5-1 POISONING

LEARNING OBJECTIVE: Recall assessment and treatment procedures for ingested, inhaled, absorbed, and injected poisons

A poison is a substance that, when introduced into the body, produces a harmful effect on normal body structures or functions. Poisons come in solid, liquid, and gaseous forms, and they may be ingested, inhaled, absorbed, or injected into the system.

Every chemical in a sufficient dose can cause toxic effects in a human—or in any organism. The amount or concentration of a chemical and the duration of exposure to it are what determine the chemical’s dose and toxicity. A 16th century quotation from Paracelsus states, “Dose alone makes a poison... .All substances are poisons, there is none which is not a poison. The right dose differentiates a poison and a remedy.”

A poisoning is defined as the presence of signs or symptoms associated with exposure or contact with a substance. If there are no clinical manifestations or toxic effects, the incident is simply an “exposure” or a contact with a potentially poisonous substance. Just being exposed to a chemical does not mean that a poisoning has or will occur. It is a matter of dose and a few other variables (e.g., age, sex, individual resistance, or state ofhealth) that determine if, or what, toxic effects will occur.

ASSESSMENT AND TREATMENT OF PATIENT

In most cases, ASSESSMENT AND TREATMENT OF THE PATIENT IS MORE IMPORTANT THAN EFFORT TO IDENTIFY AND TREAT A SPECIFIC POISON. Supportive therapy—managing the ABCs (Airway, Breathing, and Circulation) of basic life support and treating the signs and symptoms—is safe and effective in the vast majority of poisonings. Extraordinary means to enhance elimination of the poison (hemodialysis and hemoperfusion) are seldom needed. Except for agents with a delayed onset of

toxicity (such as acetaminophen), most ingested poisons produce signs and symptoms in less than 4 hours, and most efforts to decontaminate the gut (remove an ingested poison) have little value more than 1 hour after ingestion.

In acute poisonings, prompt treatment is indicated. After the patient has been evaluated and stabilized, general poison management can be initiated. There are six steps in the initial evaluation and follow-on poison management:

1. Stabilization, which consists of a brief evaluation and assessment directed toward identifying the measures required to maintain life and prevent further deterioration of the patient.
   1. Observe the ABC + D & E (Drug-induced central nervous system (CNS) depression, and undressing/uncovering to Expose the patient for disabilities (injuries) to ensure areas of contact or exposure to a chemical can be seen.)
   2. Check the pupils for size and reactivity to light, and do a basic neurologic exam.
   3. Administer oxygen as needed, IV line for fluids.
   4. Watch for signs and symptoms of anaphylaxis.
2. Evaluation, which must be performed once the patient is stabilized.
   1. Include a full history, physical exam, and ordering of appropriate tests (i.e., labs, EKG, x-rays) directed toward identification of toxic agent, evaluating the severity of toxic effects, and searching for trauma and complications.
   2. Periodically reassess the patient. Look for changes. Monitor vital signs, urine output, and cardiac rhythm.
   3. Record your findings (including time), and respond to important changes appropriately.
3. Prevention or limitation of absorption, through skin decontamination, flushing of eyes, ventilation, stomach emptying, administration of charcoal and cathartics, and whole bowel irrigation.
4. Elimination enhancement, through serially administered activated charcoal, ion-trapping (pH adjustment of the urine to promote excretion of certain poisons), hemodialysis, and hemoperfusion (similar to hemodialysis, but used for larger size molecules).
5. Administration of specific antidotes. Less than 5 percent of poisons have specific antidotes. All patients who present should receive glucose, thiamine, and naloxone. Consider supplemental oxygen.
6. Continuing care and disposition, including a period of observation and education (i.e., poison prevention) or psychiatric counseling. Establish follow-up.

THE DIAGNOSIS OF POISONING

In most situations, the treatment of a poisoning victim will be under the direction of a medical officer. However, in isolated situations, a medical technician must be ready to treat the victim.

Poisoning should be suspected in all cases of sudden, severe, and unexpected illness. You should investigate such situations by ascertaining, as quickly and thoroughly as possible, the answers to the following questions:

• What are the signs and symptoms of the illness?
• What was happening before the illness occurred? (Remember, there may have been a chronic exposure over time with the signs and symptoms just becoming apparent.)
• What substances were in use? Could more than one substance have been involved?
• Is there a container of the suspected substance? If so, how much was there initially, and how much is there now? (If possible, bring the container to the treatment facility. The label will often identify the contents and the recommended precautions and treatment. The label may also list a contact number for emergency advice. Remember, though, that other people— including you—may become contaminated through contact with the container. Handle it carefully.)
• What was the duration of exposure? When did it happen?
• What is the location of the bite or injury (if applicable)?
• Has this happened before?
• Are there other people involved?
• Does the patient have a significant past medical history?
• Is the patient’s condition improving/ deteriorating?

The presence of a toxic syndrome or toxidrome can help establish that a poison has been involved by suggesting the class of poison(s) to which the patient may have been exposed. Table 5-1 provides a list ofcommonly encountered toxidromes, their sources and symptoms.

The “non-syndrome syndrome” is of special importance. The only method to recognize the potential for a delayed onset poisoning to occur is to suspect the possibility from the history or presentation of a person. In some cases, the individual’s affect or behavior may provide a clue. In other cases, the examiner must rely on clinical experience or even a hunch.

GENERAL TREATMENT

Once poisoning has been established, the general rule is to quickly remove as much of the toxicsubstance from the victim as possible. The method of removal of the poison varies depending upon how the poison was introduced:

• Ingested poisons: There is a choice between emetics and gastric lavage, followed by adsorbents and cathartics.
• Inhaled poisons: Oxygen ventilation is the method of choice.
• Absorbed poisons: Removal of the poison is primarily attained by cleansing the skin.
• Injected poisons: Antidotal medications are recommended.

INGESTED POISONS

Ingested poisons are those poisons which have been consumed, whether accidentally or intentionally, by the victim. Ingestion is the most common route of exposure to toxic materials in the home.

The local actions of an ingested poison can have irritant, acidic (corrosive), or basic (caustic) effects at the site of contact.

Table 5-1.—Commonly Encountered Toxidromes

Ingested substances can be absorbed into the body and transported to a distant site with systemic action(s). In such situations, the poisonous substance may cause few effects—or even no effect—at the site of contact or absorption, but it may have severe systemic effects.

Ingestion of substances that do not produce local effects can be divided into two types:

• nontoxic substances (latex paint, dirt, silica gel, spider plant), and
• potentially toxic substances (poisonous fish, medications, heavy metals (lead, mercury), pesticides, and personal care products).

Episodes involving the ingestion of non-toxic substances do not require decontamination of the gut. (Swallowing a non-toxic foreign body, however, like a coin or button battery in a child, may result in choking and require prompt medical intervention.)

The toxicity range of absorbed poisons extends from essentially non-toxic to extremely toxic (remember Paracelsus’ “dose”). Ingestion of substances with a low order of toxicity may result in the production of only minor systemic effects (nausea, vomiting, diarrhea), effects that are mild, self-limiting, and do not require significant medical intervention.

Table 5-2.—Common Stomach Irritants and Possible Sources of Contact

Noncorrosives

The many different noncorrosive substances have the common characteristic of irritating the stomach. They produce nausea, vomiting, convulsions, and severe abdominal pain. The victim may complain of a strange taste, and the lips, tongue, and mouth may look different than normal. Shock may also occur. Examples of noncorrosives are listed in table 5-2.

First aid for most forms of noncorrosive poisoning centers on quickly emptying the stomach of the irritating substance. The following steps are suggested:

1. Maintain an open airway. Be prepared to give artificial ventilation.
2. Dilute the poison by having the conscious victim drink one to two glasses of water or milk.
3. Empty the stomach using emetic, gastric lavage, adsorbent, and/or cathartic.
   1. Giving an emetic is a preferred method for emptying the contents of the stomach. It is quick and—except in cases of caustic or petroleum distillate poisoning, or when an antiemetic has been ingested—can be used in almost every situation when the victim is conscious. In most situations, a medical technician will have access to syrup of Ipecac. This emetic acts locally by irritating the gastric mucosa and centrally by stimulating the medullary vomiting center in the brain. The usual adult dose is 15-30 cc, and the dose for a child (age 1 to 12 years) is 15 cc. The dosage should be followed immediately by a glass of water. Most people will vomit within 30 minutes. The amount of stomach contents (and poison) recovered will vary. In an emergency room, the medical officer can rapidly induce vomiting by the injection of various medications. If nothing else is available, tickle the back of the victim’s throat with your finger or a blunt object. This procedure should induce vomiting.
   2. Trained personnel may use gastric lavage by itself or after two doses of Ipecac syrup has failed to induce vomiting. After passing a large—caliber nasogastric tube, aspirate the stomach contents. Next, instill 100 ml of normal saline into the stomach, then aspirate it out again. Continue this flushing cycle until the returning fluid is clear. Gastric lavage is preferred when the victim is unconscious or—as in the case of strychnine poisoning—is subject to seizures.
   3. Activated charcoal (AC) adsorbs many substances in the gut and prevents absorption into the body. After the substance is adsorbed to the AC, the bound substance moves through the gut and is eliminated with the production of a charcoal-black bowel movement. AC may be administered after emesis or lavage, or it may be used alone.
4. A cathartic (magnesium sulfate or sorbitol) may be used to “speed” the movement of the bound substance and minimize absorption.
5. Collect the vomitus for laboratory analysis.
6. Soothe the stomach with milk or milk of magnesia.
7. Transport the victim to a definitive care facility if symptoms persist.

Corrosives

Acids and alkalies (bases) produce actual chemical burning and corrosion of the tissues of the lips, mouth, throat, and stomach. Acids do most of their damage in the acidic stomach environment, while alkalies primarily destroy tissues in the mouth, throat, and esophagus. Stains and burns around the mouth, and the presence of characteristic odors provide clues as to an acid or base ingestion. Swallowing and breathing may be difficult, especially if any corrosive was aspirated into the lungs. Stridor, a high-pitched sound coming from the upper airway, may be heard. The abdomen may be tender and swollen with gas, and perforation of the esophagus or stomach may occur. NEVER ATTEMPT TO TREAT AN ACID OR BASE INGESTION BY ADMINISTERING A NEUTRALIZING SOLUTION BY MOUTH. GIVE WATER ONLY, UNLESS DIRECTED BY A POISON CONTROL CENTER (PCC) OR MEDICAL OFFICER. Monitor the ABC+D&Es, and watch for signs of shock.

Examples of corrosive agents and sources of contact are listed in table 5-3.

Table 5-3.—Examples of Common Acids, Alkalies, and Phenols, with Possible Sources of Contact

When providing treatment for the above poisons, DO NOT INDUCE VOMITING. The damage to the mouth and esophagus will be compounded. In addition, the threat of aspiration during vomiting is too great. Gastric lavage could cause perforation of the esophagus or stomach. Therefore, use it only on a doctor’s order. First aid consists of diluting the corrosive and keeping alert for airway potency and shock. If spontaneous vomiting occurs, administer an antiemetic.

Irritants

Substances such as automatic dishwasher detergent, diluted ammonia, and chlorine bleach can produce local irritation to the mucous membranes and potentially cause mild chemical burns. The pH of irritants may be slightly acidic or basic. If a person has ingested an irritant, direct the patient to spit the product out and rinse the mouth repeatedly with water. Spit the rinse water out also. Do NOT administer anything other than water unless directed by a PCC or medical officer.

Petroleum Distillates or Hydrocarbons

Volatile petroleum products (such as kerosene, gasoline, turpentine, and related petroleum products

like red furniture polish) usually cause severe chemical pneumonia as well as other toxic effects in the body. Symptoms include abdominal pain, choking, gasping, vomiting, and fever. Often these products may be identified by their characteristic odor. Mineral oil and motor oil are not as serious since they usually do nothing more than cause diarrhea.

When providing treatment for the ingestion of petroleum distillates, DO NOT INDUCE VOMITING unless told to do so by a physician or poison control center. Vomiting may cause additional poison to enter the lungs. However, the quantity of poison swallowed or special petroleum additives may make gastric lavage or the use of cathartics advisable. If a physician or poison control center cannot be reached, give the victim 30 to 60 ml of vegetable oil. Transport the victim immediately to a medical treatment facility.

Food Poisoning

Food poisoning can occur from ingesting animal or plant materials, or even from the chemicals that are used in raising, processing, or preserving crops and livestock. Although illness associated with a contaminated water supply could be considered a type of food poisoning, this issue will not be addressed.

Most bacterial and viral food poisonings appear within 8 hours of ingesting food. The signs and symptoms of poisoning include nausea, vomiting, diarrhea, muscle aches, and low-grade fever. The general treatment is supportive and directed at preventing dehydration through the administration of fluids. If diarrhea persists more than 24 hours, or if the patient is unable to keep fluids down, further definitive medical care is necessary. Food poisoning can also occur from ingestion of parasites.

Marine food-borne illnesses from ingesting fish and shellfish is a concern especially when traveling to new destinations. Wherever you are in the world, you should learn which local seafood is known to be safe and which present the potential for harm. Table 5-4 lists some of toxins found in fish and shellfish and their potential sources.

Table 5-4.—Examples of Toxins from Fish Known to be Poisonous.

Mussels, clams, oysters, and other shellfish often become contaminated with bacteria during the warm months of March through November (in the northern hemisphere). Numerous varieties of shellfish should not be eaten at all. Therefore, wherever you are in the world, you should learn which local seafoods are known to be safe and which present the potential for harm.

Most fish poisonings occur from eating fish that normally are considered to be safe to eat. However, fish can become poisonous at different times of the year because of their consumption of poisonous algae and plankton (red tide) that occur in certain locations. The signs and symptoms of red tide paralytic shellfish poisoning are tingling and numbness of the face and mouth, muscular weakness, nausea and vomiting, increased salivation, difficulty in swallowing, and respiratory failure. Primary treatment is directed at evacuating the stomach contents as soon as possible. If the patient has not vomited, select the appropriate method to remove the stomach contents by either syrup of Ipecac or gastric lavage. If respiratory failure develops, support ventilation and other life-sustaining systems as needed.

Examples of fish that are known to be poisonous AT ALL TIMES are shown in figure 5-1.

Figure 5-1.—Poisonous fish.

The symptoms of shellfish and fish poisoning are tingling and numbness ofthe face and mouth, muscular weakness, nausea and vomiting, increased salivation, difficulty in swallowing, and respiratory failure.

Primary treatment is directed toward evacuating the stomach contents. If the victim has not vomited, cause him to do so. Use syrup of Ipecac, gastric lavage, or manual stimulation; then administer a cathartic. If respiratory failure develops, give artificial ventilation and treat for shock.

INHALATION POISONS

Inhalation is the most common route of exposure to toxic substances. The irritants and corrosives mentioned in tables 5-2 and 5-3 are more often a source of poisoning by means of inhalation rather than by ingestion. An inhaled poison can act directly on the upper respiratory tract or lungs with immediate, delayed, or chronic effects, or the substance can use the pulmonary system to gain entry into the body, be absorbed into the blood, and cause toxic effects (systemic toxicity) at a distant site of action.

The handling of large quantities of petroleum products (fuel oil and gasoline, in particular) constitutes a special hazard, since all of these products give off hazardous vapors. Other poisonous gases are by-products of certain operations or processes: exhaust fumes from internal combustion engines; fumes or vapors from materials used in casting, molding, welding, or plating; gases associated with bacterial decomposition in closed spaces; and gases that accumulate in voids, double bottoms, empty fuel tanks, and similar places. Some sources of inhalation chemical poisoning are listed in table 5-5.

Table 5-5.—Sources of Inhalation Poisoning

Carbon monoxide is the most common agent of gas poisoning. It is present in exhaust gases of internal combustion engines as well as in sewer gas, lanterns, charcoal grills, and in manufactured gas used for heating and cooking. It gives no warning of its presence since it is completely odorless and tasteless. The victim may lose consciousness and suffer respiratory distress with no warning other than slight dizziness, weakness, and headache. The lips and skin of a victim of carbon monoxide poisoning are characteristically cherry red. Death may occur within a few minutes.

Most inhalation poisoning causes shortness of breath and coughing. The victim’s skin will turn blue. If the respiratory problems are not corrected, cardiac arrest may follow.

Inhaling fine metal fumes can cause a special type of acute or delayed poisoning. These metal fumes are generated from heating metal to boiling and evaporation during hot metal work in such operations as metal cutting or welding. The resulting illness is often called metal fume fever (MFF). The most common cause of MFF is the inhalation of vaporized zinc found in the galvanized covering of iron/steel. Proper local and general ventilation and/or the use of respiratory protection are necessary to prevent this illness.

The first stage of treatment for an inhalation poisoning is to remove the victim from the toxic atmosphere immediately. WARNING: Never try to remove a victim from the toxic environment if you do not have the proper protective mask or breathing apparatus, or if you are not trained in its use. Too often, well-intentioned rescuers become victims. If help is not immediately available, and if you know you can reach and rescue the victim, take a deep breath, hold it, enter the area, and pull the victim out. Next,

1. start basic life support (the ABC+D&Es);
2. remove or decontaminate the clothing (if chemical warfare agents or volatile fuels were the cause);
3. keep the victim quiet, treat for shock, and administer oxygen; and
4. transport the victim to a medical treatment facility for further treatment.

ABSORBED POISONS

Some substances may cause tissue irritation or destruction by contact with the skin, eyes, and lining of the nose, mouth, and throat. These substances include acids, alkalies, phenols, and some chemical warfare agents. Direct contact with these substances will cause inflammation or chemical burns in the affected areas. Consult the “Chemical Burns” section of chapter 4 and the “Chemical Agents” section of chapter 8 of this manual for treatment.

INJECTED POISONS AND ENVENOMATIONS

Injection of venom by stings and bites from various insects and arthropods, while not normally life-threatening, can cause acute allergic reaction that can be fatal. Poisons may also be injected by snakes and marine animals.

Bee, Wasp, and Fire Ant Stings

Stings from bees, wasps, and ants account for more poisonings than stings from any other insect group. Fortunately, they rarely result in death. The vast majority of stings cause a minor local reaction at the injection site, with pain, redness, itching, and swelling. These symptoms usually fade after a short time. A small percentage of these stings can cause an allergic victim severe anaphylactic reactions, presenting with itching, swelling, weakness, headache, difficulty breathing, and abdominal cramps. Shock may follow quickly, and death may occur.

The following first aid measures are recommended for all but minor, local reactions to bites or stings:

1. Closely monitor vital signs (and the whole patient), and remove all rings, bracelets, and watches.
2. Remove stingers without squeezing additional venom (remaining in poison sacs attached to stingers) into the victim. To do this, scrape along the skin with a dull knife (as if you were shaving the person). The dull blade will catch the stinger and pull it out.
3. Place an ice cube or analgesic-corticosteroid cream or lotion over the wound site to relieve pain. Do NOT use “tobacco juice,” saliva, or other concoctions.
4. For severe allergic reactions (generalized itching or swelling, breathing difficulty, feeling faint or clammy, unstable pulse or blood pressure), immediately give the victim a subcutaneous injection of 1:1000 aqueous solution of epinephrine. Dosage is 0.5 cc for adults and ranges from 0.1 to 0.3 cc for children.
5. Patients with severe allergic reactions should be
   evacuated immediately to a medical facility.

Scorpion Stings

About 40 species of scorpions (fig. 5-2) exist in America. Centruroides exilicauda may cause severe effects. Most dangerous species are found from North Africa to India. Scorpion stings vary in severity, depending on the species of the scorpion and the amount of poison actually injected. They cause severe pain in the affected area.

Figure 5-2.—Black widow and brown recluse spiders and scorpion.

Mild reactions may include local swelling, skin discoloration, swollen lymph nodes near the sting area, itching, paresthesias (“pins and needles,” numbness), and even nausea and vomiting. The duration of symptoms is less than 24 hours.

The following first aid treatment should be given for scorpion stings:

1. Place ice over the sting site (cool the area for up to 2 hours). Do NOT use tobacco juice, saliva, or other concoctions.
2. Elevate the affected limb to approximately heart level.
3. Give acetaminophen for minor pain.
4. Calcium gluconate, 10 ml of 10 percent solution, may be given intravenously to relieve muscle spasms.
5. Valium may be used to control excitability and convulsions.
6. An antivenom is available for severe bites by Centruroides exilicauda (also called “bark scorpion,” it is the scorpion found in Mexico and the American southwest). It is available from the Antivenom Production Laboratory, Arizona State University, Tempe, Arizona 85281, phone (602) 965-6443 or (602) 965-1457, and from Poison Control in Phoenix, phone (602) 253-3334.

CAUTION: Morphine and meperidine hydrochloride may worsen the respiratory depression from the venom of Centruroides exilicauda.

Spider Bites

Spiders in the United States are generally harmless, with several exceptions. The most notable are the black widow (Latrodectus mactans) and brown recluse (Loxosceles reclusa, also found in South America) spiders. Their bites are serious but rarely fatal. Wandering spiders (Phoneutria species, found in South America), funnel web spiders (Atrax species, found in Australia), and more widely distributed spiders of the Chiracanthium species may also cause moderate to severe human reactions. Check current MEDIC CD-ROM for management of specific situations and venues.

The female black widow spider is usually identified by the red hourglass-shaped spot on its belly (fig. 5-2). Its bite causes a dull, numbing pain, which gradually spreads from the region of the bite to the muscles of the entire torso. The pain becomes severe, and a board-like rigidity of the abdominal muscles is common. Nausea, vomiting, headache, dizziness, difficulty in breathing, edema, rash, hypertension, and anxiety are frequently present. The bite site can be very hard to locate (there is little or no swelling at the site), and the victim may not be immediately aware of having been bitten. The buttocks and genitalia should be carefully examined for a bite site if the suspectedvictim has recently used an outside latrine. The following first aid treatment steps are suggested:

1. Place ice over the bite to reduce pain.
2. Hospitalize victims who are under 16 or over 65 (for observation).
3. Be prepared to give antivenom in severe cases.

The brown recluse spider (fig. 5-2) is identified by its violin-shaped marking. Its bite may initially go unnoticed, but after several hours, a bleb develops over the site, and rings of erythema begin to surround the bleb. Other symptoms include skin rash, fever and chills, nausea and vomiting, and pain. A progressively enlarging necrotic (dead tissue) ulcerating lesion (with a crusty black scab) eventually develops. Intravascular hemolysis (breakdown of the blood) is most often seen in children and may be fatal. Antivenom is not currently available.

Treatment for brown recluse spider bites includes:

• Debridement of lesion, followed by peroxide cleansing and Burrow’s solution soaks
• Application of polymyxin-bacitracin-neomycin ointment and sterile dressing
• Dapsone 50-100 mg twice a day is used to promote healing in some cases, but only after screening for G6PD deficiency. Other antibiotics may be used to treat infection, and steroids to reduce inflammation

• Based upon medical consultation, excision of the lesion and optional commencement of corticosteroid therapy

Centipede Bites

Centipedes can attain sizes of over one foot in length! Their bite, though rare, leaves two tiny red marks and causes redness and swelling. Severe pain, swelling, and inflammation may follow, and there may be headache, dizziness, vomiting, irregular pulse, muscle spasm, and swollen lymph nodes. No long-term effects are usually seen. Treat discomfort with acetaminophen, cool packs, and elevation of the affected limb to heart level.

Snakebites

Poisonous snakes are found throughout the world, with the exception of certain islands and the Antarctic. There are five venomous families of snakes.

• Viperidae–includes rattlesnakes, moccasins, South American lance-headed vipers and bushmaster, Asian pit vipers, African and Asian vipers and adders, the European adder, and saw-scaled viper (Middle-eastern). Kills mainly by coagulopathy (a blood clotting disorder) and shock.
• Elapidae–Includes cobras, kraits, mambas, and coral snakes. Kills from neurotoxic venom that can cause respiratory failure, paralysis, and cardiac failure.
• Hydrophidae–Includes sea snakes and venomous snakes from the islands of the southern Pacific Ocean, including Australia, New Zealand, and New Guinea. Also kills from neurotoxic venom.
• Colubridae–Includes most of the common nonvenomous species, as well as the boomslang, and vine/twig/bird snake (Africa); Japanese yamakagashi; Southeast Asian red-necked callback. Venom’s method of toxic action varies according to type of snake.
• Atractaspididae–Includes the burrowing asps/mole vipers, stiletto snakes, and adders. Venom’s method of toxic action varies according to type of snake.

Within the United States, poisonous snakes are Crotalids (rattlesnakes, copperheads, and moccasins) and the Elapids (coral snakes).

CROTALIDS.—Crotalids are of the Viperidae (viper) family and are called “pit vipers” because of the small, deep pits between the nostrils and the eyes (fig. 5-3). They have two long, hollow fangs. These fangs are normally folded against the roof of the mouth, but they can be extended when the snake strikes. Other identifying features of the Crotalids include thick bodies; slit-like pupils ofthe eyes; and flat, triangular heads. The most identifying feature of a pit viper is the relative width of the snake’s head compared to the thickness of the body. The head will be much wider than the body, giving the appearance of an arrowhead. The difference in size is so obvious that identification of a snake as a pit viper can usually be made from a safe distance.

Figure 5-3.—American pit vipers.

Further identification can be made by examining the wound for signs of fang entry in the bite pattern. Pit viper bites leave two puncture marks (sometimes only one, and sometimes more). Nonvenomous snakes (for example, garter snakes) leave a series, often in a curve or semi-circle, of tiny scratches or punctures. Individual identifying characteristics include rattles on the tails of most rattlesnakes, and the cotton-white interior of the mouths of moccasins.

ELAPIDS.—Coral snakes are of the family Elipidae and related to the cobra, kraits, and mamba snakes in other parts of the world (fig. 5-4). Corals, which are found in the Southeastern United States, are comparatively thin snakes with small bands of red, black, and yellow (or almost white). Some nonpoisonous snakes have similar coloring, but in the North American coral snake, the red band always touches the yellow band, and the bands go all the way around the body. (In some of the nonvenomous, similarly colored varieties, the bands are only on the back and sides, not the belly.) There is an old saying that only applies to NORTH American coral snakes: “Red on yellow, kill a fellow; red on black, venom lack.” The coral snake has short, hollow fangs that chew into its victim and introduce the poison. Coral snake venom is dangerous, so if the skin is broken, give antivenom before envenomation is evidenced by symptoms or findings.

Figure 5-4.—Corals, cobras, kraits, and mambas.

Venom, which is stored in sacs in the snake’s head, is introduced into a victim through hollow or grooved fangs. An important point to remember, however, is that a bitten patient has not necessarily received a dose of venom. The snake can control whether or not it will release the poison and how much it will inject. As a result, while symptoms in a poisonous snakebite incident may be severe, they may also be mild or not develop at all.

SIGNS AND SYMPTOMS OF SNAKE­BITE.— In a snakebite situation, every reasonable effort should be made to positively identify the culprit, since treatment of a nonpoisonous bite is far simpler and less dangerous to the victim than treatment of a poisonous bite. However, unless the snake can be POSITIVELY identified as nonpoisonous, CONSIDER ALL SNAKEBITES AS POISONOUS! SEEK CONSULTATION FROM EXPERT SOURCE.

Signs and symptoms of venomous snakebite may include

• a visible bite on the skin (possibly no more than a local discoloration);
• pain and swelling in the bite area (may develop slowly, from 30 minutes to several hours);
• continued bleeding from site of bite (often seen with viper bites);
• rapid pulse;
• labored breathing;
• progressive weakness;
• dim or blurred vision;
• nausea and vomiting;
• seizures; or
• drowsiness (or loss of consciousness).

Usually enough symptoms present themselves within an hour of a poisonous snakebite to erase any doubt as to the victim’s having been envenomated or not. The victim’s condition provides the best information as to the seriousness of the situation.

The aims of first aid for envenomated snakebites are to reduce—not stop—the circulation of blood through the bite area, delay absorption of venom, prevent aggravation of the local wound, maintain vital signs, and transport the victim as soon as possible to an MTF with minimum movement.

TREATMENT OF SNAKEBITES.—The proper steps in the treatment of snakebites are listed below.

1. Try to identify the snake. Positive identification is important to selecting the correct antivenom for the treatment of the patient.
2. Certain suction extractors have benefit (for example, the Sawyer extractor), especially if used within the first 3 minutes. If available immediately, use the extractor and leave it on for 30 minutes. The cups may fill up. Empty and re-use them as necessary.
3. GENTLY wash the wound with soap and water (it may remove some of the venom). Do NOT rub vigorously, as it may cause the venom to be absorbed more rapidly.
4. Place the victim in a comfortable position.
5. Tell the patient to remove any jewelry (especially rings and bracelets, as these may impede blood flow if there is swelling of the extremities). Assist, if necessary.
6. Startan IV line.
7. Monitor vital signs (including ABC+D&Es) closely, responding appropriately as necessary.
8. Until evacuation or treatment is possible, ensure the victim lies quietly and does not move any more than necessary.
9. Do not allow the victim to smoke, eat, or drink any fluids. (Water is permissible if you anticipate more than several hours will pass before arriving at a hospital and being able to establish an IV line.)
10. Transport the victim to a hospital or other appropriate facility.
11. Place a lymphatic (light) constriction on the extremity (if the bite is on an extremity). The goal is to obstruct lymphatic—not blood-flow. (See instructions below.) DO NOT USE A TOURNIQUET!

12. Splint the extremity at the level of the body (heart). DO NOT ELEVATE THE EXTREMITY!
13. Hospitalize and observe all snakebites for at least 24 hours.

In the case of spitting cobras (found in Africa, Thailand, Malaysia, Indonesia, and the Philippines), which attempt to spray venom into victims’ eyes, rinse the eyes with large volumes of water (neither a blast nor a trickle, and not with hot water). Apply antibacterial (tetracycline or chloramphenicol) eye ointment, and apply a patch with just enough pressure to keep the eyelid from blinking.)

Other aid will be mainly supportive:

• Check pulse and respiration frequently. Give artificial ventilation, if necessary.
• Treat for shock, including IV fluids (normal saline or lactated Ringer’s solution).
• When possible, clean the area of the bite with soap and water, and cover the wound to prevent further contamination.
• Give acetaminophen for pain if delay in hospital treatment is anticipated.

Antivenom.—Antivenom (also called antivenin) is available for many snakes, and is indicated for severe envenomations by Viperidae family snakes and most envenomations by snakes of the other poisonous families. Antivenom is best given as soon as possible after an envenomation, but may be of value up to a few days after a bite.

If possible, antivenom specific to the snake should be used. Otherwise, a “polyspecific” antivenom may be used. READ THE PACKAGE INSERT OF THE ANTIVENOM FOR VALUABLE INFORMATION. Epinephrine and diphenhydramine must be available, as allergic reactions (including anaphylaxis) to antivenom have occurred (they are often prepared from horse serum, which some people are allergic to).

Antivenom is diluted (for example, 1:10) and given at 5 ml/minute IV, and the dose is based on stopping the progression of signs and symptoms, not the victim’s body weight (the children’s dose is the same as the adult dose). For neurotoxic snakebites, if there is no improvement in 30 minutes, the dose should be repeated. For Viperidae (which can cause bleeding disorders), spontaneous bleeding should stop after sufficient antivenom is given; continue giving antivenom until bleeding stops and progression of swelling is retarded. Because you may need to administer antivenom a number oftimes, one vial may not be enough to treat a patient.

Antivenom is available via PCCs and hospitals. It may also be available at zoos and embassies.

The “Don’ts” of Snakebite Treatment.–The following are the “don’ts” when it comes to treatment of snakebite.

• DO NOT use any ice or cooling on the bite.
• DO NOT use a tourniquet. Obstructing blood flow can make local tissue injury much worse.
• DO NOT use electric shock.
• DO NOT make any cuts or incisions in the wound. Cuts at the bite site may impede circulation and promote infection and make local tissue injury much worse.
• DO NOT give victim alcohol or narcotics.

Further information may be obtained on an emergent basis from a PCC or from Arizona Poison Control, (520) 626-6016.

Bites, Stings, and Punctures from Sea Animals

A number of sea animals are capable of inflicting painful wounds by biting, stinging, or puncturing. Except under rare circumstances, these stings and puncture wounds are not fatal. Major wounds from sharks, barracuda, moray eels, and alligators can be treated by controlling the bleeding, preventing shock, giving basic life support, splinting the injury, and transporting the victim to a medical treatment facility. Minor injuries inflicted by turtles and stinging corals require only that the wound be thoroughly cleansed and the injury splinted.

JELLYFISH INJURIES.—Other sea animals inflict injury by means of stinging cells located in tentacles. This group includes the jellyfish and the Portuguese man-of-war (fig. 5-5). The tentacles (which may be impossible to see, even in relatively clear water) release poison or tiny stingers through which poison is injected into the victim. Jellyfish stings may cause symptoms ranging from minor irritation (pain and itching) to death. Contact with the tentacles produces burning pain, a rash with small hemorrhage in the skin, and, on occasion, shock, muscular cramping, nausea, vomiting, and respiratory and cardiac distress. Treatment for minor jellyfish injuries consists of pouring sea water over the injured area and then removing the tentacles with a towel or gloves. Next, pour rubbing alcohol, formalin, vinegar, meat tenderizer, or diluted ammonia over the affected area to neutralize any remaining nematocysts (minute stinging structures). Finally, cover the area with any dry powder (to which the last nematocysts will adhere), and then scrape off with a dull knife. Apply cool packs and hydrocortisone cream.

Figure 5-5.—Jellyfish and Portuguese Man-of-war.

Some jellyfish (notably, the Portuguese man-of-war, the box jellyfish, and certain jellyfish from northeastern Australia) may cause serious injuries and even have the potential to be lethal. In cases where the kind of jellyfish that caused the sting is either unknown or is known to have been from a box jellyfish or Portuguese man-of-war, the injury should be treated as a serious one, regardless of initial symptoms. The following steps should be taken in the case of serious jellyfish stings.

1. Retrieve the victim from the water if necessary.
2. Send others for an ambulance and antivenom. (Antivenom is available for boxjellyfish stings. It is from sheep, and should be given in all serious stings.)
3. Pour vinegar liberally (2 liters) over the sting area for at least 30 seconds to inactivate stinging cells that may remain.
4. Remove any remaining tentacles carefully. (Excessive manipulation may cause rupture of nematocysts and further poison release.) Carefully (and gently) use a towel if necessary, or use a dull knife edge (as described above to remove arthropod stingers).
5. Apply a compression bandage to stings covering more than half of one limb or causing altered consciousness.
6. Start an IV.
7. Remain with the victim, and monitor vital signs (the ABCs and consciousness, responding appropriately (possibly including CPR) and as necessary).
8. Transport the patient to a hospital as quickly as possible.

Opiate analgesics (morphine or meperidine) may be necessary for pain relief.

“SPINE” INJURIES.—Spiny fish, stingrays, urchins, and cone shells inject their venom by puncturing with spines (fig. 5-6). General signs and symptoms include swelling, nausea, vomiting, generalized cramps, diarrhea, muscular paralysis, and shock. General emergency care consists of prompt flushing with cold sea water to remove the venom and to constrict hemorrhaging blood vessels. Next, debride the wound of any remaining pieces of the spine’s venom-containing integumentary sheath. Soak

Figure 5-6.—Stingray sting.

the wound area in very hot water (110°F/43° C) for 30 to 60 minutes to neutralize the venom. Finally, completely debride the wound, control hemorrhage, suture, provide tetanus prophylaxis and a broad-spectrum antibiotic, and elevate the extremity. For minor injuries, a steroid cream to the wound area may relieve discomfort. For serious injuries—wounds that are deep, very painful, or causing the patient distress—stabilize the patient and transport immediately to a hospital.

In the case of contact with stonefish, scorpionfish, zebra, or lionfish, immerse the wound in very hot water for a minimum of 30 minutes until the pain is decreased. Inject emetine hydrochloride directly into the wound within 30 minutes, and provide meperidine (or other opiate) for pain. Monitor the victim’s vital signs closely. Obtain antivenom (from local zoos or aquariums) for all serious cases.

SEA SNAKE INJURIES.—Sea snakes are found in the warm water areas of the Pacific and Indian Oceans. Their venom is VERY poisonous, but their fangs are only 1/4 inch long. The first aid outlined for land snakes also applies to sea snakes.