How to Evaluate Endocarditis for the Physician Assistant Exam
Endocarditis is an inflammation of the heart valve, and for the purposes of the Physician Assistant Exam (PANCE), you should know some specifics about the different flavors: infective endocarditis and subacute bacterial endocarditis.
The staph: How to find infective endocarditis
Infective endocarditis (IE) is a baddie. It commonly affects the mitral valve, although IV drug users may have right-sided endocarditis causing tricuspid regurgitation. The most common cause of infective endocarditis is Staphylococcus aureus.
The diagnosis of infective endocarditis is made by at least two sets of blood cultures being positive (where S. aureus is concerned) and the presence of vegetation on a cardiac valve. This requires a transesophageal echocardiogram (TEE) to diagnose; it may be missed on a transthoracic echocardiogram (TTE).
The PANCE may ask you about a plethora of signs concerning infective endocarditis on physical examination. Sometimes the initial cause is intermittent and relapsing fevers. Cyanosis may or may not be present (note that there are many causes of cyanosis outside of pulmonary disorders).
Other big physical exam findings include Roth spots, Janeway lesions, and/or Osler’s nodes. Roth spots are retinal, flame-shaped hemorrhages in the eye that you can see on fundoscopic examination. Janeway lesions are splinter hemorrhages that you see on the fingernails. Osler’s nodes are papular, erythematous lesions found on the palms and soles.
The treatment for infective endocarditis is 6 weeks of intravenous antibiotics, usually a beta-lactam agent such as penicillin or the antibiotic vancomycin (Vancocin), and an aminoglycoside antibiotic such as gentamicin (Garamycin) for the first week or two. Any more than this, and the person is at risk of developing aminoglycoside ototoxicity.
Depending on the extent of the vegetation, a cardiothoracic surgeon is often consulted to see whether intervention is warranted.
The strep: Structural issues with subacute endocarditis
Subacute endocarditis (SBE) is primarily caused by Streptococcus viridans. Less-common causes include other Streptococcus species and Enterococcus. Here are three key points about subacute endocarditis:
It’s less acute than infective endocarditis in its presentation.
When you find subacute endocarditis, order a transesophageal echocardiogram (TEE) not only to look for vegetation but also to look for evidence of a structural heart problem (an incompetent valve).
Subacute endocarditis requires at least 4 to 6 weeks of antibiotics to treat. The standard treatment is a minimum of 4 weeks of high-dose intravenous penicillin with an aminoglycoside such as gentamicin (Garamycin).