Painful swollen legs in a diabetic patient

A 52-year-old man presented with a 6-week history of bilateral painful thighs and reduced mobility. Glycaemic control of his type 2 diabetes of 25 years' duration was poor and he had recently commenced on insulin. His disease was complicated by retinopathy, peripheral neuropathy and nephropathy. He denied trauma to the legs. The thighs were swollen with pitting oedema extending from the ankles. There was no erythema or temperature disparity. The thighs were exquisitely tender on palpation of the anterior muscle compartment. Both calves were also tender to palpate. No mass was identified. The peripheral pulses were intact and the upper limbs were entirely normal. Haematological investigations revealed erythrocyte sedimentation rate 136 mm/hr, C reactive protein 13 mg/dl, normal white cell indices and normal coagulation profile. On biochemical analysis urea and creatinine were elevated; creatine kinase was increased at 250 U/litre. Glycosylated haemoglobin was 14%. All immunological and vasculitic profiles were normal. Urinary protein excretion was 12 000 mg/24 hours. This man was admitted for investigations, rest and rigorous control of his diabetes. He underwent ultrasound Doppler of his legs ruling out deep venous thrombosis or insufficiency of the large arteries. A computed tomography scan of the thighs revealed diffuse inflammation of the right thigh musculature. Nuclear bone scan confirmed increased uptake in the muscles but no bony abnormality. Magnetic resonance imaging was the definitive investigation showing diffuse enhancement on T2 weighted images of the anterior muscle compartment of the right thigh (vastus intermedius and vastus lateralis) with lesser changes noted in the left thigh and both calves (soleus) (Figure 1). A focal area of nonenhancement in the right rectus femoris following administration of gadolinium was consistent with an area of infarction (Figure 2). An open biopsy specimen showed non-specific inflammation and regenerating muscle fibres. Occasional necrotic muscle fibres were remarked upon. No haemorrhage was noted and the intramuscular blood vessels were normal. The diagnosis of diabetic muscle infarction was made. After 1 month of rest, analgesia and good glycaemic control the swelling and pain had completely resolved. A similar episode affecting the left thigh some months previously was reported. He is the only recorded patient to have had involvement of both thighs and calves bilaterally in the same episode.