Hypertension Case 4

Hypertension Case 4


Case 4

A 19-year-old woman presents to her doctor's office for an annual physical examination. She has been previously healthy and is currently doing well without complaints. She is a non-smoker and has no significant past medical history or family history. Her temperature is 36.9 C (98.5 F),
blood pressure is 160/90 mm Hg (confirmed in all extremities), pulse is 84/min, and respirations are 16/min. Her pulses are symmetric and equaI, her cardiac and pulmonary examinations are unremarkable, and there is an abdominal bruit with a systolic and diastolic component.

Serum chemistry reveals:

Sodium 145 mEq/L
Potassium 3.1 mEq/L
Chloride 102 mEq/L
Bicarbonate 28 mEq/L
BIood urea nitrogen 14 mg/dL
Creatinine 1.0 mg/dL
GIucose 80 mg/dL


Q 1

Which of the following is the most likely cause of her elevated blood pressure?
/ A. Coarctation of the aorta
/ B. Cushing syndrome
/ C. Pheochromocytoma
/ D. Renovascular hypertension
/ E. Thyrotoxicosis


Q 2
Which of the following is the most likely cause of the low potassium in this patient?
/ A. Acidosis
/ B. Gastrointestinal wasting
/ C. Hyperaldosteronism
/ D. Inadequate nutritional intake
/ E. Thyrotoxicosis


Q 3
The patient is initially treated with atenolol to lower her blood pressure. Which of the following is the mechanism of action of this medication?
/ A. AIpha-1 receptor blockade
/ B. AIpha-2 receptor stimulation
/ C. Calcium channel blockade
/ D. Nonselective beta blockade
/ E. Selective beta-1 receptor blockade


Q 4
Which of the following tests would help confirm the diagnosis in this patient?
/ A. Bilateral arteriography with renal vein and systemic renin measurements
/ B. Renal biopsy
/ C. Thyroid function studies
/ D. Twenty-four hour urine evaluation for creatinine clearance
/ E. Urine catecholamine levels


Q 5
Biopsy of the affected tissue would likely reveal which of the following?
/ A. Adrenocortical adenoma
/ B. Atrophic thyroid follicles with dense, focal lymphocytic infiltration
/ C. Fibromuscular dysplasia
/ D. Hyperplasia of the zona glomerulosa of the adrenal gland
/ E. Psammoma bodies


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Hypertension Case 4 answers


A1
The correct answer is D. Secondary hypertension should be considered in a young previously healthy patient with new onset hypertension. In this case, renovascular hypertension should be highly suspected in the presence of an abdominal bruit on physical exam. Abdominal bruits, particularly those with a systolic and diastolic component, are specific for renovascular hypertension due to renal artery stenosis. Renovascular hypertension is the most common cause of correctable secondary hypertension.
Coarctation of the aorta (choice A) is a major cause of hypertension in young children. It is characterized by diminished peripheral pulses, particularly in the lower extremities. The hypertension is often limited to the upper extremities, as the narrowing usually occurs distal to the origin of the subclavian arteries.
Cushing syndrome (choice B) can cause hypertension, but one should find other suggestive findings on physical examination, including central obesity, moon facies, dorsal hump, purple striae, and ecchymoses.
Pheochromocytoma (choice C) can also cause secondary hypertension, but patients have paroxysms of blood pressure elevation, which correlate with symptomatic episodes of sweating and palpitations.
Thyrotoxicosis (choice E) can also cause secondary hypertension, but one should expect to find other symptoms of hyperthyroidism such as restlessness, tremor, heat intolerance, hyperdefecation, weight loss in spite of increased appetite, and menstrual abnormalities in females.


A2
The correct answer is C. In renovascular hypertension, there is decreased perfusion of the renal tissue, which activates the renin-angiotensin system. This, in turn, stimulates the oversecretion of aldosterone, which acts on the distal convoluted tubule to enhance sodium reabsorption in exchange for potassium excretion.
Alkalosis, rather than acidosis (choice A), is associated with hypokalemia.
Gastrointestinal wasting (choice B) can cause hypokalemia but there is no indication of diarrhea or vomiting in this patient.
Inadequate nutritional intake (choice D) can also cause hypokalemia, but this patient gives no history of poor nutrition.
Thyrotoxicosis (choice E) can cause hyperdefecation resulting in diarrhea, which could cause hypokalemia, but this patient does not have signs or symptoms suggestive of thyrotoxicosis.


A3
The correct answer is E. Atenolol is a selective beta-1 receptor blocker. It acts to decrease cardiac output, decrease heart rate, and decrease contractility, thus decreasing blood pressure. Metoprolol and esmolol are also selective beta-1 receptor blockers.
Alpha-1 receptor blockers (choice A), such as terazosin and doxazosin, are used in the treatment of hypertension and benign prostatic hypertrophy.
Alpha-2 receptor stimulation (choice B) is a mechanism of action used by clonidine. It is a centrally acting antihypertensive agent that lowers blood pressure and heart rate.
Calcium channel blockade (choice C) in vascular smooth muscle causes vasodilation, and in the heart, causes a decrease in contractility. Examples of calcium channel blockers include nifedipine, verapamil, and diltiazem.
Nonselective beta blockers (choice D) block beta-2 receptors in addition to beta-1 receptors. Examples of nonselective beta-blockers include propranolol, timolol, pindolol, and labetalol.


A4
The correct answer is A. Bilateral arteriography with renal vein and systemic renin measurements is the most definitive diagnostic procedure for the diagnosis of renal artery stenosis. Arteriography can demonstrate renal artery stenosis and comparison of renin levels help confirm the diagnosis.
Renal biopsy (choice B) would be done if renal parenchymal disease such as glomerulonephritis were suspected. In renovascular hypertension, the pathology occurs in the renal artery and/or one of its major branches.
Thyroid function studies (choice C) would be helpful if this patient had signs and symptoms suggestive of thyrotoxicosis.
Twenty-four hour urine evaluation for creatinine clearance (choice D) would estimate the glomerular filtration rate in this patient, but it would not be helpful in suggesting a possible cause of the hypertension.
Urine catecholamine levels (choice E) would be helpful if this patient were suspected of having a pheochromocytoma.


A5
The correct answer is C. Fibromuscular dysplasia is an intrinsic structural abnormality of the arterial wall. It generally occurs in young women. When it occurs in the renal vein and/or one of its major branches, it causes renal artery stenosis. The renal artery stenosis activates the renin-angiotensin system, causing an increase in aldosterone secretion and hypertension.
Adrenocortical adenoma (choice A) is an aldosterone-secreting tumor of the adrenal gland. Hyperplasia of the zona glomerulosa of the adrenal gland (choice D) also results in increased secretion of aldosterone. They both cause a primary hyperaldosteronism and hypertension, but are both associated with low renin levels. Patients with renovascular hypertension have increased release of renin, which causes secondary hyperaldosteronism.
Atrophic thyroid follicles with dense, focal lymphocytic infiltration (choice B) are seen in Hashimoto thyroiditis.
Psammoma bodies (choice E) are seen in papillary carcinoma, a malignant tumor of the thyroid gland.