally compatible with those of hereby reported PPMA cases. On reviewing the western literature and the great epidemic of polio around 1960 in Japan, an increasing number of patients with PPMA can be anticipated in near future; possibly in 10 years.
Insights
Late-onset postpolio progressive muscular atrophy (PPMA) presents with new muscle weakness decades after polio. This study characterizes four Japanese male cases, highlighting clinical features and potential future increases in PPMA incidence.
Area of Science:
- Neurology
- Clinical Medicine
- Epidemiology
Background:
- Postpolio progressive muscular atrophy (PPMA) is a late-onset neurological condition affecting individuals with a history of poliomyelitis.
- Understanding the clinical characteristics and epidemiological trends of PPMA is crucial for patient management and forecasting future healthcare needs.
- Previous studies have described PPMA, but late-onset cases, particularly in Japan, require further characterization.
Purpose of the Study:
- To clinically characterize four Japanese male cases of late-onset postpolio progressive muscular atrophy (PPMA).
- To discuss the epidemiological implications of these cases in the context of Japan's polio history.
- To compare findings with existing literature on PPMA.
Main Methods:
- Clinical evaluation of four male patients diagnosed with PPMA based on established criteria.
- Detailed medical history including age at polio onset, residual deficits, and time to PPMA onset.
- Laboratory investigations (serum CK, CSF protein), electrophysiological studies (EMG), imaging (Muscle CT, MRI), and muscle biopsy analysis.
Main Results:
- Patients developed PPMA 28-55 years after initial polio, with onset at a mean age of 43.5 years.
- New muscle weakness and atrophy occurred in previously unaffected limbs, accompanied by fasciculations and myalgias, without sensory or upper motor neuron signs.
- EMG revealed neurogenic changes, muscle CT showed fatty replacement, and biopsy indicated grouped atrophy and fiber type grouping; MRI was unremarkable.
Conclusions:
- The clinical and pathological findings in these four Japanese PPMA cases are consistent with previously reported cases.
- Given Japan's polio epidemic history, an increase in PPMA patients is anticipated in the coming decade.
- Further epidemiological surveillance and clinical studies are warranted to monitor and manage the expected rise in PPMA cases.