Fatigue | Medical Council of Canada
Close this search box.


Version: March 2023
Legacy ID: 33


Fatigue is a common presenting symptom, particularly in primary care. However, the cause may not be immediately apparent because fatigue is a nonspecific symptom. Therefore, the key to making a diagnosis is taking a careful and detailed history, followed by an appropriate physical examination and limited laboratory testing.

Although fatigue can be a symptom of almost any illness, the disorders listed here are those characterized almost exclusively by fatigue as a predominant symptom.

Causal Conditions

(list not exhaustive)

  1. Iatrogenic/pharmacologic
    1. Hypnotics
    2. Antihypertensives
    3. Antidepressants
    4. Substance use disorder
  2. Idiopathic
    1. Idiopathic chronic fatigue
    2. Chronic fatigue syndrome
    3. Fibromyalgia
  3. Other disease categories associated with fatigue
    1. Psychiatric
    2. Endocrine and metabolic
    3. Cardiopulmonary
    4. Infectious and postinfectious (e.g., long COVID)
    5. Connective tissue disorders
    6. Sleep disturbances (e.g., shift work)
    7. Neoplastic
    8. Hematologic

Key Objectives

Given a patient with fatigue, the candidate will perform a thorough and complete history and physical examination to establish an underlying cause.

Enabling Objectives

Given a patient with fatigue, the candidate will

  1. list and interpret critical clinical findings, including
    1. features that are more likely associated with either a psychological or iatrogenic cause of fatigue; and
    2. results of a complete physical examination;
  2. critically select and interpret clinical investigations, recognizing that in the absence of localizing features, tests may be of limited value; and
  3. construct an effective initial management plan, including
    1. treating any underlying causes; and
    2. outlining a plan of management that will help minimize the effect of fatigue on function and quality of life if no underlying cause can be identified.