FIGURE 90.18 Management of suspected brown recluse spider bite Clinical recognition Bites are seldom mistaken if the child is old enough to describe the spider There is generalized pain and rigidity of muscles to hours after the bite, typically without local symptoms The pain is cramping and felt in the abdomen, flanks, thighs, and chest Nausea and vomiting are often reported in children Respiratory distress, chills, urinary retention, tachycardia, hypertension, myocarditis and priapism can occur Patients might become anxious and report generalized diaphoresis and flushing There is a 4% to 5% mortality rate, with death resulting from cardiovascular collapse The mortality rate in young children may be as high as 50% if untreated The syndrome after a black widow spider bite may easily confuse the clinician as it mimics many medical or surgical conditions such as myocardial infarction, alcohol/opiate withdrawal, organophosphate poisoning, acute abdomen, rabies, tetanus, renal colic, food poisoning, or Staphylococcal sepsis TABLE 90.20 GRADING SCALE FOR LATRODECTUS ENVENOMATION Grade Symptoms Asymptomatic Local pain at bite site Normal vital signs Muscular pain—localized Diaphoresis—localized Normal vital signs Muscular pain—generalized Abnormal vital signs Nausea, vomiting Headaches Diaphoresis Management A child who has severe pain and muscle rigidity after a spider bite should be considered a Latrodectus bite victim A clinical grading scale has been developed by Clark ( Table 90.20 ) Local treatment of the site of the bite with the use of a tourniquet or with incision and suction of the venom has not proven beneficial Treatment with Latrodectus antivenin (Lyovac, Merck, Sharp & Dohme) should be instituted as soon as a bite is confirmed in children who weigh less than 40 kg; the usual dose is 2.5 mL (one vial) Antivenin should be administered by following the package insert and after skin testing to determine the risk of hypersensitivity to horse serum For children who weigh more than 40 kg, it is not as urgent to institute antivenin treatment, but indications for its use include patients who are younger than 16 years, who have respiratory difficulty, or who have significant hypertension Antivenin is usually effective within 30 minutes and may be repeated once within hours if symptoms return Serum sickness is a possible side effect Because the dosage is low, however, serum sickness is uncommon, with a rate lower than reported for other types of antivenin A black widow spider bite in pregnancy is an indication for antivenin due to the risk of venom-induced abortion, although the antivenin is a category C drug Other supportive measures include prolonged warm baths and intravenous injection of 10% calcium gluconate as needed for muscle pain If there is extreme restlessness, barbiturates or benzodiazepines may be used, but with caution as the venom is a neurotoxin and can cause respiratory paralysis Muscle relaxants such as diazepam have also been advocated, but they are variably effective and the effects are short lived Analgesia may be achieved with opiates Tarantulas and Others Tarantulas not bite unless provoked The venom is mild, and envenomation is not a problem The wolf spider (Lycosa species) and the jumping spider (Phidippus species) have also been implicated in bites They also have mild venom that causes only local reactions Bites from all three of these spiders should be treated with local wound care Tick Paralysis Current evidence Ticks are responsible for transmitting a variety of infectious agents, including spirochetes, viruses, rickettsiae, bacteria, and protozoa Examples of tick-borne illness, which are discussed in Chapter 94 Infectious Disease Emergencies , include Rocky Mountain spotted fever, Lyme disease, tularemia, ehrlichiosis, babesiosis, relapsing fever, and Colorado tick fever Tick paralysis is associated with the bite of the wood tick, Dermacentor andersoni; the dog tick, Dermacantor variabilis; and the deer tick, Ixodes scapularis The gravid engorged tick releases a neurotoxin that can produce cerebellar dysfunction or an ascending paralysis The mechanism of action of the toxin is not well understood Clinical assessment Following tick attachment, there is a latent period of to days, followed by symptoms of restlessness, irritability, and ascending flaccid paralysis Respiratory paralysis and death may follow if the tick is not detected Laboratory data, including cerebrospinal fluid, are usually normal, but lymphocytic pleocytosis has been reported Management Management is based on general supportive care and a diligent search for the tick Tick removal is curative Ticks should be removed using blunt forceps or tweezers The tick should be grasped as close to the skin surface as possible and pulled upward with a steady even pressure A twisting or jerking motion may cause the mouthparts to break off Do not squeeze or crush the body of the tick because this may introduce infective agents After the tick is removed, the bite site should be cleaned Once the tick is removed, the paralysis is rapidly reversible without apparent sequelae Centipedes and Millipedes Centipedes (class Myriapoda order Chilopoda) are venomous, biting with jaws that act like stinging pincers Bites can be extremely painful; however, the toxin is relatively innocuous, causing only local reaction Treatment consists of injection of local anesthetic at the wound site and local wound care American millipedes (order Diplopoda) are generally harmless Insects The insects (class Insecta) constitute the largest number of animal species Hymenoptera is the most important order of the class and includes bees, wasps, hornets, yellow jackets, and ants ( Fig 90.19 ) Hymenoptera is responsible for 50% of human deaths from venomous bites and stings A variety of toxic reactions are seen but the most common is allergic Ants are discussed separately due to differences in venom composition and rate of systemic reactions Bee, Hornet, Yellow Jacket, Wasp Clinical recognition Clinically, the stings of bees and wasps differ because the barbed stinger of the bee remains in the victim’s skin, whereas the wasp may sting multiple times The venoms of the bee, hornet, yellow jacket, and wasp contain protein antigens that can elicit an immunoglobulin E antibody response Venoms contain various biogenic amines, phospholipase, phosphatase, and hyaluronidase Because of the similarity of the venoms, cross-reactivity can occur A single sting by a hymenopteran insect can lead to death from anaphylaxis, and multiple stings can cause serious harm through the deleterious effects of large doses of venom released Local reaction to a sting results in pain, erythema, and swelling that may involve the whole limb and persist for up to a week