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answer (C) is not the one that we are looking for! (A) is correct!
- Constrictive pericarditis (CP)
usually presents with progressive increase of abdominal girth (ascitis)
followed by edema of the lower extremities. This patient has
two possible etiologies. They include radiation therapy to the mediastinum
and prior CAB surgery. Other findings in patients with CP include:
- Exertional dyspnea and orthopnea are common
but PND is not.
- Pulmonary congestion is rare since the left
ventricle is under-filled and protected from overload by the restriction
of constrictive pericarditis.
- JVD may be so marked that the upper level
of pulsation may not be seen even in the siting position. Also,
this involves the internal jugular veins (JV) and the external JV
may not be impressive. The ear lobes may bob secondary
to the distended and pulsatile internal JV.
- A pericardial knock may be heard. The timing
(0.12-0.14 sec) is intermediate between an opening snap (0.06-0.12)
and an S3 (>0.16 sec).
- Review of radiation induced cardiac
disease:
- Various studies have shown that 6-96% of
patients who have received 3600-4000 cGy of radiation, and are followed
up for one or two decades, have clinical evidence of radiation-induced
cardiac disease.
- Radiation causes myocardial fibrosis and
ventricular diatolic dysfunction. However, isolated cases of systolic
dysfunction have been reported.
- Radiation induced valvular and conduction
system disorders may occasionally occur.
- Radiation may induce induced intimal fibrosis
and adventitial thickening of the coronary arteries. The stenoses
are usually located in the ostial and proximal segments. Also, the
patients are usually younger.
- The internal mammary artery usually become
friable and atherosclerotic and become unsuitable as a conduit for
purposes of CAB surgery.
- Effusive pericarditis
is the most frequent form of pericardial disease caused by radiation
therapy. They occur 6-12 months after therapy, are usually asymptomatic
and noted as an incidental finding of cardiomegaly on the chest x-ray.
Echocardiography is usually confirams the diagnosis.
- The characteristic presentation of occult
constrictive pericarditis is in the form of unexplained chest
pain and exertional dyspnea that occurs several years after radiation
therapy. Physical exam is usually not diagnostic. Neck vein engorgement
may be noted in a well hydrated state. The diagnosis may be made by
detecting a thickened pericardium by echocardiography, CT scan or MRI.
An elevated right heart pressure (following a fluid challenge during
right heart catheterization) may be present.
- Ischemic cardiomyopathy was not a consideration
since the heart was not dilated by physical exam and no supportive findings
(S3 gallop, symptoms of preceding predominant LV failure, etc.) were
presented.
- The exclusion of restrictive cardiomyopathy
(RCMP) is not as easy. The presence of a pericardial knock and the history
of radiation therapy favors constrictive pericarditis. RCMP usually
causes signs of LV plus RV failure, unlike constrictive pericarditis
which causes predominant RV problems. A combination of RCMP and CP may
also be associated with radiation therapy. Echocardiography may be useful
in establishing the diagnosis. However, cardiac cath and a biopsy may
be needed for confirmation.
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