Description

A 36-year-old man underwent adrenal vein catheterisation to investigate the aetiology of hypertension. He had resistant hypertension as high as 220/120 despite three oral medications. He had recurrent lower extremity weakness with documented hypokalaemia as low as 2.1 mmol/L. A diagnosis of primary aldosteronism (PA) was made based on unsuppressed aldosterone of 27.7 ng/dL after 2 L of saline solution was given intravenously. A CT scan revealed a 1.1×1.5×1.3 cm well-defined hypodense nodule in the lateral limb of the right adrenal, while the left adrenal was normal. This was suggestive of an aldosterone-producing adenoma (APA). As recommended by Endocrine Society, an adrenal vein sampling (AVS) was conducted to confirm the laterality of aldosterone excess and establish the diagnosis of an APA. Angiography of the right adrenal vein of the patient demonstrated circular configuration of the veins surrounding a round structure consistent with a nodule (figure 1). Blood sampling yielded lateralised aldosterone excess to the right (selectivity index >2 and lateralisation index=5.74) consistent with an APA.

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Figure 1

Right adrenal venogram demonstrated circular configuration of the veins surrounding a round structure consistent with a nodule (arrow).

AVS is an invasive procedure employed to establish the subtype of PA. The Endocrine Society recommends that when surgery is practicable and desired, AVS should be conducted after an adrenal CT scan to establish laterality of aldosterone excess. The absence of laterality is seen in bilateral adrenal hyperplasia for which treatment is medical. Lateralisation is seen in APA or unilateral adrenal hyperplasia for which adrenalectomy is indicated.1 On fluoroscopic image, the adrenal veins adopt a circular configuration to surround the tumour.