The brain, through its connections with the spinal cord and peripheral nerves, coordinates all activities, thoughts, senses, feelings, emotions, movement, and body functions. If the brain is damaged, this can lead to behaviour changes, seizures, loss of coordination, paralysis, or coma.
Brain injuries are frequently caused by physical injuries, especially as a result of road traffic accidents; they can also result from poisoning with certain substances, such as snake venom and organophosphate insecticides. Injury to the brain can also be caused by meningitis – inflammation of the tissue around the brain – and encephalitis – inflammation of the brain itself. Causes of encephalitis include distemper and rabies – diseases that are preventable through routine inoculation ). Dogs with brain injuries behave and move differently; there may be seizure, stupor,with the cause of the injury. See a vet immediately after a road traffic accident, before signs of brain injury develop, for the best chance of successful treatment.
A coma may be caused by a physical injury, such as a concussion, or by heart failure, heatstroke, or very high fever. Kidney or liver failure, high or low blood sugar, lack of oxygen to the brain, and many infections and toxins can also result in coma. Initially, an affected dog appears confused, but this evolves through a state of stupor until consciousness is finally lost. The unconscious dog cannot be roused and is insensitive to pain. If your dog is in a coma, seek urgent veterinary attention.
Seizures or fits
A seizure may be stunningly dramatic or so subtle it is easily dismissed as a momentary loss of concentration.In general, seizures may involve loss of consciousness, accompanied by involuntary muscle contractions, dilation of the pupils, paddling with the limbs, trembling, and face twitching. During a seizure, dogs also frequently salivate, urinate, and defecate. Seizures can be mild, occur in clusters, or be prolonged, lasting more than five minutes. Some dogs have an inherited predisposition for seizures, but they can also be caused by a number of other conditions, including:
- Brain injury;
- Scar tissue on the brain;
- Brain tumour;
- Low blood calcium;
- Low blood sugar;
- Migrating intestinal worm larvae;
- Hydrocephalus – increased fluid in the brain;
- Post-distemper encephalitis;
Brain tumours are rare; they occur in only around 1 in 6,500 dogs. Clinical signs associated with this type of cancer include behaviour and temperament changes, seizures, circling, changes in movement and gait, blindness, and altered mental abilities, senses, and facial nerve control. With the increasing availability of brain scans, tumours are being diagnosed more frequently. As with other types of cancer , initial treatment for an affected dog is aimed at controlling clinical signs and improving a dog’s quality of life. This often includes the use of anticonvulsants and corticosteroids. The second objective of treatment is to prolong good quality life; this may involve radiation therapy, surgery, or a combination of both.