Brain injuries are fatal and terrifying, said Tammy Hunter, DVM and Robin Downing, DVM, DAAPM, DACVSMR, CVPP, CRP, of VCA, an operator of over 1,000 animal hospitals in the US and Canada. Primary brain injuries occur when there is a direct insult to the brain while secondary brain injuries happen after the primary brain injury.
In veterinary clinical care, traumatic brain injury is a widely used term that supplants “head trauma”— which has been previously used to refer to the neurologic dysfunction of the brain, explained Kiko Bracker, DVM, DACVECC, of MSPCA (Massachusetts Society for the Prevention of Cruelty to Animals-Angell Animal Medical Center), a non-profit organization. Traumatic injury is common to both dogs and cats, which can occur due to falls from heights, bite wounds, and more.
An Online Survey On the Current Trends In The Management of Canine Traumatic Brain (TBI) Injury (2019)
Emma Kathryn Evan and Alberto L. Fernandez of life sciences and biomedical research portal PMC found that all respondents most frequently reported seeing or treating one to five cases of canine TBI each month, including polytrauma cases suspected to have TBI. The clinical criteria most often selected to further evaluate TBI in dogs were changes in mentation/responsiveness (98.4%), changes in pupil size, symmetry, responsiveness, or other cranial nerve deficits (97.8%), and hypertension/bradycardia (92.9%). The respondents also mentioned evidence of external trauma (88.5%), evidence of seizures (86.8%), and changes in posture or ability to ambulate (82.4%).
73.6% mentioned that the modified Glasgow Coma Scale (MGCS) was part of the clinical criteria. 62.6% said that the MGCS was moderately useful. Meanwhile, a smaller proportion of respondents said they were either moderately comfortable (37.9%) or very comfortable (39.0%) using the MGCS. When asked about the frequency of using MGCS in canine TBI patients, 48.4% of DVM-VTH practitioners said they used it in all patients while 23.9% of DVM-PP practitioners used it in all patients. The DVM-PP practitioners were more likely to never use the MGCS unlike BCS-PP practitioners (5.9%). The most frequently performed diagnostic tests on a TBI patient within the first four hours of admission were packed cell volume/total solids (PCV/TS) (95.6%), blood glucose (96.7%), and blood pressure (95.0%).
Regarding the initial therapeutic interventions for TBI, the most frequently selected ones were mannitol (89.0%), hypertonic saline (85.1%), crystalloid fluids (91.2%), elevation of the head (93.4%), oxygen therapy (93.4%), and opioid analgesia (84.6%). BCS-PP practitioners (94.1%) were more likely to choose hypertonic saline than DVM-PP practitioners (74.6%). 10.4% of DVM-PP practitioners selected corticosteroids as part of their initial treatment plan while none of the BCS-PP clinicians corticosteroid therapy. 73.1% of DVM-PP clinicians were more likely than 47.1% of BCS-PP practitioners to select anticonvulsant therapy.
99.4% cited improved mentation or responsiveness as the most important clinical criterion to guide TBI treatment. The respondents also mentioned the following: solution of the hemodynamic changes associated with intracranial hypertension (90.6%) and improvement of pupil size, symmetry, and reactivity (93.4%). Some respondents also cited control of clinical seizures (76.3%) and improving the MGCS score (64.2%). 42.3% of practitioners were very familiar with the pathophysiology of secondary brain injury compared to those who said they were somewhat familiar with the subject (43.4%). 63.6% BCS-VTH practitioners and 66.7% of BCS-PP practitioners said they were very familiar with secondary brain injury while 38.7% of DVM-VTH practitioners and 14.9% of DVM-PP clinicians were very familiar with the topic.
Classifications of Brain Injury
Primary injury refers to the direct injury of the brain after contact or trauma. Primary brain injury includes hemorrhage resulting in cerebral contusions, parenchymal tears, vascular tearing, and skull fractures with parenchymal compression. Secondary injuries, on the other hand, are a “series of biochemical events” that transpire minutes or hours following the primary injury. Secondary injuries cause neuronal damage and death. Some examples include hypotension, hypo- and hyperglycemia, cerebral edema, and more.
What Are the Signs of Traumatic Brain Injury?
Your dog may have altered consciousness, suggesting bleeding in the skull, reduced blood flow to the brain, or fluid-causing swelling within the brain. Seizures may also occur as a result of brain injury. Some evidence of trauma on the head or other body parts may be present. Bleeding into the yes or bleeding from the nose or ears is a sign of brain injury. Additionally, your dog may struggle in regulating its body temperature, causing its temperature to plummet and suffer from fever. Check the pupils. If the sizes are uneven and possibly react abnormally to light, then that’s a sign of brain injury. Note that your dog’s overall function of its nervous system may change or become compromised in some way. Hence, the aforementioned abnormalities may gradually change.
What Are the Treatment Options?
Treatment depends on the cause of the brain injury. The objective of the treatment is to maximize the brain tissue’s oxygen levels. Supporting blood pressure helps improve brain blood flow if your pet’s blood pressure is too low. In case it has high blood pressure or if there is high pressure in the skull for some reason, your veterinarian will prioritize reducing the pressure in the skull. If necessary, intravenous fluid therapy must be administered carefully to prevent fluid from building up in the brain, including bleeding that requires fluid replacement. Your veterinarian will balance your pet’s blood pressure, preventing it from going too low or too high. Some dogs do not blink their eyes normally if they suffer from brain injury, so lubricating them may aid in recovery.
Your dog must also receive proper and adequate nutrition to help it recover. Tube feeding may be initially done if your dog struggles to eat or found it impossible to do. Surgery may be a necessary option in case of a skull fracture, a foreign object in the skull, or blood or fluid build-up in the skull. Medications may be prescribed to reduce the pressure inside the skull to either help the body remove extra fluid or pull extra fluid from the brain’s tissues. Likewise, pain relievers, heavy sedation, or a temporary state of general anesthesia can prevent your dog’s brain from sustaining more injuries. Your veterinarian will provide it with adequate levels of oxygen using a tube that passes into the windpipe to help it breathe.
Traumatic brain injuries are terrifying for both owners and pets. It takes several months or more for animals to completely recover from brain injury and changes to your pet’s behavior or health should be checked by your veterinarian immediately.