Name:
A 28-Year-Old Woman with Hypertension
Description:
A 28-Year-Old Woman with Hypertension
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Duration:
T00H07M46S
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Upload Date:
2022-02-28T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[upbeat intro music]
DR. HANDY: Hi, welcome to Harrison's Podclass, where we discuss important concepts in internal medicine. I'm Cathy Handy.
DR. WIENER: And I'm Charlie Wiener and we're coming to you from the Johns Hopkins School of Medicine. Welcome to episode 63, a 28-year-old with hypertension. Okay Cathy, today's patient is a 28-year-old woman who has hypertension that has been difficult to control with medications. She was diagnosed with the hypertension at the age of 26 and since that time she has been on increasing amounts of medication. Her current regimen consists of labetalol 1000 mg twice a day, lisinopril 40 mg once a day, clonidine 0.1 mg twice a day, and amlodipine 5 mg once a day.
DR. HANDY: Okay, so this is unusual for a young woman to have such difficult to control hypertension. While most patients, 80 to 95% of hypertensive patients are diagnosed as having essential hypertension, this presentation would really make you consider one of the secondary causes of hypertension as the main driver of her disease in this case.
DR. WIENER: Okay, well let me give you a little bit more information then. On physical examination, she appears without distress. Her blood pressure is 168/100, and her heart rate is 80 beats per minute. Her cardiac examination is unremarkable except for an S4. She has no murmurs and no rubs. She has good peripheral pulses and has no peripheral edema. Her jugular venous pressure is estimated at about seven centimeters based on her position at 30 degrees.
DR. WIENER: Her BMI is 20 and her physical appearance does not reveal any hirsutism, fat maldistribution or abnormalities of her genitalia.
DR. HANDY: Okay, well with that information you did sort of bring up potential other secondary causes, but the physical exam actually points me away from those. So I would lean away from polycystic ovarian syndrome or congenital adrenal hyperplasia, Cushing syndrome, or growth hormone excess. And you also note that her BMI is within the normal range. Lab studies here would be helpful.
DR. WIENER: Okay. Laboratory studies are notable for potassium of 2.8, a serum bicarb of 32, and a fasting blood glucose of 114. Everything else, including her renal function is normal.
DR. HANDY: Okay, so this is interesting. She has hypokalemia and a metabolic alkalosis and there's no evidence of glucose intolerance or renal dysfunction.
DR. WIENER: Okay. So the question is going to ask us, which of the following is the most likely diagnosis? Option A is congenital adrenal hyperplasia; option B is Cushing syndrome; option C is Conn's syndrome; option D is fibromuscular dysplasia; and option E is pheochromocytoma.
DR. HANDY: Well, based on what we said before I don't think she has congenital adrenal hyperplasia which is answer A or Cushing's, because of the physical examination being relatively normal. People with Cushing syndrome classically have central obesity, broad purple stretch marks, and thin skin. It is important to remember the physiology of aldosterone because I think that's where this case is going. Aldosterone is the mineralocorticoid hormone released by the adrenals that acts on the kidney and other organs to preserve intravascular volume by promoting sodium reabsorption into the vasculature.
DR. HANDY: It acts on the distal tubules and the collecting ducts to increase sodium and bicarbonate reabsorption and does so by increasing potassium and hydrogen excretion. So this would lead to the hypokalemia and the metabolic alkalosis seen in this case. Aldosterone is stimulated by high renin levels and therefore plays a pivotal role in blood pressure regulation. So I'm thinking this patient may have aldosterone excess, that would explain the hypertension, her young age, the lab abnormalities, and the lack of any other physical findings.
DR. WIENER: So you're telling me this is Conn's syndrome?
DR. HANDY: Yes. Conn's syndrome is primary hyperaldosteronism typically caused by an adrenal adenoma. So, I think the answer is C.
DR. WIENER: All right. What about the other options that you did not mention yet?
DR. HANDY: Fibromuscular dysplasia is a hyperplastic disorder that affects medium size and small arteries. It does occur predominantly in females and usually involves the renal and carotid arteries but it can affect extremity vessels such as the iliac and subclavian arteries. The iliac arteries are the limb arteries most likely to be affected. It is a strong consideration in young women but it will not typically cause hypokalemia and metabolic alkalosis.
DR. HANDY: When limb vessels are involved the clinical manifestations are similar to those for atherosclerosis, so you'd present with claudication and rest pain. I leaned away from pheochromocytoma because of the history. We did not hear history of labile hypertension or episodic exacerbations of symptoms which would be more typical for that.
DR. WIENER: Okay. So we're thinking that she has a primary hyperaldosteronism due to an adrenal adenoma, or Conn's syndrome. The question goes on to ask, in this patient which of the following is the best way to diagnose her disease? Option A is a 24-hour urine collection for cortisol; option B is a 24-hour urine collection from metanephrines; option C is an MRI imaging of the renal arteries; option D is a plasma aldosterone to renin ratio; option E is renal vein renin levels.
DR. HANDY: Well, again, let's go back to the pathophysiology of aldosteronism. I said that in appropriate settings, low blood pressure or volume depletion causes the release of renin which subsequently increases aldosterone. In Conn's or primary hyperaldosteronism, renin levels are low and aldosterone levels are high. So you can measure the plasma aldosterone to renin levels, and an elevated ratio is diagnostic. So a ratio of over 30:1 in conjunction with a plasma aldosterone concentration over 555, or over 20 ng/dL, reportedly has a sensitivity of 90% and a specificity of 91% for an aldosterone producing adenoma.
DR. HANDY: The one caveat of that is you must ensure that the patient is not on an ACE inhibitor, which would obviously be a commonly prescribed antihypertensive, because that will cause elevation of renin levels. So for this question the answer is D, the plasma aldosterone to renin ratio. Now if imaging does not localize an adenoma you can perform this test directly from the adrenal veins to determine the site.
DR. WIENER: And as I recall, this patient was on lisinopril so we probably would have to stop that put her on another medication and then do the testing. Is that what you're saying?
DR. HANDY: Correct.
DR. WIENER: Okay, what about the other options? What are they used for and why are they not correct?
DR. HANDY: 24-hour urine cortisol measure may be used to diagnose Cushing's and metanephrines are useful for the diagnosis of pheochromocytoma. As I mentioned, the most likely cause of Conn's syndrome or primary aldosteronism is an adenoma, so imaging of the adrenals but not of the renal arteries would be indicated.
DR. WIENER: Great. The teaching points to this case are, that difficult to control hypertension in a young woman is likely secondary to genetic, metabolic or tumor related causes. The physical examination and laboratory tests are helpful in determining the etiology. Primary aldosteronism typically caused by a benign adenoma will cause hypertension, hypokalemia, and a metabolic alkalosis. The diagnosis may be confirmed by measuring the plasma ratio of aldosterone to renin.
DR. HANDY: And you can read more about this in Harrison's chapter on hypertensive vascular disease. [outro music] [Mr. Shanahan] This is Jim Shanahan, publisher at McGraw Hill. Harrison's Podclass is brought to you by McGraw Hill's Access Medicine, the online medical resource that delivers the latest trusted content from the best minds in medicine. Go to accessmedicine.com to learn more.