MEDICAL PALM READING – Fever & joint pain in both thumbs: what is the diagnosis?
November 2, 2010
A 48-year-old man presents with a 10-day history of fever, hand pain, watery diarrhea, weight loss, anorexia, and intermittent vomiting. Two nodules are noted on both thumbs of his hands. What is the diagnosis?
The lesions depicted in the photographs are Osler’s nodes. The nodes coupled with the clinical history were suspicious for infective endocarditis (IE). Medical records were obtained while the patient was undergoing evaluation in the ED. During his recent admission for these symptoms, he was told that he had endocardial vegetations and was treated with antibiotics, but he left the hospital against medical advice. Given his recent evaluation, subjective fevers, and the physical finding of Osler’s nodes, he was admitted for treatment of IE.
The incidence of IE ranges from 2.4 to 11.9 cases per 100,000 patient years. Of these, half occur in patients between the ages of 31 to 60 years. It is much more common in patients with preexisting cardiac structural anomalies or with other risk factors, such as injection drug use, prosthetic cardiac valves, or indwelling intravenous catheters. Native-valve IE occurs in 59% to 70% of cases, whereas prosthetic valve IE occurs in 14% to 30% of the time. Infective endocarditis associated with injection drug use accounts for 11% to 16% of cases.
The clinical presentation of infective endocarditis 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. 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.
Physical examination findings of IE include Osler’s 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’s nodes and Janeway lesions are highly specific for IE. Osler’s 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. There is disagreement about the etiology of these nodes. Many sources believe that Osler’s 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. In contrast to painful Osler’s 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 up to 40% of IE cases; however, central nervous system manifestations of IE are not diagnostic of the condition.
The Duke Criteria 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).
Given the diagnostic requirements, initial diagnostic studies include blood cultures, echocardiography, electrocardiography, and chest radiography. Blood cultures should be drawn 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 exist. Management of these patients requires infectious disease consultation.
The mainstay of treatment of bacterial endocarditis is intravenous antibiotics. Empiric therapy should be based on the characteristics of the given patient, whether an artificial valve is or is not involved, and local resistance patterns. Ultimately, definitive therapy should be based on the results of the blood culture and sensitivity. Empiric antibiotic therapy for endocarditis is tailored to cover the organisms that are most likely to infect a given patient group. For uncomplicated IE, bacteria commonly found in the upper respiratory tract, gastrointestinal tract, and skin are likely to be the causative bacterium in patients with native-valve endocarditis acquired in the community. These include staphylococci, viridans streptococci, and Streptococcus bovis, as well as the “HACEK” organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella); therefore, for empiric therapy for uncomplicated native-valve IE, intravenous ceftriaxone or nafcillin plus gentamicin is recommended. If the incidence of methicillin-resistant S aureus (MRSA) is high, vancomycin should be used.
Complicated IE includes hospital-acquired infections, intravenous drug users, and artificial valve infections. Patients with hospital-acquired infections or intravenous drug use are more likely to have infection due to S aureus. Other common organisms for this patient population include gram-negative bacteria, such as Pseudomonas aeruginosa, group D enterococci, and fungal species (such as Candida). Patients with suspected MRSA infection, intravenous drug use, or suspected hospital-acquired infections should be empirically treated with a combination of vancomycin and gentamicin. For patients with artificial valves, the organisms are most likely to be S aureus and other coagulase-negative Staphylococcal species, enterococci, and gram-negative bacilli; therefore, these patients should be empirically treated with gentamicin, vancomycin, and rifampin. Rarely, patients with blood culture-negative endocarditis may be colonized with fastidious organisms, such as Granulicatella species, Abiotrophia species, Bartonella, Coxiella burnetii, Brucella, and Tropheryma whipplei.
Prophylaxis for patients with high-risk cardiac conditions (such as prosthetic heart valve or previous IE) is indicated when they are undergoing certain procedures. Amoxicillin or ampicillin is indicated for nonpenicillin-allergic patients 1 hour before the procedure. For penicillin-allergic patients, premedication with clarithromycin, azithromycin, clindamycin, cephalexin, cefazolin, or ceftriaxone is appropriate. Antibiotic or practice guideline references should be consulted before recommending prophylaxis.
The patient in this case was admitted and underwent TEE that confirmed the presence of 2 distinct lesions on the aortic valve suspicious for vegetations. He was started on a course of intravenous antibiotics, but unfortunately, he once again left the hospital against medical advice before completion of therapy.
FINAL HINT: Consider the history of fever, weakness, and tender, painful nodules on each thumb..
DIAGNOSIS: ‘Infectious endocarditis’ (in this case: resulting from injection drug abuse!).
READ MORE: MEDICAL HAND ANALYSIS.