A 27-year-old man comes to the physician for follow-up of hypertension. He feels healthy and has no complaints. Two weeks ago, he was found to have high blood pressure during an emergency department visit for a sports injury. The patient has a strong family history of hypertension and stroke. His blood pressure is 155/97 mm Hg and pulse is 78/min. Physical examination and basic laboratory workup are unremarkable. He is instructed to follow a low-salt diet and started on low-dose (12.5 mg daily) hydrochlorothiazide. Two weeks later, the patient comes to the emergency department complaining of muscle cramps, weakness, and palpitations. His blood pressure is 150/93 mm Hg and pulse is 82/min. Mucous membranes are moist. Laboratory results are as follows: Which of the following is the best next step in management of this patient?

Question

A 27-year-old man comes to the physician for follow-up of hypertension.  He feels healthy and has no complaints.  Two weeks ago, he was found to have high blood pressure during an emergency department visit for a sports injury.  The patient has a strong family history of hypertension and stroke.  His blood pressure is 155/97 mm Hg and pulse is 78/min.  Physical examination and basic laboratory workup are unremarkable.  He is instructed to follow a low-salt diet and started on low-dose (12.5 mg daily) hydrochlorothiazide.  Two weeks later, the patient comes to the emergency department complaining of muscle cramps, weakness, and palpitations.  His blood pressure is 150/93 mm Hg and pulse is 82/min.  Mucous membranes are moist.  Laboratory results are as follows:  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d3b0_5bff_bc81_7b8a35b1dd02_MD0003_00 This younger hypertensive patient with significant family history raises suspicion for a secondary cause of hypertension. The easily induced hypokalemia after starting a thiazide diuretic suggests primary hyperaldosteronism. Patients with mild primary hyperaldosteronism may not have spontaneous hypokalemia, but they are prone to developing diuretic-induced hypokalemia. Other findings include metabolic alkalosis and mild hypernatremia (143-147 mEq/L). The best screening test is early-morning plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio. A PAC/PRA ratio >20 with plasma aldosterone >15 ng/dL suggests primary hyperaldosteronism. (Choice A) Computed tomography angiography of the abdomen is a screening test for renovascular hypertension due to renal artery stenosis or fibromuscular dysplasia. These conditions cause secondary hyperaldosteronism. A PAC/PRA ratio <10 will be present in these patients. Computed tomography angiogram is not required in this patient at this time. (Choice B) Dexamethasone suppression test can diagnose Cushing's syndrome. Patients typically develop findings such as central obesity, purple striae, proximal muscle wasting, glucose intolerance, and hypertension. This patient's normal glucose makes this unlikely. (Choice D) Thiazide diuretics can cause hypokalemia. However, low-dose thiazide is usually not associated with the degree of hypokalemia seen in this patient. (Choice E) Urine potassium excretion by collecting 24-hour urine has been used to document inappropriate potassium excretion. A 24-hour urinary potassium level >30 mEq in the presence of hypokalemia suggests hyperaldosteronism. However, this test is no longer commonly used. Educational objective: Patients with mild primary hyperaldosteronism may not have spontaneous hypokalemia, but they are prone to developing diuretic-induced hypokalemia.

A 27-Year-Old Man Comes to the Physician for Follow-Up of Hypertension