title: Causes of acute thrombotic microangiopathy in patients receiving kidney transplantation.
abstract: OBJECTIVE
  Thrombotic microangiopathy is a well-known problem in patients following renal transplantation. In postrenal transplantation, thrombotic microangiopathy is often a reflection of hemolytic uremic syndrome. We aimed to determine the causes of thrombotic microangiopathy in a population of renal transplantation recipients and discuss the literature.
  
  
  METHODS
  We investigated the causes of thrombotic microangiopathy during a 1-year period, from June 2003 to June 2004, at the King Fahad National Guard Hospital in Riyadh, Saudi Arabia, by reviewing the slides of all transplant biopsies (n=25) performed during this interval. Pre- and posttransplant crossmatching was done when possible.
  
  
  RESULTS
  Five cases of thrombotic microangiopathy were found. Three of these cases were from the 25 transplantations performed at King Fahad National Guard Hospital, while the other 2 transplantations had been performed abroad and were referred to us for follow-up. Three cases were related to cyclosporine, and 1 case was secondary to both cyclosporine and tacrolimus. The fifth case had features of thrombotic microangiopathy related to an antiphospholipid syndrome in a patient with systemic lupus erythematosus.
  
  
  CONCLUSIONS
  In the literature, the most-frequent cause of hemolytic uremic syndrome in patients following renal transplantation is recurrence of the hemolytic uremic syndrome. Other causes include drug-related (cyclosporine, tacrolimus) toxicity, procoagulant status, and antibody-mediated rejection. We found that the most-frequent cause of thrombotic microangiopathy was drug related, secondary mainly to cyclosporine. In the current study, the frequency of thrombotic microangiopathy was similar to the percentage reported in the literature (20%).
authors.affiliation: Division of Nephrology, Transplant and Hypertension, King Fahad National Guard Hospital, Riyadh, Saudi Arabia. aqjumani@hotmail.com
authors.forename: Abdul
authors.initials: A
authors.lastname: Jumani
authors.forename: Kfoury
authors.initials: K
authors.lastname: Hala
authors.forename: Saadi
authors.initials: S
authors.lastname: Tahir
authors.forename: Ghormullah
authors.initials: G
authors.lastname: Al-Ghamdi
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Flaiw
authors.forename: Fayez
authors.initials: F
authors.lastname: Hejaili
authors.forename: Junaid
authors.initials: J
authors.lastname: Qureshi
authors.forename: Hammad
authors.initials: H
authors.lastname: Raza
authors.forename: Muhammed
authors.initials: M
authors.lastname: Ghalib
authors.forename: Abdullah Al
authors.initials: AA
authors.lastname: Khader
mesh_terms: D000208:Acute Disease; D000328:Adult; D016736:Antiphospholipid Syndrome / Q000150:complications; D016572:Cyclosporine / Q000009:adverse effects; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects; D016030:Kidney Transplantation; D008180:Lupus Erythematosus, Systemic / Q000150:complications; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D011184:Postoperative Period; D012189:Retrospective Studies; D016559:Tacrolimus / Q000009:adverse effects; D013927:Thrombosis / Q000139:chemically induced / Q000209:etiology*
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D016559:Tacrolimus