Syringomyelia/ PSOM       Ohio State Veterinary School

by Ronaldo da Costa, DVM, MSc, PhD, DACVIM, Assistant Professor, Neurology and Neurosurgery Valerie Samii, DVM, DACVR, Associate Professor, Radiology and Diagnostic Imaging 

Chiari-like Malformation and Syringomyelia (CM/SM) is a neurologic condition that commonly occurs in Cavalier King Charles Spaniels. It is characterized by an accumulation of spinal fluid within the spinal cord (syrinx) in the neck region. The cause for the syrinx formation is believed to be a malformation of the brain and skull. Essentially, the brain may be too big for the skull, and the back of skull cannot accommodate the brain. This leads to shifting of the back part of the brain (cerebellar herniation) which then interferes with the movement of spinal fluid, resulting in accumulation of spinal fluid within the spinal cord. This fluid accumulation leads to clinical signs of the disease. Interestingly, the brain and skull malformation are also present in many asymptomatic dogs. It is unknown why some dogs develop clinical signs of the disease and others do not.

A common clinical sign in the affected dogs is discomfort or pain in the neck region. The pain is often manifested by scratching on one side, many times without making skin contact. This symptom is the reason the disease is also referred to as “neck scratcher’s disease.” Facial pain can also be seen, which can be confused with ear pain. The pain can be severely debilitating. Neurological signs can also include front limb weakness, pelvic limb ataxia, sensory receptor deficits, facial nerve paralysis, deafness, seizures, balance deficits, vision deficits, and head tremors. The age of onset of the signs is usually between five months and three years, but in more severe cases, the onset is usually by two years of age.

The only way to conclusively diagnose CM/SM is by performing an MRI of the brain and neck. CM/SM is an inherited disease. Unfortunately, the exact mode of inheritance is still unknown. Treatment of CM/SM can be provided either medically or surgically. There are several drugs that can be used to control the pain of dogs with CM/SM. Surgical treatment is usually indicated after a dog fails to improve with medical management.

Primary Secretory Otitis Media (PSOM)

in the Cavalier King Charles Spaniel

by Dr. Lynette Cole, DVM, MS, DACVD, Associate Professor, Dermatology

PSOM is a form of otitis media (inflammation of the middle ear) that seems to affect the Cavalier King Charles Spaniel (CKCs) in particular. Due to the mucoid nature of the disease and the fact that it is uncommonly associated with disease of the external ear canal, the condition has been referred to as PSOM or “glue ear.”

The presenting signs of PSOM may include pain localized to the head and neck, balance problems, drooping of the ear or lip, drooling saliva, inability to blink the eye, involuntary rapid movement of the eyeball, head tilt and/or hearing loss. However, these signs are also symptoms of syringomyelia, while hearing loss alone may be due to progressive hereditary deafness, both of which are diseases identified in the CKCs.

The best tests for diagnosis of PSOM include CT scans, MRI and radiographs, which inform us if there is fluid, mucus, pus, or a mass in the middle ear. To identify the material seen on the CT scan or MRI, a myringotomy (incision into the ear drum) must be performed, if the ear drum is intact. The best treatment option for PSOM is to flush the mucus out of the middle ear once the myringotomy has been performed.


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