Week 10: Acute Pericarditis and Rheumatic Heart Disease

Question 1

Acute rheumatic fever

Answer 1

• autoimmune consequence of infection with group A strep infection
• results in a generalized inflammatory response affecting brains, joints, skin, subQ tissues and heart
• clinical presentation vague and difficult to dx
• currently the modified duckett-jones criteria form the basiss of the diagnosis of the condition

Question 2

rheumatic heart disease

Answer 2

• defined by the constellation of results of the physical exam, autoimmune marker and other serologic tests, tissues patho, and imaging
• recognition of clinical patterns remains essential for dx bc there is no single dx test and results may be positive in the abscence of disease
• permanent heart valve damage (mitral #1, aortic #2)

Question 3

causes of rheumatic heart disease

Answer 3

• inflammatory immune response
• only develops in kids and adolescents following group a beta-hemolytic strep pharyngitis
• genetic studies show strong correlation b/w progression to rheumatic heart disease and human leukocyte antigen (HLA)-DR class II alleles and the inflammatory protein-encoding genes MBL2 and TNFA

Question 4

patho rheumatic heart disease

Answer 4

• infection leads to rheumatic fever several weeks after the sore throat resolves in 0.3-3%
• organism spreads by direct contact with oral or resp secretions. Enhanced spread by crowded living/work environment
• pt remains infected for several weeks after symptomatic resolution of pharyngitis and mya serve as a reservoir for infecting others

Question 5

epidemiology of rheumatic heart disease

Answer 5

• uncommon among US children
• affects females worse than men
• decreased incidence attributed to introduction of penicillin or a change in the virulance of strep

Question 6

major diagnostic criteria for rheumatic heart disease dx

Answer 6

• confirming antecendent rhumatic fever
• presence of 2 major or 1 major and 2 minor criteria
• major: carditis, polyarthritis, chorea, subQ nodules, erythema marginatum, pancarditis, syndenham chorea
• minor: fever, arthralgia, leukocytosis and raised ESR

Question 7

phsyical findings of RHD

Answer 7

• cardiac and noncardia manifestations
• lean forward, it gets better
• pancarditis: most serious and second most common (50%)
• new onset murmor
• dyspnea, mild-to-moderate chest discomfort, edema, cough, orthopnea, CHF, pericarditis

Question 8

murmors of acute rheumatic fever are typically due to?

Answer 8

• valve insufficiency
• most common are: apical pansystolic, apicial diastolic, basal diastolic

Question 9

congestive heart failure and RHD

Answer 9

• develops secondary to severe valve insufficiency or myocarditis
• physical findings associated with hf include: tachypnea, orthopnea, JVD, rales, hepatomegaly, gallop rhythm, edema, swelling of peripheral extremities

Question 10

pericarditis and RHD

Answer 10

• friction rub indicates it’s present
• increased cardiac dullness to percussion and muffled heart sounds
• paradoxical pulse (accentuated fall in systolic bp) with decreasd systemic pressure and perfusion evidence of diastolic indentation of the right ventricle on echocardiogram reflect impending pericardial tamponade

Question 11

non cardiac manifestations of RHD

Answer 11

• polyarthritis
• chorea erythema marginatum: 1-3 cm diameter pink-red nonpruritic macules or papules located on trunk and proximal limbs but never on face. Spread outward to form a ring with margins and central clearing
• sub Q nodules
• abd pain
• arthralgias
• epistaxis
• fever
• rheumatic pneumonia

Question 12

cardiac hemolutic anemia

Answer 12

• related to disruption of RBC’s by a deformed valve
• increased destruction and replacement of platelets occurs

Question 13

lab studies for RHD

Answer 13

• throat culture: throat culture findings for group a beta hemolytic strep are usually negative by the time symptoms are rheumatic fever or rheumatic heart disease appear
• rapid antigen detection test: allows rapid detection of group A strep antigen and allows dx of strep pharyngitis and the initiation of antibiotic therapy while the pt is still int he physicians office
• antistrep antibodies: begins at time of antistrep antibody levels are at the peak. Titers checked every 2 weeks to detect rising. (aso, dNase, antistreptokinase, antistreptococcal esterase, anti-DNA)

Question 14

rapid detection test for d8/17

Answer 14

this immunoflourescence technique for identifying the B cell marker d8/17 is positive in 90% of patients with rheumatic fever

Question 15

imaging studies for RHD

Answer 15

• chest reontgenography: cardiomegaly, pulmonary congestions, and other findings consistent with heart failure may be seen on chest radiography. Helps differentiate form HF
• Doppler echo: identifies and quantitates valve insufficience and ventricular dusfunction Left ventricle frequently dilated. Can help track the progression of valve stenosis and help determine time of surgical intervention

Question 16

histologic findings

Answer 16

• patho exam of insufficient valves reveal verucous lesions at the line of closure
• in pericardium fibrinous and serofibrinous exudates may produce an appearane of “bread and butter” pericarditis

Question 17

treatment and management of RHD

Answer 17

• includes attempts to prevent
• if already developed, therapy is toward eliminating group A strep, supressing inflammation from autoimmune response, and providing supportive treatment for CHF
• after acute episode, therapy directed towards preventing recurrent rheumatic heart disease in children and monitoring for complications and sequalae of chronic RHD in adults

Question 18

prevention of RHD

Answer 18

• PO penicillin is drug of choice, but ampicillin and amoxicillin are equally effective
• can use single dose of IM benzathine penicillin G or benzathine/procain penicillin combination is therapeutic
• do not use tetracyclines or sulfonamides to treat GABHS pharyngitis