Case Presentation: A 54-year-old male was admitted for six weeks of progressive lower extremity weakness and bowel and bladder incontinence. Work-up revealed an epidural abscess at T12-S1 with severe spinal stenosis at L1 and L2. He was started in empiric vancomycin and ceftriaxone before undergoing a T12-L5 hemilaminectomy and abscess drainage. During the surgery, absorbable combination vancomycin and tobramycin cement beads were placed. On postoperative day 6, the intraoperative bone pathology resulted in diffuse large B cell lymphoma at which time, treatment of suspected infection was abandoned and the intravenous antibiotics were stopped. That same day, the patient developed thrombocytopenia with a nadir of 16,000. Over the next several days, the patient required a total of four units of platelets to maintain a platelet level of 20,000/mL and had self limited epistaxis. Work up for etiology was negative and the source was thought to be due to the implanted vancomycin. He was successfully treated with one infusion of rituximab and four days of intravenous dexamethasone with resultant normalization of his platelet counts.
Discussion: Vancomycin is a commonly used antibiotic by hospitalists. Drug induced thrombocytopenia is a known but rare adverse effect of vancomycin, caused by the production of antiplatelet antibodies. The mean time to platelet nadir tends to occur on day 8, with a platelet range of between 2,000 to 100,000/mL in patients who experience bleeding. Platelet transfusions alone do not allow an adequate increase in platelet counts if vancomycin is continued; however, after the discontinuation of vancomycin, platelets will often normalize. This case is unique in that it was not possible to withdraw the vancomycin exposure without causing significant harm, yet the implanted beads would release vancomycin for up to six weeks after implantation. Further, this case also demonstrates the successful treatment of vancomycin induced thrombocytopenia using immunosuppressive therapy.
Conclusions: Vancomycin induced thrombocytopenia from implanted beads can occur and is not often considered, leading to prolonged exposure to the offending medication. Immunotherapy can be successful for platelet recovery in these cases of vancomycin induced thrombocytopenia when vancomycin discontinuation is not possible.