Desmopressin may be hazardous in thrombotic microangiopathy

A 59‐year‐old woman presented in 1991 with carcinoma of the right breast. She underwent a right mastectomy and started tamoxifen 20 mg daily. In 1997 she represented with recurrent carcinoma. A left mastectomy and axillary clearance was performed. Chemotherapy was started comprising mitozantrone, methotrexate and mitomycin‐C. Anaemia developed at 6 months, requiring repeated blood transfusions. She completed 9 months of treatment, then tamoxifen was increased to 40 mg daily. A relapse 9 months later required a further course of chemotherapy. At this time her serum creatinine had risen from normal to 206 μmol/l. 5‐Fluorouracil, epirubicin and cyclophosphamide were prescribed. Her renal function continued to deteriorate reaching 269 μmol/l 5 months into this treatment (Figure 1). At this stage, the patient's platelet count fell to a nadir of 99×109/l. Bone marrow examination was normal. The chemotherapy was stopped. The patient developed atypical chest pain and was admitted with a possible sub‐endocardial myocardial infarction. ECG was normal and a cardiac exercise stress test did not induce ischaemic changes. The serum creatinine deteriorated to 460 μmol/l (creatinine clearance 10 ml/min) and she was referred for renal investigation. Urine dipstick showed protein +++, blood ++. Renal ultrasound was normal. A full autoimmune screen was normal. The serum C3 level was low at 0.65 (0.85–2) mg/l. Serum C4 was normal.