Resolution of life-threatening dysphagia caused by caudal occipital malformation syndrome following foramen magnum decompressive surgery

Clinical Presentation of Chiari-like Malformation in 2 Persian Cats

Two Persian breed cats, 10 and 5 years of age, were presented separately for difficulty prehending food as well as behavioral abnormalities including interanimal aggression and restlessness, pacing, or compulsive overgrooming. Both cats would regularly rest their head and neck in an extended position. Neurologic examination demonstrated calvarial and craniocervical junction pain in both and an L4-S3 myelopathy in one. Brain MRI of both cases, and CT and necropsy in 1 case, demonstrated ventriculomegaly and caudal fossa crowding, cerebellar indentation, and foramen magnum herniation consistent with Chiari-like malformation. No syringomyelia was present in either cat. The 2 cats were treated with anti-inflammatory doses of prednisolone with little to no clinical response, but experienced improvement with pregabalin and omeprazole. The 2 cats' clinical signs were consequently attributed to neuropathic and posture-related pain secondary to Chiari-like malformation. Persian breed cats may have a predisposition to Chiari-like malformation, which may not be solely a morphometric variant, and symptomatic cats may present with manifestations of neuropathic pain different from the classic signs reported in dogs.

Magnetic Resonance Imaging of Chiari Malformation Type I in Adult Patients with Dysphagia

Objective

To explore the magnetic resonance imaging (MRI) characteristics of Chiari malformation type I (CMI) in patients with dysphagia.

Methods

Adult patients diagnosed with CMI were retrospectively and consecutively reviewed from January 2013 to December 2016. Symptoms and medical characteristics were recorded. According to the clinical manifestations, we divided the patients into two groups. The first group had 21 patients with symptoms of dysphagia and the second group had 71 patients with nondysphagia symptoms. Various length or angle measurements of the posterior cranial fossa (PCF), syringomyelia, and degree of cerebellar tonsillar herniation were investigated using magnetic resonance imaging (MRI). Univariate, correlation, and multivariate logistic regression analyses were used to compare and analyze the data of the two groups.

Results

The mean length of the clivus, height of PCF, and slope inclination angle of clivus significantly decreased in the dysphagia group compared to the nondysphagia group. The mean cranial spinal angle (CSA) and degree of cerebellar tonsillar herniation were significantly larger in the dysphagia group. There were no correlations between the age, sex, disease duration, and the length of cerebellar tonsillar herniation or CSA. There was a positive correlation between dysphagia level and CSA (r=-0.50; p=0.021). Among CSA, age, sex, the degree of tonsillar herniation, syringomyelia, and disease duration, CSA was the individual sign that correlated significantly with dysphagia (OR: 1.447; 95% CI: 1.182-1.698; P<0.001). Interactions between CSA and the degree of cerebellar tonsillar herniation, syringomyelia, and dysphagia existed (OR: 1.104; 95% CI: 1.042-1.170; P=0.001 and OR: 1.081; 95% CI: 1.023-1.142; P=0.006, respectively).

Conclusions

The CMI patients with dysphagia were more likely to have a large CSA on MRI compared with CMI patients without dysphagia. An increased probability with syringomyelia or length of cerebellar tonsillar herniation can enhance the contribution of CSA to dysphagia in patients with CMI.

Chiari-like Malformation

Chiari-like malformation is a condition of the craniocervical junction in which there is a mismatch of the structures of the caudal cranial fossa causing the cerebellum to herniate into the foramen magnum. This herniation can lead to fluid buildup in the spinal cord, also known as syringomyelia. Pain is the most common clinical sign followed by scratching. Other neurologic signs noted are facial nerve deficits, seizures, vestibular syndrome, ataxia, menace deficit, proprioceptive deficits, head tremor, temporal muscle atrophy, and multifocal central nervous system signs. MRI is the diagnostic of choice, but computed tomography can also be used.