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Spina bifida
Synonym(s): Spina bifida occulta
Introduction
- Rare congenital abnormality. Seen more often in the English Bulldog and the Beagle.
- Cause: failure of halves of dorsal spinous processes to fuse.
- May be concurrent with myelodysplasia, abnormal position of central grey matter, anomalies of dorsal and ventral horns.
- Signs: noticed when puppy begins to walk; pelvic limb ataxia and paresis, fecal and urinary incontinence, dimpling of skin over site of defect.
- Treatment: surgical repair in some cases.
- Prognosis: poor to guarded if severe neurological signs. Death is uncommon unless abnormality in cervical area.
Presenting signs
- Abnormal gait when puppy begins to walk.
- Dimpling of skin over site of defect.
- Bony abnormality palpable.
- Pelvic limb ataxia.
- Fecal and urinary incontinence.
Age predisposition
- Young (4-6 weeks).
Breed/Species predisposition
- Bulldog Bulldog.
- Beagle Beagle.
Special risks
- Infection of the central nervous system may be a risk if the defect communicates with the external environment, eg menigomyelocele, dermoid sinus.
Pathogenesis
Etiology
- Hereditary in Bulldogs?.
Predisposing factors
General- Animals with associated vertebral defects may be at an increased risk.
- This is most often seen in Bulldogs.
Pathophysiology
- Failure of the vertebral arch to form dorsal to the spinal cord:
- If many adjacent vertebrae are affected this is termedrachischisis.
- If the skin and subcutaneous tissues cover the vertebral defect this is termedspina bifida occulta.
- This defect may also be associated with abnormal formation of the spinal cord due to faulty development of neuronal and supporting cells or abnormalities in migration of differentiating cells.
- In some instances, the meninges and spinal cord may protrude through the vertebral defect.
- Failure of halves of dorsal spinous processes (usually lumbar) to fuse → protrusion of spinal meninges or spinal cord → additional associated spinal anomalies → failure of spinal reflexes to establish → variably impaired neurological function → variable degree of spinal disability.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Bailey C S & Morgan J P (1992) Congenital spinal malformations. Vet Clin North Am Small Anim Pract 22 (4), 985-1015 PubMed.
- Fingeroth J M et al (1989) Neuroradiographic diagnosis repair of tethered cord syndrome in an English bulldog with spina bifida and myeloschisis. JAVMA 194 (9), 1300-1302 PubMed.
- Clayton H M & Boyd J S (1983) Spina bifida in a German shepherd puppy. Vet Rec 112 (1), 13-15 PubMed.
- Deforest M E & Basrur P K (1979) Malformations and the Manx syndrome in cats. Can Vet J 20 (11), 304-314 PubMed.
- Leipold H W, Huston K, Blauch B & Guffy M M (1974) Congenital defects of the caudal vertebral column and spinal cord of Manx cats. JAVMA 164 (5), 520-523 PubMed.
- McGrath J T (1965) Spinal dysraphism in the dog. Pathologia Veterinaria Suppl 2, 1-36 PubMed.
Other sources of information
- Noden D M & De Lahunta A (1985)The Embryology of Domestic Animals.Baltimore: Williams & Wilkins, pp 152-153.