Shock and Severe Anemia in a Pediatric Patient

A 10-year-old boy with speech delay and intellectual disability presents with decreased activity and reduced oral intake for 4 days. An interpreter assists in the evaluation and care of the patient because of a language barrier. His presenting vital signs include a temperature of 36.6°C, heart rate of 120 beats per minute, respiratory rate of 20 breaths per minute, blood pressure of 117/66 mm Hg, and oximetry at 96% in room air. At initial assessment, he is listless, with 1+ peripheral pulses and a capillary refill of 4 seconds. His skin examination shows a warm, hyperpigmented, macular rash with rough texture on his trunk and upper extremities (Figure 1). Given his ill appearance, a venous blood gas (VBG) is obtained with a pH of 7.04, Pco2 of 27, Po2 of 34, bicarbonate ion (HCO3) of 7, and base excess of −21.6. Additional laboratory values collected included a complete blood cell count (CBC), basic metabolic panel, blood glucose, and blood culture (Table 1). The peripheral smear showed erythrocytes with marked anisocytosis, moderate polychromasia, some microspherocytes, red blood cell (RBC) fragments, and neutrophils with increased left shift and toxic granulation, which is consistent with hemolysis and leukemoid reaction. A urinalysis was unable to be obtained owing to the patient’s critical condition and underlying volume deficit. His physical examination and laboratory result abnormalities prompted rapid initiation of fluid, unmatched packed RBCs, and antibiotic administration.After the initial fluid bolus, the patient becomes hypotensive, with laboratory values demonstrating worsening acidosis, ie, a repeated VBG with a pH of 6.89, Pco2 of 22, Po2 of 35, HCO3 of 4, base excess of −29, and a lactate of 27 mmol/L. Resuscitative efforts included oxygen, intravenous (IV) fluid boluses, a dextrose bolus, antibiotics, blood transfusion, and sodium bicarbonate. During resuscitation, the patient has worsening mentation and increased respiratory effort; high-flow supplemental oxygen is started, with mild improvement in his respiratory status. He is admitted to the pediatric intensive care unit (PICU) for continued medical management and further evaluation of an underlying source of illness. After initial stabilization in the PICU, further history reveals he had completed treatment with a 7-day course of amoxicillin 1 week prior to presentation for suspected soft tissue cellulitis at the left shoulder and was doing well at home. Continued evaluation during PICU hospitalization demonstrates an evolving, desquamating diffuse rash and an area on his left shoulder that develops into an eschar (Figure 2), which suggests the diagnosis.The examination and history of the patient is suggestive of a range of diagnoses, including septic shock, hemolytic anemia, hypovolemic shock, toxic shock syndrome, drug reaction with eosinophilia and systemic symptoms, leukemia, Stevens-Johnson syndrome, and systemic loxoscelism. Continued evaluation and treatment of the patient strongly suggests the final diagnosis of systemic loxoscelism.Systemic loxoscelism is a rare and life-threatening condition occurring from a brown recluse (Loxosceles reclusa) spider bite that should be considered in patients with hemolysis and acidosis, especially in the setting of recent suspected cellulitis or eschar formation. The brown recluse spider is native to the midwestern and south-central United States and is a non–web-forming spider that is found in dark enclosed spaces (eg, garage, basement, etc).1 It is 1 of 2 venomous spiders native to North America. Many patients do not know that they were bitten by the spider at the time of injury. The venom has 2 main toxins: sphingomyelinase D, causing hemolysis and tissue necrosis, and hyaluronidase, which allows for hematogenous spread of the venom.2 The bite typically will present as a flat, painless lesion with central pallor caused by capillary bed destruction. Patients may have significant pain out of proportion to the rash, owing to the cytokine release over the first 2 to 8 hours.3 Brown recluse bites may develop localized swelling (