Eastern massasauga rattlesnake envenomations in an urban wilderness

Transcription

1 Journal of Wilderness Medicine 5, (1994) CASE REPORT Eastern massasauga rattlesnake envenomations in an urban wilderness KIMBERLY SING, MD 1,2, TIMOTHY ERICKSON, MD 1,3*, STEVEN AKS, D0 1,4, HEIDI ROTHENBERG, MD5 and JACK LIPSCOMB, RPh l 1 The Toxikon Consortium: University of Illinois, Cook County Hospital, Rush-Presbyterian St. Luke's Medical Center, IL, USA 2MacNeal Hospital, Department ofemergency Medicine, Berwyn, IL, USA 3 University ofillinois at Chicago, Program in Emergency Medicine, IL, USA 4Mercy Hospital, Department ofemergency Medicine, Chicago, IL, USA 5Evanston Hospital, Department ofemergency Medicine, Chicago, IL, USA The eastern massasauga rattlesnake (Sistrurus catenatus), one of the few members of the Crotalidae family indigenous to the Great Lakes region, is considered to be more reclusive and docile than other types of rattlesnake. We report three cases of eastern massasauga rattlesnake envenomation within the Chicagoland area which required therapy with Crotalidae antivenin. Although bites are relatively uncommon, provoked snakes can inflict significant morbidity. Key words: massasauga rattlesnake, envenomation, antivenin Introduction Members of the genus Sistrurus in the US are divided into the pigmy rattlesnakes (Sistrurus miliarius) and the massasaugas (Sistrurus catenatus). The massasaugas are comprised ofthree subspecies: the desert (subspecies edwardsi) located in the southwest, the western (subspecies tergeminus) located in the middle midwest, and the eastern (subspecies catenatus). The latter is one of the few members of the Crotalidae family indigenous to the Great Lakes region (Fig. 1). This species of snake (Fig. 2) which has a slender tail, small rattles and average length of 24 in, can be distinguished from true rattlesnakes (Crotalus) by nine large plates arranged in rows across the crown of the head (Fig. 3). In contrast to Sistrurus, Crotalus species have small crown scales [1]. In body build, the eastern massasauga is similar to other small rattlesnakes, such as the twinspotted or ridge-nosed. Following rainstorms, with flooding of the marshland habitat, the eastern massasauga or swamp rattler will often seek higher ground, thereby increasing its chance for human encounter [2]. Although this snake will bite if cornered or provoked, it remains more reclusive and docile than other types of rattlesnakes [3], resulting in few reports of its behavior and potential hazard. We report three cases of eastern massasauga *To whom correspondence should be addressed at the University of Illinois at Chicago, Program in Emergency Medicine (M/C 724), Room 618 College of Medicine West, 1819 West Polk Street, Chicago, IL 60612, USA Chapman & Hall

2 78 Singet al. rr - I \ '-'-.-._.~. >,\. / I J I ~- -~ -7 7 \ ~ _...r I \ / \ I I 1, I \"'-J.~_l \ ".." \ " "f'~1 "f) mas~asiluqa Sl~lturus cal rj;hus rergemltlus Easl,n massasauqa S's rurus cal tlillus aretla us Fig-ure 1 us O'SlllllullQn 01 massasauga species Adapled I,om Russell FE. Snake Venom Poisoning. Groal Nec. NY Schollum In(elnatlonal. Inc p 63 Used Wllh permission, Fig. 1. US distribution of massasauga species. Adapted from Russell, F.E. Snake Venom Poisoning. Great Neck, NY, Scholium International, Inc., 1983, p. 63. Used with permission. Fig. 2. Example of eastern species of massasaugas (subspecies catenatus).

3 Eastern massasauga rattlesnake envenomations 79 Fig. 3. Head of eastern massasuga demonstrating large crown plates. rattlesnake envenomation within the Chicagoland area which required therapy with Crotalidae antivenin. Proper management of rattlesnake envenomations in general is also discussed. Case reports The following cases all occurred during the summer months in and around the greater Chicago area. Case 1 A 22-year-old male self-proclaimed amateur herpetologist walked into a community emergency department (ED) stating he had been bitten on his right hand by a 14 in eastern massasauga snake with three rattles and a 'button' at 15:00 hrs. He deliberately sought out the snake along the banks of a city river. The patient described tingling lips and crampy abdominal pain in the immediate post-bite period. About one half hour later, he noted lightheadedness and pain on swallowing. One hour later, his right hand began swelling and turned blue over an additional half hour. Two hours after envenomation, he complained of chills and vomited, just before arriving at the ED. No pre-hospital care was given. The patient had denied previous snake bites or treatment with antivenin. His initial vital signs and physical exam were normal with the exception of his right arm and hand. The web and dorsum of the right hand were swollen and ecchymotic. Four hours after being bitten, the swelling had extended halfway up his forearm and the ecchymosis had increased. Capillary refill, flexion and extension of the fingers and sensory function were intact. Gross hematuria was noted. Testing showed a progressive

4 80 Table 1. Coagulation Profile Singet al. Day] Day] Day 2 Day 2 17:30 22:30' 04:00" 12:30 Hgb (mg dl- l ) Het (%) Platelets (XlOOO) PT (see)t PTT (see)tt FSP (0-9) Fibrinogen ( ) Day 2 Day3 22:00 07: *30 min after five vials and two units FFP ** 4 h after ten vials, one unit FFP, ten units platelets and eight units cryoprecipitate Icontrol: s Ilcontrol: s coagulopathy (Table 1). A type and cross-match of blood was obtained. Compartment tissue pressures were not measured. Because of the clinical presentation (moderate to severe envenomation), antivenin was given. A skin test dose of antivenin was given with no reaction noted. The first five vials and two units of fresh frozen plasma (FFP) were infused by 7 h post-envenomation. The patient also received 400 mg cortisol sodium succinate intravenously. An additional five vials, (total of ten vials) of antivenin, one additional unit of FFP, ten units of platelets, and eight units of cryoprecipitate were given 2 h later. After the wound was cleansed with povidone-iodine and irrigated with normal saline, the patient received 1.5 g cefoxitin and anti-tetanus immunization. No surgical intervention was performed. By the following morning, the urine was clear and the forearm swelling noticeably reduced. There was no sign of infection, so antibiotics were discontinued on day 3 when the patient was discharged. He was prescribed methylprednisolone 40 mg BID for 7 days and did not develop signs or symptoms of serum sickness. ease 2 A 25-year-old white female turned over a log in a suburban vacant lot and suffered a bite to the volar aspect of her right wrist. The 2 ft long snake was later identified by a local expert as Sistrurus catenatus. No pre-hospital care was given. The patient denied any previous snakebite or treatment with antivenin. She had no other medical problems. She arrived at the ED within 1 h of envenomation. At that time, swelling extended to her upper arm. She did not complain of paresthesias or fasciculations. Her main complaints were pain in her arm and shortness of breath. Vital signs were blood pressure 112/60 mm Hg, pulse 90 beats per min, respirations 22 per min and temperature 98.7 OF. She appeared to be in mild respiratory distress, but was alert and awake. Her arm initially showed two fang marks on the volar aspect of her right wrist. Extensive edema developed after 1 h, which extended to one half of her upper arm. Sensation, flexion, extension and capillary refill were intact. Serum electrolytes were within normal limits. The coagulation profile was normal with

5 Eastern massasauga rattlesnake envenomations 81 hemoglobin 11.1 mg dl- I, hematocrit 31.8%, prothrombin time 12.5 s, partial thromboplastin time 23.0 s, fibrinogen 285 and fibrin split products negative. Urinalysis was normal. Compartment tissue pressures were not measured. Because of marked edema and rapid extension (mild to moderate envenomation), the patient was given a skin test dose of antivenin, which was negative. Within 2 h of envenomation, the patient began receiving a total of eight vials of antivenin. The wound was cleansed with povidone-iodine and irrigated with normal saline. The patient was given cefuroxime IV and a tetanus booster during her hospitalization. The wound was not surgically debrided. The patient was released 3 days post-envenomation. Ten days after antivenin administration, she developed signs and symptoms of serum sickness which resolved after a short course of methylprednisolone and antihistamines. Case 3 A male in his early twenties presented to a suburban ED stating he had a pet snake which had bitten him 1 h earlier on the right hand during a 'satanic ritual'. He had originally captured this snake, later identified by a herpetologist as Sistrurus catenatus, in the nearby forest preserve. The patient denied previous snakebite or antivenin therapy. No pre-hospital care was given. On presentation, all vital signs were stable. Two fang marks were noted on the right hand. Movement and sensation in the hand were intact. Over the next hour, the swelling in the hand extended proximally to the elbow. Mild ecchymosis was noted without blistering. All laboratory values, including coagulation studies, were within normal limits. After the patient had a negative reaction to a skin test dose of antivenin, he was initially given eight vials of antivenin within 2 h of envenomation. He developed no systemic symptoms. However, because swelling had not resolved, the physician chose to give an additional eight vials 6 h after the initial administration of antivenin. The patient was given a broad-spectrum antibiotic and tetanus prophylaxis after the wound was cleansed with povidone-iodine and irrigated with normal saline. The coagulation profile remained normal throughout the hospitalization. The patient was discharged on day 3 and developed serum sickness 1 week after antivenin administration. A short course of methylprednisolone was prescribed, but the patient was lost to follow-up. Discussion Statistics reported by the American Association of Poison Control Centers (AAPCq National Data Collection System reflect the high morbidity and low mortality associated with snake venom poisoning [3]. Many texts report an approximate annual incidence of 7000 to 8000 poisonous snakebites in the US with 9-14 deaths per year [1,3,4]. Most bites occur in March and October [4]. The case fatality rate from snake envenomation is quite small [5] and morbidity is usually due to deformities and amputations [6]. The 1991 annual report of the AAPCC noted that 1177 snake bites were due to poisonous snakes, 1905 were due to unknown snakes, and 1326 were due to nonpoisonous snakes; there were no fatalities reported [7]. In a large urban area, physicians do not expect to encounter a patient with a significant envenomation. However, exposures occur to people who venture into less developed areas, to pet owners with indigenous or exotic snakes, and to dealers and smugglers of exotic snakes [8,9]. Physicians in urban regions need to be aware of the treatment required, as well as of their available resources.

6 82 Sing et al. In the Chicagoland area, it is not commonly known that an indigenous species of pit viper exists. The eastern massasauga rattlesnake (Sistrurus catenatus) inhabits the Great Lakes region, and is found in the greater Chicago area [1]. It is light brown or gray in color, with mid-dorsal light-edged, dark, round or concave spots. Distinctive light stripes extend from the pit to the angle of the jaw on either side of the head. The juvenile massasauga has a paler ground color and a more distinct pattern; yellow on the tip of the tail with a 'button' rather than a rattle. This snake is found primarily in prairie marshes or fields with heavy grass cover, but is occasionally found in bogs and wooded areas, often under logs. It mainly inhabits the northern four-fifths of Illinois and the other Great Lakes states. It is rarely reported in the southern areas of Illinois [10]. The venom of S. catenatus reportedly has an LD so of 2.91 mg kg-iwhen given intravenously to mice. This toxicity is greater than that of copperheads (Agkistrodon contortrix, mg kg-i) or cottonmouths (A. piscivorus, 4.17 mg kg-i) [ll]. There are four other venomous snakes indigenous to this area, with territories that only minimally overlap. The timber rattler (Crotalus horridus horridus x. atricaudatus) is gray, light yellow or greenish white, with 26 black dorsal spots or angular rings and a tail that is usually black. It is found in southwest Illinois, Wisconsin and Indiana, and throughout the southern and eastern states. The preferred habitat of this reptile is in forested bluffs and rock outcrops, especially along the Mississippi River. It is often found in abandoned buildings, sawmills and brush piles. During the fall, the timber rattlers gather in den sites in rock bluffs. They are not aggressive, but when disturbed, will strike. Human deaths have been reported from the Illinois species [10]. The western cottonmouth or water moccasin (Agkistrodon piscivorus leucostomus) is red-brown with bands and a distal tail tip that is yellow in the young. It is darker brown with light flecked scales that border the bands in sub-adults, and dark olive dorsally with dark crossbands ventrally in adults. These snakes are more ill-tempered, inhabiting swamps. In the fall they migrate to bluffs to hibernate. They are rarely seen during the day. Cottonmouths are found in southern Illinois and the southeastern US [10]. The northern copperhead (Agistrodon contortrix mokeson) is light red-brown or yellowish brown with hourglass-shaped crossbands having dark margins, resembling the juvenile cottonmouth [10]. It has a large head and lacks a rattle [1]. The main territory of this reptile is in wooded hillsides or bluffs, especially in rocky terrain in southern Illinois along the Mississippi River bluffs. It is active during both day and night. It is occasionally seen in meadows during the summer but is found primarily in dilapidated abandoned buildings. Deaths have not been reported from this snake in Illinois. The northern copperhead is found in southern Illinois and in a distribution similar to the timber rattler throughout the south and eastern US [10]. The final species, Elaps fulvius, is the coral snake, which is extremely rare in the Great Lakes region [11]. This case series describes envenomations caused by S. catenatus in an adult population, all with symptoms which were severe enough to warrant treatment with crotalidae antivenin. These patients did not complain of paresthesias or fasciculations. They exhibited extensive upper extremity swelling and edema, with one patient developing a coagulopathy which is consistent with previous authors' experiences [2,12,13]. Similar to one of our cases, Hankin et al. [2] described a 3-year-old who developed marked swelling, tenderness and ecchymosis over the involved leg, combined with coagulopathy. Resolution occurred after administration of five ampules of crotalidae antivenin. Although the eastern massasauga was suspected, it was never positively

7 Eastern massasauga rattlesnake en venomations 83 identified. There were a total of 16 pediatric cases in this Michigan series, 13 requiring administration of intravenous antivenin (1-15 vials), with three children developing serum sickness. The authors did not comment on positive identification of the perpetrating snakes. They concluded that children bitten by the eastern massasauga rattlesnake appear to do well with antivenin and supportive care [2]. In 1971, Poticha described two cases of suspected envenomation by the massasauga rattlesnake. Both patients developed swelling of the involved extremity and only mild coagulation defects. Each received treatment that is no longer recommended (surgical incision of the bite to remove the venom and cryotherapy) and received minimal vials of antivenin. Both patients survived [13]. Case reports describe how untreated massasauga rattlesnake bites can lead to death from coagulopathy [11,14]. General treatment for snake envenomation has varied over the years. With the advancement of therapy, controversies still occur, although a greater consensus exists. At the basis of treatment are Findlay Russell's words of advice: 'If you do nothing, you will not do something wrong' [15]. In the pre-hospital setting, the patient should be kept quiet and calm, with the extremity placed in a splint to prevent excessive movement at or just below heart level [1]. If possible, identification of the snake should be attempted, but not with risk to any other persons. A herpetologist may be helpful in identifying the snake. Constriction bands have been a controversial pre-hospital issue. Theoretically, a band placed proximal to the bite would prevent the spread of the venom. Some concern has been raised at the possible surge of venom after the band is released. A pressure wrap dressing seems to be useful following envenomation from elapid Australian snakes [16]. In North American crotalid bites, it has not been recommended because of the massive edema associated with the bites and sudden elevation of pf0thrombin time and partial thromboplastin time after the removal of the pressure wrap dressing [17]. However, recent data in an animal model again raise questions. In a pharmacokinetic study utilizing radioactive labeled venom and a swine model, Burgess et al. [18] were able to show benefit from a constriction band after Crotalus atrox envenomation. A decrease in early plasma venom concentration was noted, and no difference was noted when the band was removed 4 h later. However, because of the marked swelling, the constriction bands had to be loosened to maintain the desired 45 mm Hg pressure to prevent a tourniquet-like effect and subsequent extremity damage. Recommendation for use in pre-hospital care would be limited to situations where the blood and tissue pressures can be closely monitored [18]. Although these results appear promising, further studies are necessary to define the use of constriction bands. Incision and suction has been recommended in the past. However, even in experienced hands, severe damage to tendons, fascia and muscle have been reported [19]. If incision is employed, it should be in a linear rather than cross-like fashion, and should penetrate only the skin [20]. Using the mouth as a suction device should be avoided since it has been shown to increase morbidity due to infection. Currently, a negative suction device may remove 27.5!!g of crotalid venom per ml of serosanguinous fluid during initial suction if used early, which drops to 4.4!!g ml- 1 by the end of five repeated suctionings [21]. The advantage of this system is that it does not require an incision, and therefore decreases the chances for infection [3]. No human clinical trial has yet been reported [3]. Once the patient reaches a medical facility, advanced life support measures should be implemented. Laboratory tests should include complete blood count with platelets,

8 84 Singet al. Table 2. Degrees of crotalid envenomation Vials o >20 Degree No envenomation: fang marks; no local or systemic reactions Mild: fang marks; local swelling and pain; no systemic reactions Moderate: fang marks, swelling beyond site; systemicsigns and symptoms (nausea, vomiting, paresthesias) and/or laboratory orthostatic changes, hemoconcentration and mild coagulation parameter changes Severe: fang marks with marked swelling, subcutaneous ecchymosis, severe symptoms and marked coagulopathy with increased CPK, proteinuria and hematuria Adapted from [3]. fibrinogen, fibrin split products, prothrombin time, partial thromboplastin time, electrolytes, BUN, creatinine, CPK and urinalysis. Blood for type and cross-match should be sent if envenomation is moderate or severe. The patient should be observed over time for extension of edema, ecchymosis and pain. Coagulation studies should be monitored for any developing abnormalities. The severity of envenomation should be determined (Table 2) [3] and the need for antivenin assessed. Antivenin should be given to patients with moderate to severe envenomation, or to patients who have progressive deterioration or extension of signs and symptoms. A skin test prior to antivenin administration is still often recommended. Patients with a positive skin reaction should receive antivenin under close monitoring for anaphylaxis. Antivenin has been given to patients with positive skin tests who do not develop a hypersensitivity reaction, and conversely, hypersensitivity reactions have occurred despite a negative skin test [22,23]. One must therefore interpret the skin test cautiously. Antivenin is most efficacious if given within 4 h of a bite, is of less value if delayed for 8 h and is of questionable value after 24 h [12]. In animal studies, Russell et al. [24] and Dart et af. [25] showed decreased tissue damage if antivenin was given within h after envenomation. The exact time when antivenin is no longer useful remains to be determined [25]. Some authors advise only supportive therapy rather than administration of antivenin. However, these studies involved mainly copperhead envenomations [26]. Other methods for therapy of snake envenomations are also highly controversial. The use of electric shock treatment was introduced in the US with a letter from Ecuador [27]. Recent case reports and animal studies have not documented any improvement with this treatment, and at this time electric shock cannot be recommended [28-30]. Cryotherapy was reported to cause inactivation of venom. Controlled animal studies show that cooling a limb does not increase survival but causes necrosis, increasing the need for subsequent amputation [31]. Because an extremity can develop marked edema, fasciotomies have been used as a method of treatment. Recent literature reports superior muscle preservation with the use of antivenin alone rather than fasciotomy alone or in conjunction with antivenin [32]. If fasciotomy is considered, checking compartment pressures prior to treatment is highly recommended.

9 Eastern massasauga rattlesnake envenomations 85 The use of blood products such as FFP, packed red blood cells, platelets and/or cryoprecipitate should be reserved for the specific coagulopathy encountered and should only be entertained when active bleeding is noted. Antivenin is the first treatment of choice for coagulopathy, and is often the only treatment required in patients with mild coagulopathy and bleeding [33]. Thrombocytopenia has been shown to be refractory to replacement therapy and may last for several days. Administration of antivenin causes a rapid sustained rise in platelet count [34]. Antibiotics should be considered for high-risk wounds (e.g. severe envenomations, prior treatment with incision and suction by human mouth, bites on the hand or the foot) [1]. A recent study on non-venomous bites in Massachusetts indicates that antibiotics may not be necessary [35]. Complications of antivenin therapy include anaphylaxis and serum sickness. Anaphylaxis seems to be caused by the numerous nonspecific horse proteins within the equine-based antivenins. Affinity chromatography has shown promise in elimination of these proteins and maintaining the efficacy of the new antivenin [36]. Serum sickness is a flu-like syndrome with fever, malaise, arthralgia, lymphadenopathy, erythematous rash, pruritus and urticaria which usually develops 1-20 days after administration of antivenin. Development of serum sickness correlates with the amount of antivenin given (> 6-10 vials) rather than with negative skin testing. In this case series, the two patients who received 8 and 16 vials of antivenin developed serum sickness within 2 weeks. Serum sickness is effectively treated with antihistamines and/or a short course of steroids [37], and is typically self-limited. Conclusions Envenomation due to poisonous snakes occurs in urban as well as rural areas. Physicians should be aware of the basic management of these emergencies, and the indications for administration of antivenin. If a patient presents following a snake bit suffered in the wild within the Great Lakes region, envenomation from the eastern massasauga rattlesnake should be considered. These snakes can inflict significant morbidity responsive to supportive care and Crotalidae antivenin administration. Because Sistrurus catenatus is an indigenous pit viper in the Chicago area as well as the surrounding Great Lakes region, the public as well as the medical profession should be educated to the dangers of this poisonous snake. Acknowledgements The authors would like to thank Dr R. Pawley (Head Curator Reptile House) and T. Orsay of the Brookfield Zoo, Chicago, Illinois, for their invaluable assistance and consultations regarding poisonous snakes and to J. Lava, MD, of Holy Family Hospital, Des Plaines, Illinois. Figures 2 and 3 photographed by Michael Greer, CZS, Brookfield Zoo, Brookfield, IL. References 1. Ellenhom, M.J. and Barceloux, D.G. Medical Toxicology; Diagnosis and Treatment ofhuman Poisoning. Amsterdam: Elsevier Science Publishing Co., 1988.

10 86 Singet al. 2. Hankin, F.M., Smith, M.D., Penner, J.A and Louis, D.S. Eastern massasauga rattlesnake bites. J Pediatr Orthop 1987; 7(2): Sullivan, J.B. and Wingert, W.A Reptile bites. In: Auerbach, P.S. and Geehr, E.c., eds. Managementof Wilderness and Environmental Emergencies, 2nd ed. St. Louis, Missouri: C.V. Mosby Co., 1989: Dart, RC. Snake bite. In: Rakel, RE., ed. Current Therapy. Philadelphia: W.B. Saunders, 1993: Parrish, H.M. Analysis of 450 fatalities from venomous animals in the United States. Am J Med Sci 1963; 245: Christopher, D.G. and Rodning, C. Crotalidae envenomation. South Med J 1986; 79: Litovitz, T.L., Holm, K.c., Bailey, K.M. and Schmitz, B.F Annual report of the American Association of Poison Control Centers National Data Collection System. Ann Emerg Med 1992; 10(5): Brown, R, Brasch, L., Leichter, D. and Canfield, D. Gaboon viper envenomation: an unexpected big-city emergency. Pediatr Emerg Care 1989; 5(4): Stueven, H., Aprahamian, C., Thompson, B., Horwitz, L. and Darin, J. Cobra envenomation: an uncommon emergency. Ann Emerg Med 1983; 12(10): Smith, P.W. Amphibians and Reptiles of Illinois. Illinois Natural History Survey Bulletin. 28, article 1. Springfield, Illinois: Department of Energy and Natural Resources, Natural History Survey Division, Lyon, M.W. and Bishop, C.A Bite of the Prairie Rattlesnake, Sistrurus Catenatus RAF. Proc Indiana A cad Sci 1936; 45: Russell, F.E.Snake Venom Poisoning. Great Neck: Scholium International, Inc., Poticha, S.M. Massasauga rattlesnake bite in the Chicago area. Illinois Med J 1971; 140(2): Jaffe, F.A A fatal case of snake bite. Can MedAssoc J 1957; 76: Wingert, W.A First aid for pit viper bites. J Wild Med (Letter) 1992,8(3): Sutherland, S.K., Coulter, AR and Harris, RD. Rationalization of first-aid measures for elapid snakebite. Lancet 1979; 1: Sutherland, S.K. and Coulter, AR Early management of bites by the eastern diamondback rattlesnake (Crotalus adamenteus): studies in monkeys (Macaca faxciularis). Am J Trop Med Hyg 1981; 30(2): Burgess, J.L., Dart, RC., Egen, N.B. and Mayersohn, M. Effects of constriction bands on rattlesnake venom absorption: a pharmacokinectic study. Ann Emerg Med 1992; 21(19): Glass, T.G. Early debridement in pit viper bites. JAMA 1976; 235: Nelson, B.K. Snake envenomation: incidence, clinical presentation and management. Med Toxico11989; 4: Bronstein, A.C., Russell, F.E. and Sullivan, J.B. Negative pressure suction in field treatment of rattlesnake bite victims. Vet Human Toxicol1986; 28(5): Jurkovich, G.J., Luterman, A, McCullar, K., Ramenofsky, M.L. and Curreri, P.W. Complications of Crotalidae antivenin therapy. J Trauma 1988; 28(7): Otten, EJ. and McKimm, D. Venomous snakebite in a patient allergic to horse serum. Ann Emerg Med 1983; 12(10): Russell, F.E., Ruzic, N. and Gonzolez, H. Effectiveness of antivenin (Crotalidae) polyvalent following injection of crotalus venom. Toxicon 1973; 11: Dart, RC, Goldner, AP. and Lindsey, D. Efficacy of delayed administration of Crotalid antivenin and crystalloid fluids. Toxicon 1988; 26(12): Burch, J.M., Agarwal, R, Mattox, K.L., Feliciano, D.V. and Jordan, G.L. Treatment of Crotalid envenomation without antivenin. J Trauma 1988; 28(1): Guderian, RH, Mackenzie, C.D and Williams, J.F. High voltage shock treatment for snake bite. Lancet 1986; 2: 229.

11 Eastern massasauga rattlesnake en venomations Dart, RC. and Gustafson, RA Failure of shock treatment for rattlesnake envenomation. Ann Emerg Med 1991; 29(6): Howe, N.R and Meisenheimer, J.L. Electric shock does not save snakebitten rats. Ann Emerg Med 1988; 17(3): Johnson, E.K., Kardong, K. and Mackessy, S.P. Electrical shocks are ineffective in treatment of lethal effects of rattlesnake envenomation in mice. Toxicon 1987; 25: Stewart, M., Greenland, S. and Hoffman, R First-aid treatment of poisonous snake bite. Ann EmergMed1981; 10: Stewart, RM., Page, C.P., Schwesinger, W.H., McCarter, R, Martinez, J. and Aust, J.B. Antivenin and fasciotomy/debridement for the treatment of the severe rattlesnake bite. Am J Surg 1989; 158: Burgess, J.L. and Dart, RC. Snake venom coagulopathy: use and abuse of blood products in the treatment of pit viper envenomation. Ann Emerg Med 1991; 20(7): Riffer, E., Curry, S.c. and Gerkin, R Successful treatment with antivenin of marked thrombocytopenia without significant coagulopathy following rattlesnake bite. Ann Emerg Med 1987; 16(11): Weed, H.G. Nonvenomous snakebite in Massachusetts: prophylactic antibiotics are unnecessary. Ann Emerg Med 1993; 22(2): Russell, F.E., Sullivan, J.B., Egen, N.B., Jeter, W.S. Markland, F.S., Wingert, W.A and Bar Or, D. Preparation of a new antivenin by affinity chromatography. Am J Trop Med Hyg 1985; 34(1): Jurkovich, G.J., Luterman, A, McCullar, K., Ramenofsky, M.L. and Curreri, P.W. Complications of Crotalidae antivenin therapy. J Trauma 1988; 28(7):