Fatigue Causes and Evaluation

Common Causative Factors

The National Comprehensive Cancer Network recommends assessing pain as it often clusters with fatigue and requires effective treatment 1, 3
Anemia should be evaluated through complete blood count and iron studies, as recommended by the National Comprehensive Cancer Network 2, 4
Sleep disorders, ranging from hypersomnia to insomnia, affect 30-75% of patients with fatigue, according to the National Comprehensive Cancer Network 5, 6
Poor sleep hygiene, including irregular sleep schedules, daytime napping, and caffeine/alcohol consumption before bed, contributes to fatigue 5
Nutritional deficiencies, such as weight changes, caloric intake alterations, and electrolyte imbalances, can contribute to fatigue, as noted by the National Comprehensive Cancer Network 1
Decreased physical activity can worsen fatigue symptoms, as stated by the National Comprehensive Cancer Network 1
Medication side effects, including sedation and fatigue, are common, according to the National Comprehensive Cancer Network 2, 7
Depression frequently co-occurs with fatigue, with studies showing 25-33% of patients with fatigue also experiencing depression, as reported by the National Comprehensive Cancer Network 2, 3
Anxiety often accompanies fatigue and requires specific assessment, as recommended by the Ca-A Cancer Journal for Clinicians 8
Emotional distress can both cause and exacerbate fatigue symptoms, according to the National Comprehensive Cancer Network 1, 2

The National Comprehensive Cancer Network suggests using a numeric rating scale (0-10) to quantify fatigue severity, although this specific recommendation is from Praxis Medical Insights 7
A thorough review of systems should be conducted to identify affected organ systems, as recommended by the National Comprehensive Cancer Network and Praxis Medical Insights 3, 7
Evaluating onset, pattern, duration, and changes in fatigue over time is essential, as stated by the National Comprehensive Cancer Network and Praxis Medical Insights 1, 7
Core tests for moderate to severe fatigue should include complete blood count, thyroid-stimulating hormone, basic metabolic panel, liver function tests, and inflammatory markers like C-reactive protein, as recommended by Praxis Medical Insights 4

Fatigue rarely occurs in isolation and often clusters with other symptoms, according to the National Comprehensive Cancer Network 2
Laboratory results affect management in only about 5% of fatigue cases but are essential to rule out treatable causes, as noted by Praxis Medical Insights 4
Overlooking psychological causes, such as depression and anxiety, can lead to inadequate treatment, as warned by the National Comprehensive Cancer Network 2, 6
Ignoring medication side effects can worsen fatigue, as cautioned by the National Comprehensive Cancer Network and Praxis Medical Insights 2, 7
Missing sleep disorders can lead to inadequate treatment, as noted by the National Comprehensive Cancer Network 5, 6