新生儿枫糖尿病的临床及颅脑磁共振成像特点

Clinical and brain MRI features of maple syrup urine disease in the newborns

目的分析新生儿枫糖尿病(MSUD)的临床及颅脑磁共振成像(MRI)特点,加强对MSUD的认识。方法收集我院6例新生儿MSUD患儿的临床资料,6例均行MRI检查,结合以往其他相关文献资料,总结MSUD的临床及影像特点。结果本组6例,包括男4例,女2例。患儿均有血或尿支链氨基酸增高,4例伴代谢性或呼吸性酸中毒,2例伴血氨升高,1例伴低血糖。患儿临床表现为尿液异味,食欲减退或拒乳,反应迟钝及嗜睡,呼吸困难,抽搐及昏睡。颅脑MRI呈T1WI低、T2WI稍高或高信号,DWI呈明显高信号。病变区域主要位于脑桥背侧及大脑脚、小脑半球、丘脑及苍白球等,也可累及大脑半球深部白质。结论新生儿MSUD血或尿支链氨基酸增高,其他临床表现除尿中含有焦糖味之外并不具有特征性。MSUD的影像表现以细胞毒性水肿为主,病变区域通常与正常新生儿髓鞘化进程相一致的神经纤维束,多呈对称性分布,弥散受限明显。熟悉掌握这些MRI特征可为临床早期及时诊断MSUD提供重要影像学信息。

Objective To analyze the clinical and brain magnetic resonance imaging(MRI)characteristics of neonatal maple diabetes mellitus(MSUD)and to enhance the understanding of MSUD.Methods The clinical data of 6 newborn children with MSUD in our hospital were collected,and MRI examination was performed in all 6 cases.Results There were 6 cases,including 4 males and 2 females.All children had increased blood or urine branch chain amino acids,4 cases with metabolic or respiratory acidosis,2 cases with elevated blood ammonia,1 case with hypoglycemia.The clinical manifestations of the child are urine odor,anorexia or milk repellent,slow response and drowsiness,dyspnea,convulsions and lethargy.Brain MRI showed low T1WI,slightly high T2WI or high signal,and significantly high signal on DWI.The lesion areas are mainly located in the dorsalis pontine and the cerebellum,cerebellum hemisphere,thalamus and pallidum,and may also involve the deep white matter of the cerebral hemisphere.Conclusion Neonatal MSUD blood or urine branch chain amino acids increased,other clinical manifestations are not characteristic except the urine containing caramel taste.The imaging manifestations of MSUD are mainly cytotoxic edema,and the nerve fiber tracts in the lesion area are usually in accordance with the normal myelin process of newborn,which are mostly distributed symmetrically and have obvious diffusion limitation.Familiarity with these MRI features can provide important imaging information for early clinical diagnosis of MSUD.