A previously healthy 2-year-old girl is brought to the hospital due to lethargy and confusion for 1 day. Four days ago, the patient developed fever and nasal discharge. These symptoms resolved in 2 days, but she has been progressively tired and disoriented for the past day. The patient's older sister had a cold sore on her lip 2 weeks ago. Temperature is 37.1 C (98.8 F). On examination, she is minimally responsive. The pupils are equal and have a sluggish reaction to light. The sclerae are nonicteric, and the neck is supple. Mild hepatomegaly is present. Laboratory results are as follows: CT scan of the head reveals diffuse cerebral edema. Which of the following is most helpful to establish a diagnosis in this patient?

Question

A previously healthy 2-year-old girl is brought to the hospital due to lethargy and confusion for 1 day.  Four days ago, the patient developed fever and nasal discharge.  These symptoms resolved in 2 days, but she has been progressively tired and disoriented for the past day.  The patient's older sister had a cold sore on her lip 2 weeks ago.  Temperature is 37.1 C (98.8 F).  On examination, she is minimally responsive.  The pupils are equal and have a sluggish reaction to light.  The sclerae are nonicteric, and the neck is supple.  Mild hepatomegaly is present.  Laboratory results are as follows:  CT scan of the head reveals diffuse cerebral edema.  Which of the following is most helpful to establish a diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d68b_dd8b_bc81_353b1bf5c2f2_MD0003_00 This patient's rapid onset of encephalopathy, liver failure, and cerebral edema is concerning for Reye syndrome. This potentially fatal illness is seen in young children treated with salicylates (eg, aspirin) for a viral infection (eg, influenza, varicella). The incidence of Reye syndrome has significantly decreased since the avoidance of aspirin in the management of pediatric fever. However, sporadic cases have been linked to unintentional salicylate administration when caregivers are unaware of the contents of over-the-counter medications. Obtaining a thorough medication history in this child would help to establish the diagnosis. Pathogenesis of Reye syndrome likely relates to impaired fatty acid metabolism due to mitochondrial dysfunction. Presenting signs include vomiting and confusion after recovery from a viral illness, as seen here. Encephalopathy (ie, disorientation, lethargy) due to cerebral edema can progress rapidly to seizure, coma, and death. Characteristic laboratory findings in Reye syndrome, including elevated aminotransferases, hyperammonemia, and coagulopathy (ie, prolonged PT, INR, and PTT), reflect hepatic dysfunction due to microvesicular fatty deposits. Metabolic acidosis (ie, low bicarbonate) is typically present, and hypoglycemia may result from decreased hepatic glucose production. Regardless of the degree of liver involvement, total bilirubin usually is normal or minimally elevated, and jaundice/icterus is not typical. (Choice A) Cholinergic toxicity (eg, organophosphate exposure) presents with vomiting, diarrhea, miosis, and bradycardia, as well as excess urination, tearing, and salivation. These findings are not present in this patient. (Choice B) Unimmunized patients are at increased risk for hepatitis A and B infections, which cause elevated aminotransferases; however, hyperbilirubinemia and scleral icterus would be expected in such cases. In addition, progression of viral hepatitis to hepatic encephalopathy typically is gradual, in contrast to this patient's rapid deterioration in mental status. (Choice D) Children with encephalopathy should be evaluated for encephalitis with spinal fluid analysis. However, CNS infection is unlikely in this patient given the absence of persistent fever. Opening pressure may be elevated with Reye syndrome, but cerebrospinal fluid analysis is otherwise normal and does not aid in diagnosis. (Choice E) Urine reducing substances primarily screen for inborn errors of carbohydrate metabolism (eg, galactosemia). Although hypoglycemia and hepatomegaly can occur, these conditions present in infancy and do not cause hyperammonemia. Educational objective: Reye syndrome presents in young children with rapidly progressive encephalopathy and hepatic dysfunction after aspirin administration for a viral infection. Characteristic laboratory findings include elevated aminotransferases and hyperammonemia. Coagulopathy, hypoglycemia, and metabolic acidosis are also common. References: Reye syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/30252357) Acetylsalicylic acid as a potential pediatric health hazard: legislative aspects concerning accidental intoxications in the European Union. (http://www.ncbi.nlm.nih.gov/pubmed/27418941)

A Previously Healthy 2-Year-Old Girl Is Brought to the Hospital