Certainly we have been seeing (and will continue to see) a lot of nonspecific diarrheal illness in the Ped ED. Before you dismiss the patient as having “gastroenteritis,” consider whether this is something else, like hemolytic uremic syndrome (along with all of the other badness out there; ie Appendicitis).

HUS Basics

• Microangiopathic hemolytic anemia, thrombocytopenia, and renal insufficiency
• Has an increased incidence during summer and early fall (like now).
• HUS without associated Diarrhea (D-) does not have seasonal variation, but HUS associated with Diarrhea (D+) does.
• D+HUS is more common than D-HUS.

HUS Presentation

• The diarrhea associated with D+HUS may be bloody or merely watery.
• It is best to detect HUS early in its disease course to have the best outcome.
  • Things to look for:
    • Early signs and symptoms occur 2-14 days after the onset of diarrhea.
    • Lethargy (of course)
    • Decreased urine output in a patient that clinically is well-hydrated (listen to the parent)
    • Pallor (always good to document the presence or lack of pallor in a patient you diagnose as having Gastro)
    • Edema (often periorbital, typically in the morning – ask about this specifically)
  • If these signs are present, consider CBC, Electrolytes, and U/A. Many will also obtain these labs in patients with bloody stools.
  • Remember that thrombocytopenia (plts <150,000/mm3) within the 1st week of a diarrheal illness may be an early sign of impending HUS and can occur prior to evidence of anemia or renal insufficiency.
  • Additionally, there are findings on ultrasound that may lead to the early recognition of HUS:
    • Marked thickening of the large bowel intestinal wall
    • Increased echogenicity of the renal parenchyma (from immune-complex deposition in glomeruli)
    • May prove to be a useful adjunct in the initial evaluation of children with bloody diarrhea, where these findings may lead to the early recognition of the prodrome of HUS. [Glatstein]

Glatstein, M., et al., Timing and utility of ultrasound in diarrhea-associated hemolytic uremic syndrome: 7-year experience of a large tertiary care hospital. Clin Pediatr (Phila). 49(5): p. 418-21.