Signs consistent with syringobulbia may be detected in dogs undergoing MRI.

Abstract

Syringobulbia is a pathologic condition characterized by one or more fluid-filled cavities within the brainstem. This retrospective case series describes observations in eight dogs with syringobulbia diagnosed during MRI. All dogs were adult, small-breed dogs with concurrent syringomyelia and neurologic deficits localized to sites rostral to the spinal cord, which cannot be explained by syringomyelia (eg, six dogs had vestibular signs). On MRI, the fluid-filled cavities had signal intensity characteristics like cerebrospinal fluid, were in the medulla oblongata, and were solitary in each dog. Initially, the shape of the cavity was a slit in five dogs and bulbous in two dogs. Magnetic resonance imaging was repeated in five dogs (6-55 months of age). One dog had progression of syringobulbia from slit-like to bulbous, and four dogs had unchanged slit-like syringobulbia. One dog developed slit-like syringobulbia after cranioplasty. A variety of medical and surgical treatments were performed with improvement of some but not all clinical signs. One dog died following surgery due to cardiopulmonary failure and the other seven dogs were alive at least 1 year after the initial diagnosis, which was the least time of follow-up. One surviving dog developed a unilateral hypoglossal nerve deficit 2 months after the initial diagnosis and megaesophagus 14 months later. In conclusion, detecting a fluid-filled cavity in the medulla oblongata consistent with syringobulbia is possible in dogs undergoing MRI. The cavity is likely acquired, slit-like or bulbous, progressive, or static, and might be associated with breed size and neurologic signs localized to the medulla oblongata.