Summary:Two patients with CsA-associated neurotoxicity developed severe cerebellar swelling and thrombotic thrombocytopenic purpura after switching to FK506 and high-dose corticosteroids. The prodrome of CsAassociated neurotoxicity, TTP and hypertension while receiving FK506, and high-dose corticosteroids could all be implicated in the development of this syndrome. Close monitoring of patients receiving FK506 and highdose corticosteroids, for the development of TTP is warranted. Early radiological examination should also be considered in such patients to allow early surgical intervention. Keywords: cerebellar swelling; TTP; FK506; cyclosporine neurotoxicity; steroids Common side-effects of cyclosporin A (CsA) include renal dysfunction, hypertension and tremors.1,2 Rare severe neurotoxicity including ataxia and occipital blindness is also reported. [3][4][5][6] This syndrome resembles thrombotic thrombocytopenic purpura (TTP). There are numerous case reports of TTP following BMT. [7][8][9][10][11][12][13] Clinical manifestations include: hypertension, edema, renal failure, neurologic changes and microangiopathic hemolytic anemia. Although the syndromes are both associated with CsA use, the presence or absence of microangiopathic hemolytic anemia can distinguish them. 14 Treatment of CsA neurotoxicity consists of discontinuing the drug, correcting electrolyte abnormalities and controlling hypertension. 3,13,15 Neurologic changes typically resolve within 48 h of discontinuing CsA. In contrast, patients with TTP have a much poorer outcome despite discontinuing CsA, often requiring intensive support.14 Although ideal management is unclear, it appears that plasma exchange alone 16 or combined with protein immunoadsorption may be effective modes of therapy. and to alter the ratio of thromboxane to prostacyclin production resulting in procoagulant activity. [18][19][20][21][22][23][24] Since patients who develop neurologic symptoms attributable to CsA without microangiopathic changes and those who develop TTP are frequently early post-transplant, discontinuing CsA may be associated with development of severe GVHD. The introduction of FK506 into clinical use has allowed substitution of FK506 for CsA in patients developing TTP following BMT and solid organ transplantation. 25 However, the safety of this approach is not well established as there are now reports of FK506-induced TTP following BMT and solid organ transplantation.
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Case 1A 28-year-old male with Hodgkin's disease received an HLA-matched unrelated donor BMT 2 years after relapsing following an autologous BMT. Conditioning was with thiotepa and carboplatin. He received low-dose intravenous heparin as hepatic veno-occlusive disease (VOD) prophylaxis. GVHD prophylaxis consisted of cyclosporine, methotrexate and methylprednisolone. On day +8, he developed hyperbilirubinemia (primarily direct), associated with an elevated CsA level of 514 (normal range, 250-450). CsA was held and restarted at one-third the previous dose on day +10. On day +11, he developed cort...