Snakebite treatment often complicated, costly
Published: Wednesday, June 12, 2013 at 6:45 p.m.
Last Modified: Wednesday, June 12, 2013 at 6:45 p.m.
A week and a half after being bitten in the leg by an eastern diamondback rattlesnake, Ben Smith remains in the pediatric intensive care unit at UF Health Shands Hospital.
To date, the 11-year-old has received at least 75 to 80 vials of antivenin, his doctors say. He's stable but still has at least one more round of antivenin therapy to go before he can go home.
That's not unusual for a severe snakebite, said Dr. Torrey Baines, a pediatric critical care physician at Shands.
Diamondback rattlesnakes have the most toxic venom in North America, and a deep bite from a large snake, like Ben had, will typically keep a patient in the hospital for as long as two weeks, Baines said.
"Those certainly can cause a lot more trouble," he said. "(Ben's) gotten, clearly, a lot more venom than usual."
Ben was running through a wooded area in Newberry at a friend's birthday party when he felt a sharp pain, like a knife had cut his leg. When he looked down, he saw the diamondback rattlesnake.
Ben ran before the snake could strike again, and his friends and older sister scooped up the 65-pound boy and carried him to safety.
Venomous snakebites are treated with antivenin, a serum made from horse or sheep antibodies to snake venom, which is given to humans intravenously. The antivenin binds to the venom in the bloodstream, deactivates it and then is eliminated by the body.
For a healthy person who hasn't been bitten too deeply or by a highly venomous snake, Baines said, a typical dose might be four to six vials of antivenin immediately, followed by a smaller maintenance dose of about two vials several hours later.
But even with a more typical dose of antivenin, the cost of treatment packs as much punch as the bite itself.
CroFab, an antivenin manufactured by BTG International, is the only FDA-approved antivenin in the United States for bites from pit vipers, including rattlesnakes, copperheads and cottonmouths, also known as water moccasins.
"It is quite complicated to make," said BTG communications manager Ashley Tapp. The antibodies are created in sheep, which reduces the occurrence of allergic reactions in people who receive the drug.
BTG sells CroFab for as much as $2,700 per 1-gram vial, although Shands pharmacists say hospitals usually pay about 80 percent of that price.
But because of the costs of storing, preparing and administering the drug, Shands charges about $20,000 for one vial of CroFab.
That "typical" snakebite Baines described could put a patient back about $160,000 before insurance, which offers variable coverage.
At 80 vials, the cost of antivenin therapy is closer to $1.6 million. It's unclear what insurance Ben's family has or how much of the therapy it would cover.
Despite the staggering cost, that much antivenin is needed to purge venom from the body in severe cases.
Deeper bites from more toxic snakes often cause recurrence, meaning the venom leaches out of the muscle gradually until it reaches the bloodstream.
Since antivenin can't penetrate deeply into muscle tissue, doctors have to administer many rounds of the drug as the venom continues to seep.
Although the puncture wound from the fangs tends to heal without much complication, venom recurrence from a highly toxic snake such as the eastern diamondback can keep the blood from clotting normally for about two weeks.
That's where Ben is at now, Baines said.
Once Ben's blood clotting tests produce normal results, the hospital will keep him for another 24 to 48 hours for observation. Then he can go home.
"This is one of the worst ones I've seen" as far as recurrence of problems with blood clotting, Baines said. "Other than that, he's doing pretty well."
Although 80 vials of antivenin is a lot more than the average snakebite victim receives, it's not unheard of.
Between 7,000 and 8,000 people report being bitten by snakes in the United States each year, but fewer than 10 die. Before the development of antivenin, the mortality rate following snake bites was closer to 15-30 percent, Baines said.
Dr. Dawn Sollee, assistant director of the Florida/U.S. Virgin Islands Poison Information Center in Jacksonville, said antivenin dosing depends less on the size of the person and more on the amount and type of venom.
Of the six types of venomous snakes in Florida, the eastern diamondback is the most potent and has a higher incidence of recurrence.
But diamondback bites are fairly rare compared with bites from pygmy rattlesnakes, which are more aggressive than their cousins but far less potent.
A copperhead's venom is so weak it might not even require antivenin in a healthy person, although deaths following copperhead bites have been reported.
But if you're bitten by any snake, Sollee said, seek immediate medical attention. Prior illnesses or medical conditions contribute to the prognosis after a bite.
"That's a lot of different factors," she said.
Contact Erin Jester at 338-3166 or firstname.lastname@example.org.