What Is a Traumatic Brain Injury?

Traumatic brain injury (TBI) occurs when a sudden event, such as a blow or fall, happens to the head. In both humans and animals, a head injury severe enough to damage the brain is referred to as traumatic brain injury or TBI.

Humans are diagnosed with concussions (a mild form of TBI), and veterinarians may use that terminology to describe a dog or cat with an externally caused brain injury. A concussion is a mild form of TBI that occurs when there has been a rapid back-and-forth movement of the head, essentially causing the brain to come in contact with the skull.

There has been increased attention on TBI in humans as sports injuries have become more recognized and acknowledged, and you may hear the term TBI more often now than in the past.

How Does it Happen?

TBI can occur in any age group or breed of dog or cat. Pets spending time outdoors may be more vulnerable to traumatic brain injury as they are likely exposed to more injury-causing risks. One fortunate advantage that dogs and cats have over humans is that their skulls are relatively thicker and, thus, a bit more protective of the brain. However, violent trauma can easily overcome the protective effect of a thicker skull.

How is TBI Diagnosed?

If your pet is not stable upon arriving at the veterinary hospital, it will be stabilized. A clinical examination will be completed, and your veterinarian may recommend various tests depending on your pet’s status. Your pet may have also been injured in other parts of the body, and your veterinarian will check for those. Blood and urine testing can help determine the extent of the injuries and establish a baseline for further evaluation. Neurological examinations and images of the head and brain using X-rays, MRI, or Computed Tomography (CT) may be needed when there is a suspected history of head trauma. Blood pressure may be monitored.

Evidence of an injury may be apparent. Cuts, scrapes, or broken bones may help tell the story if you were not present when the trauma happened.

If your pet is showing signs consistent with TBI, seeing these signs exhibited can be frightening. More so if you have no idea what is causing them.

Suppose the potential TBI happened in the past, and the history of the trauma that caused the head injury is available. In that case, your veterinarian will use this information to help evaluate the effects of the original injury.

There can be a variety of neurological symptoms from brain trauma that your pet may experience. Motor control issues such as circling in one direction, head tilting or displaying rapid or abnormal eye movement, or a difference in the size of the pupils may be present. Your pet may experience seizures.

Another severe and recognizable symptom of TBI is known as decerebrate posture. The limbs are held unnaturally, straight out, and ridged, with the head back and neck arched. This behavior generally suggests a more serious brain injury.

X-rays will usually be recommended as your pet may have a skull fracture or other broken bones (in other areas). Continuous electrocardiogram (ECG) monitoring may be needed to check your pet’s heartbeat. Additional imaging such as ultrasound, MRI, or CT scanning may be indicated so that your veterinarian can see your pet’s brain and other areas, if needed, in better detail.

Generally, TBI is divided into two categories: primary, which refers to results from the initial injury, and secondary, referring to damage caused by the primary injury.

Primary Injury

There is swelling where there is an injury to any of the body’s tissues. Swelling reduces blood flow, and compressed blood vessels cause pressure to build up in and around the brain. Broken blood vessels cause blood to pool, forming clots (hematomas).

If there is a skull fracture, brain damage can be worse. Surgery may be considered in this case. The severity of the condition is determined by how bad the initial injury and trauma were.

Depending on the overall injury causing a TBI, your pet may also experience difficulties with physical movement or injuries to other parts of the body.

Secondary Injury

Changes within the brain occur immediately after the primary injury, affecting the processes, or metabolism, at work in the entire body.

Because metabolism uses energy to drive many functions of the body, the changes are linked and result in numerous systems reacting, furthering the damage to the brain. Poor blood flow and bleeding in the brain add to these issues.

After the initial injury, a cascade of issues may develop over time. Brain swelling and inadequate blood and oxygen flow occur not only in the brain but also in other organs, such as the heart. Increased pressure within the cranium and brain swelling are major causes of death from TBI in dogs and cats.

Further laboratory testing and follow-up exams help your veterinarian evaluate additional damage to the whole body in addition to the brain that may be present.

Treatment

Treatment for TBI involves mainly supportive care, which may include hospitalization with continuous monitoring, medications, appropriate wound care, blood work, and follow-up X-rays.

Prognosis

Recovery for your pet depends on how severe the primary injury was. Patients who survive the first 24 hours following injury will most likely recover but may need treatment and monitoring depending on the injuries. If referred to a neurologist, you may need to take your pet for checkups or additional therapy, depending on the situation. Brains, both human and animal, have amazing powers of recovery, and positive outcomes happen all the time. Working closely with your veterinarian and/or veterinary neurologist and knowing what signs to look for (both good and bad) can help your pet have the best chance at recovery and, if possible, get back to their normal activities.

Depending on the location and extent of brain injury, the animal may recover fully or be left with varying degrees of altered mental or motor functions. One possible long-term result of TBI is epilepsy, which is recurring seizures. These can usually be managed with medications so that the animal's quality of life remains good.