RAAS

RAAS US Medical PG Question 1: A 75 year-old gentleman presents to his general practitioner. He is currently being treated for hypertension and is on a multi-drug regimen. His current blood pressure is 180/100. The physician would like to begin treatment with minoxidil or hydralazine. Which of the following side effects is associated with administration of these drugs?

• A. Persistent cough
• B. Cyanosis in extremities
• C. Fetal renal toxicity
• D. Systemic volume loss
• E. Reflex tachycardia (Correct Answer)

RAAS Explanation: ***Reflex tachycardia*** - Both **minoxidil** and **hydralazine** are direct arterial vasodilators, causing a significant drop in **peripheral vascular resistance**. - This vasodilation triggers a **baroreflex response**, leading to an increase in heart rate and **cardiac contractility** to maintain cardiac output, resulting in reflex tachycardia. *Persistent cough* - **Persistent cough** is a common side effect associated with **ACE inhibitors**, such as lisinopril or enalapril, due to the accumulation of **bradykinin**. - This side effect is not typically seen with **minoxidil** or **hydralazine**, which act directly on vascular smooth muscle to cause vasodilation. *Cyanosis in extremities* - **Cyanosis** (bluish discoloration of the skin and mucous membranes) usually indicates **hypoxemia** or poor peripheral perfusion. - While sometimes associated with severe cardiogenic shock or specific drug toxicities like methemoglobinemia (not related to minoxidil or hydralazine), it is not a direct or typical side effect of these vasodilators. *Fetal renal toxicity* - **Fetal renal toxicity**, including **fetal renal dysfunction** and **oligohydramnios**, is a well-known risk associated with **ACE inhibitors** and **ARBs** during pregnancy. - Neither **minoxidil** nor **hydralazine** are primarily linked to this specific fetal adverse effect, though hydralazine can be used in pregnancy for severe hypertension. *Systemic volume loss* - **Systemic volume loss** is usually caused by conditions like **dehydration**, excessive diuresis, or hemorrhage. - While vasodilators can reduce blood pressure, they do not directly cause **systemic volume depletion**; rather, the reflex response to vasodilation can include fluid retention to counteract the blood pressure drop.

RAAS US Medical PG Question 2: A 32-year-old African American man presents to the office for a routine examination. He has no complaints at this time. Records show that his systolic blood pressure was in the 130–138 range and diastolic blood pressure in the 88–95 range despite counseling on lifestyle modification. He admits that he was not compliant with this advice. He takes no medications and works at home as a web designer. He does not drink alcohol but smokes marijuana on a weekly basis. Temperature is 37°C (98.6°F), blood pressure is 138/90 mm Hg, pulse is 76/min, and respirations are 12/min. BMI is 29.8 kg/m2. Physical examination is normal except for truncal obesity, with a waist circumference of 44 inches. Fasting laboratory results are as follows: Blood glucose 117 mg/dL Total cholesterol 210 mg/dL LDL cholesterol 120 mg/dL HDL cholesterol 38 mg/dL Triglycerides 240 mg/dL Which of the following mechanisms contribute to this patient’s condition?

• A. Excessive cortisol secretion and activity
• B. Granulomatous inflammation in medium-sized vessels
• C. LDL receptor gene mutation
• D. Insulin receptor resistance (Correct Answer)
• E. Autoimmune destruction of pancreatic beta cells

RAAS Explanation: ***Insulin receptor resistance*** - The patient exhibits features of **metabolic syndrome**, including **truncal obesity** (BMI 29.8 kg/m², waist circumference 44 inches), **elevated blood pressure** (138/90 mm Hg), **impaired fasting glucose** (117 mg/dL), **high triglycerides** (240 mg/dL), and **low HDL cholesterol** (38 mg/dL). These are all key manifestations of insulin resistance. - **Insulin resistance** is central to metabolic syndrome, leading to compensatory hyperinsulinemia, which contributes to hypertension, dyslipidemia, and impaired glucose tolerance, eventually progressing to type 2 diabetes if pancreatic beta cells fail. *Excessive cortisol secretion and activity* - **Cushing's syndrome**, characterized by excessive cortisol, also causes truncal obesity, hypertension, and hyperglycemia, but typically presents with additional features like **moon facies**, **buffalo hump**, and **skin striae**, which are not mentioned here. - The patient's blood pressure and glucose levels, while elevated, are not severe enough to strongly suggest Cushing's syndrome in the absence of other characteristic signs. *Granulomatous inflammation in medium-sized vessels* - This description is characteristic of various forms of **vasculitis**, such as **Polyarteritis Nodosa** or **Giant Cell Arteritis**. - Vasculitis typically presents with constitutional symptoms, organ ischemia, and specific inflammatory markers, none of which are present in this patient's routine examination. *LDL receptor gene mutation* - An **LDL receptor gene mutation** is associated with **familial hypercholesterolemia**, primarily causing greatly elevated LDL cholesterol levels and premature cardiovascular disease. - While this patient has elevated LDL, his overall lipid profile with high triglycerides and low HDL is more consistent with metabolic syndrome than a primary LDL receptor defect. *Autoimmune destruction of pancreatic beta cells* - This is the underlying mechanism of **type 1 diabetes mellitus**, which usually presents with profound hyperglycemia, polyuria, polydipsia, and weight loss, typically in younger patients. - This patient's mild hyperglycemia and features of metabolic syndrome are more indicative of **insulin resistance (type 2 diabetes)** rather than autoimmune beta-cell destruction.

RAAS US Medical PG Question 3: A 33-year-old woman presents to her primary care physician for a wellness check-up. She states that recently she has been feeling well other than headaches that occur occasionally, which improve with ibuprofen and rest. She has a past medical history of hypertension and headaches and is currently taking hydrochlorothiazide. Her temperature is 99.2°F (37.3°C), blood pressure is 157/108 mmHg, pulse is 90/min, respirations are 14/min, and oxygen saturation is 98% on room air. Physical exam reveals a young woman who appears healthy. A normal S1 and S2 are auscultated on cardiac exam, and her lungs are clear with good air movement bilaterally. From her previous visit, it was determined that she has an elevated aldosterone and low renin level. Laboratory values are ordered as seen below. Serum: Na+: 139 mEq/L Cl-: 100 mEq/L K+: 3.7 mEq/L HCO3-: 29 mEq/L BUN: 20 mg/dL Creatinine: 1.1 mg/dL Which of the following is the most likely diagnosis?

• A. Benign essential hypertension
• B. Pheochromocytoma
• C. Cushing syndrome
• D. Narrowing of the renal arteries
• E. Primary hyperaldosteronism (Correct Answer)

RAAS Explanation: ***Primary hyperaldosteronism*** - The patient presents with **hypertension**, **mild hypokalemia (K+ of 3.7 mEq/L)**, and **metabolic alkalosis (HCO3- of 29 mEq/L)**, which are classic signs of primary hyperaldosteronism. - The elevated aldosterone and low renin levels, as noted from her previous visit, are diagnostic for primary hyperaldosteronism. *Benign essential hypertension* - While essential hypertension is common, the presence of **hypokalemia**, **metabolic alkalosis**, and particularly the **elevated aldosterone with low renin** points away from benign essential hypertension, which typically has normal renin-aldosterone ratios. - This patient's hypertension is likely **secondary** due to a specific endocrine imbalance. *Pheochromocytoma* - This condition presents with **episodic or paroxysmal hypertension**, **tachycardia**, **sweating**, and headaches, often in a more dramatic fashion. - The patient's blood pressure is consistently elevated, and she lacks the typical paroxysmal symptoms and signs of catecholamine excess. *Cushing syndrome* - Cushing syndrome is characterized by **hypertension**, central obesity, moon facies, buffalo hump, and striae, none of which are described. - While it can cause hypertension, it is due to cortisol excess and does not typically present with the specific aldosterone-renin profile seen in this patient. *Narrowing of the renal arteries* - **Renal artery stenosis** causes **renovascular hypertension** and is associated with **elevated renin levels** as the kidney perceives hypoperfusion and activates the renin-angiotensin-aldosterone system. - This patient presents with **low renin levels**, which directly contradicts the pathophysiology of renal artery stenosis.

RAAS US Medical PG Question 4: A 55-year-old woman comes to the physician because of involuntary hand movements that improve with alcohol consumption. Physical examination shows bilateral hand tremors that worsen when the patient is asked to extend her arms out in front of her. The physician prescribes a medication that is associated with an increased risk of bronchospasms. This drug has which of the following immediate effects on the cardiovascular system? Stroke volume | Heart rate | Peripheral vascular resistance

• A. ↓ ↓ ↓
• B. ↓ ↓ ↑ (Correct Answer)
• C. ↓ ↑ ↑
• D. ↑ ↑ ↑
• E. ↑ ↑ ↓

RAAS Explanation: ***↓ ↓ ↑*** - This patient likely has **essential tremor**, which is characterized by **bilateral hand tremors** that improve with alcohol and worsen with intention (postural tremor). The prescribed medication is a **beta-blocker** (e.g., propranolol), which is associated with an increased risk of bronchospasms due to blocking **beta-2 receptors** in the airways. - Beta-blockers **decrease heart rate** (negative chronotropic effect) and **stroke volume** (negative inotropic effect) by blocking beta-1 receptors in the heart, reducing cardiac output. - **Peripheral vascular resistance increases** acutely due to: (1) **unopposed alpha-1 adrenergic tone** in blood vessels (loss of beta-2 mediated vasodilation), and (2) baroreceptor-mediated reflex vasoconstriction in response to decreased cardiac output. This helps maintain blood pressure despite reduced cardiac output. *↓ ↓ ↓* - While beta-blockers decrease **heart rate** and **stroke volume**, peripheral vascular resistance does not decrease acutely. A decrease in all three parameters would cause severe hypotension. - The loss of beta-2 receptor-mediated vasodilation and baroreceptor reflexes lead to increased, not decreased, peripheral vascular resistance. *↓ ↑ ↑* - Beta-blockers **decrease heart rate** through beta-1 blockade, not increase it. This is their primary cardiac mechanism of action. - An increase in heart rate would be expected with sympathomimetic drugs or anticholinergics, not beta-blockers. *↑ ↑ ↑* - This combination indicates increased cardiovascular activity, which is the opposite effect of **beta-blockers**. - Beta-blockers reduce heart rate and stroke volume by blocking beta-1 receptors; they do not increase these parameters. - This pattern would suggest sympathetic activation or administration of an adrenergic agonist. *↑ ↑ ↓* - Beta-blockers **decrease** (not increase) both heart rate and stroke volume through beta-1 receptor blockade. - While decreased peripheral vascular resistance occurs with vasodilators, beta-blockers acutely **increase** PVR due to unopposed alpha-adrenergic tone.

RAAS US Medical PG Question 5: A 32-year-old man presents with hypertension that has been difficult to control with medications. His symptoms include fatigue, frequent waking at night for voiding, and pins and needles in the legs. His symptoms started 2 years ago. Family history is positive for hypertension in his mother. His blood pressure is 160/100 mm Hg in the right arm and 165/107 mm Hg in the left arm, pulse is 85/min, and temperature is 36.5°C (97.7°F). Physical examination reveals global hyporeflexia and muscular weakness. Lab studies are shown: Serum sodium 147 mEq/L Serum creatinine 0.7 mg/dL Serum potassium 2.3 mEq/L Serum bicarbonate 34 mEq/L Plasma renin activity low Which of the following is the most likely diagnosis?

• A. Renal artery stenosis
• B. Coarctation of aorta
• C. Cushing syndrome
• D. Primary aldosteronism (Correct Answer)
• E. Essential hypertension

RAAS Explanation: ***Primary aldosteronism*** - The patient presents with **resistant hypertension**, **hypokalemia** (2.3 mEq/L), **metabolic alkalosis** (bicarbonate 34 mEq/L), and **low plasma renin activity**, which are classic features of primary aldosteronism. - Symptoms like **fatigue**, **nocturia**, and **paresthesias** (pins and needles) in the legs are consistent with severe hypokalemia, directly resulting from excessive aldosterone secretion. *Renal artery stenosis* - This condition typically causes **secondary hypertension** with **elevated renin levels** due to decreased renal perfusion, which contradicts the low plasma renin activity seen in this patient. - While it can cause hypokalemia because of increased renin-angiotensin-aldosterone system activation, the **primary driver** in this case, based on low renin, points away from renal artery stenosis. *Coarctation of aorta* - Characterized by **differential blood pressures** between the upper and lower extremities and sometimes between the arms, and a **systolic murmur** that is often present. - It does not typically present with severe **hypokalemia** or metabolic alkalosis or the low plasma renin activity observed in this patient. *Cushing syndrome* - This syndrome is caused by **excessive cortisol** and can lead to hypertension and hypokalemia, but it is also associated with distinct clinical features like **central obesity**, buffalo hump, moon facies, and proximal muscle weakness, which are not described. - While it can cause similar electrolyte imbalances, the lack of classic Cushingoid features makes it less likely, and the specific **low plasma renin** points more strongly to aldosterone excess. *Essential hypertension* - This is a diagnosis of exclusion, typically presenting without a clear secondary cause and with **normal electrolyte levels**. - The presence of severe **hypokalemia**, **metabolic alkalosis**, and **low plasma renin activity** indicates a secondary cause, ruling out essential hypertension.

RAAS Flashcard 1 of 5

Question: At high concentrations, cortisol can bind to _____ receptors

Answer: mineralocorticoid (aldosterone)

RAAS Flashcard 2 of 5

Question: The renin-angiotensin II-aldosterone system is activated in response to a _____ in mean arterial pressure

Answer: decrease

RAAS Flashcard 3 of 5

Question: The renin-angiotensin II-aldosterone system regulates mean arterial pressure primarily by adjusting blood _____

Answer: volume

RAAS Flashcard 4 of 5

Question: To what receptor does angiotensin II bind?_____

Answer: AT1 receptor

RAAS Flashcard 5 of 5

Question: Secondary hyperaldosteronism is due to activation of _____ system

Answer: renin-angiotensin