From the Guidelines
Low ACTH levels indicate secondary adrenal insufficiency, where the pituitary gland doesn't produce enough adrenocorticotropic hormone to stimulate the adrenal glands to make cortisol, and management should be as per guidelines for primary and secondary adrenal insufficiency, with emergent therapy using dexamethasone or hydrocortisone 100 mg if the diagnosis is already confirmed 1. This condition can cause symptoms like fatigue, weakness, weight loss, low blood pressure, nausea, and dizziness.
Key Points to Consider
- The relationship between ACTH and cortisol is crucial in distinguishing between primary and secondary adrenal insufficiency, as stated in the American Society of Clinical Oncology clinical practice guideline 1.
- Treatment typically involves cortisol replacement therapy, and the choice of medication, such as hydrocortisone, depends on the individual case and the presence of salt-wasting symptoms.
- It is essential to investigate the underlying cause of low ACTH, which could be due to various factors such as pituitary tumors, brain injury, inflammation, or long-term use of steroid medications that have suppressed natural hormone production.
- Regular medical follow-up is necessary to adjust medication and monitor for complications, especially during stress situations that require increased dosing.
Management and Treatment
- Emergent therapy for suspected adrenal insufficiency should be done with dexamethasone, as it allows for a stimulation test to be performed later, according to the guideline 1.
- If the diagnosis is already confirmed, hydrocortisone 100 mg can be used for management.
- Patients should carry emergency medication and wear a medical alert bracelet to ensure prompt treatment during stress situations.
From the Research
Low ACTH Levels
Low Adrenocorticotropic hormone (ACTH) levels can indicate a problem with the hypothalamic-pituitary-adrenal (HPA) axis, which is essential for responding to stressful stimuli 2.
- Causes of Low ACTH: Low ACTH levels can be caused by various factors, including organic growth hormone deficiency (GHD) or structural hypothalamic-pituitary abnormalities, which can lead to additional anterior pituitary hormone deficits 2.
- Consequences of Low ACTH: Patients with low ACTH levels may be at risk of developing complete or partial corticotropin (ACTH) deficiency, which can have potentially life-threatening consequences if not properly diagnosed and treated 2.
- Diagnosis of Low ACTH: The diagnosis of adrenal insufficiency due to low ACTH levels can be challenging, and various tests such as the insulin tolerance test (ITT), short synacthen test (SST), low-dose SST (LDSST), and corticotropin-releasing hormone (CRH) test can be used to evaluate the integrity of the HPA axis 2.
- Interpretation of Test Results: The results of these tests should be interpreted with caution, as none of them can be considered completely reliable for establishing or excluding the presence of secondary or tertiary adrenal insufficiency 2.