Pediatric emergency medicine trisk 1458 1458

Laboratory tests show profound hyponatremia that is not accounted for by gastrointestinal losses A sweat test or DNA analysis will help confirm the diagnosis Rare inborn errors of metabolism, such as inherited urea cycle disorders , may produce vomiting in young infants, who will then present with lethargy, seizures, or coma resulting from metabolic acidosis, hyperammonemia, or hypoglycemia (see Chapter 95 Metabolic Emergencies ) Galactosemia is due to a genetic defect in the metabolism of galactose and presents with vomiting, acidosis, failure to thrive, and jaundice when exposed to this sugar Hypoglycemia and liver dysfunction with coagulopathy are often present, and many develop urinary tract infections or sepsis due to gram-negative organisms Testing with a CBC, electrolytes, bicarbonate, blood glucose, liver function (including coagulation studies), urinalysis for ketones, and plasma ammonia levels is indicated in young infants with gastroenteritis, lethargy, or irritability to evaluate for metabolic conditions Collect extra plasma (2 mL) and urine (5 mL) for additional testing, ideally before providing fluid resuscitation and dextrose Inquiry about neonatal screening is important; consider sending a follow-up blood filter paper specimen to the newborn screening laboratory Rapid bedside testing for glucose and sodium is recommended for immediate recognition and therapy Hypoglycemia also can be secondary to sepsis, certain drugs, or alcohol intoxication Young infants are incapable of accidental ingestions, but one should consider toxins (see Chapter 102 Toxicologic Emergencies ) in certain cases Wellmeaning parents may rarely cause salicylism in their attempts to aggressively treat fever with aspirin Affected infants can then present with vomiting, hyperpnea, hyperpyrexia, convulsions, or coma The history of medication given is crucial because the physical examination will not distinguish this ill baby from the infant with sepsis The laboratory evaluation may lead to the suspicion of a metabolic problem because abnormalities of sodium, blood sugar, or acid–base balance are often found Moreover, hypokalemia can be seen in salicylism, as well as abnormal liver function or renal function studies An elevated salicylate level in the serum confirms the diagnosis of aspirin poisoning, but in chronic poisoning, the aspirin level may be relatively low, even in patients with a fatal course Carbon monoxide poisoning may present as an unknown intoxication when families are unaware of a defective heating system in the home A history of sluggishness, poor feeding, vomiting, and other family members who are also ill with headache, syncope, or flu-like symptoms that improve after leaving the home environment, suggest this poisoning The classic “cherry red” skin color