Fibrocartilaginous Embolism (FCE)

Fibrocartilaginous Embolism (FCE) is an acute infarction of the spinal cord that occurs when a piece of fibrocartilage, most likely from the nucleus pulposus of an intervertebral disc (see 2/11/26 blog on IVDD for explanation of disc anatomy), breaks off and blocks one of the blood vessels in the spinal cord causing an ischemic event. The cause is unknown. Adult large and giant dog breeds and miniature schnauzers are most commonly affected. FCE can occur in cats but is rare. FCE has a sudden onset, often during activity, and the dog will often yelp at the time of occurrence, though there is usually no spinal pain on examination. This lack of spinal pain helps in diagnosis as it rules out other causes such a fracture or a disc extrusion. Any area of the spine may be affected although the thoracolumbar (lower back) region is most common. The neurological signs that present depend on where the infarction occurs. Maximal neurologic deficits usually appear in the first 24 hours. The effects are usually noted on only one side of the body, similar to stroke symptoms in humans.

Diagnosis is based on exam, clinical findings and exclusion of other diagnoses. FCE indications are the sudden onset of symptoms, non progressive nature, lack of spinal pain, and unilateral presentation of deficits. X-rays, cerebrospinal fluid, and myelography are all typically normal, but an MRI usually shows signs of focal spinal cord infarction.

Symptoms vary depending on location of the embolism and severity of damage to the spinal cord, but may include:

• Increased muscle tone and spasticity

• Decreased muscle tone and flaccidity

• Weakness on one side (hemiparesis)

• Ataxic (wobbly) gait

• Inability to walk

• Bladder dysfunction

• Fecal incontinence

Treatment: There is no specific treatment for this condition. Primary treatment is supportive care which includes positioning, assistance in standing and walking, manual bladder expression if the dog cannot urinate independently, and monitoring for urinary accidents and keeping the dog clean and dry to prevent skin irritation. Prognosis is good to excellent if motor function is present. Prognosis is worse if there is loss of deep pain sensation, there is no improvement in the first two weeks, or if there are severe lower motor neuron signs (loss of reflexes and tone in the limbs and/or tail) as this can indicate permanent neuron damage. Improvement can be dramatic in the first few weeks and continues for 1-3 months following injury. 85% of dogs are walking within 3 weeks. 43% of deep pain negative dogs recover ambulation. Dogs are likely to have some persistent deficits, but usually are easily managed. Rehabilitation is important for recovery and early intervention has been shown to improve prognosis. Rehab practitioners can help reduce increased tone and spasticity, or work to improve tone in flaccid muscles, improve strength, and coordination which all leads to better mobility.

References:

Platt, Simon & Olby, Natasha. (2019). BSAVA Manual of Canine and Feline Neurology (4th edition). British Small Animal Veterinary Association

Millis, Darryl L. & Levine, David. (2014). Canine Rehabilitation and Physical Therapy (2nd edition), Elsevier

Next week: Wobbler’s Syndrome