A 42-year-old woman is evaluated for depression and poor sleep. She also has mild headaches and muscle weakness. The review of hospital records indicates emergency department visits for anxiety and kidney stones. The patient is a lifetime nonsmoker and does not use illicit drugs. Blood pressure is 160/105 mm Hg and pulse is 85/min. Laboratory results are as follows:
| Sodium | 139 mEq/L |
| Potassium | 3.8 mEq/L |
| Chloride | 102 mEq/L |
| Bicarbonate | 24 mEq/L |
| Blood urea nitrogen | 13 mg/dL |
| Creatinine | 0.9 mg/dL |
| Glucose | 98 mg/dL |
| Calcium | 11.7 mg/dL |
| Albumin | 3.7 g/dL |
Which of the following best explains this patient's hypertension?
Secondary causes of hypertension | |
Condition | Clinical clues/features |
Renal parenchymal disease |
|
Renovascular disease |
|
Primary hyperaldosteronism |
|
Obstructive sleep apnea |
|
Pheochromocytoma |
|
Cushing syndrome |
|
Thyroid disease |
|
Primary hyperparathyroidism |
|
Coarctation of the aorta |
|
This patient with hypertension associated with hypercalcemia, muscle weakness, kidney stones, and neuropsychiatric symptoms (eg, depression, poor sleep) likely has primary hyperparathyroidism (PHPT).
Excess parathyroid hormone causes hypercalcemia due to increased renal calcium reabsorption, gastrointestinal calcium absorption, and bone resorption. In addition to kidney stones, neuropsychiatric symptoms, and muscle weakness, other common manifestations include abdominal pain, constipation, and polyuria or polydipsia. The majority (~80%) of PHPT cases are due to parathyroid adenoma.
PHPT is commonly associated with hypertension; proposed mechanisms include increased renin secretion, sympathetic hyperresponsiveness, and peripheral artery vasoconstriction. Other cardiovascular manifestations of hyperparathyroidism include left ventricular hypertrophy, arrhythmias, and vascular and valvular calcification. Treatment of PHPT usually results in normalization of blood pressure.
(Choice A) Amphetamine abuse can cause hypertension associated with additional signs and symptoms of sympathetic stimulation (eg, tachycardia, diaphoresis, hyperthermia) but would not cause hypercalcemia and kidney stones.
(Choice B) Findings suggestive of Cushing syndrome include central obesity, muscle wasting, thin skin, and abdominal striae. Laboratory findings include hyperglycemia, leukocytosis, and hypokalemia.
(Choice D) Hypertension can be induced by both hyperthyroidism (predominantly systolic hypertension) and hypothyroidism (predominantly diastolic hypertension). Although hyperthyroidism can cause hypercalcemia due to increased bone turnover, hypothyroidism does not have a significant effect on serum calcium concentration.
(Choice E) Primary hyperaldosteronism (Conn syndrome) can cause hypertension and muscle weakness, but it is typically associated with hypokalemia (especially when patients are given diuretics) rather than hypercalcemia.
(Choice F) Although renal artery stenosis can occur in young women with fibromuscular dysplasia, it is much more common in older men with atherosclerosis. Suggestive findings include resistant hypertension, abdominal bruit, recurrent flash pulmonary edema, and acute kidney injury following initiation of an ACE inhibitor.
(Choice G) Renal parenchymal disease can cause secondary hypertension but usually presents with elevated serum creatinine and abnormal urinalysis. In addition, patients are usually hypocalcemic rather than hypercalcemic.
Educational objective:
Hyperparathyroidism is a cause of secondary hypertension and should be suspected in patients who have hypertension associated with hypercalcemia, renal stones, abdominal pain, or neuropsychiatric symptoms. Other cardiovascular manifestations of hyperparathyroidism include left ventricular hypertrophy, arrhythmias, and vascular and valvular calcification.