Pelvic limb paresis and paralysis

20 Pelvic limb paresis and paralysis

Causes of Acute Nonambulatory Paraparesis/Paraplegia

Paraparesis and paraplegia most commonly occur as a result of a spinal cord lesion caudal to the C6–T2 segment (cervicothoracic intumescence). Spinal cord disorders that commonly cause paraparesis or paraplegia are listed in Box 20.1. In some cases spinal cord injury is due to a cause with an acute onset (e.g. traumatic disc injury, fibrocartilaginous embolism) while in others it occurs due to acute deterioration of a more chronic disease (e.g. neoplasia).

BOX 20.1 Common causes of acute pelvic limb paresis and paralysis

• Type I intervertebral disc protrusion
• Trauma: vertebral fracture, vertebral luxation/subluxation
• Fibrocartilaginous embolism (FCE)
• Inflammatory central nervous system diseases (e.g. granulomatous meningoencephalomyelitis (GME))
• Discospondylitis
• Neoplasia
• Aortic thromboembolism (typically cats)
• Spontaneous spinal cord haemorrhage (e.g. canine angiostrongylosis)

Approach to Acute Nonambulatory Paraparesis/Paraplegia

Signalment

Signalment may allow certain differential diagnoses to be viewed with a lesser or greater index of suspicion. For example, chondrodystrophic dog breeds (e.g. Dachshunds, Pekingese) are classically affected by Hansen type I intervertebral disc disease, inflammatory disease is more common in younger dogs and neoplasia is more common in older dogs. Spinal lymphoma is always a differential diagnosis in cats.

History

History may be useful with respect to establishing the likely differential diagnoses, in particular for traumatic causes. A chronic history of intermittent pelvic limb neurological abnormalities prior to acute deterioration may be more suggestive for example of neoplasia.

The owner should also be asked about urination following onset of clinical signs as this may help to localize the lesion more accurately.

Major body system examination

Clinical Tip

• The pelvic limbs are intuitively the focus of the physical examination in animals with paraparesis or paraplegia. However, it is important to remember that paraparesis and paraplegia in themselves are not life-threatening conditions and assessment of cardiovascular status, respiratory status, mentation and pain should be prioritized. Life-threatening abnormalities, typically the result of trauma in these cases, should be addressed first.

In the absence of traumatic injury, physical examination findings may help to raise the index of suspicion for certain differential diagnoses. For example, pyrexia may be more suggestive of an inflammatory cause rather than intervertebral disc disease. Gait assessment and testing of postural reactions are clearly not applicable to animals with nonambulatory paraparesis or paraplegia. Neurological examination of the pelvic limbs in such cases incorporates the following:

• Assessment of deep pain perception: this is a useful prognostic indicator in spinal cord disease. Deep pain perception is confirmed as a conscious response (e.g. head turning, trying to bite, growling) to a painful stimulus and must be differentiated from limb withdrawal which only requires an intact local flexor reflex. The withdrawal reflex assesses the integrity of the L4–S2 spinal cord segments and their associated nerve roots, as well as the femoral and sciatic nerves.
• Spinal reflexes, typically patellar reflex: may be normal, hyperreflexive (upper motor neuron) or hyporeflexive (lower motor neuron).
• Spinal palpation: normal or painful depending on lesion; intervertebral disc disease, inflammatory causes and traumatic injuries are often painful, while fibrocartilaginous embolism is typically considered nonpainful. Neoplasia may or may not cause spinal hyperaesthesia.

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Pelvic limb paresis and paralysis

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