Stupor and Coma in Dogs

Marginal Consciousness and Complete Unconsciousness in Dogs

When an animal is unconscious but can be aroused with very strong external stimulus, the term stupor is used to describe the condition. Whereas a patient that is in a coma will remain unconscious even if the same level of external stimulus is applied. Dogs of any age, breed, or gender are susceptible to stupor.

Symptoms and Types

The symptoms can be highly variable, depending on the primary disease that has led to the loss of consciousness.

The major symptom is varying levels of unconsciousness, with the degree of consciousness depending on the nature and severity of the underlying disease.

Causes

• Abnormally low blood glucose levels (hypoglycemia)
• Abnormally high blood glucose levels (hyperglycemia)
• Abnormally high levels of sodium in the blood (hypernatremia)
• Abnormally low levels of sodium in the blood (hyponatremia)
• Low blood pressure
• Kidney failure
• Primary brain disease
• Trauma, especially to the head and brain
• Infections (viral, bacterial, parasitic, fungal)
• Drugs which lead to loss of consciousness
• Unknown cause (idiopathic)
• Immune-mediated (immune system overreacts or attacks the body)
• Chemical or drug toxicity

Diagnosis

Both of these conditions are health emergencies and will require that you take your dog to a veterinarian immediately for treatment. You will need to give a thorough history of your dog’s health including a background history of symptoms and the time of onset. After taking a detailed history, your veterinarian will conduct a complete physical examination on your dog. Laboratory tests will include a complete blood count (CBC), biochemistry profile, and urinalysis. There are a number of diseases/conditions that can lead to these symptoms and laboratory tests will show any abnormalities that could be related to an underlying disease.

For example, in case of lead toxicity, abnormal red blood cells will usually appear in the complete blood count tests. In cases with infection and inflammation, an increased number of white blood cells, cells that multiply in response to infection and trauma, will be seen.

The biochemistry profile may indicate lower or higher than normal values of glucose in the blood, higher than normal levels of sodium in blood, and accumulation in the blood of nitrogenous waste products (urea), which are usually excreted out of the body through the urine.

The urinalysis may indicate high levels of glucose in the urine, a common sign in diabetes mellitus; abnormally high levels of proteins that are normally not present in the urine, such as with immune-mediated diseases; and abnormal crystals in the urine, such as what is seen in the presence of liver disease or ethylene glycol toxicity.

If the cause is not so readily apparent, more specific testing may be required to diagnose the underlying disease. Infections are one of the most important risk factors for developing stupor or coma, especially in case s of untreated infections. Your veterinarian will test for various infections that commonly affect dogs and that are known to cause serious symptoms like stupor or coma.

Bleeding inside the brain is also a possible cause of stupor or coma, and your veterinarian can order tests to measure the normal blood clotting mechanisms in your dog’s system. Besides laboratory analyses and tests, visual diagnostics can also be used to great advantage. X-rays of the abdomen and chest can be used to confirm if there is a diseased condition present in these areas, or whether there have been resultant changes in the organs. Similarly, head X-rays can be used to evaluate whether an unknown injury has occurred, whether there is fracture, inflammation or any other injury that might be affecting the brain’s ability to function normally.

Your doctor will need to determine which machine will give the clearest image of the head. In some cases, X-ray may not be enough, and a computed tomography (CT) scan or magnetic resonance imaging (MRI) will be needed to diagnose the presence of hemorrhage, fracture, mass, accumulation of fluid, or a penetrating foreign body in the skull and/or brain. An electrocardiogram (ECG) may also be used to evaluate cardiac functions as cardiac diseases and abnormalities can also lead to stupor or coma.