Lamb Stephanie, Aye Christina Yi Ling, Murphy Elaine, Mackillop Lucy
Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford, UK.
BMJ Case Rep. 2013 Jan 2;2013:bcr2012007416. doi: 10.1136/bcr-2012-007416.
Ornithine transcarbamylase (OTC) deficiency is the most common inborn error in the metabolism of the urea cycle with an incidence of 1 in 14,000 live births. Pregnancy can trigger potentially fatal hyperammonemic crises. We report a successful pregnancy in a 29-year-old primiparous patient with a known diagnosis of OTC deficiency since infancy. Hyperammonemic complications were avoided due to careful multidisciplinary management which included a detailed antenatal, intrapartum and postnatal plan. Management principles include avoidance of triggers, a low-protein diet and medications which promote the removal of nitrogen by alternative pathways. Triggers include metabolic stress such as febrile illness, particularly gastroenteritis, fasting and any protein loading. In our case the patient, in addition to a restricted protein intake, was prescribed sodium benzoate 4 g four times a day, sodium phenylbutyrate 2 g four times a day and arginine 500 mg four times a day to aid excretion of ammonia and reduce flux through the urea cycle.
鸟氨酸转氨甲酰酶（OTC）缺乏症是尿素循环代谢中最常见的先天性疾病，活产发病率为1/14000。怀孕可能引发潜在致命的高氨血症危象。我们报告了一名29岁初产妇的成功妊娠病例，该患者自婴儿期就被确诊为OTC缺乏症。由于采取了包括详细的产前、产时和产后计划在内的精心多学科管理措施，避免了高氨血症并发症。管理原则包括避免诱发因素、低蛋白饮食以及通过替代途径促进氮清除的药物。诱发因素包括代谢应激，如发热性疾病，尤其是肠胃炎、禁食和任何蛋白质负荷。在我们的病例中，除了限制蛋白质摄入外，还给患者开了苯甲酸钠4克每日4次、苯丁酸钠2克每日4次和精氨酸500毫克每日4次的处方，以帮助氨的排泄并减少尿素循环中的通量。
