Brain Injury in Dogs

Dogs can incur brain injuries from a variety of causes, including severe hyperthermia or hypothermia and prolonged seizures. Primary brain injuries, for example, involve direct trauma to the brain, which once acquired, cannot be altered. Secondary brain injury, meanwhile, is the alteration of brain tissue that occurs after primary injury, but this form of injury can be managed, prevented, and improved with optimal supportive care and treatment.

Symptoms and Types

Being that it is a vital organ, the brain requires constant supply of oxygen and nutrition. Any deficiency of oxygen or direct trauma to the brain, therefore, may result in bleeding and fluid buildup, which can cause excessive pressure on the brain. This in turn can cause complications involving the heart, eye, and several other body systems. Symptoms vary and depend on the cause and severity of the brain injury. Some of the more common symptoms include:

• Seizures
• Spontaneous Loss of consciousness (syncope)
• Abnormal posture or irregular movements
• Ear or nose bleed
• Bleeding inside the eye (involving the retina)
• Bluish discoloration of the skin and mucous membranes (cyanosis); a sign that oxygen in the blood is dangerously diminished
• Insufficient oxygen reaching body tissues (hypoxia)
• Purplish or bluish patch under the mucous membranes) or under the skin due to ruptured blood vessels (ecchymosis)
• Red or purple spot on the body caused by a minor hemorrhage (petechiation)
• Heavy or rapid breathing (dyspnea or tachypnea, respectively)
• Abnormal heart functions, such as abnormally slow heart rate (bradycardia)

Causes

The following are some of the more common causes to brain injuries:

• Head trauma
• Severe hypothermia or hyperthermia
• Abnormally low of blood glucose (severe hypoglycemia)
• Prolonged seizures or shock
• High blood pressure
• Brain parasites
• Brain tumors
• Infections involving the nervous system
• Toxicity
• Immune-mediated diseases

Diagnosis

You will need to give a thorough history of your dog’s health to your veterinarian, including the onset and nature of the symptoms, and possible incidents that might have precipitated the unusual behaviors or complications. He or she will then perform a complete physical examination as well as a biochemistry profile, urinalysis, and complete blood count. Although the findings for these tests depend on the underlying cause of the brain injury, often the biochemistry profile may indicate abnormalities in the blood glucose level. Blood gases are also measured to confirm oxygen deficiency in the blood.

When fractures involving the skull are suspected, X-rays, CT (computed tomography) scans, and MRIs (magnetic resonance imaging) are extremely useful to evaluate the severity of the brain trauma. These diagnostic tools also help in determining the presence of bleeding, fractures, foreign bodies, tumor, and other abnormalities involving brain. The ECG (electrocardiogram), meanwhile, is used to evaluate heart functions and rhythm.

Your veterinarian may also collect cerebrospinal fluid sample to determine the level of inflammation and to confirm possible infections.

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retina

The layer of the eye that is charged with receiving and processing images

hypoxia

Less oxygen than normal in the blood

syncope

Fainting; the respiratory and circulatory systems are suspended for a time

trachea

The windpipe; it carries air from the bronchi to the mouth

urinalysis

An in-depth examination of the properties of urine; used to determine the presence or absence of illness

hypothermia

A body temperature that is too low

tachypnea

The term for a quick heartbeat

hyperthermia

High body temperature

dyspnea

Having a hard time breathing; breathing takes great pains

bradycardia

A particularly slow beating heart.

ecchymosis

A patch of bleeding beneath the skin; a bruise

electrocardiogram

A record of the activity of the myocardium

blood pressure

The amount of pressure applied by the blood on the arteries.

hemorrhage

Extreme loss of blood

hypoglycemia

Low amounts of glucose in the blood

Courtesy of petmd.com Original Article