Mr. K.D., a 38-year old man with a history of type 2 diabetes for over 10 years, presents with severe pain and swelling of his thighs. He describes it as a burning pain, mainly localized to the front of both thighs, that started spontaneously two weeks previously. Within days, it became severe enough to hinder walking. He denies any injury or heavy exertion prior to the onset of symptoms. He has no history of recent viral or febrile illness, or travel. He’s used anti-inflammatory agents with some relief. He feels no pain in other muscle groups, nor has any symptoms of fever, chills or night sweats.

He has a history of hypertension, diabetic stage 3 chronic kidney disease with proteinuria and diabetic retinopathy treated by laser photocoagulation. There’s no recent history of HMG-coenzyme reductase inhibitor use.

Mr. K.D. doesn’t smoke and denies alcohol use. His daily medications include NPH and insulin 30/70, perindopril 8 mg, amlodipine 10 mg, hydrochlorothiazide 25 mg and aspirin. He’s on diclofenac 50 mg twice a day.

Blood pressure is 154/70 mm Hg with regular rhythm. Heart sounds are normal, lungs are clear and abdomen is benign. There’s no ankle edema.

The exam is remarkable for diffuse induration, warmth and tenderness on the lateral aspect of both thighs. Movements at the knee joints is limited by pain without effusion or erythema. There’s no evidence of cellulitis or lymphangitis. There are small non-specific lymph nodes in inguinal areas. Tinel’s sign is negative at both anterior superior iliac spines. Peripheral pulses are symmetrical. There’s no muscle fasciculation or atrophy, nor any evidence of neurovascular compromise of lower extremities.

Lab results

Laboratory data show slightly elevated white blood cell count of 11.9 with normal eosinophil count, slightly low hemoglobin of 118 g/L, normal platelets of 371, and elevated erythrocyte sedimentation rate of 66. Blood urea nitrogen is 19.5 mmol/L with serum creatinine at 265 µmol/L and normal electrolytes with serum potassium of 4.0 mmol/L. Serum uric acid is 544, and calcium is 2.15 mmol/L. Serum phosphate is elevated at 1.72 mmol/L and serum albumin is low at 22 g/L. Creatine kinase is 442 U/L and thyroid stimulating hormone is slightly elevated at 12.89. A urinalysis shows 3+ protein. MRI scan of complete spine is unremarkable save for mild degenerative disease at L4-L5 and L5-S1. What’s wrong with Mr. K.D.?