Mycotic aneurysm is a term that was first used by Osler to describe aortic aneurism in a patient with bacterial endocarditis. This term is now used for all aneurysms caused by infection. Femoral artery is the most common site of involvement followed by the abdominal aorta.1 Peripheral aneurysms do not usually cause death but limb loss is probable. Hand aneurysms are categorized as traumatic, arteriosclerotic and mycotic. The traumatic form is the most common. The classical form of mycotic aneurysms of hand (due to infected emboli arising from bacterial endocarditis) are rare and only a few cases have been reported.2–6 Signs and symptoms may be nonspecific and mild during the early phase, so there should be high clinical suspicion to make the diagnosis. We report a case of mycotic aneurysm of the ulnar artery occurring nine days after starting antibiotic therapy in culture-negative infective endocarditis.
Case Report
A 39-year-old man presented to the medical office complaining of fever, generalized malaise, and fatigability. One month ago the patient had been admitted in another hospital of Esfahan with subacute bacterial endocarditis (SBE) and had been treated with cephazolin and gentamycin and discharged one week later. Upon initial physical examination his body temperature was 38°C, blood pressure was 140/70 mm/hg, pulse rate was 120 per/minute, and respiratory rate was 20 per/minute. Head and neck examination revealed petechiae of left conjunctiva. Jugular venous pressure was normal. There was no sign of lymphadenopathy. A cardiac examination showed that the first and second heart sounds were decreased. A high-pitched early diastolic murmur in left sternal border (LSB) and a systolic murmur II/VI were auscultated. The lungs were clear. The abdomen was soft with no guarding or tenderness and the spleen was palpable. In extremities, the pulses were bounding and clubbing of the fingers of right hand was detected. Laboratory data showed three plus C-reactive protein, leukocytosis, normal erytocyte sedimentation rate (ESR), and anemia. The blood cultures were negative. Echocardiography demonstrated large aortic and mitral valve vegetation.
This case constitutes one major and two minor Duke criteria. He was treated as culture negative subacute bacterial endocarditis with ampicillin 2 g every four hours and gentamycin 80 mg every eight hours. One week later he was generally well and afebrile but the murmur remained unchanged. The patient had severe and intolerable muscle pain in the lower extremities, especially in the quadricep muscles. The diagnosis was muscle cramps owing to the gentamycin, and the gentamycin was replaced by ciprofloxacin. The muscle cramps resolved after 24 hours. Three weeks after starting antibiotics the patient developed pain and tenderness of the left hand, in the hypotenar region. The pain was relieved by diclofenac, to some extent, but the patient became febrile and the ESR rose.
Ciprofloxacin was changed to vancomycin and aortic valve replacement and mitral valve repair were carried out, because of the poor response to treatment; including large aortic vegetation and persistent symptoms owing to inflammation (as evidenced by the elevated ESR and clubbing). Two weeks later, redness and tenderness were developed in the hypotenar region of the left hand and the severity of pain was also increased. Examination revealed a painful rapidly progressive pulsatile mass in the left hypotenar region (see Figure 1). An ulnar artery aneurysm was confirmed by ultrasonography and angiography (see Figure 2). Allen’s test showed an inadequate collateral blood supply and a radial pulse was not palpable. The aneurysm was resected (see Figure 3) and the radial artery of the right hand was harvested and anastomosed to the left ulnar artery and the deep palmar arch (see Figure 4). After the operation, the left hand became warm and well perfused. Histopathological studies revealed severe infiltration of acute and chronic inflammatory cells in the artery wall and the lumen field, with fibrinous thrombus. There was also granulation tissue in the thrombus.
Discussion
22–50 % of patients with bacterial endocarditis may be affected by embolism. Emboli tend to stick to arterial branch points.7 Except for the intracranial arteries, mycotic aneurysms occur most frequently in the visceral arteries, followed by the upper and lower extremity vessels. Aneurysms in body cavities are diagnosed late and frequently lead to death because of rupture and uncontrolled hemorrhage.8 Large vegetation, antibiotic resistant organisms, prosthetic valves, and recurrent emboli increase the risk of embolization.9 However, although the rate of embolic events decrease dramatically during and after two to three weeks of proper and adequate antibiotic therapy,9 it is still frequent (12.9 %) even when blood culture is reported to be negative. The patient might benefit from surgical intervention to prevent systemic embolization, especially in the early stage of infective endocardities when the likelihood of embolic events is high and other predictors of complications are present.
This case demonstrates that despite adequate antibiotic therapy, mycotic aneurysms may still develop even if blood culture is sterile. The diagnosis may be difficult because signs and symptoms can be nonspecific, mild, and misleading during the early stages, resulting in delay in treatment. A persistent fever of unrecognized origin and other inflammatory symptoms are likely to be associated with slow and gradual aneurismal growth, particularly if antibiotics have been given at an early stage.