Boa Constrictor Bite to the Eye

Ocular injury to the eye from snake bite is extremely rare with few cases being reported in the literature. We report the case of man who sustained a penetrating injury to the eye from a snake bite.

An 18-year-old man was bathing his pet snake, a 6-ft-long North Brazilian boa constrictor (Boa constrictor), when it attacked him and bit him on the right eye. The snake had infectious stomatitis, a bacterial infection in the mouth. When the snake struck, the patient partially blocked the attack with his right hand; however, the snake was able to engage the patient's right eye with its lower teeth, and his hand with its upper teeth. It would not release its bite and tried to wrap around the patient's neck. The patient managed to telephone a neighbor, who dialed 911, and the police arrived. The policeman who answered the call, however, was ophidiophobic (fear of snakes) and was unable to lend assistance. The fire department arrived shortly thereafter, and a fireman, using a large knife, cut the snake's head from its body. The multiple small recurved teeth could not be disengaged, so the patient was transferred to a nearby emergency department with the snake's head attached to his eye. The attending physician removed the snake's head from the patient, and diagnosed a ruptured globe. Photographs were obtained before the snake's head was removed (Figure 1). After receiving 1 g of the ampicillin and sylbactam sodium combination drug (Unasyn) intravenously, the patient was transferred to our institution with a shield over his right eye while awaiting definitive treatment. The head of the snake was sent in a specimen bag (Figure 2).

When the patient arrived, he was in minimal discomfort. His eyelids were mildly swollen on the right side. There was a puncture wound in the right upper eyelid. Visual acuity was 20/50 OD. Three small puncture wounds were noted in the cornea; 2 were Seidel positive. A small conjunctival puncture wound was also noted in the inferonasal quadrant. The anterior chamber was deep and fibrin was adherent to the internal surface of the wound. The retina and vitreous humor appeared normal. Initial management consisted of a bandage contact lens and topical and intravenous antibiotics; ofloxacin was applied topically every hour, and standard doses of intravenous vancomycin hydrochloride, ceftazidime, and clindamycin were given. The next day, the chamber had shallowed, and 1 wound remained Seidel positive. Glue was applied, but over the next 48 hours the wound failed to seal, so the patient was taken to the operating room where 2 No. 11-0 nylon sutures were sewn in place. The patient was discharged from the hospital after receiving a 72-hour course of prophylactic antibiotics with no signs of infection. Three months postoperatively, the patient's best-corrected visual acuity is 20/25 OD (Figure 3).

On arrival at the hospital, cultures were made from the teeth of the snake, and numerous species of gram-negative rods were identified. No further attempt to classify the bacteria was made, as the patient did not develop an infection.

In the United States, approximately 50000 people per year are bitten by snakes, most of which are nonvenomous.¹ We reviewed MEDLINE from 1966 to the present and found only 2 cases of snakebites to the eye.^2,3 Both patients were bitten by venomous snakes and both were children. One patient eventually required enucleation and the other recovered. The patient who recovered was bitten on the medial canthus and did not suffer a penetrating ocular injury.

Infectious stomatitis is a relatively common infection in captive snakes.⁴ This disease is known to occur when snakes are stressed environmentally by poor husbandry. The most common predisposing cause is not providing the snake its preferred optimal temperature zone, which decreases the effectiveness of the animal's immune system and allows opportunistic pathogens to cause disease. Gram-negative organisms such as Pseudomonas, Salmonella, Klebsiella, and Peromonas species are frequently implicated. A culture made from the boa constrictor's mouth from this case yielded multiple organisms consistent with bacterial stomatitis.

Most snakebites probably do not need prophylactic antibiotics. In studies on snakebites, fewer than 5% of patients had resultant infections.¹ Nevertheless, we treated our patient with a 72-hour course of prophylactic antibiotics that was initiated almost immediately. The concern for infection in this case was considerable, because the snake had bacterial stomatitis, the patient's cornea was punctured, and endophthalmitis is potentially devastating to vision. We believe that prophylactic antibiotics may be indicated for snakebites when the development of an infection would have very serious consequences, such as with a bite to the eye.

Reprints: Michael J. Taravella, MD, University of Colorado School of Medicine, 4200 E Ninth Ave, Campus Box B-204, Denver, CO 80262.