Chiari 1.5 malformation (C1.5) is a rare condition characterized by caudal descent of the brain stem, together with descent of the cerebellar tonsils characteristic of Chiari I malformation (CIM). Syringobulbia (SB) is rarely associated with CIM and to date has not been reported in a patient with C1.5. An adolescent female presented with Valsalva-induced headaches and a left abducens nerve palsy. Imaging revealed C1.5 and a huge syringomyelia extending cranially into the herniated medulla oblongata as syringobulbia. Simultaneous cases of C1.5 and syringomyelia (SM) have been described, but, to our knowledge, this is the first reported case of simultaneous C1.5 and SB. As SB can have life altering consequences, the clinician should keep this possibility in their differential diagnosis.

Chiari 1.5 畸形 (C1.5) 是一种罕见的疾病，其特征是脑干尾部下降，以及 Chiari I 畸形 (CIM) 的小脑扁桃体下降。Syringobulbia (SB) 很少与 CIM 相关，迄今为止尚未在 C1.5 患者中报告。一名青春期女性出现 Valsalva 引起的头痛和左侧外展神经麻痹。影像学显示 C1.5 和一个巨大的脊髓空洞症，颅内延伸到突出的延髓中，为延髓空洞症。已经描述了 C1.5 和脊髓空洞症 (SM) 的同时病例，但据我们所知，这是第一个报告的同时 C1.5 和 SB 病例。由于 SB 可能会产生改变生命的后果，临床医生应在鉴别诊断中保留这种可能性。