妊娠後骨粗鬆症による胸腰椎多発性圧迫骨折の1例

Multiple Compression Fracture of Thoracolumbar Spine due to Post-pregnancy Osteoporosis : Case Report

　抄録：妊娠後骨粗鬆症により，胸腰椎に多発性の圧迫骨折を生じた1例を経験した．症例は25歳の女性で，出産後2カ月半で急激な腰痛とともに体動困難となった．各種精査を行い，Th11～L1，L3～5の圧迫骨折と診断した．外固定により症状の軽快を認め，かつ椎体の変形を予防し得た．妊娠後骨粗鬆症は，授乳によるCaの喪失，低エストロゲン血症などにより発症し，産褥6カ月間で腰椎骨量は平均6.5％減少すると報告されている．治療は，授乳の中止による骨量減少の防止，外固定による椎体の圧潰の予防が第一であり，授乳中止後6～12カ月で失われた骨量のほとんどが回復する．産褥婦の腰背部痛は本症を考慮する必要がある．

　Post-pregnancy osteoporosis, which was reported for the first time by Nordin in 1955 originates from vertebral compression fracture during pregnancy or delivery. This disease is so rare that few reports are available in the literature. We experienced a 25-year old woman who developed severe back pain a few months after delivery of her first child and had non-traumatic thoraco-lumbar multiple compression fracture, which was relieved by conservative treatment. Post-pregnancy osteoporosis seems to stem from transient failure of bone metabolism (loss of calcium due to lactation, hypoestrogenemia, and so on) during pregnancy and puerperal period. At six months after postpartum, there is a 6.5％ loss of bone mass in the literature. But this disease is self-limited and interruption of lactation and conservative treatment (bed rest, cast, body brace) lead to remission within several months with a favorable prognosis.