LAUSR

A 40 year old woman was admitted for intense fatigue of the lower limbs with pain in the right thigh. She had no personal medical history and no treatment. She was of Algerian origin, veiled and had just given birth to her sixth child. She breastfed her children up to 18 months. Since about 1 year, she had a real disability and fell several times. She had a proximal muscle weakness of the pelvic girdle without atrophy, predominantly right-side. She had a characteristic waddling gait and could not stand up from a chair without help. There was no sensory disturbance and tendon reflexes were present. Creatine phosphokinase (CK) was normal and thyroid function tests were normal. Nerve conduction studies were normal and there was no myogenic pattern on electroneuromyogram. However, according to the importance of this pure proximal motor weakness, a muscle biopsy was performed and only found non-specific type II muscle atrophy. Autoimmune and infectious broad assessment was negative. The clue to the diagnosis was supported by an important elevation of alkaline phosphatase (ALP) to 20 times the normal 2347 UI/L, contrasting with normal liver function. Serum 25(OH)D level was undetectable. Phosphorus was reduced to 0.54 mmol/L with normal serum calcium and elevated parathyroid hormone level (1036 pg/mL) was in favor of severe hyperparathyroidism due to sustained vitamin D deficiency. Bone review revealed major bone fragility with Tscore of the spine to 4 standard derivation and T score of the femoral neck to 2 standard derivation. The imaging studies revealed cracks in two femoral necks (Fig. 1) and rarefaction of the bone structure of the pelvis and vertebrae. Adequate supplementation had a spectacular resolution of muscle symptoms. Phosphorus and ALP gradually normalized. So the diagnosis of osteomalacic myopathy is retained related to severe vitamin D deficiency.