Cauda equina syndrome

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MRI image showing spinal cord compression due to a diseased, bulging intervertebral disk[1]

Cauda equina syndrome (hyperesthesia syndrome) is a degenerative lumbosacral stenosis resulting in cauda equina compression, commonly reported in German Shepherd dogs[2] and other large breed dogs such as the Doberman.

This disease of dogs is commonly observed in middle-aged large-breed dogs and occurs when soft tissue and bony changes, possibly in conjunction with abnormal motion of the lumbosacral joint, impinge on the nerve roots or vasculature of the cauda equina[3].

Causes if this disease include degenerative disc disease, herniated lumbar discs (discospondylitis), synovial cysts[4]spinal stenosis, spinal neoplasia, ischemic insults, arteriovenous malformations or fragments of the fractured bones.

The consequent vertebral instability leads to a polyradiculoneuritis[5], resulting in compression of L3 - S5 nerve roots with consequent nerve degeneration[6] and neurological disease.

The cauda equina nerve roots provide the sensory and motor innervation of most of the lower extremities, the pelvic floor and the sphincters. Therefore, in a fully developed cauda equina syndrome, multiple signs of sensory disorders may appear[7].

Affected dogs show an insidious development of urinary and fecal incontinence, hindlimb paresis and hemiparesis with ataxia, knuckling of hind paws and eventual paralysis.

Diagnosis is based on presenting clinical signs and is usually confirmatory on radiographic, CT or MRI imaging, with signs of vertebral compression and sometimes gas-filled lumbosacral disk space (vacuum disk phenomenon) and facet phenomena between the degenerated L5 - L6 dorsal articular facets[8].

A differential diagnosis would include immune-mediated arthritis and osteoarthritis.

In cases involving severe clinical signs, surgical intervention is usually required, such as hemilaminectomy.

Use of NSAIDs such as carprofen, meloxicam, gabapentin or leflunomide may alleviate pain associated with this condition.


  1. Enpe Vet
  2. Flückiger MA et al (2006) A lumbosacral transitional vertebra in the dog predisposes to cauda equina syndrome. Vet Radiol Ultrasound 47(1):39-44
  3. De Risio L et al (2000) Degenerative lumbosacral stenosis. Vet Clin North Am Small Anim Pract 30(1):111-132
  4. Forterre F et al (2006) Synovial cysts associated with cauda equina syndrome in two dogs. Vet Surg 35(1):30-33
  5. Griffiths IR et al (1983) Polyradiculoneuritis in two dogs presenting as neuritis of the cauda equina. Vet Rec 112(15):360-361
  6. Marsala J et al (2003) Cauda equina syndrome and nitric oxide synthase immunoreactivity in the spinal cord of the dog. Physiol Res 52(4):481-496
  7. Orendácová J et al (2001) Cauda equina syndrome. Prog Neurobiol 64(6):613-637
  8. Schwarz T et al (2000) Vacuum disk and facet phenomenon in a dog with cauda equina syndrome. J Am Vet Med Assoc 217(6):862-864