OzEMedicine - Wiki for Australian Emergency Medicine Doctors

fatigue

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

the following list is not exhaustive:
physiological:
- sedentary lifestyle & lack of exercise
- sleep deprivation
persistent stressors:
- workplace-related:
  - shift work
  - career “burn-out” - see coping strategies for ED staff
  - change-induced
- personal-related:
  - marital disharmony
  - financial stress - unemployment, high debt levels, gambling
  - complex, excessively demanding lifestyle
drugs:
- medications - beta blockers
- alcohol & drug dependence
infectious diseases:
- HIV/AIDS, chronic hep. B/C
- post EBV / glandular fever / infectious mononucleosis
autoimmune disorders:
- systemic lupus erythematosus (SLE), rheumatoid arthritis, Sjogren's syndrome
endocrine disorders:
- hypothyroidism, diabetes mellitus
cardiorespiratory disorders:
- chronic airflow limitation, cardiac failure
GIT disorders:
- coeliac disease, inflammatory bowel disease
haematological disorders:
- anaemia
sleep disorders:
- obstructive sleep apnoea
neuromuscular disorders:
- myasthenia gravis, multiple sclerosis (MS)
metabolic disorders:
- hypercalcaemia
psychiatric & psychological disorders:
- major depression, anxiety disorder, somatisation disorder, school phobia
occult malignancy
occupational & environmental factors:
- organic solvents, heavy metals
chronic fatigue syndrome

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:
- detailed evaluation of medical & psychological disorders:
  - hypothyroidism
  - anaemia
  - major depression
- R/V monthly
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