MON-320 CONN’S SYNDROME MASQUERADING AS NORMOTENSIVE HYPOKALEMIC PARALYSIS, WITH SUBSEQUENT KALIOPENIC NEPHROPATHY

Abstract

Hypokalemic paralysis even without hypertension, can herald a diagnosis of primary hyperaldosteronism (PHA). This patient presented with hypokalemic paralysis without evidence of hypertension during the initial 2 – 3 years. Following a diagnosis of adrenal carcinoma, he developed features of chronic tubulointerstitial nephritis denoting kaliopenic nephropathy due to prolonged hypokalemia. A 34-year-old male with a history of muscle cramps since 2 – 3 years, presented with flaccid lower limb weakness causing difficulty in walking over 3 days. His s. potassium was 1.6 meq/L. He was normotensive with alkalosis, increased TTKG and normal magnesium levels. Past records didn’t reveal any evidence of anorexia, laxative or diuretic abuse. Initial USS scan didn’t reveal any adrenal masses. Creatinine was normal. A working differential of Gitlemann’s syndrome was made despite normal magnesium levels and urine calcium excretion. He was treated with high dose KCL with prompt recovery of his weakness. His CPK was 9600 mg/dl denoting hypokalemia-induced rhabdomyolysis. During follow up his compliance was poor. After 2 years he presented with hypokalemic paralysis and blood pressure of 170/100mmHg. Investigations revealed elevated serum aldosterone levels >1650 pg/ml; with suppressed serum renin 0.4 ng/L. 24-hr urinary VMA, 9am s. cortisol, thyroid test, dexa.Sup.T., DHEA levels, parathyroid hormone, calcium and phosphate levels were normal. USS scan followed by CECT abdomen on this occasion revealed a left heterogeneous suprarenal mass, measuring 5.8 x 4.8 cm with poor contrast enhancement, favoring an adrenal carcinoma. He underwent open left adrenalectomy, which resolved his hypokalemia. Histological findings were consistent with an adrenal cortical adenoma. Subsequently, creatinine rose to 1.7mg/dl. Renal biopsy revealed primary tubular interstitial nephritis with isometric vacuolations in proximal tubules without evidence of hypertensive nephrosclerosis, conforming a diagnosis of kaliopenic nephropathy. He didn’t attend the clinic for 9 months, and he presented again with leg weakness due to severe hypokalemia. USS scan and CT scan reveled recurrence of adrenal carcinoma with metastases. He’s followed up with weekly radiotherapy for his cancer recurrence. Prevalence of PHA is 5 – 20 % of hypertensive patients in current literature (1) (2). Normotensive PHA is exceedingly rare, with only about 20 cases reported so far (3). Differential for normotensive hypokalemic patients usually does not ponder PHA, which led to an initial presumptive diagnosis of Gitelmann’s syndrome in our patient. Therefore lack of hypertension in hypokalemic patients should not exclude primary aldosteronism. Primary aldosteronism presenting as a paralytic myopathy, although rare is well established in literature (4) (5). Rhabdomyolysis can often be missed in patients presenting with non-spinal metabolic paralysis associated with hypertension, as symptoms overlap. Tubular vacuoles in kaliopenia of adrenal origin was first observed by Conn and Louis (6). Although literature reveals that early changes are potentially reversible with resurrection of potassium deficit, recovery of damages due to chronic kaliopenia is deemed impossible. This case highlights the importance of investigating for PHA even in patients with normotensive hypokalemia when no other apparent cause is found.