Two cases of pregnancy- and lactation- associated osteoporosis successfully treated with denosumab

Case 1. A 35-year-old woman in the 8^th month of her first pregnancy suffered acute lumbar pain that persisted for 4 months. In the 5^th month postpartum an acute increase in the low back pain led to a MRI which showed recent deformity in L1 and deformities of undetermined time of evolution in L2, L4, and L5. Laboratory evaluation did not reveal metabolic derangements. She had low bone mineral density (BMD, DXA) and severe deterioration of the microarchitecture of distal appendicular bone (HR-pQCT). Kyphoplasty of all 4 vertebrae was performed in 2 stages, and treatment with subcutaneous denosumab, 60 mg every 6 months, was begun. There was rapid and almost complete improvement in pain. An increase in trabecular bone was documented with HR-pQCT. Case 2. A 33-year-old mother who was breastfeeding her first-born child experimented acute dorsal pain. RMI revealed partial compression fractures in vertebrae D5-7. Her axial BMD was low. There was no family history of osteoporosis, and causes of secondary osteoporosis were ruled out. Her pain slowly subsided with conservative measures, oral analgesics, and nasal calcitonin. Then, treatment with oral strontium ranelate was prescribed; after 3 months serum alkaline phosphatase and osteocalcin had not increased, and after one year lumbar bone mineral density (BMD) was unchanged. Treatment was switched to subcutaneous denosumab. After one year, lumbar BMD had increased 14%, and the pain had almost completely subsided.