When snakebites complicate: a paediatric case with shock and compartment syndrome

Abstract

We report the case of an 11-year-old boy brought to our emergency department 2 hours after a viper bite to his right hand. He suffered severe pain and rapidly progressive swelling with signs of haemodynamic compromise in keeping with distributive shock. The oedema progressed from his right wrist upwards to his forearm and upper arm with compartment syndrome ultimately resulting. He underwent fasciotomy of the right upper limb and antivenom serum was given. The patient required vasopressors for 48 hours and a total of nine surgical interventions were necessary. In the event of a snakebite, it is essential to promptly recognise the signs of severity, complications and indications for the administration of antivenom serum. We intend to highlight this rare shock aetiology and the need for emergency management if severe clinical signs are present. Early administration of antivenom serum is essential and it should be available in all emergency departments.

Background

Worldwide snakebite envenoming is an important cause of morbidity and mortality¹ with approximately 81 000–138 000 annual deaths.^1–3 Snakebites remain poorly characterised because of under-reporting. The available data are typically derived from extrapolated hospital records and community surveys.^{1 4} The incidence and the progression to severe envenoming is more frequent in children because they have smaller limbs and less subcutaneous tissue. As such, they receive a larger dose of venom per kilogram.^{5 6} In Portugal, both snakes and snakebites are rare with only two native species—Vipera seoanei and Vipera latastei.^{7 8} Yet the consequences of a snake bite can be severe as illustrated here.

In this article, the authors present the case report of an 11-year-old boy bitten by a snake while playing in Serra do Espinhal (district of Coimbra, central region of Portugal), presenting criteria of high severity at hospital admission.

Case presentation

An 11-year-old boy was bitten on the dorsum of his right hand by a snake, in June, while he was playing in the forest. This child lived in a rural place, was lacto-ovo-vegetarian and did not have any vaccination coverage. The patient experienced an immediate, severe pain in his hand with rapidly progressive swelling and persistent vomiting. Two hours after the envenomation, the child presented to the paediatric emergency department of his local hospital, brought by the prehospital emergency services. On admission, he had already developed ecchymosis and local swelling with extension to the ipsilateral hand, wrist and forearm (figure 1). The child was conscious, without any breathing difficulty or hypoxemia, but had periods of agitation, obnubilation and persistent vomiting. Oxygen saturation was 100% with a high output mask, heart rate of 134 beats per minute and hypotension (systolic 70 mm Hg, diastolic 29 mm Hg), which prompted two boluses of intravenous saline solution and one epinephrine bolus. Due to recurrent hypotension, a dopamine infusion was started. The antivenom Viperfav was requested immediately, considering the severity of the case.

Figure 1.

Boy right hand and wrist with ecchymosis and local swelling.

Laboratory investigation demonstrated severe thrombocytopoenia (22 000 platelets/uL) and haemoglobin concentration of 17.3 g/dL. Coagulation parameters were within normal limits. Echocardiography revealed good biventricular systolic function, but less-filled inferior vena cava than the abdominal aorta despite the high input of fluids.

The child was transferred to the Paediatric Intensive Care Unit (PICU), having also started an epinephrine infusion and increasing dopamine to 8 mcg/kg/min. He was started on amoxicillin clavulanate combined with clindamycin.

One hour after admission in the PICU, the patient reported increased pain in his arm. The physical examination revealed progression of the swelling to the shoulder, becoming larger in circumference than the contralateral limb. His radial pulse was palpable and fingertip capillary refill time was less than 2 seconds. The paediatric and orthopaedic surgeons were consulted and confirmed the clinical diagnosis of compartment syndrome, as the upper limb was becoming more firm and tender, with increasing pain on passive stretching of the forearm. He was then taken immediately to the operating room as his condition was deteriorating rapidly, about 3 hours after his hospital admission. Extensive fasciotomies were performed in order to alleviate the increased pressure and extensive tissue oedema was observed once the compartments were released (figure 2).

Figure 2.

Boy right upper limb after extensive fasciotomies.

During the stay in the operating room, he was given the first vial of antivenom serum. Fresh frozen plasma, platelets and cryoprecipitate fibrinogen transfusions were also administrated.

In the following hours, a second dose of the antivenom was given and the patient showed a marked improvement with haemodynamic stabilisation and normalisation of the thrombocytopenia. Vasopressor therapy was suspended after 48 hours. As the child had no vaccination history, tetanus immunoglobulin was administered in the second day of admission.

Outcome and follow-up

The patient was transferred to the orthopaedic department 7 days after admission to the PICU, completing upper arm retraining. The patient underwent a total of nine surgical interventions for progressive wound closure and cleaning using vacuum-assisted closure therapy system, with gradual anatomical and functional recovery. He was discharged home 1 month after admission. At this time, he is partaking in an upper limb rehabilitation programme and maintains a slight limitation of the wrist extension.

Discussion

In Europe, most cases of snakebites occur between April and September, when the snakes are more active. They affect the extremities in 90% of the cases, especially the hands and arms, resulting from the deliberate attempt to catch or kill the reptile.^{8 9} The poison inoculated by the snakes contains a variety of toxins and specific components that have a local effect of cell destruction, changes in blood cells, coagulation and in vascular resistance.⁶

The initial cutaneous lesion consists of two painful red dots approximately 1 cm apart corresponding to the site of venom inoculation. After the bite, swelling appears at this site and in adjacent tissues and localised pain is usually felt; pain intensity increases as the swelling progresses. Ecchymosis, signs of lymphangitis, with tender regional lymph nodes or even an area of necrosis may appear and the progression of oedema and local tissue damage can lead to compartment syndrome.^{6 9}

The systemic manifestations occur later and usually include nausea, vomiting, perioral paresthesia or a metallic taste in the mouth, lethargy and weakness. In severe cases, patients may present with hypotension, tachypnea, respiratory distress, tachycardia and altered sensorium.^{6 9} The patient that we described showed most of these signs. Haemolysis may result from altered permeability of red-cell membranes. Pooling of blood and fluids in the microcirculation may lead to a distributive shock. Renal failure is secondary to prolonged hypotension or rhabdomyolysis.⁹ Death is rare; in most cases, it is associated with secondary infection and/or bleeding dyscrasia with multiorganic failure.⁸

As occurred with our patient, the appearance of local inflammatory signs following the snakebite suggests the existence of poison inoculation, so the initial approach at the scene of the accident is extremely important. Prehospital treatment should be focused on minimising patient activity, immobilising the injured part of the body in a functional position below the level of the heart, and removing rings, watches and constrictive clothing. The wound should be disinfected and the inflammatory signs monitored. Localised cold treatments should be applied and analgesics provided. However, prolonged cryotherapy does not appear to offer any benefit and may be harmful to tissue. Tourniquet, wound suction or patching are contraindicated. The child should be transported immediately to the hospital.6–8 10 11 An intravenous access and the preparation of the resources needed for immediate resuscitation should be the first priority. The affected extremity should be elevated and intravenous fluid infused if the patient is in shock.^{4 6} Proper analgesia should be assured, according to the level of pain. Prophylactic antibiotics, namely with amoxicillin and clavulanic acid, can be administered although there is no evidence supporting its use.^{6 7} Tetanus immunity status should be evaluated and treated accordingly.⁶

A grading scale for viper envenominations^{11 12} using clinical features divides patients into four severity grades, each one with different treatment approaches (table 1). Regarding its management, if the patient presents with grade 2 or 3 envenomation, it is necessary to undertake the only specific treatment with proven effectiveness, that is, intravenous immunotherapy with antivenom.¹² The case presented was an example of a grade 3 envenomation, with compartmental syndrome and shock with coagulopathy.

Table 1.

Viper envenomation grading scale

Grade	Envenomation	Clinical features	Management
0	No venom injected	Only fang marks, no local inflammatory signs	Local wound care only
1	Minor	Local swelling and pain, no general symptoms	Symptomatic
2	Moderate	Extensive swelling and/or moderate general symptoms (hypotension, gastrointestinal)	Antivenom
3	Severe	Extensive swelling and severe general symptoms (rhabdomyolysis, acute renal failure and disseminated intravascular coagulopathy)	Antivenom

Antivenom is the only effective specific antidote for the systemic effects of snakebite envenoming. The most commonly used antivenom in Europe is Viperfav. Its administration should be performed under close surveillance due to the risk of anaphylactic reactions, although it appears to be well tolerated with no reports of any severe adverse effects.^{6 7 11} In the case of this child, the administration of the antivenom was crucial for his haemodynamic stabilisation.

A possibility of compartment syndrome following snakebite envenomation, with marked swelling of muscles contained in a tight fascial compartment that might jeopardise the blood supply, should always be considered.¹² Important clues to the development of compartment syndrome include rapid progression of symptoms and signs over a few hours, namely pain out of proportion to apparent injury, increasing pain with passive stretch of muscles, paresthesias, tenderness and muscle weakness. In this context, surgeons should determine the need for measuring compartment tissue pressures, which can aid diagnosis. However, this may be unnecessary if the clinical diagnosis is obvious.^{4 6 7} In the case presented, the surgeons opted to take the patient to the operating room on the basis of the history and examination findings alone. The timely performed extensive fasciotomies seemed crucial to avoid the need for amputation.

The tetanus vaccine has been shown to be effective and safe.¹³ Rural areas have a higher risk for tetanus and for other conditions related with animal bites. Tetanus symptoms can be interpreted as snakebite complications, leading to considerable morbidity and mortality.¹³ The described child lived in a rural area and had not received any vaccinations, so tetanus immunoglobulin was administered.

In conclusion, viper snakebites are uncommon but the variety of clinical manifestations requires careful severity grading to optimise outcomes and prevent severe harm. Effective and timely antivenom administration reduces the impact of snakebite morbidity and mortality. This case also highlights the need to check vaccination status due to the risk of tetanus from a snakebite. Depending on the clinical progression, a multidisciplinary team approach may be required.

Learning points.

• Snakebite envenoming is more frequent in the paediatric age population and may have greater severity and risk of fatal complications due to the smaller body volume of the patient.

• After the bite, swelling appears at the site and in adjacent tissues and localised pain is usually felt; more severe clinical presentation with extensive swelling and general symptoms with haemodynamic compromise can occur.

• Early administration of antivenom serum reduces the impact of snakebite morbidity and mortality, and as such we advocate that it should be available in all emergency units.

• Compartment syndrome should always be considered following snakebite envenomation, requiring a multidisciplinary approach such as fasciotomy to fully decompress all involved compartments.