Syringomyelia

Syringomyelia is the name for a condition affecting the brain and spinal cord, it is mainly seen in brachiocephalic breeds with the Cavalier King Charles Spaniel being particularly prone.

The condition is characterised by a collection of fluid pockets affecting the flow of cerebrospinal fluid (CSF) between the skull and spinal cord. CSF is produced in the brain and protects the brain and spinal cord from injury. If there is an obstruction between the ventricles in the brain that produce CSF and the spinal cord, then CSF is forced into the spinal cord resulting in fluid filled cavities. This puts pressure on nerves and results in pain or problems with message transfer to/from the brain.

The most common reason for this obstruction is a mismatch in the size of the skull and brain (soft tissue of the brain is too big compared to the size of the skull). It can also be due to spinal cord injury.

If Syringomyelia is mild it may not produce any clinical signs. There is a huge variation in the severity and variety of clinical signs displayed by affected dogs. The most common is intermittent pain and this can be manifest as vocalisation, reluctance to exercise or be picked up. Some dogs experience abnormal sensations and may try to air scratch their neck, rub face or lick paws excessively (importantly there are no abnormal skin symptoms to be seen and often a dog won’t connect with the area of the body that is apparently irritated). Dogs can be more sensitive to being touched on a particular side of the head, ear or neck. The degree of discomfort is directly correlated with the size of Syringomyelia.

Dogs with wide cavities often have scoliosis (curvature of the spine). As well as pain, some dogs may show limb weakness and poor coordination. In severe cases seizures can develop although this is rare.

MRI scanning is used for diagnosis, dogs require a full general anaesthetic for this procedure. In some severe cases surgery maybe a treatment option- bone is removed from the base of the skull to allow free flow of CSF from the brain to spinal cord. However, most cases are managed medically.

Treatment is aimed at reducing CSF pressure and this is often enough to alleviate signs of pain but if insufficient then non-steroidal anti-inflammatory drugs can be added. Other drugs used for nerve induced pain such as Gabapentin can be indicated if neuropathic pain is suspected. Most dogs can be managed successfully but euthanasia is required in a small number if pain is persistent and uncontrollable