Cats are cuddly, adorable little things but sometimes they get overly playful, even outright angry, biting you when you least expect. The bites may seem deceptively minor because they are often tiny puncture wounds. As a result, most people don’t access medical care in a timely fashion after a cat bite. These wounds tend to be contaminated with multiple strains of bacteria and get infected more often than not, up to 80% of the time. A few factors make cat bite wounds particularly prone to infection.
For one, a cat’s mouth, like the mouths of all mammals, is colonized by a mix of germs, living together in harmony without causing infection to the cat. One bacterium in the mix that stands out is Pasteurella species. Three quarters of wound infections from cat bites culture positive for Pasteurella.
Another special feature of cat bite wounds which makes them more prone to infection is the fact that they are usually deep. This is because cats have sharp, thin teeth. Because the wounds are small punctures they look deceptively minor but often extend to deep structures. Bacteria from the cat’s mouth therefore get carried into the deep tissues. Additionally, bacteria present on the surface of the skin of the person who is bitten, also gets pushed down deep into the bite wound. It is difficult to throughly clean these small, deep wounds so the bacteria introduced into the deep tissues remain and soon start “brewing” into an infection.
Probably the most complicating feature of cat bite wounds is that they most often involve the hand. The problem with the hand is that it has many ‘compartments’ so to speak. There are separate tendons to move all 5 fingers and these tendons are all encased in their own protective sheaths. Then, there are 14 joints of the hand (excluding those of the wrist), each within their own capsule. Penetration of the cat’s sharp teeth through tendons and joints of the hand, results in the introduction of bacteria into these spaces. Because tendons and joints don’t have the most abundant blood supply, bacteria is able to remain relatively unbothered and tendonitis and septic arthritis may occur. A cat bite may also breach one of the bones in the hand causing bone infection or osteomyelitis.
Cat bite wound infections usually occur within 24 hours of the bite. Pain at the site starts within a few hours, followed by increasing swelling, redness and throbbing. As the infection progresses, redness can streak beyond the bite wound, usually up the forearm for bites on the hand.
The reason for the excess pain, often more severe than the appearance of the wound would suggest, is because the infection is usually in an enclosed space. Tendons are enclosed within sheaths, and joints are enclosed within capsules. When inflammation and infection progress in these enclosed spaces, there is not much room for swelling to expand and so the tissues become squeezed in the enclosed/fixed spaces, causing severe pain. If not treated quickly tissues can become starved for blood and end up being destroyed, resulting in scarring and dysfunction of affected areas.
Because the hand is such a vital part of the body, hand infections are usually surgical emergencies. To avoid destruction of the tendons and joints, emergency surgery often has to be done, to relieve the pressure and clean out the infection.
It is advisable to seek medical attention for all cat bite wounds, within a day at most, that is, before they become infected. An antibiotic should be prescribed to prevent infection and should be started as soon as possible, preferably within 8 hours of the bite. In the meantime, the wound is kept clean and covered until it heals.