Resistant hypertension post-transsphenoidal surgery for pituitary Cushing’s disease, leading to a diagnosis of primary aldosteronism

Summary: We describe a case of a 42-year-old gentleman, 5 years post-transsphenoidal surgery (TSS) for pituitary-dependent Cushing's disease, initially presenting with malignant hypertension. Despite an initial improvement in his blood pressure post-TSS, he was found to be persistently hypertensive on follow-up despite no clinical or biochemical evidence of recurrence of hypercortisolism. His blood pressure remained elevated despite five antihypertensive agents. His renin concentration was <5 mIU/L (9-103.5) and aldosterone concentration was 877 pmol/L (0-670). A subsequent CT of the adrenals showed a 1.2 cm left adrenal nodule. He was not suitable for adrenal vein sampling (AVS) at this time due to difficult-to-control hypertension. Biochemistry was difficult to interpret in the context of a multitude of interfering medications, which were necessary given his difficult-to-control hypertension and hypokalaemia. Once suitable, his initial AVS was unsuccessful due to failure to cannulate the right adrenal vein. He was given the further options of repeat AVS vs ¹¹C-metomidate PET vs medical management of his blood pressure. He proceeded with a repeat AVS, with successful cannulation of both adrenal veins. This showed evidence of hyperaldosteronism on the left side, with a lateralisation index of 39.5 and a contralateral suppression index of 0.28. He proceeded with a robotic left adrenalectomy, leading to significant improvement in his blood pressure, dropping from a mean reading of 142/85 during daytime and 150/88 mmHg at nighttime on five antihypertensive agents to normotensive levels of 114/77 mmHg on two agents.

Learning points:

• It is important to consider a broad differential for uncontrolled hypertension.
• It must be considered that patients can present with multiple, isolated endocrinopathies.
• There are diagnostic challenges with primary aldosteronism, with medication regimens regularly effecting suitability of testing and interpretation of results.
• AVS can be a challenging procedure, leading to diagnostic challenges in the lateralisation of primary aldosteronism; however, it or another form of lateralisation is essential to guide management options.