Unit 1 Day 6 (3/30/15)

Question 1

Furosemide (loop)

Answer 1

• loop diuretic
• site and mechanism of action at the nephron: inactivates Na/K/Cl pump, dec. K+ exit from lumen, leading to dec. in Mg and Ca entry into lumen
• role in the treatment of heart failure: used in HF pts with volume overload, most commonly used
• adverse effects: hypokalemic metabolic alkalosis, hypocalcemia, hypomegnesemia (all)
• first line tx in HRrEF and HFpEF
• sulfa drug
• in loop of henle

Question 2

Torsemide (loop)

Answer 2

• loop diuretic
• site and mechanism of action at the nephron: inactivates Na/K/Cl pump, dec. K+ exit from lumen, leading to dec. in Mg and Ca entry into lumen
• role in the treatment of heart failure: used when pt does not tolerate furosemide (more reliable absorption)
• adverse effects: hypokalemic metabolic alkalosis
• first line tx in HRrEF and HFpEF

Question 3

Bumetanide (loop)

Answer 3

• loop diuretic
• site and mechanism of action at the nephron: inactivates Na/K/Cl pump, dec. K+ exit from lumen, leading to dec. in Mg and Ca entry into lumen
• role in the treatment of heart failure: used when pt does not tolerate furosemide (more reliable absorption)
• adverse effects: hypokalemic metabolic alkalosis
• first line tx in HRrEF and HFpEF

Question 4

Thiazides (hydrochlorothiazide, chlorthalidone, and metolazone)

Answer 4

• site and mechanism of action at the nephron: interacts with Na/Cl pump, leading to inc. reabsorption of Ca in distal convoluted tubule
• role in the treatment of heart failure: prevents refractory edema (blcoks distal tubule Na reabsorption and counters loop induced inc in Na delivery, will also enhance diuresis and ameliorate the K wasting of loop diuretics
• adverse effects: hypokalemia, hyperglycemia, gout, allergic reactions (sulfa)

Question 5

•Na+-channel blockers (Amiloride-Triamterene)

Answer 5

• potassium sparing diuretic
• site and mechanism of action at the nephron: direct effect to block the Na channels on collecting duct lumen and dec. Na reabsorption
• role in the treatment of heart failure: no utility in HF (do not block pro-fibrotic actions of aldosterone)
• adverse effects: hyperkalemia

Question 6

Aldosterone Antagonists (Spironolactone and Eplerenone)

Answer 6

• K+ sparing diuretic
• end in -one
• target and mode of action: dec. aldosterone activation on kidney, competative antagonist at aldosterone receptor (blocks synthesis of Na and K channels) in collecting tubule
• role in the treatment of heart failure: tx for chronic HFrEF, produce vasodilation, antiremodeling action
• adverse effects: spiro causes gynecomastia

Question 7

Acute Myocarditis

Answer 7

• inflammation of the cardiac muscle that is usually viral in etiology
• most common in younger people
• signs: congestion (rales), edema, enlarged heart, may hear S3
• outcomes: dilated cardiomyopathy, hypertrophic/obstructive cardiomyopathy, restrictive cardiomyopathy

Question 8

Dilated Cardiomyopathy

Answer 8

• enlarged left ventricle
• etiology: idiopathic, ischemic, viral, familial, chemotherapeutic, ethanol, concaine, hemochromatosis (Fe excess), muscular dystrophies, peripartum cardiomyopathy
• tx: tx for HF, anticoagulation, anti-arrhyhtmic agents, anti-inflammatory/immunosuppressive agents

Question 9

Hypertrophic/Obstructive Cardiomyopathy

Answer 9

• disproportionate thickening of the intravascular septum
• big R waves
• obstructive type:
• asymmetric myocardial hypertrophy
• diastolic dysfunction
• enhanced systolic dysfuction
• muscle fibers markedly disrupted
• clinical manifestations: dyspnea, angina, sudden death
• tx: avoid competitive sports, dec. contractility, surgical myomectomy, implant defibrillator

Question 10

Restrictive Myopathy

Answer 10

• impaired ventricular filling due to still ventricles
• most commonly infiltrative (amyloidosis, sarcoidosis)
• systolic function often normal
• dx: echo or MRI