Clinical Assessment of Fatigue

Factors to Consider in Diagnosis

1. Classification by Duration

• Recent: Lasting less than 1 month [1].
• Prolonged: Lasting more than 1 month [1].
• Chronic: Lasting more than 6 months [1].

2. History and Nature of Fatigue

• Onset can be sudden, suggesting infection or toxins, or gradual, suggesting chronic conditions like heart failure or diabetes [1].
• Assess if the fatigue is exacerbated by minor activity or if there is a specific recovery period [1-3].
• Determine if fatigue is persistent or worse in the morning [2].
• The severity of exhaustion can be measured on a scale of 1–10 [1, 4].

3. Red Flags

• Unexplained weight loss or loss of appetite [5, 6].
• Lymphadenopathy (swollen lymph nodes) [5, 7].
• Haemoptysis, dysphagia, rectal bleeding, breast lumps, or post-menopausal bleeding [5].
• Focal neurological signs or features of inflammatory arthritis/vasculitis [5].
• Previously well patients over 60, and specifically men over 80, where cancer is a high risk [6].

4. Risk Factors and Specific Exposures

• Travel history, tick exposure (Lyme disease), or contact with kittens/uncooked meat (toxoplasmosis) [3, 8].
• Occupational exposure to unpasteurised dairy (brucellosis) [3, 8].
• IV drug use or unprotected sexual intercourse (HIV/Hepatitis) [3, 8].
• Physiological stressors like pregnancy, breastfeeding, sleep deprivation, or excessive exercise [3, 9].

5. Associated Symptoms

• Cardio-respiratory signs such as shortness of breath or snoring [5, 8, 10].
• Endocrine signs like polyuria and polydipsia (diabetes) or temperature intolerance [8, 10].
• Gastrointestinal signs such as steatorrhoea (Coeliac disease) [8, 10].

6. Medication and Psychiatric Screening

• Review use of drugs like anti-arrhythmics, antidepressants, antihistamines, and antihypertensives [9, 11].
• Screen for depression and alcohol misuse (CAGE assessment) [5, 9, 11].

7. Physical Examination Findings

• Check general appearance for psychomotor agitation or poor grooming [12].
• Assess for pallor, jaundice, tachycardia, or heart murmurs [7, 12].
• Check for specific signs like a blue tinge to the sclera, which can indicate iron deficiency [7].

Typical Initial Blood Tests

• FBC (Full Blood Count): To check for anaemia or leukaemia [13].
• TFT (Thyroid Function Test): To rule out thyroid disorders [13].
• Ferritin: To assess iron levels, even if not yet anaemic [13].
• LFT (Liver Function Test): To screen for chronic liver disease [13].
• U&E (Urea and Electrolytes): To screen for uraemia [13].
• Glucose: To screen for diabetes [13].
• ESR/CRP: Markers for underlying inflammatory conditions [13].
• IgA Transglutaminase: To screen for Coeliac disease [13].

Consideration and Yield

• Tests like Vitamin D, B12, or HIV screening are considered based on specific risk factors [6, 13].
• Statistically, somatic pathology is uncommon; only 4% of tests lead to a significant clinical diagnosis [4, 14].
• A 4-week postponement of initial tests often does not affect patient satisfaction as many cases resolve on their own [13].