Page 1859 - Cote clinical veterinary advisor dogs and cats 4th

933.e2 Spinal Malformations, Congenital

Spinal Malformations, Congenital
VetBooks.ir

cord. Depending on the degree of compres-
BASIC INFORMATION
sion, dogs show signs of hyperesthesia or • Spinal dysraphism is caused by abnormal
closure of the developing neural tube, result-
Definition paresis/plegia. ing in a defective neural arch and associated
A developmental abnormality of the spinal Abnormalities of spinal cord and meninges: spinal cord abnormalities.
cord and/or vertebrae. Malformations of the • Spina bifida: failure of closure of the dorsal
spinal cord are referred to as spinal dysraphism. aspect of the vertebrae DIAGNOSIS
Not all congenital malformations, particularly ○ Can affect the vertebrae alone; incidental
vertebral malformations, cause clinical signs. If radiographic finding Diagnostic Overview
signs develop, they are often not detected until ○ Defect can be associated with protusion of Slowly progressive neurologic deficits in a young
early adulthood. the meninges (meningocoele) or meninges animal from an overrepresented breed should
and spinal cord (meningomyelocele); raise the suspicion of a congenital vertebral
Synonyms affected animals can exhibit ataxia, malformation. Malformations involving the
Vertebral malformations, spinal/vertebral paraparesis, paraplegia, or incontinence. spinal cord often present with neurologic
anomalies, spinal dysraphism • Sacrocaudal dysgenesis: complex form of deficits at weeks to months of age.
spina bifida with incomplete or absent
Epidemiology formation of the sacral and coccygeal ver- Differential Diagnosis
SPECIES, AGE, SEX tebrae and associated spinal cord segments. • Infectious/inflammatory myelopathies
Dogs and cats, any sex; age of onset of clinical Affected animals often have urinary and • Congenital spinal cord disorders
signs is variable, depending on the nature and fecal incontinence and can have pelvic limbs • Traumatic myelopathy
severity of the anomaly. deficits.
Initial Database
GENETICS, BREED PREDISPOSITION HISTORY, CHIEF COMPLAINT • Neurologic examination (p. 1136): findings
Certain breeds are overrepresented: • Most congenital vertebral malformations, if supporting a myelopathy; neurolocalization
• Hemivertebrae: English bulldogs, French clinically significant, cause a slow, chronic depends on site of malformation
bulldogs, pugs, Boston terriers progression of gait deficits. • Spinal radiographs: confirm the presence
• Spina bifida: Manx cats, English bulldogs, • Signs associated with spinal malforma- of a vertebral malformation. Radiographic
Rhodesian ridgebacks (associated with tions are usually present at birth but may abnormalities can be incidental; further
dermoid sinus tracts) not become obvious until the animal testing is needed in animals with neuro-
• Sacrocaudal dysgenesis: English bulldog, begins to ambulate or housebreaking is logic deficits to investigate whether the
French bulldog, pug, Manx cat attempted. malformation is the cause of the clinical
• Spinal stenosis: basset hounds, Doberman • Urinary or fecal incontience can be recog- signs or another spinal cord disease is
pinschers, Great Danes nized at an early age in animals with spinal present.
abnormalties.
ASSOCIATED DISORDERS Advanced or Confirmatory Testing
Concurrent congenital anomalies of other PHYSICAL EXAM FINDINGS • MRI (p. 1132) can demonstrate any spinal
regions of the nervous system or other body • Various degrees of neurologic abnormality, cord pathology associated with an anomaly
systems often occur. ranging from none to hyperesthesia to plegia and helps rule out other structural conditions.
• Incontinence is a common finding with • CSF analysis (pp. 1080 and 1323) helps rule
Clinical Presentation anomalies affecting the lumbosacral out inflammatory disease
DISEASE FORMS/SUBTYPES intumescence. • CT often is used to aid surgical planning,
Abnormalities of vertebral and intervertebral • Scoliosis can be evident with vertebral if surgery is indicated.
discs: malformations.
• Hemivertebrae: failure of formation of one • A fluctuant, dorsal midline mass can be TREATMENT
sagittal half of the vertebral body. This can palpable in animals with meningomyelocele.
lead to vertebral instability and clinical signs Uncommonly, a fistula connecting to the Treatment Overview
of myelopathy, which often are not present skin on the dorsal midline occurs, with If clinical signs are present and progres-
until 1 year of age. continuous leakage of cerebrospinal fluid sive, surgery is often indicated for vertebral
• Butterfly vertebrae: failure of formation of a (CSF). anomalies. Depending on the malformation,
portion of vertebral body, with a sagittal cleft decompressive surgery or stabilizing techniques
in vertebral body apparent on ventrodorsal Etiology and Pathophysiology are used. Alternatively, a conservative approach
radiographs; can cause kyphosis but no • Genetic defects are suspected, but mode of consisting of 8 weeks of crate rest and admin-
neurologic deficits inheritance or exact genetic mutation has istration of analgesics in combination with a
• Block vertebrae: failure of segmentation of not been identified. nonsteroidal antiinflammatory drug (NSAID)
adjacent vertebrae; usually not clinically • Vertebral anomalies that occur during or glucocorticoids can be tried. No treatment
significant embryonic development are associated with is possible for most malformations that involve
• Transitional vertebrae: vertebrae at the cer- defects in formation (butterfly vertebrae, the spinal cord.
vicothoracic, thoracolumbar, or lumbosacral hemivertebrae); can also see neural tube
junction that show anatomic characteristics defects resulting in spinal dysraphism. Acute General Treatment
of an adjacent vertebral spinal segment (e.g., Vertebral anomalies that occur during Pain medication as needed
lumbar vertebra with a rib). They usually are fetal development are associated primarily
not clinically signficant. with defects in segmentation and, to a Chronic Treatment
• Spinal stenosis: narrowing of the vertebral lesser extent, formation (block vertebrae, General nursing care, as indicated for animal
canal; can result in compression of the spinal transitional vertebrae, spinal stenosis). with spinal cord disease:

www.ExpertConsult.com