From the Guidelines
The workup for adrenal insufficiency should begin with evaluating morning ACTH and cortisol levels, as well as a basic metabolic panel, and consider an ACTH stimulation test for indeterminate results, as recommended by the most recent guideline update 1. The initial evaluation should include morning cortisol and ACTH levels, as well as a basic metabolic panel to assess for electrolyte abnormalities and glucose levels.
- Evaluate AM levels of ACTH and cortisol level
- Basic metabolic panel (Na, K, CO2, and glucose)
- Consider standard dose ACTH stimulation test for indeterminate results
- Evaluate for precipitating cause of crisis such as infection
- Adrenal CT for metastasis or hemorrhage (most common causes of primary AI) 1. If primary adrenal insufficiency is suspected, further testing may include aldosterone levels, renin activity, and adrenal antibodies.
- Renin and aldosterone levels should be evaluated to assess for primary adrenal insufficiency 1. Imaging studies such as CT or MRI of the adrenal glands can identify structural abnormalities, while pituitary imaging may be necessary for suspected secondary insufficiency.
- Adrenal CT for metastasis or hemorrhage (most common causes of primary AI) 1. During the workup, it's essential to consider the clinical context, including symptoms like fatigue, weight loss, hyperpigmentation, hypotension, and electrolyte abnormalities.
- Patients with suspected acute adrenal crisis should receive immediate treatment with hydrocortisone 100 mg IV, fluids, and glucose before completing diagnostic testing 1.
From the Research
Diagnostic Tests for Adrenal Insufficiency
- The diagnosis of adrenal insufficiency can be established using a short corticotropin test (250 μg) as the "gold standard" diagnostic tool 2
- If a short corticotropin test is not possible, an initial screening procedure comprising the measurement of morning plasma ACTH and cortisol levels can be used 2
- The high- and low-dose ACTH stimulation tests have similar diagnostic accuracy in adults and children, but both tests have low sensitivity and high specificity 3
- The use of assay-specific cutoffs is essential for reducing misclassification and overtreatment in patients with suspected adrenal insufficiency 4
Interpretation of ACTH Stimulation Test Results
- A threshold of 14.6 μg/dL for the level of cortisol at 60 minutes after ACTH stimulation is recommended for the Abbott Architect immunoassay 4
- Proposed cut-off levels for 30-minute delta cortisol are Δ < 1.8 µg/dL for both low-dose and high-dose tests, and Δ > 11.8 µg/dL for low-dose and Δ > 10.5 µg/dL for high-dose tests 5
- The 30-minute serum delta cortisol test provides diagnostic performance for adrenal insufficiency equal to that of the 60-minute test and is more convenient and cost-saving 5
Special Considerations in Critically Ill Patients
- The diagnosis of adrenal insufficiency in critically ill patients can be challenging due to nonspecific manifestations, and clinicians should have a high index of suspicion 6
- The low-dose ACTH stimulation test has been shown to be more sensitive and specific than the high-dose test, but the high-dose test is preferred since the low-dose test has not been validated 6
- Administration of low-dose corticosteroids for a longer duration can decrease the amount of time that vasopressors are required and mortality at 28 days 6