Which clinical history findings are characteristic of pediatric hemolytic uremic syndrome (HUS)?

Updated: Nov 12, 2018
  • Author: Robert S Gillespie, MD, MPH; Chief Editor: Craig B Langman, MD  more...
  • Print
Answer

Features of all forms of hemolytic-uremic syndrome include the following:

  • Hematology: Hemolysis occurs in all patients with hemolytic-uremic syndrome. It can proceed rapidly, resulting in a rapid fall of the hematocrit. Platelet counts usually fall below 40,000/µL. However, the degree of thrombocytopenia does not correlate with the severity of hemolytic-uremic syndrome, and some children can maintain relatively normal kidney function despite severe hematologic abnormalities. Many patients have petechiae, purpura, and oozing from venipuncture sites. Overt bleeding is less common.

  • CNS: Patients often present with sudden onset of lethargy and irritability. Other findings may include ataxia, coma, seizures, cerebral swelling, hemiparesis, and other focal neurologic signs. CNS changes may be caused by cerebral ischemia from microthrombi, effects of hypertension, hyponatremia, or uremia. aHUS tends to be associated with a greater number of neurologic symptoms than STEC-HUS.

  • Renal system: Acute renal insufficiency usually begins with the onset of hemolysis. Although patients have decreased urine output, frequent diffuse watery stools may mask this sign. If renal insufficiency is not recognized and treated, hyponatremia, hyperkalemia, severe acidosis, ascites, edema, pulmonary edema, and hypertension ensue.

  • GI tract: STEC-HUS is usually preceded by 3-12 days of watery or bloody diarrhea. Vomiting and crampy abdominal pain are also common. Note that diarrhea may improve as the other hemolytic-uremic syndrome symptoms begin (eg, thrombocytopenia, renal insufficiency). Life-threatening complications include intestinal perforation or necrosis. Even without these complications, the colitis of hemolytic-uremic syndrome may cause severe abdominal pain, which may persist for several days into the illness.

  • Infectious signs: Fever is present in 5-20% of patients. The presence of fever, leukocytosis, or both is a prognostic indicator of the risk of developing more severe hemolytic-uremic syndrome.

  • Pancreas: Mild pancreatic involvement is common but can be severe on occasion, with necrosis, pseudocysts, or both, which can leave the patient with type 1 diabetes and, on rare occasion, exocrine dysfunction.

  • Cardiovascular: Congestive heart failure may occur.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!