Resistant hypertension with adrenal nodule: are we removing the right gland?

Sex modifies the predictive value of computed tomography combined with serum potassium for primary aldosteronism subtype diagnosis

Objective

We aimed to investigate the predictive value of the CT findings combined with serum potassium levels for primary aldosteronism (PA) subtype diagnosis, with a particular interest in sex differences.

Methods

In this retrospective study, we eventually included 482 PA patients who underwent successful adrenal venous sampling (AVS) and had available data. We diagnosed the subjects as having either unilateral (n = 289) or bilateral PA (n = 193) based on AVS. We analyzed the concordance rate between AVS and adrenal CT combined with serum potassium and performed a logistic regression analysis to assess the prevalence of unilateral PA on AVS.

Results

The total diagnostic concordance rate between CT findings and AVS was 51.5% (248/482). The prevalence of hypokalemia in men and women was 47.96% (129/269) and 40.85% (87/213), respectively. The occurrence of unilateral lesions on CT and hypokalemia was significantly associated with an increased prevalence of unilateral PA [odds ratio (OR) 1.537; 95% confidence interval (CI) 1.364-1.731; p < 0.001]. In male participants, G2 (bilateral lesion on CT and normokalemia), G3 (unilateral lesion on CT and normokalemia), G4 (bilateral normal on CT and hypokalemia), G5 (bilateral lesion on CT and hypokalemia), and G6 (unilateral lesion on CT and hypokalemia) were significantly increased for the prevalence of unilateral PA on AVS (G2: OR 4.620, 95% CI 1.408-15.153; G3: OR 6.275, 95% CI 2.490-15.814; G4: OR 3.793, 95% CI 1.191-12.082; G5: OR 16.476, 95% CI 4.531-59.905; G6: OR 20.101, 95% CI 7.481-54.009; all p < 0.05), compared with G1 (patients with bilateral normal on CT and normokalemia). However, among female participants, we found an increased likelihood for unilateral PA in patients with unilateral lesions on CT and hypokalemia alone (OR 10.266, 95% CI 3.602-29.259, p < 0.001), while no associations were found in other groups (all p > 0.05). Sex had a significant effect on modifying the relationship between unilateral PA and the combination of CT findings and serum potassium (p for interaction <0.001).

Conclusion

In conclusion, our results indicated that CT findings combined with serum potassium levels have a great value for predicting the subtype of PA and are stronger in men.

Primary hyperaldosteronism: a case of unilateral adrenal hyperplasia with contralateral incidentaloma

Primary hyperaldosteronism is one of the most common causes of secondary hypertension but clear differentiation between its various subtypes can be a clinical challenge. We report the case of a 37-year-old African-American woman with refractory hypertension who was admitted to our hospital for palpitations, shortness of breath and headache. Her laboratory results showed hypokalaemia and an elevated aldosterone/renin ratio. An abdominal CT scan showed a nodule in the left adrenal gland but adrenal venous sampling showed elevated aldosterone/renin ratio from the right adrenal vein. The patient began a new medical regimen but declined any surgical options. We recommend clinicians to maintain a high level of suspicion to consider the less common subtypes of primary hyperaldosteronism, especially given the fact that the management greatly varies.