The most common cause of head and spinal trauma is an impact with a motor vehicle although falls, running into objects and kicks from large animals also account for a proportion of injuries. Signs are typically sudden in onset and there is usually other evidence of trauma such as abrasions or broken teeth and claws. Likewise, the animal is very likely to have suffered injuries to internal organs such as the bladder or heart after sustaining trauma severe enough to damage the skull or break the spine.
Head trauma in dogs and cats is not quite as common as it is in humans, in part because animals have relatively thicker skulls that are protected by a good deal of muscle. Animals also seem much less prone than humans to subdural hematomas, which are blood clots that develop underneath the skull after trauma.
Following the emergency assessment, any animal that has sustained head trauma should ideally undergo intracranial imaging by CT scan or MRI. Some animals may benefit from surgery to remove depressed skull fractures or remove blood clots. The principles of diagnosis and management of head trauma in animals are identical to those in humans. Treatment recommendations for humans have been detailed in the Guidelines for the Management of Severe Head Injury produced by the Brain Trauma Foundation, shown below.
In general, the long-term prognosis for animals that survive the first 24 hours after sustaining severe head trauma is more favorable than it is for humans. This is mainly because animals are not nearly as dependent on their higher brain functions as are humans. In humans, motor function, complex cognitive skills, social awareness, and intelligence are crucial to our existence whereas they are not nearly so important in order for an animal to function as a pet. The main complications include the long period of nursing care that may be required as well as the risk of pneumonia until the animal regains a normal level of consciousness.
- Cranial Trauma REQUIRES LOGIN; FOR VETERINARIANS In Braund’s Clinical Neurology in Small Animals: Localization, Diagnosis and Treatment. C.H. Vite (ed).
- Brain Trauma Foundation Guidelines for the Management of Severe Head Injury
Figure 16-1: Jack Russell terrier that sustained severe head trauma after being hit by a car. These two images (A: & B:) taken from the CT scan at different levels of the skull show multiple fractures (black arrowheads). A: There are also two fragments of skull bone that have been forced into the brain (black arrows). Note that the bone of the jaw is also fractured (white arrow). The dog underwent emergency surgery to remove these fragments and the associated blood clot. It made a slow but steady recovery and was normal within 3 months of the injury.
Spinal trauma is usually sudden in onset and produces neurological deficits in either the rear legs or in all four legs. In some animals, only one limb is paralyzed and in such cases, this is usually due to either brachial plexus injury or to a complication of pelvic fracture. Diagnosis of spinal trauma is usually evident from spinal X-rays but a CT scan or MRI are of great assistance in deciding how best to manage each case. Non-surgical management is generally recommended for most injuries to the neck unless the animal is unable to move its limbs at all or has difficulty breathing. Non-surgical management can also work well for some injuries to the spine in the chest or lumbar area although in general, these respond better to surgical management. The most important factor in determining the prognosis of an animal that has suffered a spinal injury causing rear limb paralysis is whether or not it can feel a painful stimulus applied to its limbs and tail. If all sensation is lost behind the injury then very few animals will recover to become functional pets. Dogs that retain normal sensation usually make a good recovery provided that their injury can be stabilized.
Figure 16-2: Dog that sustained a fracture of the seventh lumbar vertebra in its spine after being hit by a car. A: The two pieces of the fractured vertebra are displaced by several centimeters (black arrows). The floor of the vertebral canal on either side of the fracture is marked by the horizontal black lines, note the marked step due to the displacement of the fragments B: The two pieces of the fractured vertebra have now been realigned (black arrows); note that the horizontal lines are now in the same plane. The spine has been stabilized using screws across the lumbosacral facet joints combined with large pins connected to an external apparatus. The spine is now in much better alignment compared to the image in A. This dog made an excellent recovery.
The main complication after surgery is the small risk of implant failure, as well as the fact that many dogs will develop urinary tract infections until they regain the ability to urinate normally (the latter is also true for animals that do not undergo surgery).
- Spinal Trauma. REQUIRES LOGIN; FOR VETERINARIANS In Braund’s Clinical Neurology in Small Animals: Localization, Diagnosis and Treatment. C.H. Vite (ed).