The clinical presentation of IE may vary. Patients whose IE is caused by highly virulent organisms, such as S aureus, have much higher morbidity and mortality, and they typically present with high fevers and rapid cardiopulmonary collapse. This rapidly deteriorating clinical course culminating in death within a few days is often referred to as acute bacterial endocarditis. Subacute bacterial endocarditis is a more indolent disease caused by less virulent bacteria, such as Streptococcus, and patients present with fever, malaise, and other nonspecific symptoms.[2] The clinical presentation of IE can occur along a continuum between acute and subacute clinical pictures and may have overlapping bacterial etiologies. Classic presentations are uncommon; patients with IE can present with fever, chills, weakness, dyspnea, anorexia, malaise, nausea, and vomiting. In a busy ED, these common chief complaints can be easily overlooked.[3]
Physical examination findings of IE include Osler nodes, Janeway lesions, Roth spots, and infectious embolic complications. Roth spots are not specific for IE and can occur in the context of other illnesses, such as systemic lupus erythematosus; however, Osler nodes and Janeway lesions are highly specific for IE.[2] Osler nodes are small, painful nodules that appear on the palms of the hands and soles of the feet as well as the distal phalanges. They are between 2 mm and 15 mm in diameter, occasionally have a blanched center, are usually multiple, and transiently appear and resolve at different times over a period of days.[4]
The etiology of these nodes is unclear. Many sources believe that Osler nodes are vascular phenomena resulting from immune-complex deposition into the vascular endothelium, whereas others describe the lesions as the result of microabscesses within the dermal arterioles and the papillary dermis.[5] In contrast to painful Osler nodes, Janeway lesions are painless hemorrhagic plaques that are mostly present on the palms or soles. Roth spots are oval retinal hemorrhages located near the optic disc. Infectious valvular vegetations can embolize to the brain in as many as 40% of IE cases; however, central nervous system manifestations of IE are not diagnostic of the condition.
The Duke Criteria[6] used to diagnose endocarditis may be fulfilled by the finding of 2 major criteria, 1 major and 3 minor, or 5 minor criteria. The major criteria include 2 positive blood cultures or evidence of endocardial involvement on echocardiography. Minor criteria include predisposing factors, fever, vascular phenomena, immunologic phenomena, other microbiologic evidence (not meeting major criteria), and other echocardiographic findings (not meeting major criteria).[7]
Given the diagnostic requirements, initial diagnostic studies include blood cultures, echocardiography, electrocardiography, and chest radiography. Blood cultures should be obtained from 3 separate sites over the course of an hour to increase the likelihood of identifying the bacterial species. Antibiotic therapy for acutely ill patients should be administered promptly. Cardiac echocardiography, either by noninvasive transthoracic echocardiography or transesophageal echocardiography (TEE), which is more sensitive and specific for diagnosing IE, can aid in the diagnosis of IE and provide critical information regarding the structure and function of the affected valves.
Electrocardiographic findings are often nonspecific or normal, but they can show characteristic PR interval prolongation, bundle branch block, or complete heart block when the infection affects the conduction system. Surgical intervention is usually reserved for patients with severe valvular dysfunction, which is best elucidated by TEE; however, several other indications for surgery are recognized. Management of these patients requires infectious disease consultation.
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Cite this: Andrew Melone, David F. Baehren. A 48-Year-Old Man With Swollen, Painful Areas on His Thumbs - Medscape - Jan 06, 2020.
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