Aetiology and pathogenesis

• aetiology and pathogenis are unknown (1,2,3,4)
• a significant proportion of patients relate the onset of chronic fatigue syndrome to an infection
• a community based study has shown that up to 10% of patients fufilled the definition of chronic fatigue syndrome (CFS) following Epstein-Barr virus infection (2) CFS has also been associated with other herpes viruses, enterovirus and hepatitis virus infections, and non-viral infections such as toxoplasmosis, Q fever, brucellosis, salmonellosis and Lyme disease (3)
• it is unclear whether infections have a role in the continuing illness or act as a trigger in predisposed individuals
• other noted triggers include chemotherapy and immunisations
• CFS patients may show features of other syndromes, particularly fibromyalgia and irritable bowel syndrome. This association suggests that these syndromes may share similar pathogenetic, predisposing or trigger factors

Reference:

• Prescribers' Journal (2000);40 (2): 99-106.
• White PD et al. A community-based study of chronic fatigue syndrome. Arch Intern Med 1999; 159: 2129-37.
• Working Group convened by the Royal Australian College of Physicians. Chronic fatigue syndrome: draft clinical practice guidelines on the evaluation of prolonged fatigue and the diagnosis and management of chronic fatigue syndrome. Medical Journal of Australia, 1997.
• Brurberg KG et al. Case definitions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME): a systematic review. BMJ Open. 2014 Feb 7;4(2).