Fever, or pyrexia, is an increased body temperature, surpassing 102.5 °F (39.2 °C) in cats.
- The rise in temperature occurs when the body adjusts its internal temperature set point as a physiological response to illness or injury
- A fever is most commonly the result of the body’s natural defense mechanism after viral or bacterial infections
- While body temperatures in excess of 103F° (39.4 °C) warrant veterinary attention if the fever persists for more than 24 hours, a temperature surpassing 105F° (41 °C), is an emergency as it poses a serious risk of damage to tissues and vital organs
- Taking a cat's temperature may not be easy for inexperienced pet owners and a trip to the veterinarian may be the safest way of knowing with certainty if the cat has a fever
- Veterinary attention is recommended to determine the root cause of a fever
- Treatment and prognosis vary in accordance with the underlying cause of the fever
A closer look: Fever in Cats
Fever is not necessarily a concern in and of itself. In some cases, such as specific types of infections, it may be advantageous to let the fever run its course. In these cases, it is wise not to suppress the fever
If a cat exhibits a fever of 103F° (39.4 °C) for more than 24 hours, veterinary attention is advised. Higher fevers warrant more urgent veterinary care. Fevers over 104.5 °F (40 °C) are an emergency.
Fevers are often accompanied by other symptoms that may also indicate an emergency, including labored breathing (dyspnea), collapse, and seizures.
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Possible causes
Fever is generally associated with many different feline conditions, disorders, and syndromes.
Risk factors
Outdoor cats are more likely to contract a virus or infection associated with fever.
Fever varies greatly in severity depending on the underlying condition causing the increased body temperature. Some fevers are beneficial. Mild fever: Cats with a mild fever (103°F (39.4 °C)) may exhibit lethargy and lack of appetite. Temperatures lower than 103 °F (39.4 °C) are not expected to cause permanent damage. Moderate fever: Body temperatures ranging from 103 °F (39.4 °C) - 104.5 °F (40 °C) put a cat’s tissues at risk of damage. Fevers in this range typically indicate more serious underlying causes that warrant urgent veterinary attention. **High fevers over 104.5 °F (40 °C) are an emergency. Fevers over 106 °F (41 °C) are life-threatening. ** Never give human medication to a cat in an attempt to diminish a fever, as many human medications such as paracetamol are very toxic to cats.
Testing and diagnosis
The initial diagnosis is carried out by taking the cat's temperature. The most accurate method is by way of a digital rectal thermometer. If a veterinarian confirms that a fever is present, the following diagnostics are typically performed:
- Physical examination
- Blood work
- Urinalysis
- Diagnostic imaging
If the cause of the fever can not be ascertained and the fever persists, the cat is categorized as having fever of unknown origin (FUO).
Treatment varies widely depending on the root cause. Symptomatic treatment often involves fluid administration (IV or subcutaneous), anti-inflammatories, and/or antibiotics.
In the case of lower fevers, treatment does not usually include efforts to lower the cat’s body temperature because the fever may help the cat fight off the infection.
Bite wound abscesses may require minor surgery for lancing and flushing.
Similar symptoms
Hyperthermia caused by heat exhaustion or heat stroke may be mistaken for fever. Note: heat exhaustion can rapidly develop into heat stroke, which is life threatening. Always take steps to reduce symptoms of heat exhaustion as soon as they appear.
Associated symptoms
A cat suffering from fever may present several additional symptoms.