-IBIS-1.5.0-
tx
cardiovascular system
congestive heart failure
diagnoses

definition and etiology

definition:
A clinical syndrome where the heart is unable to pump blood forward normally, causing congestion in the pulmonary and/or systemic circulation, and decreased blood flow to the body tissues due to diminished cardiac output. Also called "dilated or congestive cardiomyopathy".

etiology:
CHF results from primary changes in the myocardium caused by secondary factors creating increased cardiac work. It is thought to be the end result of a variety of toxic, infectious, and metabolic agents adversely affecting the heart tissues, including anemia, thyrotoxicosis, infection, embolism, arrhythmias, dietary excess and so on. Congenital heart defects are also major risk factors to developing CHF later in the life of the patient.

signs and symptoms

Heart failure usually occurs in either the left (most commonly) or right ventricle. In acute episodes of heart failure, the patient will often present with considerable anxiety and distress; and will also typically be seated on the edge of a chair or bed and be leaning forward in attempts to breathe better. Accessory muscles may be used by the patient to aid with inhalation.

» left-sided failure: This is due to decreased cardiac output; it causes increased pulmonary venous pressure. Results are increased water in the lungs, increased work to breathe, and reduced pulmonary compliance.

signs and symptoms: paroxysmal nocturnal dyspnea, coughing, general and exertional fatigue, aggravation with cold, cardiac signs (palpable/audible 3rd and 4th heart sounds, inspiratory basilar rales, etc.)

causes: hypertension, septal defect, mitral regurgitation, coronary artery disease, aortic valvular disease, patent ductus arteriosus

right-sided failure: usually occurs as a result of left-sided failure

signs and symptoms: worsening fatigue, fullness in the neck and abdomen, enlarged liver, systemic hypertension, ascites and dependent peripheral pitting edema, increased A or V waves in the external jugular pulse, other cardiac signs

causes: left ventricular failure, pulmonary embolism/stenosis, atrial septal defect, tricuspid regurgitation

biventricular failure: usually occurs as a result of of alcoholic, viral, or non-specific cardiomyopathy. The symptoms typically correlate with those of right-sided failure.

lab findings:
• chest x-rays: butterfly/batwing picture, hilar congestion
• EKG: nonspecific for CHF
• (+) echocardiography
• (+) radionuclide studies
• (+) cardiac catheterization
• amino acid analysis: for low levels of taurine
• urine may show slight proteinuria with red and white cells and hyaline casts
• urine is concentrated; oliguria with RCHF, increased urobilinogen
• ESR sometimes elevated
• moderate BUN increase (<60 mg/dl)
• mild elevation of indirect bilirubin, may see increased ALT, AST, LDH, and alkaline phosphatase
• PT increased

course and prognosis

The prognosis is not favorable. Most patients, particularly those over 55, die within two years of diagnosis. Death is due to CHF, cardiac arrhythmias, or pulmonary embolism. Acute pulmonary edema is a medical emergency. Conventional treatment of CHF consists of salt restrictions, diuretics, digitalis, and vasodilators.

differential diagnosis

• other causes of breathlessness or edema (see: edema)


footnotes