Adrenal Insufficiency Assessment with Morning Cortisol of 14.1 and ACTH of 36.4
A morning cortisol level of 14.1 with an ACTH of 36.4 does not meet diagnostic criteria for adrenal insufficiency in a perimenopausal woman with fatigue and long COVID symptoms, as these values fall within normal ranges. 1
Diagnostic Criteria for Adrenal Insufficiency
The diagnosis of adrenal insufficiency requires specific laboratory findings:
- According to the European Society of Endocrinology, a high-dose ACTH stimulation test is the gold standard for diagnosing adrenal insufficiency 1
- Normal response is defined as cortisol exceeding 18-20 μg/dL at either 30 or 60 minutes after stimulation 1
- Morning serum cortisol and ACTH measurements help distinguish between primary and secondary adrenal insufficiency:
| Type | ACTH Level | Cortisol Level | Electrolytes |
|---|---|---|---|
| Primary | High | Low | ↓Na, ↑K |
| Secondary | Low | Low | Normal |
Interpretation of Patient's Values
- The patient's morning cortisol of 14.1 is not considered low enough to indicate adrenal insufficiency
- The ACTH level of 36.4 is within normal range (7.2-63.3 pg/mL) 2
- These values do not show the characteristic pattern of either primary adrenal insufficiency (low cortisol with high ACTH) or secondary adrenal insufficiency (low cortisol with low ACTH) 1
Long COVID and Adrenal Function
While there have been case reports of adrenal insufficiency following COVID-19 infection 2, these typically present with:
- More severe laboratory abnormalities (e.g., morning cortisol <3 μg/dL)
- Characteristic electrolyte disturbances (hyponatremia, hyperkalemia)
- Positive antibody tests (e.g., anti-21-hydroxylase antibodies)
Recommended Next Steps
If clinical suspicion remains high despite these values:
Consider a high-dose (250-μg) ACTH stimulation test, which remains the gold standard for diagnosis 1, 3
Screen for associated conditions that may cause similar symptoms:
- Thyroid function tests
- Complete blood count
- Vitamin B12 levels
- Plasma glucose and HbA1c 1
Evaluate for other causes of fatigue in perimenopausal women:
- Hormonal fluctuations
- Sleep disturbances
- Other long COVID manifestations
Clinical Pitfalls to Avoid
- Relying solely on morning cortisol and ACTH levels without performing an ACTH stimulation test when clinical suspicion is high 1
- Attributing non-specific symptoms like fatigue exclusively to adrenal insufficiency without ruling out other causes
- Initiating glucocorticoid replacement therapy without definitive diagnosis, which can lead to unnecessary side effects 4
- Failing to consider that long COVID symptoms may mimic adrenal insufficiency but have different underlying pathophysiology
In conclusion, while adrenal insufficiency should be considered in patients with persistent fatigue after COVID-19, the laboratory values presented (morning cortisol 14.1 and ACTH 36.4) do not support this diagnosis without further testing.