title: Prolonged ceftriaxone-induced immune thrombocytopenia due to impaired drug clearance: a case report.
abstract: BACKGROUND
  Antibody-mediated drug-induced thrombocytopenia (DIT) typically requires the presence of the sensitizing drug in the plasma. Therefore, platelet (PLT) counts often start to recover 1 to 2 days after discontinuation of the offending medication. We present a case of ceftriaxone-induced DIT that resulted in severe, prolonged thrombocytopenia.
  
  
  METHODS
  A 65-year-old woman with liver and renal insufficiency was transferred to our hospital for liver transplant evaluation. Two days after a 5-day course of ceftriaxone, her PLT count declined from a stable baseline of approximately 70 × 10(9) /L to a value of 3 × 10(9) /L, with coincident onset of mucocutaneous purpura. Her PLT count remained in the 1 × 10(9) to 6 × 10(9) /L range until her death 13 days later, despite intravenous immune globulin, steroids, and PLT transfusions. The persistently low PLT count impeded central catheter placement for hemodialysis and possible therapeutic plasmapheresis. A strong ceftriaxone-dependent, PLT-reactive antibody was identified in a sample drawn 7 days after ceftriaxone was last administered, and ceftriaxone remained detectable in her serum for at least 8 days after the last dose.
  
  
  CONCLUSIONS
  A ceftriaxone-dependent, PLT-reactive antibody was responsible for the persistent thrombocytopenia in this patient. Although DIT is generally expected to improve within a few days of drug discontinuation, impaired drug clearance can significantly alter the outcome. This case highlights the importance of altered drug metabolism and clearance in critically ill patients, especially those with combined hepatic and renal dysfunction. DIT should be strongly suspected in patients with acute thrombocytopenia, and all treatment options to reduce serum drug levels should be seriously considered.
authors: Department of Laboratory Medicine, University of California at San Francisco, San Francisco, California; Department of Internal Medicine, University of California at San Francisco, San Francisco, California; Clinical Laboratory, San Francisco General Hospital, San Francisco, California; Blood Centers of the Pacific, San Francisco, California.
authors: Cyril
authors: C
authors: Jacquot
authors: Morvarid
authors: M
authors: Moayeri
authors: Benjamin
authors: B
authors: Kim
authors: Sarah
authors: S
authors: Shugarts
authors: Kara L
authors: KL
authors: Lynch
authors: Andrew D
authors: AD
authors: Leavitt
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001792:Blood Platelets / Q000276:immunology; D002443:Ceftriaxone / Q000009:adverse effects* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008657:Metabolic Clearance Rate; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000139:chemically induced*
chemical_list: D000900:Anti-Bacterial Agents; D002443:Ceftriaxone