Is it quinine TTP/HUS or quinine TMA? ADAMTS13 levels and implications for therapy.

Thrombocytopenia with or without microangiopathy following quinine is often referred to as quinine "hypersensitivity." When schistocytes are present it is frequently termed "quinine-associated TTP/HUS." A severe deficiency of the vWF-cleaving protease, ADAMTS13, is associated with idiopathic TTP. A previous study of patients with "quinine-associated TTP/HUS" found that ADAMTS13 activities were not abnormal in 12/12 patients. A retrospective review of TTP patients with quinine-associated thrombotic microangiopathy (TMA) for whom ADAMTS13 was measured before plasma exchange was performed. Six patients were identified. All were females (age range: 43 to 73, mean = 61.7 years) and had taken quinine for leg cramps. Four of the six experienced renal failure requiring dialysis. Five of the patients had D-Dimers levels measured, all were elevated. In four patients the levels were > or = 18 times the upper limit of normal. ADAMTS13 was normal in four patients and mildly decreased in two patients. We conclude that while thrombocytopenia and schistocytosis can be seen in quinine-associated TTP/HUS, the pathophysiology seems to be distinct from that seen in most cases of idiopathic TTP (i.e., severely decreased ADAMTS13 with an inhibitor). We recommend that a TMA in association with quinine be consistently referred to as quinine-associated thrombotic microangiopathy (quinine-TMA) to better distinguish this entity from idiopathic TTP. The use of plasma exchange in quinine-TMA is called into question.