Recluse spider envenomation is a clinical diagnosis. Diagnostic studies may assist when other medical conditions are in the differential diagnosis and when evaluating for systemic loxoscelism. A urinalysis suffices for patients without systemic symptoms. Additional studies, including CBC, BUN, creatinine, serum electrolytes, fibrinogen, and a hepatic panel, are recommended in symptomatic patients and when there are findings on urinalysis suggestive of hemolysis. Imaging is rarely necessary, but ultrasound may be helpful in distinguishing an abscess from the local findings of a recluse bite, which is important because treatments for the two are entirely different. Local effects following recluse envenomation are best managed conservatively. The area should be kept clean. Cool packs may relieve local discomfort. Prophylactic antibiotics should not be prescribed. Most importantly, recluse bites should not be incised. Unlike soft tissue infections, there is nothing to be drained from a recluse bite. Furthermore, only a small minority of recluse bites—as few as 3% in one study—will require skin grafting, and premature surgical intervention can delay or even prevent wound healing. 89 Other previously recommended treatments that have proven to lack efficacy and may even cause harm include dapsone, nitroglycerin, and corticosteroids for local findings. The benefit of hyperbaric oxygen in recluse bite wound healing is uncertain. Systemic loxoscelism is managed supportively. In addition to previously recommended interventions, blood transfusion may be necessary in patients with significant hemolysis leading to anemia. Plasmapheresis may be necessary. Although corticosteroids do not provide benefit for local effects, they may be indicated for significant systemic loxoscelism.
Figure 17. Recluse Spider Bite at 10 Days
Source: Spencer Greene In addition to the classic local findings attributed to recluse spider bites, patients can also develop systemic illness. Loxoscelism develops 24–96 hours after the bite and is characterized by some combination of diffuse erythematous rash, fever, myalgias, nausea, vomiting, abdominal pain, and diarrhea. Hemolysis may be severe, particularly in children, and this can lead to renal failure, pulmonary edema, disseminated intravascular coagulation, cardiac collapse, and death. Children are particularly vulnerable. In a retrospective study of 111 L. reclusa bites by Wright et al., 15 (14%) patients had systemic loxoscelism. 89 There were no deaths. Tarantulas Worldwide, there are more than 1,000 spider species described as “tarantulas.” However, there is only one genus of tarantula native to the U.S., Aphonpelma , and multiple species are distributed throughout the Southwest. 70 A variety of tarantulas are maintained in private collections. Popular spiders kept in captivity include the Peacock tarantula ( Poecilotheria metallica ), Mexican Redknee tarantula ( Brachypelma hamorii ), and Chilean Rose tarantula ( Grammostola rosea ). Bites from native tarantulas typically cause minor effects, including edema and local pain. When these spiders are provoked, they may also use their hind legs to flick hairs off of their abdomen. These hairs can be irritating to eyes and mucus membranes. Treatment includes irrigation and symptomatic relief. Case study 2: Spider bite A 2-year-old male presents to the emergency department in severe pain. He had been in his usual state of good health until just prior to arrival. He had been playing in the garage. Mom did not see any open containers and does not believe the patient ingested anything or spilled anything on himself. There has been no vomiting. Vital signs: BP 150/90, HR 154, R 20, T 99.5, 99% O2 He is uncomfortable, appearing diaphoretic. There is no dyspnea or cyanosis. The right leg is slightly erythematous and mildly swollen. There are no bruises or discrete lesions. Slight muscle spasms are noted. His abdomen is tense.
Figure 18. Peacock Tarantula (Poecilotheria Metallica)
Source: Adrian Martinez
Figure 19. Spider Bite
Source: Spencer Greene
EliteLearning.com/Pharmacy-Technician
Book Code: RPTTX2024
Page 25
Powered by FlippingBook