Med Surg Nursing Questions - Cardiac (Answers 31-35)

Rationale: This patient is most likely experiencing congestive heart failure (CHF) secondary to dilated cardiomyopathy (DCM), which is characterized by dilation and impaired contraction of one or both ventricles. Symptoms of CHF include dyspnea (especially on exertion), orthopnea, paroxysmal nocturnal dyspnea, and peripheral edema with weight gain. DCM may also present with arrhythmias such as atrial fibrillation, or sudden cardiac death. DCM has a variety of etiologies including idiopathic, myocarditis, ischemic, drug induced, hypertension, infiltrative disease, HIV infection, connective tissue disease, and the chemotherapeutic agent doxorubicin. In this case the most likely cause of the patient’s DCM is viral myocarditis following his upper respiratory infection several weeks ago. Viruses known to cause myocarditis include coxsackievirus, influenza virus, adenovirus, echovirus, cytomegalovirus, and HIV. These viruses cause myocarditis with subsequent DCM by inflicting direct cytotoxicity via receptor-mediatedentry of the virus into cardiac myocytes. Patients with myocarditis may present initially with symptoms of chest pain or arrhythmias with ECG changes; in others, symptoms of heart failure may be the initial manifestation, as in this patient.

A is Incorrect.
Rationale: Antibodies to a variety of cardiac proteins causing immune-mediated damage to myocytes is the suspected mechanism of injury in familial DCM. This disorder is usually inherited in an autosomal dominant manner and therefore is associated with a significant family history of CHF. Given the patient’s recent history of an upper respiratory infection and lack of a family history of cardiac disease, viral myocarditis leading to DCM is the more likely etiology of his CHF.

C is Incorrect.
Med Surg Nursing Questions Rationale: Granulomatous inflammation of myocytes is the mechanism of injury causing DCM in infiltrative diseases such as sarcoidosis. Cardiac sarcoidosis should be considered in an otherwise healthy young or middle- aged person with cardiac symptoms, or a patient with known sarcoidosis who develops arrhythmias, conduction disease, or CHF. Diagnosis depends upon evidence of the multisystem features of sarcoidosis, in addition to a biopsy of the myocardium showing noncaseating granulomas. In this patient, DCM secondary to viral myocarditis is a more likely etiology of his CHF given his history of a recent upper respiratory infection and lack of other systemic symptoms associated with sarcoidosis.

D is Incorrect.
Rationale: A hyperadrenergic state leading to DCM is the suspected mechanism of cardiac injury that occurs with cocaine use. Cocaine abuse is a known cause of both coronary ischemia and DCM with heart failure, and should be suspected in a young person with otherwise unexplained chest pain or heart failure. Abstinence from cocaine usually leads to a complete reversal of the myocardial dysfunction. This patient denies any drug use, and given his history of a recent upper respiratory infection, viral myocarditis leading to DCM is the more likely etiology of his CHF.

32) B - Correct
Med Surg Nursing Questions Rationale: Inferior vena cava (IVC) compression is common in women during the third trimester of pregnancy. The large uterus compresses the IVC, decreasing venous return to the heart. This reduction in preload reduces stroke volume, thus reducing cardiac output. Recall that mean arterial pressure = cardiac output × total peripheral resistance; an acute decrease in either of these parameters will reduce blood pressure.

A is Incorrect.
Rationale: Cardiogenic shock can cause hypotension by decreasing the stoke volume and cardiac output, but it would not occur only in the supine position.

C is Incorrect.
Med Surg Nursing Questions Rationale: Neurogenic shock can cause hypotension by decreasing both cardiac output and peripheral resistance, but it does not typically occur in pregnant women only when they lie supine.

D is Incorrect.
Rationale: When fluid leaves the intravascular space and enters the interstitial space, it is referred to as third spacing. In pregnancy, there is a physiologic amount of third spacing, which causes dependent edema in the hands and feet. Some women may even experience pulmonary edema, which can be dangerous. Third spacing does cause hypertension if the intravascular volume is not replaced, but it would not cause isolated hypotension in the supine position.

33) A - Correct
Med Surg Nursing Questions Rationale:  This patient is presenting with intermittent claudication. Combined with his history of smoking, this points to peripheral arterial disease, which is often the presenting sign of atherosclerosis. Peripheral atherosclerosis targets areas of high turbulence typically found at branching arterial sites; the most common sites are the abdominal aorta and iliac arteries, femoral and popliteal arteries (which is causing the calf pain in this patient), and tibial and peroneal arteries. Medical therapy with antiplatelet drugs such as aspirin has had moderate success, with surgical revascularization reserved for severe cases. Risk factors for atherosclerosis include smoking, hypertension, diabetes mellitus, hyperlipidemia, and a positive family history.

B is Incorrect.
Rationale: Arterioles help provide the dynamic regulation of blood flow through the capillary beds. Although they are the site of principle resistance in blood flow, they do not have the turbulence necessary to predispose to atherosclerotic formation. They, along with small muscular arteries, are the major site affected by hypertension.

C is Incorrect.
Med Surg Nursing Questions Rationale: Capillaries are the smallest form of blood vessel and represent the site of interchange of solutes and cells between the blood and extracellular fluid. They are not typically affected by atherosclerosis but play a major role in the pathophysiology of edema.

D is Incorrect.
Rationale: Veins are the vessels that return blood back to the heart and are not typically affected by atherosclerosis.

34) C - Correct
Med Surg Nursing Questions Rationale: Constrictive pericarditis interferes with the filling of the ventricles because of granulation tissue formation in the pericardium. It can follow purulent viral infections, trauma, neoplastic diseases, mediastinal irradiation, and other chronic diseases. Pericardial thickening and calcification are sometimes apparent on CT and MRI.

A is Incorrect.
Rationale: Cardiac tamponade is very similar in presentation to constrictive pericarditis. One defining characteristic of cardiac tamponade is the absence of Kussmaul’s sign (failure of cervical venous distention to subside on inspiration). In addition, pulsus paradoxus (decrease in systolic pressure by ≥10 mm Hg during inspiration) is usually present. X-ray of the chest should reveal an enlarged cardiac silhouette with pericardial effusion.

B is Incorrect.
Rationale: CHF produces signs and symptoms similar to those of constrictive pericarditis. However, in CHF there would be significant enlargement and hypertrophy of the ventricles.

D is Incorrect.
Rationale: The echocardiogram results are not consistent with dilated cardiomyopathy, as diastolic volumes are reduced inthis patient but end-diastolic volumes are increased in dilated cardiomyopathy.

35) C - Correct
Med Surg Nursing Questions Rationale: The inferior mesenteric artery originates from the aorta inferior to the renal arteries and superior to the bifurcation of the aorta into the common iliac arteries. This artery may sometimes be sacrificed during an infrarenal aortic aneurysm repair rather than being re-attached to a healthy segment of aorta. Usually, there is enough collateral flow to the hindgut from the superior mesenteric artery and the hypogastric arteries that the loss of the inferior mesenteric artery does not result in colonic ischemia.

A is Incorrect.
Rationale: The gastroduodenal artery is a branch of the hepatic artery, which is in turn a branch of the celiac trunk.

B is Incorrect.
Rationale:The hepatic artery is a branch of the celiac trunk and is found superior to the renal arteries.

D is Incorrect.
Rationale: The left gastric artery is a branch of the celiac trunk and is found superior to the renal arteries.

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