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psy_fatigue

fatigue

Introduction:

  • fatigue can be defined as a pervasive sense of tiredness or lack of energy that is not related exclusively to exertion.
  • fatigue, like pain, is intrinsically a brain-mediated sensation, although, as with pain, people report that fatigue is experienced as a peripheral phenomenon, apparently occurring in musculoskeletal regions. Most patients also experience “mental fatigue”, typically precipitated by complex neuropsychological tasks.
  • it is a common complaint in the community & is usually transitory, and 10-25% of patients presenting to GPs have prolonged and disabling fatigue, 5-15% have chronic fatigue whilst 0.5-2.5% have chronic fatigue syndrome (CFS)
  • after infectious mononucleosis, reporting of prominent fatigue: 41% during acute illness; 71% at 1 month; 43% at 2 months; 9% at 6 months;
  • fatigue must be differentiated from:
    • muscle weakness (eg. myopathy, polymyositis)
    • neuromuscular fatigability (eg. myasthenia gravis)
    • central fatigue of physical & mental fatigue at rest (eg. multiple sclerosis)
    • anhedonia - lack of motivation to commence tasks & lack of pleasure from tasks undertaken (eg. major depression)
    • somnolence - daytime sleepiness, short sleep latency (eg. sleep apnoea, narcolepsy)
    • breathlessness (eg. COPD, cardiac failure, anaemia)
    • inflammation/infection causing muscle/joint pain, fever, malaise (eg. SLE, influenza, fibromyalgia)
    • anxiety - panic attacks, avoidant behaviour

Differential diagnosis of persistent fatigue:

Clinical evaluation of persistent fatigue:

  • unexplained fatigue < 1 month duration:
    • routine evaluation of acute medical & psychological disorders (eg. acute EBV, bereavement)
    • R/V in 1 month
  • prolonged fatigue > 1 month duration:
  • at 3 months:
    • comprehensive fatigue assessment:
      • medical Hx & exam
      • psych. Hx & exam
      • FBE, ESR, U&E, Ca, PO4, LFTs, TSH, urinalysis for protein, blood, sugar
      • Ix as indicated by clinical evaluation
      • BUT the following are not currently routinely recommended:
        • serology for EBV, enteroviruses, Lyme disease in Australia
        • tests of immunity
        • urinary protein metabolite screening
        • neuroimaging studies
        • autoantibody assays
        • CK
    • R/V monthly
  • at 6 months:
    • chronic fatigue syndrome diagnosis & Mx:
      • make specific Dx of CFS
      • provide information about CFS
      • consider contact with support groups
      • enlist social welfare agencies
    • R/V monthly
  • at 12 months:
    • comprehensive fatigue assessment
    • annual review
psy_fatigue.txt · Last modified: 2011/07/22 15:14 by gary