Lethargy

Although there are no universally accepted definitions, fatigue can be described as a subjective symptom of malaise and exhaustion during or after usual activities or feeling inadequate energy to carry out normal activities (1).

Tiredness is defined as lethargy with no desire to sleep, and is the sort of symptom that can make the heart sink. However, with a systematic approach it can be rewarding.

Before considering it as part of an illness it is worth checking if it is likely to be physiological. At first consultation consider the physical causes.

Patients often think it may be due to infection even though there may be no other indication of this.

In 80 to 85% of GP practice the cause is apparent by end of the first consultation. The GP should have decided that the cause is psychological, physiological or physical, but should reconsider if not resolved reasonably quickly as it may a combination. If a diagnosis is not apparent, be optimistic and helpful.

Fatigue can be divided according to the duration:

• recent - onset within 1 month before presentation
• prolonged - lasting 1-6 months
• chronic - lasting > 6 months (3)

Patients with chronic fatigue may have

• chronic fatigue syndrome
• idiopathic chronic fatigue - when the diagnostic criteria of the above syndrome is not met (3)

Reference:

• 1. Wilks D, Sharpe M. Fatigue. BMJ. 2002 August 31; 325(7362): 480-483
• 2. Royal College of Psychiatrists 2008. Tiredness
• 3. Cornuz J. Fatigue: a practical approach to diagnosis in primary care. CMAJ 2006;174(6)