Fatigue may range from minimal to severe in intensity. When severe it can result in significant disability impacting work, relationships and activities of daily living.
The frequency of fatigue may vary, from occasional to continuous.
fatigue burden =
= (severity of fatigue) * (frequency)
Causes of fatigue:
(1) primary fatigue (directly related to the neurological involvement)
(2) secondary to sleep disturbances
(3) secondary to depression and mood disorders
(4) secondary to medications
(5) secondary to physical exertion
(6) secondary to infections
Primary fatigue is a diagnosis of exclusion; it is considered after evaluating each of the secondary causes. Identification of secondary causes is important since these are amenable to treatment.
