**5. Clinical manifestations**

128 Complementary Pediatrics

leaf viper because of its color and because it uses its prehensile tail to secure itself to branches. Its venom is hemotoxic and healthy adults rarely die from its bite. The feared Asiatic cobra is distributed from southeast to southwest Asia, including Indonesia. Its venom is highly neurotoxic, causing respiratory paralysis with some tissue damage. With even stronger neurotoxic venom and wider distribution (From southeast to southwest Asia,

In the pathophysiology of envenomation we can consider different factors that can be divided into human factors, which include the size of the victim, general health and wound characteristics, such as depth of fang penetration and location of the wound and snake factors which include the size of the snake, the amount of venom injected, and the strength of the particular species venom. Healthy, angered and hungry snakes unload more venom than a recently satiated and surprised snake (Hodge III and Tecklenburg 2006). Snake venom is a complex mixture of proteolytic enzymes, peptidases, proteinases, phospholipases and neurotoxins that are able to cause serious damage to the musculoskeletal, blood clotting, cardiopulmonary, renal and central nervous systems. Due to the venom, there is cell function degeneration and the final outcome depends on the type of venom injected. Generally, envenomation increases capillary permeability that results in blood and plasma loss from the intravascular to the extracellular space, creating edema, which, in case of being sufficiently important, may cause circulatory compromise and hypovolemic shock. Also, snake venom has citolytic properties, which cause local necrosis and secondary infection, which could result in sepsis and death (De la O Cavazos 2006). Venoms with neurotoxic activity produce paralysis and respiratory distress by binding the nicotinic acetylcholine receptors, and preventing the depolarizing action of acetylcholine. Hemotoxic effects induce hemolysis, fibrinogen proteolysis, and thrombocytopenia, which, along with activation of plasminogen, can lead to a bleeding diathesis in severe envenomation (Hodge III & Tecklenburg, 2006). Cardiotoxic effects lead to heart failure as well as myotoxicity and nephrotoxicity. Some are known poisons and it is important to know their mechanism of action for diagnosing anding accidents caused by these reptiles. It is also helped to unveil a number of physiological distrurbances caused by these venoms regarding neurotransmission, coagulation processes and mechanisms of inflammation. The most important effect of neurotoxins is to prevent the transmission of nerve impulses in cholinergic synapses. ALFA neurotoxins interfere with neurotransmitter release and cause muscle paralysis, respiratory failure and death by asphyxiation. Phospholipase A2 catalyzes the hydrolysis of phosphoglycerides creating phospholipids, which have detergent properties with a highly polar hydrophilic head and a hydrophobic tail and therefore they are capable of damaging cell membranes by breaking the continuity of its bilayer lipid . They have an important action in the phenomena of hemolysis, myonecrosis, neurotoxicity and anticoagulantion. The myotoxin-type crotalin protein acts through activation of sarcolemmal channels, inhibiting the activity of sarcoplasmic reticulum ATPase with significant depolarization and changes in the osmolarity of muscle fibers with vacuolization and lysis of myocytes and, local necrosis of skeletal muscle. The coagulants and anticoagulants such as the crotaline venoms cause a syndrome similar to disseminated intravascular coagulation (DIC) through an enzyme protein similar to thrombin, which

including Indonesia) we have the Egyptian cobra

**4. Pathophysiology** 

We can have diverse clinical manifestations when it comes to snakebites. The inapparent bites occur mainly when dealing with non-venomous snakes or when we have a bite by a venemous snake which did not cause symptoms. Due to the low frequency of poisoning by snake bites, it has been suggested that snakes who bite as a defensive move against humans do not inject enough venom to cause systemic symptoms, these are called dry bites.

Generally, local events occur in the time span of the first 10 to 30 minutes. Local pain is perceived along with the presence of edema, exudate and presence of bullae, accompanied by numbness of the tongue, jaw and scalp. There may be numbness around the bite with bleeding or a purpuric rash and/or necrosis or gangrene. As for the systemic manifestations, they start with the onset of fear and impending death feeling, which accelerates absorption of the venom. Other symptoms depend on the pathophysiological changes of the venom of certain species; neurotoxic venoms manifest as neuromuscular blockade resulting in flaccid paralysis, ptosis, and difficulty breathing; cardiotoxic venoms manifest as tachycardia, hypotension and ECG abnormalities, there may be fluctuations in heart rate, blood pressure and even heart failure in severe cases. There may be muscle necrosis resulting in myoglobinuria.

Different poisons trigger different clinical manifestations and it is important for healthcare staff to learn to recognize the general characteristics of every single of them or at least the more common, depending on their geographical localization.

#### **5.1 Pit vipers**

Pit viper snakes (rattlesnakes, copperheads, and water moccasins) produce hemotoxic venom. Local pain is typically intense, and a sensation of burning occurs within five to ten minutes. The pain is greater with ensuing edema and presumably increases with a larger inoculation of venom. Only in rare occasions the venom will sediment in the muscule compartment, in which cases the amount of edema will be minimal. In Diamondback rattlesnake bites, the limb may swell completely in just one hour. There can be local echymmosis and vesicles in the first hours. Lymphadenitis and some adenomegalies may become apparent. Victims of a significant rattlesnake bite often complain within minutes of perioral numbness, extending to the scalp and periphery. This parenthesis may be accompanied by a metallic taste in the mouth.

These patients also may have nausea, vomiting, weakness, chills, sweating, syncope, and other more ominous symptoms of systemic venom absorption. A copperhead envenomation produces less local symptoms, and systemic consequences are often minimal or nonexistent unless a small child, multiple bites, or a larger than average snake is involved. The water moccasin's effects are more variable.

Snake Bites in Pediatric Patients, a Current View 131

are not indicated and could actually promote the development of further infections (D. L. Morgan et al., 2007). Remember that all bite wound are already considered contaminated wounds and that these invasive measures might actually worsen the problem unless performed in the first 30 minutes after the attack has taken place and in a sterile environment (Robert L Norris & Adler, 2011). Tourniquets that completely occlude vascular irrigation have created more problems than those solved, therefore, they are not

As soon as the patient reaches the hospital it is important to asses the CAB (circulation, airway and breathing) before starting any kind of treatment, this includes appropriate management of any active bleeding and of the airway to avoid respiratory failure or aspiration. Monitoring of vital signs can be useful to forecast complications and most of the times this can be done in the emergency room without sending the patient to the ICU. After these measures have been taken care of, hydration is next, since one of the effects of snake venoms is to mobilize intravascular fluid to the interstitial space, leaving the patient dehydrated. For this, normal saline or Ringer´s lactate is used. Laboratory tests that are useful in these settings are CBC, PT/PTT, serum electrolytes, CPK, urinalysis, BUN and

The wound should be inspected, if fang marks are found, the distance between them needs to be measured in order to get an idea of the size of the snake. The distance between fang punctures smaller than 8 mm suggests a small snake, between 8 and 12 mm a medium snake and a distance greater than 12 mm suggests a large snake. In the case of the patient being bitten by a rattlesnake, the fang punctures could be hidden by hemorrhagic blebs and edema. If no puncture wounds can be found, we need to consider the fact that scratches and abrasions could be envenomed wounds until we demonstrate otherwise. When a snake attacks and bites 10 % to 20% of the time it does not inject any venom (dry bite) and if we are dealing with a non-venomous snake we could observe a row of tiny teeth without fang punctures. As a precaution, the circumference of the limb should be measured every thirty minutes for 6 hours and every 4 hours until 24 hours have passed with the aim of preventing the development of complications related to important edema. If no systemic

symptoms are evident, the wound should be cleansed, dressed and slightly elevated.

In the setting of not only the subject being bitten, but also suffering from envenomation, the use of antivenins is required. In the case of pit viper attacks, there are two antivenins, the Polyvalent Crotalic Antivenin (PCAV), which is the oldest, derived from horse's serum and highly antigenic, which is the reason for it to be discontinued from the United States market. In 2000, the FDA approved the Crotalic Polyvalent Fab Immune (FabAV) to manage patients with mild to moderate envenomations by American crotalus and since the Polyvalent Crotalic Antivenin is no longer marketed, the Fab Immune represents the only treatment option available in the United States, regardless of the severity of the envenomation. This alternative is derived from sheep's serum, a property that makes it less antigenic that its predecessor. FabAV appears to be effective in the management of severe crotaline snake envenomation (Lavonas, Schaeffer, Kokko, Mlynarchek, & Bogdan, 2009). It is available as a powder that needs to be reconstituted with normal saline. Regarding the use of PCAV, the

recommended for their prehospitalary care.

creatinine and a cross-match for blood.

**7.2 Emergency room care** 
