Page 1483 - Cote clinical veterinary advisor dogs and cats 4th

756 Paresis, Forelimb

PEARLS & CONSIDERATIONS Technician Tips SUGGESTED READING
• PNS can cause clinical signs not typically Withrow SJ, et al: Paraneoplastic syndromes. In
Comments
VetBooks.ir • Recrudescence of a PNS can indicate cancer • Understanding the dynamic behavior Small animal clinical oncology, ed 5, St. Louis,
associated with individual cancer types.
Withrow SJ, et al, editors: Withrow & MacEwen’s
of PNS can be helpful in distinguishing
2013, Saunders, pp 83-97.
relapse.
• If cause for hypercalcemia cannot be
complications.
determined based on history and baseline recurrence of cancer from treatment-related AUTHOR: Michael A. Kiselow, DVM, DACVIM
EDITOR: Kenneth M. Rassnick, DVM, DACVIM
diagnostic testing, consider bone marrow
aspiration to investigate occult neoplasia.

Paresis, Forelimb Client Education
Sheet

BASIC INFORMATION ○ Dysesthesia/paresthesia of limb and • Inflammatory (e.g., granulomatous menin-
secondary self-trauma goencephalomyelitis [p. 647])
Definition ○ Traumatic injury/fracture • Trauma (e.g., brachial plexus abnormalities)
• Monoparesis: partial loss of motor function • Vascular (e.g., fibrocartilaginous embolism
in one limb; voluntary movement exists but Etiology and Pathophysiology [p. 336])
patient cannot initiate gait and is unable to • Central nervous system (CNS)
support weight. ○ Lesions affecting spinal cord segments Initial Database
• Monoplegia/paralysis: complete loss of motor C6-T2 can cause LMN forelimb signs. • CBC, serum biochemistry panel, urinalysis:
function in one limb ○ Flaccid forelimb monoparesis generally unremarkable
• Mononeuropathy: disease or injury of a ○ Basis: injury to LMN cell bodies that • Orthopedic (p. 1143) and cardiovascular
peripheral nerve or its nerve roots innervate forelimb musculature evaluation: rule out concurrent diseases
○ Usually associated with upper motor • Neurologic exam (gait, posture, spinal
Epidemiology neuron signs for ipsilateral pelvic limb reflexes; p. 1136)
SPECIES, AGE, SEX • Peripheral nervous system ○ Distribution and severity of sensory loss
Any dog or cat can be affected. ○ Spinal/peripheral nerve disorders cause aids in localizing the injury to a particular
sensory and motor dysfunction distal to nerve or spinal cord segment; most
ASSOCIATED DISORDERS the lesion (permanent nerve damage or important test for establishing prognosis
• Horner’s syndrome temporary, self-resolving trauma called for peripheral nerve injuries
• Loss of cutaneous trunci (panniculus) reflex neurapraxia). • Forelimb and spinal radiographs (bone
• Self-mutilation/trauma to affected limb ■ Trauma: brachial plexus avulsion and fractures, luxations, neoplasia, or infection)
radial nerve injury are examples.
Clinical Presentation Advanced or Confirmatory Testing
■ Neoplasia: commonly affected are
HISTORY, CHIEF COMPLAINT brachial plexus and dorsal nerve roots. • Myelography, computed tomography scan
Weakness, lameness, or inability to use a • Cervicothoracic spinal cord, nerve roots, (CT), or magnetic resonance imaging (MRI
forelimb sympathetic trunk: Horner’s syndrome [p. 1132]) to localize unilateral spinal cord
(ipsilateral) compression (intervertebral disc disease
PHYSICAL EXAM FINDINGS • Lateral thoracic nerve (C8, T1) disruption: [IVDD] or neoplasia)
• Lower motor neuron (LMN) signs for the loss of panniculus reflex (ipsilateral) • MRI or CT to evaluate nerve/nerve sheath
affected limb: weakness and decreased muscle tumors
tone DIAGNOSIS • Electrodiagnostics (electromyography
• Various: mild forelimb lameness to complete [EMG], motor nerve conduction) to localize
loss of sensory and motor function Diagnostic Overview the dysfunctional spinal cord segment, nerve
• Denervation atrophy of forelimb muscula- A complete orthopedic and neurologic exam root, or peripheral nerve
ture, usually within 7-10 days of nerve injury; (including distribution of sensory loss) is the ○ EMG used for determining whether LMN,
differentiate from disuse atrophy, which is best means of differentiating musculoskeletal myelin, or muscle fibers may be the site of
slower to develop and generally less severe disease from neural involvement. Although the lesion. Fibrillation potentials, positive
• Nerve root signature: lameness and pain of uncommonly performed, electromyography sharp waves, and fasciculations can be seen
affected forelimb caused by entrapment of and nerve conduction may aid in confirming beginning 5 days after denervation.
a nerve root within the brachial plexus the diagnosis of a nerve injury, determining ○ Nerve conduction is polyphasic and
• Suspicion of neoplasia if chronic progres- the distribution, estimating the prognosis, prolonged with LMN disease and absent
sive monoparesis, nerve root signature and and monitoring recovery. Advanced imaging with avulsion injury.
denervation atrophy and/or surgical exploration and biopsy may • Cerebrospinal fluid analysis (CSF [p. 1323])
• Variable exam findings be necessary for definitive diagnosis. to evaluate for infection, inflammation, or
○ Horner’s syndrome (ipsilateral); common exfoliating neoplasia
with traumatic injuries to the brachial Differential Diagnosis • Surgical exploration (based on imaging
plexus • Degenerative (e.g., intervertebral disc disease results)
○ Loss of cutaneous trunci (panniculus) [p. 555]) ○ Biopsy, histopathologic exam for suspected
reflex (ipsilateral) may be seen with • Neoplasia (e.g., peripheral nerve sheath neoplasia
brachial plexus injuries. tumor [p. 692]) ○ Evaluation of type, extent, and severity
○ Palpable mass in axilla (uncommon) • Infectious (e.g., discospondylitis [p. 266]) of nerve injury

www.ExpertConsult.com