Clinical Case Presentation: Canine Fibrocartilagenous Embolism

PATIENT SIGNALMENT: Canine. English springer spaniel. Male, castrated. 11 years old.

HISTORY / CLINICAL SIGNS: According to the owner, the patient had been acting normally, running around on the owner’s large property until he suddenly went down and could no longer walk. The patient was brought into a local veterinary clinic immediately once the owner discovered him down outside.

PAST HISTORY: Previous left cranial cruciate ligament tear. Otherwise, no previous major medical issues.

CURRENT MEDICATIONS: None. Receives monthly heartworm, flea, and tick preventives.

PHYSICAL / NEUROLOGICAL EXAM FINDINGS:

  • Acute onset lameness.
  • Non-ambulatory tetraparesis.
  • Non-painful, no hyperpathia noted.
  • Mentation: BAR.
  • Head posture: upright/normal.
  • Cranial nerve exam: within normal limits.
  • Thoracic limbs:
    • conscious proprioceptive (CP) deficits (worse on the right front limb),
    • depressed spinal reflexes (worse on the right front limb),
    • weak withdrawal (worse on the right front limb),
    • sometimes looks like extensor rigidity but can bend.
  • Pelvic limbs:
    • conscious proprioceptive (CP) deficits (worse on the right rear limb, but neither pelvic limbs as severe as in the thoracic limbs),
    • normal to increased spinal reflexes,
    • brisk/strong withdrawal,
    • strong muscle tone,
    • positive crossed extensor.
  • Superficial and deep pain present.
  • Anal tone present.
  • Bladder control present.
  • Otherwise, physical exam is unremarkable.

LESION LOCALIZATION: C6-T2 myelopathy (right >>left)

INITIAL DIFFERENTIALS:

  • Fibrocartilagenous embolism (FCE)
  • Non-compressive intervertebral disc disease (IVDD)
  • Spinal cord tumor (that may not be visible on spinal radiographs)
  • Myelitis (inflammatory vs. infectious)

DIAGNOSTIC TESTS & RESULTS:

  • Bloodwork: mild stress leukogram; otherwise, unremarkable
  • IDEXX 4Dx SNAP® Test: negative
  • Spinal radiographs: no obvious lesions
  • Advanced imaging declined by owner

DIAGNOSIS: Fibrocartilagenous Embolism (FCE)

This patient has a presumptive fibrocartilagenous embolism. An FCE occurs when a piece of nucleus pulposus from a spinal disc dislodges and forms an embolism (blood vessel blockage) in the spinal cord, blocking off oxygen and nutrient supply from that segment of spinal cord, resulting in myelopathy (or spinal cord dysfunction). Though overall uncommon, FCE is most likely to occur in active young adult dogs (primarily large breed dogs and miniature Schnauzers) following activity, such as jumping or running around. (This patient is a very active dog, enjoying running after wildlife on his owner’s property of several acres.)

FCE causes asymmetric neurological deficits, affecting only one side of the body. (This patient appears to be more affected on the right side, indicating the FCE has lodged in the right side of the spinal cord between segment C6-T2.) The gray matter of the spinal cord is more severely affected by FCE because disc material enters the spinal cord terminal vessels upon kinetic injury and causes ischemic damage. Relative to white matter, gray matter tends to be more affected by ischemia because it has a higher metabolic demand (for glucose, oxygen, etc.). FCE tends to be painful at initial occurrence (the animal may cry out) but then is usually non-painful thereafter. (This would explain why this patient is currently non-painful.) The mid-caudal cervical spine is most commonly affected by FCE. FCE should be differentiated from traumatic intervertebral disc disease (or IVDD). IVDD tends to be much more painful than FCE but can otherwise be a look-alike of FCE based on clinical signs. Ideally, an MRI would have been performed as this is the only concrete means of differentiating FCE from traumatic intervertebral disc disease (IVDD); on MRI, the spinal disc appears normal if FCE. However, owners declined a neurology consultation with advanced imaging and further diagnostics.

TREATMENT:

Following his neurological evaluation, this patient was kept in-hospital for several days for monitoring and physical therapy exercises. He was given buprenorphine initially (later discontinued as it became evident that the patient was non-painful) as well as carprofen. Treating a fibrocartilaginous embolism involves physical therapy and cage rest to prevent further injuries. Surgery to remove the lodged fibrocartilagenous disc material is not necessary as new blood vessels will form to re-supply the starved spinal cord segment of vital oxygen and nutrients, allowing it a chance to heal.

PROGNOSIS:

If the FCE results in an upper motor neuron (UMN) lesion, the prognosis is good so long as the lesion is less than 2 vertebrae long and involves less than 67% intramedullary. For a lower motor neuron (LMN) lesion, the prognosis is fair. If loss of nociception occurs (which is uncommon for an FCE), the prognosis is poor.

Fortunately for this patient, he developed enough strength and control to rise to a standing position on his own within 2 days of the initial injury, also attempting to take a couple of steps before falling. This early-stage walking appears to be “double-engine” gait. With continued supportive care and at-home physical therapy exercises performed by his educated owners, he continued to make great progress and returned to full mobility within several months.

REFERENCES: available upon request

DVM Maranda Elswick
DVM Maranda Elswick
Small animal veterinarian, USA. Maranda Elswick, DVM, graduated in 2015 from Virginia-Maryland College of Veterinary Medicine in the United States of America with an emphasis in small animal general practice and special interests in preventative medicine, hospice care, client communication, and client education. Frustrated by the lack of appointment time to thoroughly explain complex pet diseases to clients, Dr. Elswick created The Meowing Vet, LLC, in 2016. The Meowing Vet’s website (www.themeowingvet.com) and social media platforms (@themeowingvet) provide free veterinary educational tools for pet owners and serve as a virtual continuation once a vet appointment ends. In addition to managing The Meowing Vet, Dr. Elswick is currently a licensed relief veterinarian in small animal community practice in the U.S. where she is focused on improving mental health in the veterinary profession and combatting compassion fatigue. She and her fiancé, a veterinary cardiologist, reside with their two dogs and enjoy traveling together. Website. Facebook. Instagram.

Leave a Reply

Your email address will not be published. Required fields are marked *

ACCOUNT