A 55-year-old electrician comes to the emergency department due to a wound to his right leg that started 3 days ago. After crawling through an attic laying electrical wire, he developed a stabbing pain and burning sensation in his right thigh. The patient noticed a small, red area on his posterior right thigh, with 2 small dots in the middle. He thinks he was bitten by one of the small, brown spiders he saw in the attic. The pain lasted a few hours and then subsided. Several hours later a blister formed. Over the next 2 days, a black area appeared in place of the blister and has expanded toward his feet. Temperature is 36.7 C (98.1 F), blood pressure is 140/80 mm Hg, pulse is 76/min, and respirations are 16/min. On examination, the patient is awake and alert, and nontoxic in appearance. He has a 2-cm, dry eschar on his posterior right thigh. There is a surrounding outer ring of erythema. No significant swelling or fluctuance is present. He has normal pulses distal to the wound. Which of the following is the best next step in management of this patient?

Question

A 55-year-old electrician comes to the emergency department due to a wound to his right leg that started 3 days ago.  After crawling through an attic laying electrical wire, he developed a stabbing pain and burning sensation in his right thigh.  The patient noticed a small, red area on his posterior right thigh, with 2 small dots in the middle.  He thinks he was bitten by one of the small, brown spiders he saw in the attic.  The pain lasted a few hours and then subsided.  Several hours later a blister formed.  Over the next 2 days, a black area appeared in place of the blister and has expanded toward his feet.  Temperature is 36.7 C (98.1 F), blood pressure is 140/80 mm Hg, pulse is 76/min, and respirations are 16/min.  On examination, the patient is awake and alert, and nontoxic in appearance.  He has a 2-cm, dry eschar on his posterior right thigh.  There is a surrounding outer ring of erythema.  No significant swelling or fluctuance is present.  He has normal pulses distal to the wound.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d851_a9f1_bc81_c531de7acf75_MD0003_00 This patient has a classic presentation of a Loxosceles reclusa (brown recluse) spider bite. L reclusa spiders, common in the United States, are found in warm, dry areas (eg, attics, woodpiles, cellars). Although their bites can be painful, they are often initially painless, so spider identification rarely occurs. Burning pain due to local ischemia can start a few hours after the bite and become severe. A small, red papule appears first and often heals in days to weeks without intervention. In severe cases, blister formation occurs in the first 24 hours with a blueish discoloration; the area becomes necrotic (10% of bites) and expands in size over the next week, usually in a gravity-dependent manner. Initial treatment involves local wound care and pain control. The site should be cleaned and cold compresses applied. The activity of venom phospholipases, believed to be responsible for most local tissue necrosis, is decreased by cold therapy. Nonsteroidal anti-inflammatory drugs or opioids should be used for pain management. Most cases resolve with these measures. The only proven therapy is antivenom (not approved for use in the United States). Other researched therapies (eg, dapsone, tetracycline, glucocorticoids, hyperbaric oxygen) have not demonstrated a conclusive benefit. In some cases, surgical wound débridement can be helpful once the necrosis has stopped advancing; however, if performed too early, this procedure may cause increased pain and wound breakdown. (Choice A) Corticosteroids have anti-inflammatory properties and are administered in immune-mediated diseases. Oral steroids are useful in management (IgE-mediated) of large local reactions to insect stings (eg, bees), characterized by exaggerated local erythema and edema. However, the benefit of corticosteroids in patients with L reclusa bites remains unclear, and their use is controversial. (Choice B) Hyperbaric oxygen therapy is sometimes used in nonhealing chronic wounds because it increases the amount of oxygen delivered to damaged tissue and promotes collagen synthesis, angiogenesis, and fibroblastic proliferation. When applied to patients with dermonecrosis from L reclusa bites, it has not proven beneficial. (Choice C) Oral antistaphylococcal antibiotics are appropriate when evidence of infection is present (eg, fever, cellulitis, abscess). This patient is afebrile; swelling and fluctuance are not present. Skin findings are a result of ischemia, not infection. Educational objective: Patients with a Loxosceles reclusa (brown recluse) spider bite initially have a small, red papule that can progress to form a larger necrotic wound (loxoscelism). Most cases will resolve with the application of cold packs and local wound care.

A 55-Year-Old Electrician Comes to the Emergency Department Due to a Wound