Bilateral inferior petrosal sinus sampling using vasopressin.

Area of Science:

• Endocrinology
• Neurosurgery
• Medical Imaging

Background:

• Accurate anatomical localization of pituitary adenomas is crucial for diagnosing adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome.
• Bilateral inferior petrosal sinus sampling (BIPSS) is the gold standard for localization, but its sensitivity can be enhanced by stimulation.
• Corticotropin-releasing hormone (CRH) is commonly used for stimulation but is not readily available in India.

Purpose of the Study:

• To evaluate the efficacy of vasopressin as a stimulating agent in BIPSS for tumor localization and lateralization in challenging cases of ACTH-dependent Cushing's syndrome.
• To assess the safety and feasibility of using vasopressin for corticotroph stimulation during BIPSS.

Main Methods:

• A prospective observational study was conducted involving six patients with ACTH-dependent Cushing's syndrome.
• Bilateral inferior petrosal sinus sampling (BIPSS) was performed using vasopressin for corticotroph stimulation.
• Patients underwent standard diagnostic tests including dexamethasone suppression tests and imaging (MRI, CT abdomen).

Main Results:

• Four out of six patients were correctly diagnosed with Cushing's disease, confirmed post-surgery.
• The remaining two patients had other causes of Cushing's syndrome: primary pigmented nodular adrenocortical disease and thymic carcinoid with ectopic ACTH production.
• Vasopressin stimulation during BIPSS demonstrated high diagnostic accuracy with no serious adverse events reported.

Conclusions:

• Vasopressin serves as a safe and effective alternative to CRH and desmopressin for stimulating corticotrophs during BIPSS.
• This finding provides a valuable option for tumor localization in ACTH-dependent Cushing's syndrome, particularly in resource-limited settings.
• Vasopressin-stimulated BIPSS aids in accurate diagnosis and surgical planning for Cushing's syndrome.