Page 848 - Clinical Small Animal Internal Medicine

816 Section 8 Neurologic Disease

Table 76.1 Differential diagnosis for acute‐onset myelopathy
VetBooks.ir Differential category Differentials Comments

Degenerative Hansen type I intervertebral disc herniation Asymmetric or symmetric
Anomalous Atlantoaxial instability Usually symmetric
Neoplastic Metastatic, vertebral body tumors, pathologic fracture, Often asymmetric
histiocytosis, lymphoma, other hematopoietic neoplasia
Inflammatory Bacterial, protozoal, and fungal meningomyelitis, canine Asymmetric or symmetric
(infectious) distemper virus, feline infectious peritonitis, discospondylitis,
spinal cord epidural empyema
Inflammatory Steroid‐responsive meningitis‐arteritis, granulomatous Usually symmetric
(noninfectious) meningoencephalomyelitis
Trauma Fracture/subluxation, acute noncompressive intervertebral Asymmetric or symmetric;
disc herniation nonprogressive
Vascular Fibrocartilaginous embolism, aortic thromboembolism Usually asymmetric;
nonprogressive
Italicized differentials indicate diseases associated with hyperesthesia on spinal palpation.

Table 76.2 Differential diagnosis for chronic myelopathy

Differential category Differentials Comments
Degenerative (spinal Degenerative myelopathy, myelinopathy, neuronopathy, axonopathy, Symmetric
cord) subarachnoid diverticulum, storage disorders
Degenerative Hansen type II intervertebral disc herniation, cervical spondylomyelopathy Symmetric or
(vertebral column) (wobbler syndrome), degenerative lumbosacral syndrome, spinal synovial cyst, asymmetric
diffuse idiopathic skeletal hyperostosis, spondylosis deformans,
mucopolysaccharidosis, osteochondromatosis
Anomalous Chiari‐like malformation (syringohydromyelia), atlantoaxial instability, Usually symmetric
vertebral malformation, myelodysplasia, spinal stenosis, dermoid sinus
Neoplastic Meningioma, primary spinal cord (oligodendroglioma, astrocytoma, Often asymmetric
ependymoma), nephroblastoma
Inflammatory Bacterial meningomyelitis, canine distemper virus, feline infectious Asymmetric or
(infectious) peritonitis, protozoal, fungal symmetric
Italicized differentials indicate diseases associated with hyperesthesia on spinal palpation.

General Proprioceptive Ataxia Paresis/Plegia
General proprioceptive (GP) ataxia reflects the lack of Paresis/plegia is a deficit/loss of ability to carry out vol-
information reaching the central nervous system untary motor function. The terms lower motor neuron
(CNS) responsible for the awareness of movement and (LMN) and UMN are applied to differentiate two basic
position of neck, trunk, and limbs in space. Due to types of neurologic weakness. Clinical signs of UMN
anatomic proximity within the spinal cord of the pro- weakness are characterized by spasticity with normal to
prioceptive pathways and motor tracts, propriocep- increased spinal reflexes and muscular hypertonia. LMN
tive abnormalities often overlap with those caused by weakness manifests as flaccidity, hyporeflexia to are-
upper motor neuron (UMN) weakness. A deficit of GP flexia and muscle atrophy that is severe and rapid in
appears as misplacement or knuckling of the foot, onset. Neuroanatomic localization to a specific spinal
which may not occur with every step, and poorly con- cord region is upon UMN or LMN signs (see Table 76.3).
trolled swaying of the body. The feet may be crossed In addition, the affected limbs have inadequate or absent
or placed too far apart. Overall movement of the limbs voluntary motion, which may be described as monopa-
lacks coordination. resis/plegia (involvement of one limb), paraparesis/