P-03 NORMALIZATION OF THE DEXAMETHASONE SUPPRESSION TEST FOLLOWING PSYCHIATRIC TREATMENT IN A PATIENT WITH PSYCHOTIC DEPRESSION: A CASE REPORT
Authors: Uysal Serhat , Usta Saglam Nazife Gamze , Durcan Emre , Sahin Serdar , Kadioglu Pinar 
Published: January 2025

Abstract

Introduction
Cushing's syndrome (CS) is characterized by hypercortisolism and is typically diagnosed through clinical and laboratory evaluations. However, severe depression can lead to misleading results. In this case, a patient with severe depressive symptoms initially showed abnormal dexamethasone suppression test (DST) results, which normalized following psychiatric treatment. This case highlights the impact of psychiatric conditions on CS assessment and demonstrates how psychiatric intervention can influence test outcomes.

Clinical Case
A 67-year-old male patient with a known diagnosis of psychotic depression was referred to our outpatient clinic for hormonal evaluation after a left adrenal mass was detected. Physical examination revealed no signs of hypercortisolism. The patient's blood pressure was 100/70 mmHg, weight 50 kg, height 168 cm, and BMI 17 kg/m². Initial tests revealed that the nadir cortisol level after a 1 mg DST was not suppressed, with a value of 16 µg/dL. Additional tests for hypercortisolism were ordered. The patient’s 24-hour urinary free cortisol (UFC) was 97 µg/dL (normal: &lt;130 µg/dL), and late-night salivary cortisol was 0.64 ng/mL (normal: &lt;2.74 ng/mL), both within normal ranges. An ACTH level of 121 pg/mL was noted, leading to a planned evaluation for ACTH-dependent hypercortisolism. The laboratory results are presented in Table 1.
The patient underwent dynamic contrast-enhanced 3-Tesla MRI to evaluate ACTH-dependent hypercortisolism. The sella MRI did not reveal any adenoma or other pathology. Due to the patient's agitation, bilateral inferior petrosal sinus sampling could not be performed. Given the absence of clinical signs of hypercortisolism, the patient’s psychiatric treatment was adjusted, and a re-evaluation from an endocrinological perspective was planned.
Following nine sessions of inpatient electroconvulsive therapy, during which the patient was initiated on olanzapine 20 mg once daily and venlafaxine 150 mg once daily, he was discharged and continued these medications as part of his outpatient treatment. The patient was subsequently reassessed in the endocrinology clinic. With the adjusted psychiatric treatment, the patient’s nadir cortisol level after 1 mg DST decreased to 0.78 µg/dL. 24-hour UFC and late-night salivary cortisol levels were within normal ranges. It was concluded that the untreated psychiatric disorder had affected the DST results. The patient was placed under regular follow-up by the psychiatric unit.

Conclusion
This case underscores the potential impact of untreated psychiatric disorders on diagnostic tests for CS, such as the DST. The normalization of test results following effective psychiatric treatment highlights the importance of considering psychiatric conditions in the comprehensive laboratory evaluation of patients, particularly those without clinical signs of hypercortisolism.Table 1:The laboratory test resultsACTH=Adrenocorticotropic hormone; DST=Dexamethasone suppression test; HbA1c=Hemoglobin A1C; UFC=Urinary free cortisol