Reptile envenomations

Antidote Use in the Critically Ill Poisoned Patient

The proper use of antidotes in the intensive care setting when combined with appropriate general supportive care may reduce the morbidity and mortality associated with severe poisonings. The more commonly used antidotes that may be encountered in the intensive care unit ( N-acetylcysteine, ethanol, fomepizole, physostigmine, naloxone, flumazenil, sodium bicarbonate, octreotide, pyridoxine, cyanide antidote kit, pralidoxime, atropine, digoxin immune Fab, glucagon, calcium gluconate and chloride, deferoxamine, phytonadione, botulism antitoxin, methylene blue, and Crotaline snake antivenom) are reviewed. Proper indications for their use and knowledge of the possible adverse effects accompanying antidotal therapy will allow the physician to appropriately manage the severely poisoned patient.

Review of Eastern coral snake (Micrurus fulvius fulvius) exposures managed by the Florida Poison Information Center Network: 1998-2010

CONTEXT

Envenomation by the Eastern coral snake is rare but may be associated with significant morbidity. While effective, acquisition of North American Coral Snake Antivenin (NACSAV) is difficult because production was discontinued for many years.

OBJECTIVE

The purpose of this study is to characterize coral snake exposures in Florida and determine the effects of varying treatment paradigms on patient outcomes.

METHODS

This study is an observational case series of cases received at Florida poison centers. Included cases were Eastern coral snake exposures occurring between January 1, 1998 and October 31, 2010. Excluded cases included those found to be unrelated or those not followed for at least 24 h post envenomation. Case comments were reviewed to obtain data. Comparisons were made between asymptomatic patients receiving empiric antivenom therapy (empiric group) and those asymptomatic patients who received antivenom upon developing signs of systemic envenomation (withhold group).

RESULTS

Of the 553 cases identified, 387 were included in the final analysis. According to case comments, 56.3% of patients had no reported systemic symptoms. Most commonly, patients were reported to have pain (40.6%), paresthesias (28.4%), nausea (12.7%), and emesis (11.4%). NACSAV was administered to 252 patients (65%). Of those patients receiving NACSAV, 18.25% were reported to have had an adverse reaction. Patients in the withhold group (n = 106) had significantly fewer minor, moderate, and major outcomes than patients in the empiric group (n = 134, p < 0.01).

DISCUSSION

While patients in the withhold group had favorable outcomes compared with those in the empiric group, this strategy cannot be applied to all patients presenting asymptomatic to healthcare facilities due to study limitations.

CONCLUSION

Further studies are needed to determine what treatment strategy is most appropriate for asymptomatic patients presenting to healthcare facilities.

Role of surgical intervention in the management of crotaline snake envenomation

Crotaline venoms produce various toxic effects. Although these are most commonly treated with specific antivenoms, surgical management of snakebite has also been practiced for many years. Surgical approaches to pit viper envenomation include incision or excision of the bite site, fasciotomy, and digit dermotomy. The evidence regarding each of these procedures is sparse; however, incision or excision of the bite site are difficult to advocate. Fasciotomy and digit dermotomy may be appropriate in carefully selected patients.

Epidemiology and hospital course of rattlesnake envenomations cared for at a tertiary referral center in Central Arizona

OBJECTIVE

To describe the demographics and primary inpatient treatment of victims of rattle-snake bites (RSBs) referred to a teritiary referral poison treatment center in central Arizona, and to compare the frequency of local tissue complications and hematologic toxicity during hospitalization in children with those for adults.

METHODS

This was a chart review of patients diagnosed as having RSB by a toxicology service between July 1994 and April 2000. Data collected included: age, sex, date, bite location, time to and length of hospitalization, time to and amount of antivenin, serial hematologic studies, and inpatient complications.

RESULTS

Of 241 patients admitted, 236 charts met inclusion criteria. The majority of RSB victims were male (81%). Children (< or =13 years) represented 22%. Most RSBs (78%) occurred between April and September. Mean time (+/-SEM) to presentation was 1.7 +/- 0.2 hours. Antivenin was administered to 77% of patients, with an average (+/-SEM) of 28.5 +/- 0.9 vials administered. Hematologic abnormalities included: coagulopathy (60%), hypofibrinogenemia (49%), and thrombocytopenia (33%). No statistically significant difference in the above parameters was detected between upper- and lower-extremity envenomations, or between children and adults. Immediate antivenin reactions occurred in 36% of patients. Hemorrhagic bullae formation occurred in 22%, occurring most frequently in upper extremities. Operative procedures were required in 3.4% of patients. Hospitalization averaged 2.5 +/- 0.1 days. There was no fatality.

CONCLUSIONS

In Arizona, RSB victims were typically adult males with upper-extremity bites. Hematologic abnormalities were common. Local tissue complications were more common with upper-extremity envenomations. No statistically significant difference was detected in frequency of hematologic disorders or local tissue complications when children were compared with adults.

Severe toxicity from crotalid envenomation after early resolution of symptoms

Initial observation of a patient who sustained a rattlesnake bite on the hand showed resolution of mild swelling over 3 hours. The patient left the emergency department against medical advice, only to return 12 hours later with severe pain and swelling, as well as a marked coagulopathy. This case illustrates the need for an observation period after crotalid bite, even when the envenomation seems to be minor or when symptoms resolve.

Update on Antidotal Therapy

Antidotal therapy is useful for only a meager number of poisonous agents in which reversal of the effects of the toxin, or treatment of the toxin-induced pathophysiologic derangements, is possible. This review of selected antidotes is meant to acquaint the reader with some of the new and/or controversial uses for a few of our older agents, to introduce two new agents recently marketed, and to refresh information on antidotes not often used.

Apparent coral snake envenomation in a patient without visible fang marks

Envenomation by the North American coral snake is an uncommon entity in the United States. In most cases fang marks will be present, although they may be quite small and difficult to see. The case of a young man who demonstrated evidence of envenomation following the bite of a Texas coral snake (Micrurus fulvius tenere), despite the absence of any apparent fang marks on close examination, is reported. The problems associated with coral snake envenomation in terms of diagnosis and management are reviewed.

The legitimacy of rattlesnake bites in central Arizona

Previous authors have classified poisonous snake bites as being legitimate or illegitimate, depending on whether the victim was taking unnecessary risks with a snake before being bitten. We reviewed medical records of 86 consecutive rattlesnake bite victims cared for at a single medical center to determine legitimacy of snake bites. A bite was considered illegitimate if, before being bitten, the victim recognized an encounter with a snake but did not attempt to move away from the snake. A legitimate bite was said to have occurred if a person was bitten before an encounter with a snake was recognized or was bitten while attempting to move away from a snake. The study group was made up of 75 male (87.2%) and 11 female (12.8%) victims. Seventy-four percent were 18 to 50 years old, and 15% had been bitten previously. Only 43.4% of all bites were considered legitimate, and pet (captive) snakes accounted for almost one third of all illegitimate bites. The ingestion of alcoholic beverages was associated with 56.5% of illegitimate bites versus 16.7% of legitimate bites (P less than .001). While 74.4% of bites were to upper extremities, only 27% of upper extremity bites were legitimate. All bites to the lower extremity were legitimate (P less than .001). Of 14 individuals bitten by pet snakes, all were men and 64.3% were under the influence of alcohol at the time of the bite.(ABSTRACT TRUNCATED AT 250 WORDS)

Life-threatening airway obstruction from rattlesnake bite to the tongue

We describe the case of a 41-year-old man who suffered a bite to the tongue from the Western Diamondback rattlesnake (C atrox). Life-threatening obstruction of his upper airway secondary to massive edema of the tongue and other soft tissue structures quickly followed envenomation. Nasotracheal intubation, IV antivenin, and supportive care resulted in complete recovery with no permanent deficits. Rattlesnake bites to the tongue are rare and pose an unusual cause of airway obstruction.