Human Bite

Diagnosis

"I done got bit."


Epidemiologic Risks

Human bites often occur when one damn fool drunk male thinks he is Clint Eastwood and punches another damn fool drunk male in the mouth. Then the damn fool drunk male passes out in a corner for 12 hours and wakes up with an infected hand.

"Clenched fist bite wounds have been estimated to penetrate the MCP joint in as many as 52-62% bites, result in tendon injuries in 20%, cartilage injuries in 6% and bone injuries in 17-58% (PubMed)."


Microbiology

Streptococci (especially milleri) + anaerobes + HACEK (Haemophilus species, Aggregatibacter species, Cardiobacterium species, Eikenella species, and Kingella species). gram-negative aerobic rods should not occur unless the dentition is really rasty: rotting black nubs of teeth.


Empiric Therapy

Ampicillin/clavulanate for prophylaxis of uninfected bites.

If allergic, who knows. I tend to suggest cephalexin PLUS metronidazole or a quinolone (other than ciprofloxacin) PLUS metronidazole. In place of metronidazole, doxycycline could be used.

If admitted for debridement and needs IV, I tend to suggest a third-generation cephalosporin PLUS metronidazole. Alternatives include a carbapenem OR penicillin/beta-lactamase inhibitors OR a quinolone PLUS metronidazole.


Pearls

Have a very low threshold for sending the patient to a hand surgeon. Infection in the tendon sheaths or the small joints of the fingers can rapidly lead to lots of destruction, disability, and lawsuits.

Do not forget vaccines (tetanus), Hepatitis B and HIV.

"Human saliva is known to contain as many as 50 species of bacteria with almost 108 microbes/ml (PubMed)." Do not think of this when kissing.


Rants

Dog and cat injuries tend to seek care sooner, which is probably why the bites are not as severe at presentation. A dog's mouth is not cleaner than a human, it does, after all, lick its butt.

Zombie bites? Nothing to do. You will become one yourself, feasting on brains, until a gunshot to the head.

Unless you follow the results of When zombies attack!: Mathematical modeling of an outbreak of zombie infection.

Last Update: 08/07/18.