Hypokalemia induced myopathy as first manifestation of primary hyperaldosteronism - an elderly patient with unilateral adrenal hyperplasia: a case report

Abstract

IntroductionPrimary hyperaldosteronism is only rarely caused by unilateral adrenal hyperplasia.Case presentationA 73-year-old hypertensive Greek man (on 10 mg amlodipine for the last ten years) presented in the emergency department with severe muscle weakness of all limbs. The initial physical and laboratory examination revealed normal blood pressure, muscle weakness, severe hypokalemia, sinus rhythm and U wave, rhabdomyolysis and metabolic alkalosis. The patient was immediately treated with intravenous administration of potassium-rich solutions, 25 mg spironolactone with progressive dose titration up to 100 mg. Because of high arterial blood pressure, irbesartan was added. On day 6, muscle weakness was completely restored with decrease of arterial blood pressure and further improvement of laboratory tests. The combination of hypokalemia with arterial hypertension raised the suspicion of primary hyperaldosteronism; therefore, we performed abdomen computed tomography scan, which revealed a nodular mass (15 mm in diameter) in the left adrenal gland. Plasma renin activity was in the lower normal range with a three-fold increase of plasma aldosterone concentration. We performed total resection of the left adrenal gland and the histopathological examination revealed hyperplasia of the left adrenal gland.ConclusionThis report presents a rare case of an elderly patient under antihypertensive treatment the last ten years for essential hypertension, who admitted to our emergency department with hypokalemia - induced myopathy as first manifestation of primary hyperaldosteronism due to unilateral adrenal hyperplasia.

Hypokalemic myopathy in primary aldosteronism: A case report

“…The cause of hypokalemia-induced myopathy in PA is obscure, but a number of reports suggest that the enhanced muscle sodium-potassium pump activity in patients with PA may result in an increase of potassium entry into the cells (4,6,10). The potassium ion is considered to be a major factor mediating the rise of muscle blood flow.…”

“…Although many cases with PA do have hypokalemia (>50%), patients with PA associated with hypokalemic myopathy are rare (1). Kotsaftis et al (4) reported a rare case of hypokalemia-induced myopathy as the first manifestation of primary hyperaldosteronism due to unilateral adrenal hyperplasia. In addition, Goto et al (5) reported a case of PA associated with severe rhabdomyolysis due to profound hypokalemia.…”

Rhabdomyolysis in Primary Aldosteronism: A Case Report and Review of the Literature

“…As there was no consensus on the level of CPK for the diagnosis of rhabdomyolysis, we considered a level equal or greater than 1,500 U/L as the criterion. A total of 15 cases of PA complicated by hypokalemic rhabdomyolysis were identified (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Clinical features, diagnosis data, and treatment and outcomes of all cases are summarized in Table 2.…”

Primary aldosteronism associated with severe hypokalemic rhabdomyolysis

“…3 We present here a patient with primary aldosteronism, who developed hypokalemia and rhabdomyolysis. This cases furnishes an instructive example of the potential for rhabdomyolysis to develop in patients with primary aldosteronism.…”

“…[3][4][5] We concluded that patients with severe hypokalemia (potassium level below 2mEq/L) are at high risk for hypokalemic rhabdomyolysis. Mineralocorticoid antagonist is the standard medical treatment for patients with primary aldosteronism.…”