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16.3.1.5 Other Causes of Cervical Myelopathies and Radiculopathies
Other conditions that can cause cervical myelopathies include trauma, discospondylitis, inflam-
matory conditions, extradural synovial cysts, spinal arachnoid diverticulum, and neoplasia
(Chapter 17).
If there is witnessed severe external trauma, vertebral fracture and luxation (VFL) is considered,
with supportive clinical evidence (e.g. severe pain and radiographic confirmation). However, the
cervical spine is an uncommon region for VFL, apart from those affecting the axis. ANNPE should
also be a differential, particularly if diagnostic imaging does not show osseous abnormalities.
Traumatic injuries resulting in fractures can frequently be diagnosed with radiography, but if they
are minimally displaced, advanced imaging may be necessary (Figure 16.1A, B). Advanced imag-
ing also allows for less manipulation and 3D reconstruction potentially required for surgical
planning.
Discospondylitis is more likely to affect gait in the pelvic limbs (Chapter 21); however, it should
be considered as a differential diagnosis for any patient presenting with spinal pain as part of the
presenting history, particularly if neurologic deficits are absent or mild.
Inflammatory conditions involving the brain (meningoencephalitis) and/or spinal cord (myelitis,
meningomyelitis, and steroid-responsive meningitis–arteritis [SRMA]) can have infectious, or
more commonly, idiopathic (likely immune-mediated) etiologies (Coates and Jeffery 2014).
Idiopathic inflammatory conditions occur most frequently in young adult, small-breed dogs, caus-
ing CNS dysfunction that is usually multifocal. If the cervical intumescence is involved, thoracic
limb gait dysfunction could be recognized. Infectious etiologies typically have progressive signs
that are also multifocal but focal infections, for example tetanus, are reported.
Extradural cystic abnormalities are reported in the spinal column of dogs (Da Costa and Cook
2016). While many times these are incidental findings, they can cause lameness or monoparesis.
Extradural synovial cysts arising from the periarticular joint tissue are commonly associated with
osteoarthritic changes as well as CSM. Spinal arachnoid diverticulum (previously known as cysts)
is focal, fluid-filled dilation of the subarachnoid space, and is common in the cervical regions of
the spinal cord, especially in large-breed dogs. Collectively, these conditions have a progressive
clinical course with variable spinal hyperesthesia.

16.3.2 Neuropathies (Nerves and Brachial Plexus)

While disorders of the peripheral nervous system (PNS) are less common than those affecting
the brain or spinal cord, they are by no means rare as a group. As such, the clinician should be
able to readily recognize the characteristic neurologic presentation localizing to PNS disease.
Many of these disorders are diffuse diseases (e.g. polyradiculoneuritis), but they can present
with lameness or monoparesis prior to generalizing; other conditions remain focal (e.g. bra-
chial plexus neuritis).
Unique to this level in the spinal column is the brachial plexus, where injury or disease can
have severe consequences on mobility of the limb, many of which present an LMN paresis and/
or an apparent lameness. Cutaneous sensation will aid in mapping which nerves are affected
(Chapter 4).
The list of causes of neuropathies is extensive, continues to grow, and many causes remain
unknown. Common causes of acute mononeuropathies include nerve root tumors (Chapter 17
and Video 4.1), traumatic neuropathies, and neuritis. Other causes such as degenerative, paraneo-
plastic, or metabolic usually have a chronic insidious onset history and usually cause generalized,
symmetric clinical signs.