Coma, Stupor and Decreased Consciousness in Dogs

Coma is the absence of alertness or consciousness. Comatose animals are unresponsive to noxious or painful stimuli. Decreased consciousness or stupor is diminished awareness or alertness. 

Coma and stupor are serious medical conditions that should be addressed immediately by a veterinarian. Persistent coma is also called persistent vegetative state. 

There are many causes of decreased consciousness. A partial list of the most common causes is listed below. The list is not inclusive and the causes are not presented in order of likelihood.

Head trauma (usually motor vehicle accidents)

Brain tumors

Encephalitis (brain infection)

Seizure activity 

Hydrocephalus

Hypoglycemia

Heart failure         

Kidney failure

Ketoacidosis (from diabetes) 

Drug intoxication

Toxic substances 

What to Watch For

Periods of unexplained, decreased or absent consciousness

Unresponsiveness to sounds or touch

Diagnosis

Coma and stupor can be serious, life-threatening medical problems that should be immediately investigated by your veterinarian. A medical history and physical exam can provide vital clues to the cause of the alteration in consciousness. 

Your veterinarian will want to know: 

When did the episode occur?

How long did it last?

Has a similar episode occurred?

Is there any potential for exposure to any medication or toxic substances?

Does your pet have a disease that could be contributing to the condition such as epilepsy, heart disease or diabetes?

Your veterinarian can assess your pet as to the level of consciousness. There are five levels of consciousness recognized in animals. 

Normal. Of course, there are many variations of normal between individuals.

Depressed, dull, quiet. These pets prefer to sleep and have responses to stimuli that are appropriate. Most ill animals are dull.

Disoriented, demented. This is similar to a dull animal but responses to stimuli are inappropriate. Pets may be hyperactive, hysterical or irritable.

Stuporous, obtunded. These pets do not respond to normal stimuli but will respond to strong, noxious stimuli such as a toe pinch. 

Comatose. These pets are unresponsive to all stimuli.

Your veterinarian will also likely test other functions of your pet's nervous system such as the pupillary light reflex, spinal reflexes and the oculo-cephalic reflex.

Diagnostic tests that may be recommended would include:

Complete blood count

Serum chemistry analysis

Urinalysis

X-rays of the head, chest, and abdomen

EKG

CT scan or MRI of the head

Spinal tap

Treatment

Treatment is aimed at stopping or reversing any cause of the decreased consciousness. Symptomatic treatment is primarily supportive and may include intravenous fluids, heart monitors and supplemental oxygen. If a cause for the altered consciousness, such as epilepsy, can be identified, specific treatment can be given.

Home Care

In the event of alterations in consciousness in your pet, lay them flat and protect them from injury. If trauma is suspected, be very careful in moving the animal. If possible, lay the pet on a board or use a tightly wrapped blanket to move your pet. If a poisoning is suspected, try to bring the container the toxic substance was in.