The occurrence of small-vessel occlu-sions (thrombotic microangiopathy) in association with anti-phospholipid antibodies (aPL) affecting, for example, the retinal vessels, 1 the nail fold, 2 3 the skin, 4 or major intrabdominal organs such as the kidney, the liver or the bowel, 5 although uncommon, is well documented. These occlusions have been described in the simple or classic antiphospholipid syndrome (APS), whether or not associated with systemic lupus erythematosus (SLE), or in the primary APS, 6 but they do not in any way dominate the clinical picture in these conditions. However, with the description and definition of the catastrophic APS (also known as Asherson’s syndrome) in 19927 8 (a new subset of the APS, often fatal, with many distinguishing characteristics separating it from the simple APS), 9–11 there has been renewed interest in the thrombotic microangiopathies and their association with aPL. Although large-vessel occlusions do occur in catastrophic APS, they do not dominate the clinical picture, and their frequency is completely different from that encountered in the classic APS itself. Additionally, the catastrophic APS is frequently accompanied by a systemic inflammatory response syndrome (SIRS). The term thrombotic microangiopathic haemolytic anaemia (TMHA) was originally introduced by Symmers12 in 1952 to describe a clinical state with localised or diffuse microvascular thrombosis in association with haemolytic anaemia and fragmented red cells referred to as schistocytes. Indeed, the great haematologist John Dacie and his colleagues13 published a seminal paper on TMHA and related the condition to vascular damage some 10years later. TMHA encompasses a spectrum of disorders including thrombotic thrombocytopenic purpura (TTP), haemolytic–uraemic syndrome (HUS), malignant hypertension, postpartum renal failure, pre-eclampsia and catastrophic APS. Recent articles still refer to the difficulty in distinguishing among these conditions14 15 as the overlap is so great.

With the advent of refined testing for aPL, many cases of TTP were published with this association, 16–21 although Kincaid-Smith22 in 1988 had already pointed out the existence of renal thrombotic microangiopathy with lupus anticoagulant positivity. The next major advance in this field was the identification of the cleaving enzyme—a von Willebrand factor Disintegrin and Metalloproteinase ThromboSpondin protein (ADAMTS–13). Three patients with TTP and aPL have been reported so far. 23 24 Espinosa et al25 in 2005 reviewed the association of aPL with TMHA comprehensively and found an association of TMHA with catastrophic APS rather than with classic APS. The association of HUS with aPL has also been anecdotically documented. 26–28 Simultaneous with the TTP and aPL story came the association of patients with the haemolysis, elevated liver enzymes and low platelets (HELLP) syndrome and aPL. 29–35 Hepatic infarctions, 36 retinal vascular occlusions37 and deep venous thrombosis (DVT) 38 39 have now been reported in patients with HELLP syndrome. Three recent papers have speculated as to whether a continuum exists between several of these conditions (TTP, HUS, HELLP syndrome and catastrophic APS). 40–42 This has been prompted by the reports of TTP and HELLP syndrome in patients in whom aPL has been demonstrated and alluded to above and also by recent case reports of patients with HELLP syndrome and catastrophic APS. 43 44 To these conditions must also be added disseminated intravascular coagulation (DIC), another situation where microvascular thromboses may be seen because of the …