Case Report
A 43-year-old African American male presented to the emergency department via ambulance with altered mental status, visual hallucinations, and excruciating back pain as reported by an accompanying caretaker. On arrival, the patient was afebrile (Temp: 97.6 ºF), mildly tachycardic (HR: 98 BPM), and hypotensive (BP: 98/63 mmHg). Further examination revealed an ill-appearing, obese male in no acute distress. The patient was disoriented to place and time and was unable to follow simple commands. A detailed neurological examination could not be performed due to a lack of cooperation. Vision was grossly intact and cardiovascular examination revealed a normal S1 and S2, irregular rate and rhythm, but no murmurs, rubs or gallops. The patient had a history of poorly controlled insulin-dependent diabetes mellitus, end-stage renal disease on maintenance hemodialysis via right internal jugular vein (IJV) vascular catheter, persistent atrial fibrillation anticoagulated with apixaban (10 mg/d), and bilateral below-the-knee amputation secondary to diabetic complications with chronic osteomyelitis from MRSA. The patient had a history of medical noncompliance and reported discontinuous medical care managed at multiple distant care facilities.
A non-contrast computed tomography (CT) scan of the neuraxis revealed a destructive process in the thoracic spine at T7-T8 suspicious for discitis and osteomyelitis (Figure 1A) with unremarkable lumbar findings (Figure 1B). CT imaging of the head was negative for neurologic abnormalities. Subsequent imaging studies were limited by the severity of the patient’s pain and positioning restrictions. A complete blood count was within normal limits besides mild anemia (Hb: 10.1 gm/dL, Ref: 13.0-18.0 gm/dL). Complete metabolic panel revealed elevated blood urea nitrogen (41 mg/dL, Ref: 10-20 mg/dL), creatinine (3.99 mg/dL, Ref: 0.6 to 1.2 mg/dL), and lactic acid (3.0 mmol/L, Ref: 0.5-2.2 mmol/L). The patient did not meet sepsis criteria on arrival and was admitted for bacteremia in light of purported vertebral osteomyelitis or renal dialysis spondyloarthropathy. At the time of admission, orders were written for post-dialysis IV vancomycin (2g every eight hours) and cefepime (1000mg daily). The patient was unable to receive dialysis until post-admission day three, at which time he was safely administered the antibiotic regimen.
The patient’s encephalopathy, back pain, and bacteremia was monitored and managed through day three of admission without significant change. Magnetic resonance imaging (MRI) of the thoracic spine confirmed osteomyelitis at T7-T8 and a similar yet earlier infectious process occurring at T10-T11 (Figure 2). Blood culture results at day three revealed methicillin-resistant S. aureus (MRSA). A CT-guided biopsy of the spinal abscess was scheduled but was later cancelled by the patient and caretaker. The patient was managed on an in-patient basis for a total of sixteen days with serial blood cultures. Repeat blood cultures at the end of week one remained positive for MRSA. The patient’s right IJV vascular catheter was removed and tested positive for MRSA. The patient’s vascular catheter was replaced in the left IJV and subsequently tested positive for MRSA. Vascular access was removed briefly before being replaced in the right IJV. Following the third MRSA positive culture and the lack of response to vancomycin, antibiotic therapy was superseded by intravenous daptomycin (800 mg post-dialysis triweekly) and rifampin (300 mg twice daily).
Blood cultures remained positive for MRSA at the beginning of week two. Concerns surrounding the persistent bacteremia prompted a transthoracic echocardiogram (TTE), which revealed the presence of a mobile vegetation on an embryological remnant of the inferior vena cava, a eustachian valve remnant, within the inferior aspect of the right atrium (Figure 3). In-patient intravenous daptomycin was continued through post-admission day 13, when the patient’s cognitive symptoms resolved. The patient was discharged at post-admission day 16 with arrangements to return for scheduled intravenous daptomycin infusions for an additional six weeks. Following antibiotic therapy, the patient has not returned for treatment related to this condition.