FIBROCARTILAGINOUS EMBOLISM

About the Diagnosis

Fibrocartilaginous embolism (FCE), also called fibrocartilaginous embolic myelopathy, is a sudden paralytic condition of the spinal cord of dogs. It is rare in cats. It occurs with no prior warning and causes paralysis of the hind legs and sometimes of the forelegs as well. The paralysis is reversible in most cases with good nursing care in the hospital or at home for a period of weeks.

With FCE, a small amount of intervertebral disk material from between the bones of the spine (vertebrae) detaches spontaneously and lodges in a nearby blood vessel. This blocks the blood supply to a section of spinal cord and the associated nerves. The resulting inflammation and nerve damage leads to weakness, incoordination (ataxia) or, often, sudden paralysis. The cause of this disease is not clearly understood. Large breed dogs, as well as Shetland sheepdogs and miniature schnauzers, seem to be more prone to FCE than other breeds. It can occur at any age.

This condition occurs suddenly and is sometimes preceded by an episode of physical exertion. Typically, owners of dogs that had FCE report that their dog was playing in the yard, yelped once, and fell over, unable to rise. Initially there may be some signs of pain in some cases, but when present, it usually resolves in a matter or minutes or hours. Symptoms develop immediately or in the first few hours, and then the condition does not worsen after the first day.
Symptoms depend on the severity and the location of the spinal cord injury. A lesion in the cervical (neck) area of the spine will affect both front and hind limbs. If the embolism is in the thoracic (ribcage) or lumbar (lower back) sections of the spine, only the hind limbs will be affected. In mild cases, where the spinal cord is not severely damaged, the dog may appear weak or unbalanced and walk in a clumsy or "drunk" manner (ataxia) without complete paralysis. In more severe cases, the animal may be partially or completely paralyzed, although consciousness and alertness are always preserved, even when there is no movement of all four limbs. There may be loss of bladder control and pain sensation. Often, the symptoms are asymmetric, or one-sided. The clot of disk material can lodge on the left or right side of the spinal cord, sometimes affecting only one leg. To summarize, typical FCE is an acute, nonpainful, asymmetric, and nonprogressive condition.

There are many different types of spinal disorders of dogs, each of which requires a different type of treatment. Therefore, it is essential to be sure that FCE is the cause of symptoms and not something else. To determine a diagnosis of FCE and to identify its exact location in the spinal cord, your veterinarian will begin by asking you several questions, which can provide vital information. Did you witness the onset of the symptoms? If so, what did you see, and how did it evolve (did things get better or worse)? Did you see other changes beforehand that in hindsight may be significant-changes in behavior, activity, appetite, and so on? Is your dog taking any medications?

This type of information can help tremendously. Your veterinarian should also perform a complete physical exam to identify the extent of the symptoms. A special neurologic exam is also important since it will help your veterinarian discern the location and severity of the problem. During this examination your veterinarian will observe your pet's mental status and gait (way of walking) to rule out disorders involving the brain. He or she will test the balance and sensation in all four limbs and will palpate the spine to localize back pain. To test for pain sensation in the limbs, the toes are pinched. Your dog may pull back her leg as a reflex but should also react (turn the head or cry out) if a pain response is present. Withdrawing the limb does not mean that your dog can feel pain. This is an important prognostic indicator (see below), meaning that the presence or absence of pain sensation is a major factor that helps determine how well dogs recover.

FCE is often a diagnosis of exclusion. This means that it is important to perform tests to rule out other spinal cord diseases that can produce the exact same symptoms. They include:

∑ Blood work-usually normal in FCE cases.

∑ Radiographs-(x-rays) also usually normal in FCE cases.

∑ Myelogram-a special x-ray series taken under general anesthetic, with dye injected to show the spinal cord. With

FCE, a myelogram can show swelling of the spinal cord or may be normal.

∑ CSF tap-while under anesthesia, a sample of CSF (cerebrospinal fluid) is collected, which can reveal signs of inflammation with FCE or various other abnormalities with other spinal cord disorders.

∑ CT scan or MRI-advanced scans also requiring general anesthesia.

Living with the Diagnosis

Having your pet suddenly become paralyzed can be devastating. The good news is that most dogs afflicted with FCE recover most or all of their limb functions, although this can take weeks. The degree of recovery also depends on where the lesion is (which region of the spinal cord) and how severe it is. Each case is different, and your veterinarian will be able to form a prognosis-meaning to get an idea of the outlook for improvement and recovery-based on the tests and neurologic examination. Unfortunately, dogs that have lost pain sensation to the limbs have a lesser chance of recovery than dogs with intact pain sensation.

You may be faced with the possibility that your dog's injury will result in temporary or permanent loss of nerve/muscle function. This can include weakness or paralysis of the hind or all limbs and loss of bladder control. As mentioned, the symptoms stabilize within the first day. Often no improvement is seen for the next 5 to14 days. After this, gradual improvement can occur over a period of 6 to 12 weeks. Some dogs continue to recover for 6 months or longer.

If your dog remains paralyzed in one leg or both hind limbs, it does not mean that he/she cannot lead a happy life. Therefore, this possibility should not discourage treatment at the outset. However, caring for a dog that cannot walk can be very demanding. It is worth discussing with your veterinarian what a realistic expected outlook is. These discussions should be updated with recheck examinations during the weeks that follow the moment FCE first happened. In this way, a pattern of progression can be observed, and some idea of an accurate long-term expectation can be reached. Most dogs show some degree of improvement. However, if your dog is a larger breed, is paralyzed in all four limbs, or if you cannot commit to the home care required by a paralyzed dog, you may decide that euthanasia is the most humane choice for your pet.

Treatment

There is no cure for FCE. Therefore, the intensity of treatment varies according to the severity of the injury but is generally based on supportive care such as physical rehabilitation, pain control (only in cases with signs of pain-first 12 to 24 hours), and basic hygiene to help with cleanliness involving urination and defecation.

Anti-inflammatory medication may be helpful if given soon after clinical signs appear (within the first 8 hours). In the first moments when symptoms are apparent, it is important to restrict your dog's activity until a diagnosis is made. Strict cage rest is recommended because some cases may worsen if the dog continues to be active before being examined by a veterinarian. It is commonly necessary to hospitalize your dog for the first several days so that repeated neurologic exams can be performed and a diagnosis reached.

There is no surgical treatment for fibrocartilaginous embolism.

Other types of treatment are also being recognized. Acupuncture may help the spinal cord to heal. Physiotherapy is also beneficial. Exercises, massage, stretching, and swimming may be performed in special clinics or at home.

Home care is a very important part of recovery. Helping a paralyzed dog to recover includes:

• Turning him/her regularly to avoid bedsores and providing soft, dry, clean bedding.

• Stretching and range of motion exercises to keep the legs limber.

• Sometimes, if possible, swimming in a bathtub or pool to help strengthen limbs. Being in a pool or deep tub requires extreme attention and often more than one person to help, since dogs with compromised limb function or paralysis need extensive support to keep afloat.

• Carrying outside to urinate and defecate.

• Expressing the bladder. Some dogs are unable to urinate on their own. You may have to squeeze the belly gently to help empty the bladder several times per day. If this is necessary, you should ask your veterinarian to show you the proper way to do this.

DOs

• Follow your veterinarian's instructions regarding recheck appointments, home care, and physiotherapy.

• Enforce strict cage rest if advised by your veterinarian.

• Keep your dog clean and dry. If he/she has lost bladder control, you will need to give frequent baths and provide fresh bedding. Trimming the hair around the hind end will help prevent painful rashes (urine scald) in females especially.

DON'Ts

• In any dog, do not ignore changes such as limping/lameness, loss of balance, or a change in gait. These signs could be the first indicators of FCE or of other spinal disorders that require urgent treatment.

When to Call Your Veterinarian

• The symptoms should not worsen. That is, once FCE has been confirmed, you should see your dog's ability to move the legs slowly improve over time. If you notice your dog's ability to move is worsening over hours to days rather than improving, call your veterinarian.

• Essential functions like comfortable breathing, a good appetite, an alert disposition, and so on should not be affected by FCE. If you find any of these body functions to become abnormal during the recovery period, contact your veterinarian to be sure that a complication is not setting in.

• For a dog that is being cared for at home, contact your veterinarian if you are unable to follow the instructions provided.

Signs to Watch For

• As signs suggesting the first occurrence of FCE:

Sudden paralysis, without pain.

Change in gait, or lameness, dragging toes, often one-sided.

• As signs suggesting that a dog with confirmed FCE may be experiencing complications: see above.