Assume ASCI is present in every MWD trauma patient until proven it is not present. Maintain a high index of suspicion! 40-50% of MWDs with ASCI have concurrent injury elsewhere that may be more life-threatening.1 Focus on initial resuscitation and stabilization, but constantly consider potential neurological injuries. Excessive movement can cause a partial injury to become a permanent injury. Limit movement during the initial exam and treatment period to that which is absolutely necessary until a detailed neurological exam is performed.
Clinical Signs Suggesting ASCI
Clinical findings of bruising over any part of the spine; spinal instability, misalignment, crepitus or pain along the spine; presence of head injury or altered mentation or level of consciousness; or major trauma to other body systems are early tips that ASCI may be present.
Specific neurological signs that strongly suggest ASCI include loss of conscious proprioception, loss of superficial and deep pain, and loss of function (paresis or paralysis).
Lesion Localization
It is ideal to localize the segment of the cord affected. Determine if upper motor neuron (UMN) or lower motor neuron (LMN) signs are present.
- UMN signs are characterized by increased motor tone causing normal or exaggerated limb reflexes, normal to increased muscle tone, and decreased proprioception and decreased superficial and deep pain sensation in areas caudal to the lesion.
- LMN signs are characterized by flaccid or weak motor tone causing depressed limb reflexes and decreased muscle tone in areas caudal to the lesion.
- With both UMN and LMN involvement, paresis or paralysis are possible.
- C1-C5 – UMN signs to all 4 limbs, possibly abnormal respiration (shallow or absent).
- C6-T2 – UMN signs to the hind limbs and LMN signs to the forelimbs.
- T3-L3 – UMN signs to the hind limbs with normal forelimbs.
- L4-S2 – LMN signs to the hind limbs with normal forelimbs.
Diagnostic Imaging
Radiographs, CT, or MRI are often necessary for definitive diagnosis in patients with fractures or dislocations to determine the site of injury. If these imaging modalities are available and the MWD can be managed without worsening possible injury, attempt imaging (See CPG 20). Heavy sedation or anesthesia will be necessary (See CPG 16).
General Management Considerations for Patients with ASCI
Goals are to reduce neurological deficit and prevent further loss of neurological function (See Figure 46).
- Follow guidance in this CPG for management of shock, hypotension, hypovolemia, hemorrhage control, and respiratory dysfunction. Be prepared to intubate patients that are not breathing or have depressed ventilation. Careful intubation using manual in-line stabilization (MILS) is essential to minimize further injury.
- If signs suggest ASCI are present and the MWD is NOT ambulatory, immobilize the MWD using a backboard (plywood sheet, plastic board, EMS backboard, etc.) to which the animal is taped, and sedate with or without analgesia as often as necessary to prevent unwanted patient movement due to anxiety and pain.
- If signs suggest ASCI is present and the MWD IS ambulatory or adequate immobilization is not possible (due to lack of sedative/analgesia or support devices or patient temperament), confine the MWD to a small area or kennel and prevent excessive movement until evacuated.
- Do NOT use nonsteroidal anti-inflammatory drugs (NSAIDs).
- Do NOT give corticosteroids to MWDs with ASCI, UNLESS the animal has no deep or superficial pain, is paralyzed, or the neurological condition deteriorates. If corticosteroids are given, use ONLY a SINGLE dose of methylprednisolone sodium succinate, IV, 30 mg/kg over 15 minutes.
Figure 46. Clinical Management Algorithm for Acute Spinal Cord Injury in MWDs.