Head injuries
Last week we commenced with a new chapter in the ailments that could afflict your companion animals. We made some general remarks about the nervous system, especially relative to its composition.
The brain itself is surrounded by fluid and is suspended by strong ligaments. The skull is the bony structure which surrounds and protects the very delicate brain. It would take a very strong blow to the head to injure the brain. Sometimes, however, a hit (we vets call such hits “mechanical trauma”) can be of such force that the skull is fractured and the brain lacerated. Often, in such cases, blood vessels are also damaged. The pressure of the blood clot on the brain can have its own repercussions.
I should also mention that even if the skull is not fractured, the severity of the blow can impact upon the brain in such a way as to negatively influence the brain function. The brain damage could be irreversible, especially since damaged or destroyed nerve cells do not heal easily, nor do they simply grow back.
The scientists have decided to classify brain injuries according to the extent of the damage. So, we speak usually of brain contusion (bruising); brain concussion (unconsciousness); brain swelling (tumour); and blood Clot on the brain.
Brain contusion
As the name suggests this is not severe mechanical trauma causing heavy injury. It is so mild, that for example, the animal does not lose consciousness. At worst, the dog is dazed and gives a confused look. He may walk unsteadily (disoriented) for a while. Usually, the condition clears up within hours and the symptoms gradually disappear.
Brain concussion
On the other hand, a concussion (by definition) presupposes that the animal has become unconscious. A concussion, depending on the severity of the blow, results in the animal being ‘out‘ for more than five minutes. Any time the animal is unconscious for more than five minutes, you must consider it a major problem, since immense brain damage might have occurred – for example, the brain has experienced great swelling or even bleeding (pressure on the brain from a blood clot can led to unconsciousness).
If the animal slowly regains consciousness, you will notice that it exhibits the same symptoms as those described above for brain contusion, as the dog (cat) goes through the phases of recovery.
Brain swelling or blood
clot on the brain
Severe head trauma is associated with swelling of the brain or the formation of a blood clot from a ruptured blood vessel.
Brain swelling, technically called cerebral edema, always is associated with a depressed level of consciousness (and often coma). Since the brain is encased in a bony skull, swelling of the brain leads to pressure on the brain stem. As the cerebellum is herniated through the large opening at the base of the skull, the vital centres are in great jeopardy: Breathing may be gasping or irregular; the heart rate may slow down to a dangerous level, and the blood pressure could be greatly elevated.
Sudden herniation usually leads to death of the dog. The signs of death are no pulse; no efforts to breathe; no blink reflex (when you touch his cornea); dilated pupils; and a soft eye.
Usually, it is impossible to tell whether sudden ‘death‘ is caused by head injury or a state of shock from internal bleeding. It is wise to administer cardiopulmonary resuscitation (CPR) immediately upon suspicion of death (we had described this procedure before under the heading of Artificial respiration and heart massage).
Blood clots form on or within the brain as a result of bleeding from ruptured vessels. They are associated with a depressed level of consciousness. Coma may or may not be present. Blood clots cause localized pressure symptoms. Often one pupil is dilated and will not constrict down when a light is flashed in the eye. A paralysis or weakness may be present on one side of as the body. (The weak side usually is opposite the side of the blood clot).
An operation on the skull to relieve the blood clot can lead to a cure.
Treatment of head trauma
Consider that the dog also may have internal injuries with bleeding, shock, and unstable limb fractures. Treatment of these may take precedence over management of the head trauma. Handle an injured dog with great care and gentleness, Pain and fright deepen the level of shock in dogs. Wrap the dog in a blanket to keep him warm. This also helps to restrain a dog who is unconscious, but who may wake up. Avoid giving him water or anything by mouth. Transport him to the nearest veterinary clinic.
Much of the above text was taken from a dog owner’s veterinary handbook, authored by Drs Carlson and Giffin.
Please implement disease preventative measures (vaccinations, routine dewormings, monthly anti-heartworm medication, etc) and adopt-a-pet from the GSPCA’s Animal Clinic and Shelter at Robb Street and Orange Walk, if you have the wherewithal to care well for the animals. Do not stray your unwanted pets, take them to the GSPCA’s Clinic and Shelter instead. If you do not wish your pet to have puppies or kittens, you may exploit the GSPCA’s free spay and neutering programme. If you see anyone being cruel to an animal, or if you need any technical information, please get in touch with the Clinic and Shelter by calling 226-4237.
