A 55 year old man consulted his general practitioner complaining of persistent pain in his left leg for three days and a numb feeling in the foot. He was taking treatment for hypertension, had a history of low back pain, and was a smoker of 20 cigarettes a day. His foot looked normal, but sensation seemed mildly reduced. The general practitioner noted a weak dorsalis pedis pulse. A diagnosis of sciatica was made, diclofenac was prescribed, and the patient was invited to return a week later if no better. Six days later he presented to a local emergency department because of intolerable pain and was found to have a profoundly ischaemic left leg necessitating an above knee amputation. Missed diagnoses of acute leg ischaemia, as in the case above, are common.1 2 An analysis of data held by the NHS Litigation Authority (NHSLA), the Medical Defence Union (MDU), and the Medical Protection Society (MPS) identified 224 cases of acute leg ischaemia leading to limb loss over a 10 year period,1 in all of which litigation had been initiated. Fifty one cases in which there had been delay in detecting and treating acute limb ischaemia were reported to the National Reporting and Learning System (NRLS) between 2003 and 2010.2 I have written almost 30 medicolegal reports on cases in which there were allegations—usually against general practitioners or casualty officers—of a negligent delay in diagnosing acute leg ischaemia, often resulting in the avoidable loss of a limb. Leg ischaemia results from thrombotic, embolic, or traumatic arterial occlusion. It is considered to be acute if the symptoms and signs have developed over less than two weeks.3 4 The …