Pathophysiology of Congestive Heart Failure
Congestive heart failure is:
1) inability of heart to deliver sufficient cardiac output to meet physiologic needs
2) both diastolic and systolic phases are abnormal
3) initially, compensatory mechanisms occur(increased catecholamines, increased atrial natriuretic factor, myocardial hypertrophy), but eventual failure of these ensues causing congestive heart failure
4) result is increase in venous pressure with congestion of liver, spleen, and kidney (“backward failure”) and sodium retention, peripheral edema, and pulmonary sequelae (“forward” failure”)
5) a “final common pathway” occurs with coronary artery disease (most common), valve dysfunction, and hypertension
Signs and Symptoms
1) dypsnea
2) orthopnea
3) distended neck veins
4) pitting edema in dependent body parts
5) rales on lung auscultation
6) ascites
7) pleural effusions
8) cough
9) pulmonary edema
10) pulmonary hypertension
11) cyanosis of lips and nail beds
12) weakness and fatigue
13) confusion
14) memory loss
15) nocturia
16) failure of right ventricle
17) abnormally increased atrial filling pressure relative to stroke volume
Characteristic Test Findings
Laboratory
1) increased renin (owing to decreased glomerular filtration rate)
2) increased angiotensin
3) increased aldosterone
4) increased sodium resorption (which causes increased fluid retention)
5) increased catecholamines (to stimulate cardiac contractility)
6) increased atrial natriuretic factor (in an attempt to excrete the excess sodium
7) moderate increase in transaminases (owing to liver congestion)
8) increased bilirubin (owing to liver congestion)
Histology/Gross Pathology
1) “nutmeg” liver
2) “brown” induration of lungs
3) fluid-filled alveoli
4) alveoli with hemodsiderin-filled macrophages
5) interstitial pulmonary fibrosis
6) dilated heart chambers
7) enlarged heart
Associated Conditions
1) precipitating factors in congestive heart failure are coronary artery disease, hypertension, bacterial endocarditis, valve failure from any cause, hemochomomatosis
2) increased incidence in congestive heart failure of pulmonary embolism, arrhythmias, myocardial infarction
Inheritance/Epidemiology
affects 2-3 million people in USA
Treatment
1) ACE inhibitors (lisinopril, enalapril)
2) beta-adrenergic blockers (metoprolol)
3) thiazide diuretics (furosemide)
4) restriction of sodium intake
5) digitalis
Tips for USMLE
1) if question mentions nutmeg liver, think congestive heart failure
2) if the patient is an 85 year old man who needs to sleep on three pillows to avoid waking up gasping for breath, who has a history of two myocardial infarctions, and who has edema around the ankles, think congestive heart failure
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