From the Guidelines
Low urine cortisol levels indicate that your body is producing less cortisol than normal, which could signal adrenal insufficiency or Addison's disease, and require immediate medical attention to prevent life-threatening complications. This condition occurs when the adrenal glands, located above your kidneys, fail to produce adequate amounts of cortisol, a hormone essential for managing stress, regulating blood pressure, controlling inflammation, and metabolizing carbohydrates, fats, and proteins. According to the most recent guidelines from the Association of Anaesthetists, the Royal College of Physicians, and the Society for Endocrinology UK 1, patients with adrenal insufficiency are at risk of adrenal crisis, particularly during times of illness or stress.
Causes and Symptoms
Low cortisol can cause symptoms like fatigue, weakness, weight loss, decreased appetite, abdominal pain, low blood pressure, and salt cravings. The underlying cause of adrenal insufficiency can be primary, secondary, or tertiary, with primary adrenal insufficiency relating to conditions where the underlying aetiology lies within the adrenal gland itself, such as Addison’s disease or congenital adrenal hyperplasia 1.
Diagnosis and Treatment
If you have low urine cortisol, your doctor will likely order additional tests such as an ACTH stimulation test to confirm the diagnosis, as recommended by the American Society of Clinical Oncology 1. Treatment typically involves hormone replacement therapy with oral hydrocortisone (usually 15-25 mg daily divided into 2-3 doses), as suggested by the Journal of Internal Medicine 1, fludrocortisone for mineralocorticoid replacement if needed, and potentially DHEA supplements. It's crucial to follow up with an endocrinologist for proper diagnosis and treatment, as untreated adrenal insufficiency can lead to a life-threatening adrenal crisis during times of illness or stress. Patients with adrenal insufficiency should also wear Medic Alert identification jewellery and carry a steroid/alert card, and receive sufficient education to manage daily medications and situations of minor to moderate concurrent illnesses 1.
Management and Follow-up
All patients with adrenal insufficiency should be reviewed at least annually, with assessment of health and well-being, measurement of weight, blood pressure, and serum electrolytes, as recommended by the Journal of Internal Medicine 1. Occasional monitoring for the development of new autoimmune disorders, particularly hypothyroidism, is also worthwhile. In cases of suspected acute adrenal insufficiency, treatment should never be delayed by diagnostic procedures, and emergent therapy with dexamethasone or hydrocortisone should be initiated immediately 1.
From the Research
Low Urine Cortisol
- Low urine cortisol can be an indicator of adrenal insufficiency, a condition where the adrenal glands do not produce enough cortisol 2, 3, 4, 5.
- Adrenal insufficiency can be primary or secondary, and the diagnosis is often made using ACTH stimulation tests 2, 4.
- The normal cortisol response to ACTH stimulation can vary depending on the assay used, and newer specific cortisol assays may have lower thresholds for a normal response 3, 5.
Diagnostic Thresholds
- The traditional cutoff for cortisol after ACTH stimulation is 18 μg/dL, but newer studies suggest that this threshold may be too high for some assays 3, 5.
- Proposed new cutoffs for cortisol after ACTH stimulation include 14.6 μg/dL for the Abbott Architect immunoassay 3 and 14-15 μg/dL for other specific cortisol assays 5.
- The 30-minute delta cortisol test has been proposed as a simpler and more convenient alternative to the 60-minute test, with proposed cut-off levels of Δ < 1.8 µg/dL and Δ > 11.8 µg/dL 6.
Clinical Implications
- Low urine cortisol can have significant clinical implications, including fatigue, weight loss, and increased risk of infection 2, 4.
- Accurate diagnosis of adrenal insufficiency is crucial to ensure proper treatment and management of the condition 2, 3, 4, 5.
- Clinicians should be aware of the new cutoffs for the assays available to them when evaluating patients for adrenal insufficiency 3, 5.