From the Guidelines
The patient's cortisol level of 4.4 mcg/dL after a 1 mg Dexamethasone Suppression Test (DST) suggests autonomous cortisol secretion, and further evaluation and management are necessary.
Next Steps
- The result indicates that the patient has failed to suppress cortisol production, which is consistent with mild autonomous cortisol secretion (MACS) or subclinical Cushing's syndrome 1.
- According to the guidelines, patients with adrenal incidentalomas and autonomous cortisol secretion should be evaluated for clinical signs and symptoms of Cushing's syndrome, and those with clinically apparent Cushing's syndrome should undergo unilateral adrenalectomy of the affected adrenal gland 1.
- However, for patients with MACS without symptoms of Cushing's syndrome, the optimal management is less clear, and the decision to proceed with surgery should be made on a case-by-case basis, taking into account the patient's overall health, presence of metabolic comorbidities, and potential risks and benefits of surgery 1.
- The patient should undergo a thorough evaluation, including a focused history and physical examination, to identify signs and symptoms of adrenal hormone excess, adrenal malignancy, and/or extra-adrenal malignancy 1.
- A multidisciplinary review by endocrinologists, surgeons, and radiologists may be necessary to determine the best course of management for the patient 1.
- Annual clinical screening for new or worsening associated comorbidities is recommended for patients who do not undergo surgery 1.
From the Research
Next Steps After 1 mg Dexamethasone Suppression Test
- The 1 mg Dexamethasone Suppression Test (DST) is used to assess autonomous cortisol secretion in adrenal incidentalomas 2, 3, 4, 5, 6.
- A cortisol level of 4.4 micrograms per deciliter (mcg/dL) after the 1 mg DST is above the commonly used cutoff of 1.8 mcg/dL, suggesting autonomous cortisol secretion 3, 6.
- The next steps may include:
- Further evaluation to confirm the diagnosis of autonomous cortisol secretion, such as repeated DST or other diagnostic tests 2, 4, 5.
- Assessment of clinical features of Cushing's syndrome, although most patients with autonomous cortisol secretion may not exhibit typical clinical features 2, 3.
- Consideration of alternative biomarkers to improve the diagnostic workup of autonomous cortisol secretion, as current diagnostic tests have limitations 2.
- Monitoring of tumour growth and autonomous cortisol secretion development during follow-up, as the risk of developing autonomous cortisol secretion is higher in patients with higher serum cortisol post-DST levels at diagnosis 6.
- It is essential to note that a cortisol level of 4.4 mcg/dL after the 1 mg DST may not necessarily indicate clinically significant autonomous cortisol secretion, and further evaluation is necessary to determine the clinical relevance of this finding 3, 6.