Brain Injury in Dogs

Because a brain injury will most often affect other systems of the body, it is of utmost importance to the well-being of your pet to attend to any injuries that may result from a trauma to the skull. A great degree of cases of mortality and morbidity in animals is related to brain injury. While dogs can survive after a loss of a considerable amount of cerebral tissue, reduction of brain swelling and analysis of damage to stem structure is vital to the prognosis.

Brain injury in dogs results from a trauma to the head, leading to neurological dysfunction. Also known as traumatic brain injury (TBI), this is an occurrence that happens quite commonly due to incidents such as vehicular accidents or falls. Due to the complexity of the injury, immediate veterinarian care is critical in the event of a brain injury.

The signs of brain injury can easily range from really obvious to not so clear or apparent. Of course, in the case of a traumatic accident that you may have witnessed such as a fall or impact, you will be aware that the demeanor of your pet is resulting from the incident. In the event of a circumstance that you did not see occur, recognition of all signs could be difficult. As in the case of any behavioral change in your pet, the following signs mean a veterinarian visit is crucial:

• Your dog is circling over and over, especially when excited or facing stress
• There is a loss in control of movements of the body (ataxia)
• There may be hemorrhage in the ears, visible to you and in the retinal area which may not be apparent to you
• You may see external signs such as cuts or lacerations, and skull fracture not easily seen by you
• You may notice a loss in perception of spatial movement
• Facial weakness and loss of sensation in face can be present
• There may be problems in the visual realm like a lack of eyelid reflex or lack of response to light by the pupil
• In severe cases there can be brain matter found in the ear canal
• Eventual coma can occur

Types

Injuries to the brain are broken down into two categories:

Primary injury - This is the trauma that occurs at the time of impact and results in a physical disruption of intracranial structures. Vascular tears (tearing of the artery causing reduced blood flow to the brain), and hemorrhaging are included in primary injury. With the primary injury, care is focused on reducing the effects that can lead to secondary complications.

Secondary injury - Along with the edema and hemorrhaging of the primary injury, further tissue damage and swelling can result, which in turn causes an increase in intracranial pressure (ICP) and breakdown of the blood-brain barrier (BBB). ICP can lead to changes in the delicate make-up of the brain, blood, and cerebrospinal fluid. Complications, for example, hypoxia (deficiency in oxygen), or ischemia (inadequate blood supply) can be life threatening.

The number of reasons that your dog may be suffering from a brain injury are numerous and broad. As with humans, the brain of the dog is protected from immediate damage by the skull. If the skull suffers an impact from a fall or collision with a vehicle, or if the skull is fractured for example by a dog bite, the following emerging difficulties can result in further cerebral damage.

• Brain contusion
• ICP (the brain, blood, and cerebrospinal fluid are unbalanced leading to severe consequences because of the pressure build up)
• Decrease in cerebral blood flow due to ICP
• Dangerous amounts of inflammation
• Hypercapnia (excessive carbon monoxide in blood owing to inadequate respiration)
• Hypoglycemia (very low blood glucose)
• Infection
• Hypothermia (dangerously low body temperature)
• Hyperthermia (excessively high body temperature)

The veterinarian will begin by assessing the clinical signs of your dog. As previously mentioned, dogs with brain injury may turn in circles when stressed or excited. The veterinarian may see pupil dilation and clear evidence of external trauma. She will check the PCV (packed cell volume) in the blood to verify the volume of cells present. A complete blood count and serum analysis can help with the diagnosis. Checking the blood glucose level is extremely important because it can give a good indication as to what condition your pet is presently in. The level of electrolytes must also be verified.

The mental status of your pet, along with reflex capabilities will be confirmed. Unequal pupil size (anisocoria) is another indication of brain injury.

The diagnostic tools of the CT scan and the MRI can be very beneficial in regards to diagnosis, but are only recommended if the chosen medical therapy is not giving any improvement. This is because your dog will need to be sedated heavily in order to do either test, which is not always deemed a safe practice for a dog with a brain injury.

The veterinarian will focus on the ABC’s to start, which is ensuring proper function of the airway, breathing and circulation because getting the proper amount of oxygen to the brain are critical for recovery. At the same time, acute effects of the brain trauma must be controlled. Equally important is the step of monitoring for secondary infection.

In order to maintain adequate oxygen levels and avoid hypoxia (deficiency in oxygen), a nasal cannula might be inserted. Fluid therapy to restore heart rate, mucous membrane color and pulse will likely be given. 

All the while, the veterinarian will carefully oversee the comfort of your dog and will administer medication for pain and anxiety. Other medical compounds, such as mannitol (used to relieve intracranial pressure and help the cerebral blood flow), might be utilized. Anticonvulsants may be given to limit seizures.

Nutrition is an important part of treatment. Many dogs are hospitalized for extended periods of time and can have significant weight loss.

The recovery of your dog will depend upon the exact type of damage to the brain, your dog’s age, his level of consciousness at treatment time, general physical shape, extent of the harm to the brain stem, and the magnitude of injuries that may accompany the trauma.

Recovery of brain injury may not ever be a complete return to normalcy. Issues such as loss of voluntary movement or blindness may remain. Physical therapy must be part of the recovery regimen, which includes an extension of limbs, swimming and supported walking.

The prognosis is grave if the time lapse between injury and release of ICP is too long because often brain herniation occurs. However, improvement has been noted in many cases, even those that seemed hopeless. With the help and expertise of your veterinary professional, your dog may recover (though most likely not fully). Be an involved partner in your pet’s rehabilitation, and you may see improvement weeks and even months later.

Cost of treating a traumatic brain injury can vary greatly depending on what specific therapy yoru dog might need.