Excerpt from the
Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors©
Unaccustomed or disabling fatigue is one of the most common symptoms expressed by polio survivors and occurs for multiple reasons. Some polio survivors describe fatigue as a decrease in stamina, in endurance, and in the ability to perform repetitive actions (rapid muscle fatiguability), either measured in ambulatory distance or in the performance of upper extremity tasks. Others report a more global sense of tiredness, describing sleepiness, decreased attentiveness, and forgetfulness. Many require more than normally expected amounts of sleep, and frequently feel refreshed by a nap. Many polio survivors also describe a major decrease in stamina following illness, surgery, or trauma (Yarnell, 1988).
While electrodiagnostic studies have shown that polio-involved muscles commonly show signs of chronic denervation/reinnervation and defective neuromuscular junction transmission (see Pathology), not all polio survivors experience fatigue. Strength and endurance testing studies indicate that survivors who report new symptoms indeed do have greater residual weakness, reduced work capacity, and recover strength after activity less readily than asymptomatic polio survivors (Agre & Rodriguez, 1990). Gait analysis of survivors indicates that weakened muscles are required to work longer and with greater intensity to compensate for paralyzed muscles elsewhere in the lower extremities (Perry et al., 1987). It is clear that fatigue may result from poor pacing or pushing past the point of "tiredness" (see Pacing).
Chronic musculoskeletal pain (see Pain), frequently a complaint of survivors, can cause fatigue and irritability and can also lead to deconditioning and disordered sleep (Yarnell, 1988). Disturbed sleep contributes to daytime sleepiness and fatiguability. Many medications, such as narcotics and benzodiazepines, when used long term for chronic pain, disturb the restful phase of sleep and can contribute to a feeling of fatigue and irritability. Fatigue also can be attributed to medications (see Medications), such as beta blockers, or excessive use of alcohol or marijuana.
Deconditioning is another contributing factor to general fatigue. It can lead to disuse atrophy and new weakness of muscles, as well as reduced cardiovascular fitness (Stanghelle et al., 1993). Polio survivors may take three to four times longer to convalesce from illness, surgery, or trauma, compared to individuals who have a full complement of anterior horn cells. While staying in condition is important, each survivor must find the balance between overworking their delicate old reinnervated motor units and appropriate conditioning exercise (see Exercise).
Respiratory problems contribute to fatigue. Polio survivors may have obstructive or central sleep apnea (see Sleep Apnea) causing daytime sleepiness and fatigue. Survivors with increased respiratory muscle weakness may develop carbon dioxide (CO2) retention due to shallow breathing, especially at night. CO2 narcosis leads to fatigue and sleepiness during the day resulting in napping during conversations or periods of mild relaxation (see Underventilation).
Dealing with additional disability is emotionally draining for many and can lead to depression (see Depression) with decreased attention and concentration, or distractibility (Backman, 1987). Sadness and/or grieving for lost function (see Loss), as well as depression, can cause fatigue.
Finally, there is the theory that some polio survivors have fatigue as a result of having had polioencephalitis. These individuals may experience a sense of central fatiguability (decreased attention and concentration and memory loss) due to involvement of various brain structures including the reticular activating system (Bruno et al., 1991).
To adequately treat the symptom of fatigue, the various contributing factors need to be identified. Fatigue due to complications of chronic pain, deconditioning, medications, depression, or breathing problems, or fatigue due to dysfunction of the motor units (see Weakness) must be treated appropriately.