Hypothermia in Cats

Primary hypothermia is associated with prolonged exposure to low environmental temperatures. Secondary hypothermia is related to pre-existing underlying conditions which have impacted the body’s ability to generate heat normally. Both forms are life threatening, but secondary hypothermia usually indicates a serious underlying illness has progressed significantly and warrants prompt veterinary investigation.

Hypothermia is categorized into four stages of increasing severity.

Stage I : The first stage of hypothermia is characterized by a body temperature of 90 to 95 F° (32-35 C°).

Stage II : The second stage of hypothermia is characterized by a body temperature of 82 to 90 F° (28-35 C°).

Stage III : The third stage of hypothermia is characterized by a body temperature of 75 to 82 F° (24-28 C°).

Stage IV : The fourth and final stage of hypothermia occurs when body temperature drops below 75 F° (24 C°). A body temperature below 75 C° will rapidly lead to cardiac arrest and death.

Hypothermia is an uncommon but life-threatening clinical finding in cats. Secondary hypothermia can be caused by severe underlying conditions that can be lethal and must be treated as an emergency.

Immediate medical care is crucial as delayed treatment can be fatal.

Note: in suspected cases of hypothermia, it is important to warm the affected cat gradually. Sudden and extreme changes from cold to hot temperatures can lead to shock, which is life threatening.

Cats who live outdoors, as well as ill, geriatric, very young, and short-haired cats, are at higher risk of hypothermia. Animals living in cold and temperate climates are also at greater risk of primary hypothermia.

Primary hypothermia is caused by environmental exposure to cold temperatures.

Secondary hypothermia results from alteration in heat production due to a variety of underlying conditions, such as injury, certain medications, and illness.

Diagnosis of hypothermia in itself is straightforward, by taking a rectal temperature measurement. Diagnosis of the underlying condition causing secondary hypothermia generally involves further diagnostic testing. In some cases, further diagnostics are warranted in cases of exposure, to identify any issues resulting from hypothermia.

Diagnostics include:

• Physical examination
• Bloodwork
• Urinalysis
• Electrocardiogram
• Discussion of dietary history
• Diagnostic imaging, including X-rays or ultrasound

Mild primary hypothermia can be treated by slowly rewarming the animal using heat insulation and blankets. Note: Sudden and extreme changes from cold to hot temperatures can lead to shock, which is life threatening.

Moderate and severe cases of hypothermia need hospitalization to stabilize the condition. Supportive treatments include:

• IV fluid therapy
• Gradual warming: warming can be of three kinds: passive surface (e.g. blankets), active surface (e.g. heated blankets, heated water), and active core rewarming (e.g. warm water enemas, warm IV fluids). Heating must be gradual and should not exceed 33.8-35.6 F° (1-2 C°) per hour
• Blood pressure and cardiac monitoring
• Oxygen supplementation

Once the affected cat is stabilized, underlying causes of secondary hypothermia must be identified and treated.

Primary hypothermia generally carries a good prognosis when treated promptly, with most animals recovering completely. If treatment is delayed or the condition is left untreated, the animal's life is in severe danger due to organ damage.

In the case of secondary hypothermia, prognosis is more complex. Hypothermia is easily treated if medical attention is prompt, but general health outcomes depend on the underlying condition.

The outcome of both primary and secondary severe hypothermia depends on the extent of internal organ damage.

Hypothermia itself is not contagious. Secondary hypothermia can be caused by a number of underlying conditions, some of which may be contagious.

Preventive strategies include

• Keeping animals indoors during extremely cold weather
• Sick and geriatric cats are at greater risk and, as such, must be kept warm even in moderately cold weather
• Keeping up with vaccinations and regular veterinarian checkups is the best way to ensure general health and early identification of diseases associated with secondary hypothermia

Hypothermia is rare in cats

• Supportive care
• Gradual rewarming
• Treatment of underlying conditions