Carbon Monoxide Poisoning in Dogs and Cats

1 Symptoms

Sources such as leaking gas appliances, car exhaust, and industrial fumes release carbon monoxide. Mild poisoning brings nausea, vomiting, dulled senses, weakness, sleepiness, and a fast heart and breathing rate.

Moderate poisoning worsens these signs: greenish-yellow vomit, weak muscles, unsteady gait, small pupils, blurred vision, cherry-red skin and gums, a weak pulse, irregular heartbeat, low blood pressure, and rapid breathing with dry rattles in the lungs, followed by seizures, coma, and collapse.

Severe poisoning shows blue or pale gums, skin blisters, eye tremors, uneven pupils, loss of hearing and reflexes, frequent vomiting (sometimes coffee-colored or with blood), labored breathing, muscle-breakdown pigment in the urine, loss of bowel and bladder control, and death from respiratory and circulatory failure.

2 Causes and Transmission

Carbon monoxide is an odorless gas produced by the incomplete burning of fuels. Pets inhale it in poorly ventilated spaces, enclosed garages, or homes with faulty heating.

The gas binds to hemoglobin far more strongly than oxygen does, so the blood can no longer carry oxygen to the tissues — producing the oxygen-starvation signs above.

3 Diagnosis

A veterinarian suspects the condition from the environment and signs such as cherry-red mucous membranes, and confirms it by measuring carboxyhemoglobin in a blood sample.

Blood work, oxygen assessment, and evaluation of heart and lung function guide treatment.

4 Treatment

Immediately move the animal to fresh air; in the clinic, oxygen therapy is the main treatment to displace carbon monoxide from the blood.

Veterinary care may include fluids, medications to support breathing and the heart, control of brain swelling, correction of acid-base imbalance, and management of seizures. Severe cases need close monitoring in an intensive-care setting.

5 Prevention

Service gas heaters and appliances yearly, never run a car or generator in a closed space with pets, and ensure good ventilation.

Install carbon-monoxide detectors and keep pets out of garages and sheds where exhaust can build up.