Grand Rounds

Obese Man With Severe Pain and Swollen Hand

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An obese 43-year-old Hispanic man presents to the emergency department (ED) with complaints of severe pain and swelling in his right hand. The patient states that he felt a bite on his hand as he was planting flowers and laying down potting soil near a tree and decorative rocks in his yard. He did not seek immediate medical treatment because the pain was minimal.

As the hours passed, though, the pain increased, and he began to notice tightness in his hand. Twelve hours after the initial bite, the pain became intolerable and his hand swelled to double its normal size, such that he could no longer bend his fingers. He then sought treatment at the ED.

The patient denies previous drug use but indicates that he smokes 1.5 packs of cigarettes daily and drinks alcohol occasionally in social settings. He has no known drug or food allergies. His history is remarkable for hypertension and hyperlipidemia, treated with simvastatin (40 mg/d) and lisinopril (10 mg/d), respectively.

The physical examination reveals an arterial blood pressure of 152/84 mm Hg; heart rate, 76 beats/min; respiratory rate, 18 breaths/min-1; and temperature, 99ºF. His height is 5 ft 8 in and weight, 297 lb. Cardiovascular examination reveals no irregular heart rhythm, and S1 and S2 are heard, with no murmurs or gallops. He denies chest pain and palpitations. Respiratory examination reveals clear breath sounds that are equal and unlabored. He denies shortness of breath or coughing. The patient states that he had nausea earlier that day, but it has subsided.

Dermatologic examination reveals severe erythema and 3+ edema in the patient’s right hand. A 3-cm, irregularly shaped, red, hemorrhagic blister is observed close to the thumb on the posterior side of the right hand. There are two small holes in the center and slight bruising around the lesion. The right hand is hard and warm to the touch upon palpation, and the patient rates his pain as severe (10 out of 10).

The symptoms of severe pain and swelling and the early observation of bruising and hemorrhagic blistering raise suspicion for venomous spider bite (ICD-10 code: T63.331A). Laboratory work-up, including complete blood count, electrolytes, kidney function studies, and urinalysis, is performed. The results are inconclusive, and the reported symptoms and objective assessment are used to make the diagnosis of spider bite.


The brown recluse spider (Loxosceles reclusa) is notorious for its bite, which can result in dermonecrosis within 24 to 48 hours. It inhabits the lower Midwest, south central, and southeastern regions of the United States and is not endemic in the West, Northeast, Mid-Atlantic, or Coastal South. Brown recluse spiders are nonaggressive and prefer warm, dark, dry habitats, dwelling under rocks, logs, woodpiles, and debris, as well as in attics, sheds, basements, boxes, travel bags, and motor vehicles.1,2 They can survive for months without food and can withstand temperatures ranging from 46.4°F to 109.4°F.3 They build irregular, cottony webs that serve as housing but are not used to capture prey.3 (Note that webs found strung along walls, ceilings, outdoor vegetation, and in other exposed areas are nearly always associated with other types of spiders.) The brown recluse is nocturnal, seeking insect prey, either alive or dead.

Brown re­cluse spiders range in size from 6 mm to 20 mm; they have a violin-shaped pattern on the cephalothorax and long legs that allow them to move quickly (see Figure 1). A distinguishing feature is their six eyes, arranged in three pairs (most spiders have eight eyes).

Loxosceles reclusa image

Venom production is influenced by the size and sex of the spider as well as ambient temperature.4 The venom contains at least eight enzyme and protein components, including the most active enzyme, sphingomyelinase D.3 This enzyme causes dermonecrosis, platelet aggregation, and complement-mediated hemolysis in vitro, and it may also be responsible for the ulcerating and systemic effects observed in humans.5 Sphingomyelinase D has been shown to induce grossly visible tissue necrosis in rabbit tissue within 24 hours after envenomation.3


The brown recluse spider bite may be imperceptible at the time of envenomation, requiring no medical attention. Depending on a person’s sensitivity level and the amount of venom injected, however, a mild stinging sensation at the site may be felt, which is usually accompanied by redness and inflammation that may disappear within seconds or last for a couple of hours.6

Within two to eight hours, severe pain may occur, progressing to a burning sensation.5 The bite site will become pale, due to venom-induced vasoconstriction, with increasing erythema and swelling in the surrounding tissue.5 This extreme pain could be due to absorption of the venom by the muscle tissues; if untreated, further tissue damage can occur. Within 12 to 24 hours, there is painful edema with induration and an irregular area of ecchymosis and ische­mia.7 Occasionally, the site will develop red, white, and blue hemorrhagic blisters, with the blue ischemic portion centrally located and the red erythematous areas on the periphery.8 In almost half of all cases, the lesion is associated with nonspecific systemic symptoms, such as generalized pruritus and rash, headache, nausea, vomiting, and low-grade fever in the first 24 to 48 hours.7

Three days after envenomation, the wound will expand and deepen, with skin breakdown noted not sooner than 72 hours after the bite (see Figure 2).7,8 After five to seven days, the cutaneous lesion forms a dry necrotic eschar with a well-­demarcated border. Within two to three weeks after the bite, the necrotic tissue should detach, and the wound should develop granulated tissue that indicates healing.8 Complete healing can take weeks or months, depending on the extent and depth of the wound, with scarring possible in severe cases.7

Bite of the Brown Recluse Spider image

Severe systemic illness (ie, systemic loxoscelism)—rare in the US—is a potential complication of the brown recluse spider bite.4 It manifests with fever, malaise, vomiting, headache, and rash; in rare instances, it results in death.7


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