Acute rhabdomyolysis and intravascular hemolysis following extensive wasp stings

Case 1: A 49-year-old woman was stung extensively by a swarm of wasps (Vespa basalis) while hiking in the mountains in southern Taiwan in November 1992. Local redness and swelling developed immediately. She ran away in panic and then lost consciousness for about 30 min. She was transferred to our emergency room 12 h later. After treatment with hydrocortisone, 100 mg, and antihistamine, the patient was discharged 1 h later in good condition, only to return the next morning with nausea, vomiting, generalized weakness, jaundice, puffy face, and oliguria, and was admitted to the intensive care unit. She had mild hypertension, but no history of wasp stings. Physical examination was remarkable for the respiratory rate (42/min), blood pressure (197/132 mmHg), and severe jaundice with hepatomegaly and pitting edema on the legs. About 100 distinct stings were noted over the neck, back, and upper extremities in association with local muscle tenderness (Fig. 1). In addition to the data given in Table 1, other abnormal data included amylase 301 U/L (normal, 25-125 U/L), lipase 980 U/L (normal, 23-208 U/L), fibrin degradation product > 1 mg/dL (normal, < 0.5 mg/dL), and haptoglobin < 5 mg/dL (normal, 53-317 mg/dL). Urinalysis revealed occult blood and protein 300 mg/dL. The results indicated severe rhabdomyolysis and hemolysis, with acute renal and hepatic failure. She developed pulmonary congestion and upper gastrointestinal bleeding. Hemoperfusion and hemodialysis were initiated on day 2. After six hemodialyses, her condition improved gradually, and she was eventually discharged in good condition on day 36. Case 2: In September 1993, a 44-year-old man was admitted to our emergency room 4 h after being stung by a swarm of wasps (V. velutina flavitarsus) while working on a mountain in southern Taiwan. He lost consciousness for about 20-30 min. Previously, he had been stung three times (only a few stings each time) without serious reaction. On examination, there were about 200 erythematous papular sting marks on his face, scalp, and around the ankles (Fig. 2). The laboratory data (Table 1) indicated severe muscle injury with some degree of hemolysis and liver function impairment. Biopsy of a skin lesion showed extensive vascular necrosis in association with skin necrosis (Fig. 3). He was treated with antihistamines and fluid supply. His condition improved and he was discharged after 5 days of hospitalization.