Disorders of Mineralocorticoid Excess
A 24-year-old lady was incidentally diagnosed to have hypertension (BP 160/110 mmHg) 3 years back during a hospital visit for neck pain. She was started on amlodipine 10 mg and losartan 100 mg per day. In view of young-onset hypertension and uncontrolled BP despite medications, she was referred for endocrinology opinion. There was no history of paroxysms or periodic paralysis. Her family history was noncontributory. On evaluation, her body mass index was 22.4 kg/m2, pulse rate 88/min, supine BP 152/90 mmHg, and standing BP 140/90 mmHg. She did not have any stigma of Cushing’s syndrome or acromegaly. Investigations revealed hypokalemia with serum potassium ranging from 3.3 to 3.5 mEq/L on multiple occasions. Her serum creatinine was 0.9 mg/dl, fasting plasma glucose 110 mg/dl, and HbA1c 6.2%. Renal Doppler did not reveal renal artery stenosis. Diagnosis of primary aldosteronism was considered and antihypertensives were changed to prazosin and verapamil along with potassium supplementation. After 2 weeks, she was advised salt ad lib for 5 days, and with normalization of serum potassium, samples for plasma aldosterone concentration (PAC) and plasma rennin activity (PRA) were taken. The PAC was 57.5 ng/dl and PRA 0.04 ng/ml/h with a PAC/PRA ratio of 1,438 ng/dl/ng/ml/h. Subsequently, saline suppression test was performed and PAC at 0 min was 24.3 ng/dl and at 4 h 34.2 ng/dl. After biochemical confirmation of primary hyperaldosteronism, CECT abdomen was done which revealed hypodense nodular lesions in both adrenal glands, likely bilateral adrenal adenomas. Right-sided lesion (10 × 8 mm) was arising from the limb, with a washout of 70%, while the left one (14 × 10 mm) was arising from the body of adrenal gland with a washout of 60%. Other hormone profiles were as follows: serum cortisol 0800h 287 nmol/L (171–536), 0800h ACTH 10.3 pg/ml (5–60), T4 8.39 μg/dl (4.8–12.7), TSH 4.03 μIU/ml(0.27–4.2), TPO 21.3 IU/ml (<24), overnight dexamethasone suppression test 38 nmol/L, and 24-h urinary metanephrines and normetanephrines were normal. She did not have hypertensive retinopathy and 24-h urinary protein was within normal range. Echocardiography revealed regional wall motion abnormality in the right coronary artery territory, concentric left ventricular hypertrophy, and ejection fraction 45 to 50%. To lateralize the source for aldosterone excess, adrenal vein sampling was performed. After continuous ACTH infusion (50 μg/h) for 30 min, both adrenal veins were simultaneously catheterized. Samples were taken from both the adrenal veins for cortisol and aldosterone, with simultaneous sampling for cortisol from femoral vein at baseline (immediately after catheterization) and at 30 min. The source of aldosterone excess was lateralized to the left adrenal gland. Detailed results of the procedure are tabulated below. After investigations, she was started on spironolactone 100 mg per day and amlodipine 5 mg per day; verapamil and prazosin were withdrawn. She was subjected to laparoscopic resection of left adrenal gland and histopathology was consistent with aldosteronoma. PAC and PRA done on the second postoperative day showed PAC of 2 ng/dl and PRA of 0.04 ng/ml/h and blood pressure 130/80 mmHg without any antihypertensive drugs. She developed hyperkalemia on the third postoperative day and was advised salt ad lib, following which serum potassium normalized within 2 weeks. After 6 months of surgery, she continues to remain normotensive without any antihypertensive drugs.
KeywordsPrimary Aldosteronism Metabolic Alkalosis Adrenal Vein Periodic Paralysis Plasma Aldosterone Concentration
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