A 44-year-old woman was admitted under the acute surgical "take" with left sided abdominal pain radiating to her back. She worked as a dental hygienist and lived with her husband and two children. She smoked 15 cigarettes a day and there was no previous history of venous thrombosis. She had a history of borderline thyrotoxicosis in the early 1990s and underwent tension-free vaginal tape treatment for stress incontinence in September 2003. She was on etonogestrel-releasing implants for contraception. She was very tender, locally, over the left side of the abdomen but rebound tenderness was absent. Rectal examination was unremarkable. Investigations showed haemoglobin of 13.2 g/dl, white cell count of 19.9 10*9/L, and platelets 214 10*9/L with neutrophilia. Amylase and renal function tests were found to be normal. Liver function tests were deranged with Gamma GT 244 u/l (twice normal). An abdominal Ultrasound Scan suggested a possible splenic infarction, which was confirmed by a CT scan of her abdomen. Tests were carried out to investigate the possibility of a post thrombotic state. Coagulation risk factors for thrombosis were within the normal limits; Protein S 67 %(60–140), Protein C 103 %(72–146), Antithrombin 3 110 %(80–120) and Activated P C Resistance was 1.9(2.0–4.3). The Hams test was negative but the Anticardiolipin antibody test was positive. IgM level was 52 (normal is up to 10) and IgG was 18.8 (normal is up to 10). She also had border line APC Sensitivity 1.9 (2 to 4.3). Kaolin time 49 sec (70–120) Ktmix 64 sec (70–120), thyroid function test revealed TSH 0.32 mu/L, fT4 20.2 pmol/L (10–25). Subsequent determination of Anticardiolipin antibody was negative. Her symptoms were settled with the use of simple analgesia and she was discharged home with long-term anticoagulation medication. The INR target for long-term anticoagulation was aimed at >3.