It Started with a Cat Bite

This is the story of Massachusetts General Hospital case #31-2010: a 29-year-old woman whom I’ll call Melissa.

I’m telling Melissa’s story not for its common-sense lesson—avoid interactions with cats*—but because it shows that doctor detective-work happens outside of TV Land.

Melissa was a veterinary assistant at an animal hospital. One day, at work, a cat bit her right hand, in the meaty part where the thumb meets the palm. Bad kitty.

Following workplace protocol, Melissa took an antibiotic, amoxicillin, and moved on.

Five days later, she woke up with a red, hot and swollen palm, throbbing in pain. She rushed to her local hospital. These are typical symptoms of infection by microorganisms, such as Pasteurella multocida, that live inside of a cat’s mouth. So the doctors prescribed a different antibiotic, ampicillin-sulbactam, and sent her home.

Melissa returned that evening, now with unbearable pain and scary new symptoms: stiff wrist, chills, neck pain, swollen lymph nodes. The docs loaded her up with more drugs and sent her to the experts at Massachusetts General. There, she received her third dose of ampicillin-sulbactam, plus strong pain meds. The ache and swelling gradually subsided, and by morning, she was discharged.

Just six hours passed before she returned to the first hospital, this time with shaking chills, a 101.3-degree fever, headache and joint pain. She rode the ambulance, once again, to Massachusetts General.

By morning of day seven, she had body aches, stomach pain, pelvic pain, tingling and numbness in her back and legs. P. multocida doesn’t cause these systemic problems. So what was causing them?

After a battery of tests and body scans came up normal, Melissa’s doctors strongly suspected a second infection. In the four days after the bite, she had handled cats, barn cats, dogs, rabbits, guinea pigs, sheep and horses at work. She had cleaned out cages. At home, she had spent time with her partner, her infant, and her pets: cats, turtles, a dog and a frog. She had smoked two packs of cigarettes. Six months earlier, she had had a cesarean section.

But the doctors didn’t have time to play detective. Their patient had made three trips to the hospital in two days and was terrified. An infection of unknown origin had attacked multiple systems, was spreading rapidly, and could easily kill her. It would take days before laboratory tests could identify the bug. The only option was to hit it, fast and hard, with all of the weapons in our dwindling antibiotic arsenal.

Melissa’s doctors pumped her with a dual-dose of ampicillin-sulbactam and azithromycin. She got a bit better. Then they gave her deoxycycline, and later, levofloxacin. She continued to improve. Finally, 10 days after being bitten, Melissa was well enough to go home with a handful of prescriptions. She was happy and healthy at a check-up seven weeks later.

It was only then, by analyzing antibodies in her blood, that the doctors figured out what had caused Melissa’s second wave of sickness. The culprit? That first mean ‘ol cat!

The cat wasn’t mean so much as sick. It had wandered away from its home in the country for several days. It drank water wherever it could, chased birds, ate mice, and, at some point during all this frolicking, picked up the nasty bacteria Francisella tularensis (which can survive for months in mud or animal carcasses).

The cat somehow made it back home, weak with fever, eyes yellow. It died at the animal hospital—but not before biting Melissa. With that single puncture, she acquired both the common P. multocida, which caused the initial swelling in her hand, and the rarer F. tularensis, which wreaked widespread havoc throughout her body.

Case closed. You already know the moral of the story.

*I am not what you would call a ‘cat person’.

The case report and this cartoon image appear in today’s issue of The New England Journal of Medicine.

Hissing cat image courtesy of Hannibal Poenaru.

This post was originally published on The Last Word on Nothing