Criteria for diagnosis of post-polio syndrome*
· Prior paralytic poliomyelitis with evidence of
motor neuron loss, as confirmed by history of the acute
paralytic illness, signs of residual weakness and
atrophy of muscles on neuromuscular examination, and
signs of nerve damage on electromyography (EMG). Rarely,
persons have subclinical paralytic polio, described as a
loss of motor neurons during acute polio but with no
obvious deficit. That prior polio now needs to be
confirmed with an EMG. Also, a reported history of
nonparalytic polio may be inaccurate.
· A period of partial or complete functional
recovery after acute paralytic poliomyelitis, followed
by an interval (usually 15 years or more) of stable
neuromuscular function.
·
Gradual onset of progressive and persistent new muscle
weakness or abnormal muscle fatigability (decreased
endurance), with or without generalized fatigue, muscle
atrophy, or muscle and joint pain. Onset may at times
follow trauma, surgery, or a period of inactivity, and
can appear to be sudden. Less commonly, symptoms
attributed to PPS include new problems with breathing or
swallowing.
· Symptoms
that persist for at least a year.
· Exclusion of other neuromuscular, medical, and
orthopedic problems as causes of symptoms.
*Modified from: Post-Polio Syndrome: Identifying Best
Practices in Diagnosis & Care. March of Dimes, 2001.
PPS may be difficult to diagnose in some people because
other medical conditions can complicate the evaluation.
Depression, for example, also is associated with fatigue and
can be misinterpreted as PPS or vice versa. For this reason,
some clinicians use less restrictive diagnostic criteria,
while others prefer to categorize new problems as the late
effects of polio—for example, shoulder osteoarthritis from
walking with crutches, a chronic rotator cuff tear leading
to pain and disuse weakness, or breathing insufficiency due
to progressive scoliosis.
Polio survivors with PPS
symptoms need to visit a physician trained in neuromuscular
disorders to clearly establish potential causes for
declining strength and to assess progression of weakness not
explained by other health problems.
Physicians may
use magnetic resonance imaging (MRI), computed tomography
(CT), neuroimaging, and electrophysiological studies as
tools to investigate the course of decline in muscle
strength. Less commonly, they will conduct a muscle biopsy
or a spinal fluid analysis. These tests are also important
to exclude other, possibly treatable, conditions that mimic
PPS, but the tests do not identify survivors at greatest
risk for new progression of muscle weakness.
There are currently IVIg treatments for the syndrome
itself. However, a number of controlled studies have
demonstrated that nonfatiguing exercises can improve muscle
strength.
Researchers have found that CIDP is the
underlaying issue in post polio syndrome and IVIg helps it,
In an effort to reduce fatigue, increase strength, and
improve quality of life in PPS patients, scientists
conducted two controlled studies using low doses of the drug
pyridostigmine (Mestinon). These studies showed that
pyridostigmine is not helpful for PPS patients.
In
another controlled study scientists concluded that the drug
amantadine is not helpful in reducing fatigue. And other
researchers recently evaluated the effectiveness of
modifinil (Provigil) on reducing fatigue and found no
benefit.
The future of PPS treatment may center on
IVIg.