Fatal intracranial haematomas in two patients with Brown snake envenomation

The Effect of Adjunctive Fresh Frozen Plasma Administration on Coagulation Parameters and Survival in a Canine Model of Antivenom-treated Brown Snake Envenoming

This study aimed to assess the effects of dugite envenoming on blood coagulation and platelet count in a canine model, and the efficacy of fresh frozen plasma (FFP) in reversing the clotting disorder after both adequate and inadequate venom neutralization. Following initial dosing and administration studies, an intravenous venom dose of 1μg/kg was administered to eleven dogs. This was followed 30 minutes later by antivenom in either adequate or inadequate doses. A further 30 minutes later, the animals were given either two units of their own FFP or saline. Fibrinogen, aPTT and platelet levels were monitored for eight hours.

Of the six study dogs given antivenom plus FFP, two died at around 60 to 90 minutes post envenoming, at the end of the FFP infusions, and all but one of the survivors had persistent afibrinogenaemia. Of the five study dogs given antivenom and no FFP, all but one had return of detectable fibrinogen at eight hours after envenoming. The platelet count fell in all animals with recovery independent of antivenom dose, administration of FFP, or regeneration of fibrinogen. Post mortem examinations of dogs that died during dosage and administration studies showed massive intracardiac clots.

We conclude that early death from Brown Snake envenoming may be due to massive intravascular clotting. FFP administration was associated with persistent afibrinogenaemia regardless of antivenom dose. In the absence of any evidence for its efficacy, this study suggests that the role of FFP after Brown Snake envenoming should be reconsidered.

Hemorrhagic stroke in children caused by Bothrops marajoensis envenoming: a case report

According to the World Health Organization, snakebites are considered neglected diseases. Bothrops, the genus most frequently implicated in envenomations in Brazil, includes the species B. marajoensis Hoge, 1966, part of the complex B. atrox, which is found in the savannas of Marajó Island, Pará state, Brazil, a region that presents scarce epidemiological data. This work reports the first case of hemorrhagic stroke in a child, attributed to delayed medical care after snakebite envenoming by Bothrops marajoensis in Anajás city, Marajó Island, Pará, Brazil, which led to permanent hemiplegia as a sequela.

Intracranial haemorrhages associated with venom induced consumption coagulopathy in Australian snakebites (ASP-21)

Intracranial haemorrhage (ICH) is a rare life-threatening consequence of venom induced consumption coagulopathy in snake-bite. It is unclear why certain patients haemorrhage. We aimed to investigate ICH in snake envenoming. Cases of venom-induced consumption coagulopathy from July 2005-June 2014 were identified from the Australian Snakebite Project, a prospective multicentre cohort of snake-bites. Cases with venom-induced consumption coagulopathy were extracted with data on the snake-bite, clinical effects, laboratory investigations, treatment and outcomes. 552 cases had venom-induced consumption coagulopathy; median age, 40 y (2-87 y), 417 (76%) males, 253 (46%) from brown snakes and 17 died (3%). There were 6/552 (1%) cases of ICH; median age, 71 y (59-80 y), three males and five from brown snakes. All received antivenom and five died. All six had a history of hypertension. Time to onset of clinical effects consistent with ICH was 8-12 h in four cases, and within 3 h in two. Difficult to manage hypertension and vomiting were common. One patient had a normal cerebral CT on presentation and after the onset of focal neurological effects a repeat CT showed an ICH. ICH is rare in snake-bite with only 1% of patients with coagulopathy developing one. Older age and hypertension were associated with ICH.

Antivenom use, premedication and early adverse reactions in the management of snake bites in rural Papua New Guinea

OBJECTIVE

To examine antivenom use, premedication, early adverse reactions and patient outcomes after snake bite in rural Papua New Guinea.

DESIGN

Retrospective chart analysis of all admissions for snake bite with documented antivenom use at 11 rural health facilities from January 1994 to June 2004. No formal protocol was followed and there was no attempt at randomisation or blinding of prophylaxis.

RESULTS

Antivenom use was documented in 136/1881 (7.2%) snake bite admissions and most (121/136: 88.9%) received a single vial. CSL Polyvalent antivenom was administered to 112/136 (82.4%). One hundred and eleven patients (81.6%) happened to have been given premedication with adrenaline and/or promethazine and/or hydrocortisone. Early adverse reactions were reported in 25 patients (18.4%) including 23 treated with polyvalent antivenom. Intravenous test doses of antivenom were given to 32 patients, none of whom had a positive test result. Subsequent adverse reactions occurred in 9 of these 32 (28.1%) patients. One death may have been attributable to anaphylaxis after polyvalent antivenom. Reaction rates were significantly (p < or = 0.005) lower in adrenaline premedicated patients (7.7%) compared to patients premedicated without adrenaline (28.3%) and unpremedicated patients (28.0%). Adrenaline premedication caused no detectable changes in vital signs. The case fatality rate was 9.6% (13/136 patients).

CONCLUSIONS

Polyvalent antivenom is the main treatment for envenomation in rural health centres, and early adverse reactions are common. Adrenaline premedication appears to significantly reduce acute adverse reaction rates. Premedication with promethazine and/or hydrocortisone without adrenaline did not reduce early adverse reactions.

Snake venoms and coagulopathy

Snakebite affects around 2.5 million humans annually, with greater than 100,000 deaths. Coagulopathy is a significant cause of both morbidity and mortality in these patients, either directly, or indirectly. This paper reviews clinical aspects of snakebite coagulopathy, including types of coagulopathy (procoagulant, fibrinogen clotting, fibrinolytic, platelet-active, anticoagulant, thrombotic, haemorrhagic), diagnosis and treatment. Examples of clinical laboratory findings in selected types of snakebite coagulopathy are presented. Where available, antivenom is the most effective treatment, while standard treatments for other forms of coagulopathy, such as factor replacement therapy and heparin, are either ineffective or dangerous in snakebite coagulopathy, except in specific situations.

Venomous snakebites worldwide with a focus on the Australia-Pacific region: current management and controversies

Snakebites are estimated to cause approximately 100,000 deaths each year worldwide and disproportionately affect rural populations in resource-poor settings. Snake venoms may produce local tissue damage and/or distinct clinical syndromes, including neurotoxicity, coagulopathy, hypotension, rhabdomyolysis, and renal failure. Field management is aimed at delaying systemic absorption of toxins, minimizing local damage and infection, and expediting transport to medical facilities. The use of the pressure-immobilization method remains controversial. The use of antivenom, administered in a timely fashion and in adequate doses, is the mainstay of hospital treatment of significant envenomation. The availability, efficacy, and safety of antivenoms vary throughout the world, with a current crisis in antivenom supplies.

Successful resuscitation after cardiac arrest following massive brown snake envenomation

We report a 44-year-old Western Australian man who suffered a cardiac arrest several hours after a bite by a brown snake. He was successfully resuscitated after bolus administration of undiluted brown snake antivenom. We suggest that an initial bolus dose of at least five ampoules (5000 units) of undiluted brown snake antivenom should be given as primary therapy for cardiac arrest following brown snake envenomation in Western Australia.

Mild snake envenomation

Snake bite envenomation typically requires treatment with effective first aid and antivenom. There is a spectrum of envenomation seen, which includes mild envenomation, but this has not been reported previously. We report two cases of mild envenomation and describe the changes in laboratory coagulation values. The patients had a benign clinical course without receiving antivenom. We strongly recommend that if clinicians are considering not treating any envenomated patients with antivenom, they do so only on expert advice.

Fatal cerebral hemorrhage and acute renal failure after young Bothrops jararacussu snake bite

An unusual case of a patient developing severe coagulopathy disorder and a clinical picture of cerebral hemorrhage and acute renal failure after young Bothrops jararacussu snake bite is reported. The mechanisms of snake venom-induced injury are discussed and similar cases in literature are revised and compared. The use of bothropic-Crotalus antivenom in severe B. jararacussu envenomation is discussed.

Neutralisation of the clotting activity of Australian snake venoms by snake plasma

Plasmas from Pseudonaja textilis and Notechis scutatus were tested in vitro for their ability to neutralise the procoagulant activity, in human plasma, of nine elapid venoms. Pseudonaja textilis plasma inhibited the procoagulant activity of all Pseudonaja species and in one taipan (Oxyuranus scutellatus). However there was no inhibitory activity against any from the Notechis species. Plasma from Notechis scutatus exhibited no inhibitory activity against any Notechis species, including self, only weak inhibition against the Pseudonaja species and, again, total inhibition of Oxyuranus scutellatus. Thus, protection of a species from the effects of its own venom does not appear to be universal.

Efficacy and potency of antivenoms in neutralizing the procoagulant effects of Australian snake venoms in dog and human plasma

The efficacy and potency of Commonwealth Serum Laboratories (CSL) snake antivenoms in neutralizing the procoagulant action of Australian snake venoms was studied in vitro. The procoagulant action of venoms from Tiger, Brown and Taipan Snakes were measured in pooled canine or pooled human plasma. Mixtures of the venoms and their appropriate antivenoms, ranging from 0.1 to 15 times the recommended neutralizing dose of antivenom were then added to pooled canine or pooled human plasma and the efficacy and potency of the antivenoms in preventing the procoagulant action was measured. Neutralization was achieved by the addition of the appropriate antivenom in concentrations of 0.5 (Taipan), 10 (Tiger), 10 (Gwardar), 15 (Dugite) and an estimated 20 (Common Brown) times the dose expected. Similar results were obtained in canine and human plasma. The potency of Tiger and especially Brown Snake antivenom is substantially lower (10-20 times) than that predicted by CSL. These findings support an increase in the dose of antivenom to be used for the treatment of Tiger and especially Brown Snake envenomation complicated by coagulopathy. The in vitro canine model may be suitable for studying the procoagulant effects of Australian snake venoms.

Snakebite deaths in Australia 1992-1994 and a management update

Twelve deaths attributed to snakebite were reported in 1992-1994. Eight of the victims were males, and brown snakes (genus Pseudonaja) were involved in six of the deaths. Deaths caused by brown snakes were often sudden and unexpected, and autopsy findings were usually unremarkable. In no case was prompt effective first aid applied. The importance of appropriate first aid is emphasised and an update on management presented.