Chronic fatigue

Jacques Cornuz and colleagues,¹ in Box 2 of their case report, list 11 initial laboratory tests for patients with prolonged or chronic fatigue. Given that hypocortisolism is one of the most frequently reported abnormalities of patients with chronic fatigue syndrome,^2–5 it is surprising that none of the available tests for assessing cortisol production^2–5 was included. The importance of this assessment is especially evident in light of the virtually complete recovery of patients with chronic fatigue who are treated with low-dose hydrocortisone.⁶

Another rationale for assessing cortisol production in patients with chronic fatigue is the fact that this condition shares 43 clinical features with Addison's disease,^7,8 including hypocortisolism, chronic fatigue, and all of the symptoms listed in the diagnostic criteria for chronic fatigue.⁷ This impressive clinical overlap between 2 distinctly named diseases suggests that in practical terms, chronic fatigue should be regarded as a mild form of Addison's disease.⁷

Although Cornuz and colleagues, in Table 1 of their paper, correctly mention Addison's disease as one of the major underlying causes of fatigue, they should have remarked that “pigmentation in skin creases, scars and buccal mucosa”¹ is far from being a constant feature of Addison's disease.^9,10 Therefore, the absence of such pigmentation in patients with chronic fatigue should not mislead general practitioners to exclude hypocortisolism as a possible cause of that unremitting symptom.