4-year-old male presents to a local emergency room with a 2-day history of watery diarrhea and crampy abdominal pain. Over the past several hours he had some vomiting and had one stool described as liquidy red. The review of systems was negative for fever, rash, joint pain and he has had normal urine output. He was admitted and during his hospital course he continued to have bloody diarrhea, abdominal pain and then developed low-grade fever, hip pain and decreased urine output to 0.2 cc/kg/hour. His physical examination revealed diffuse abdominal pain with active bowel sounds, no organomegaly, no rectal fissures or hemorrhoids, normal musculoskeletal examination and purpura on his upper and lower extremities. His initial laboratory evaluation showed a hemoglobin = 12.4 g/dl, hematocrit = 37%, WBC = 13,000 /mm2, platelets = 300,000 /mm2, electrolytes were normal, BUN = 25 mg/dl and creatinine = 0.7 mg/dl. During his hospitalization his platelets decreased to 70,000/mm2 and his BUN and creatinine rose to 44 mg/dl and 2.2 mg/dl respectively. His potassium rose to 5.3 mEq/l. A clinical diagnosis of hemolytic uremic syndrome (HUS) was made and his stool culture later grew E. coli 0157:H7. He received peritoneal dialysis and had improving renal function at discharge.
Diarrhea is the softening of the consistency of the stools with or without a change in the frequency of the stools. Any child may have complications such as dehydration or sepsis because of diarrhea.
Infectious Diarrhea is a common cause of bloody diarrhea. For any individual case of diarrhea, bacterial causes are more likely to have blood associated with them than viral causes. But viral diarrhea is so much more common overall than bacterial diarrhea, that viruses are the most common cause of infectious bloody diarrhea.
Common infectious agents causing bloody diarrhea include:
- Bacteria – Campylobacter, Clostridium difficile, Salmonella, Shigella, Vibrio cholerae
- Viruses – Adenovirus, Norwalk virus, Rotavirus
- Parasites – Ameba, Cryptosporidium, Giardia
HUS is an uncommon but potentially life-threatening cause of diarrhea. Young children, usually 9 months-4 years, begin with a mild gastroenteritis, that overtime becomes a constellation of blood diarrhea, purpura, pallor, hematuria, decrease urine output and possibly renal failure. The children can also have seizures, liver or endocrine abnormalities, and even myocarditis. The laboratory evaluation shows thrombocytopenia, microangiopathic hemolytic anemia, proteinuria and hematuria in the urine, and electrolyte abnormalities including hyperkalemia and elevated BUN and creatinine. The cause in 85% of cases is E. coli 0157:H7. Treatment is mainly supportive with scrupulous fluid and electrolyte management. Red blood cell transfusions are sometimes used but platelet transfusions should be avoided if possible. Other treatments such as antiplatelet drugs or fibrinolytic therapy have not shown benefit. Mortality is 3-5% mainly because of neurological problems. Almost all patients are able to stop dialysis and 60% have full recovery of renal function.
Main indications for renal dialysis include:
- Creatinine clearance < 10 ml/min/1.73 M2
- General symptoms that are worsening, i.e. decreased appetite, emesis/nausea, decreased exercise tolerance/fatigue, poor school performance, growth failure, etc.
- Nutritional needs that cannot be maintained with necessary fluid restriction
- Fluid overload
- Metabolic abnormalities such as uncontrolled hyperkalemia, hyperphosphatemia, hyperuricemia, hypernatremia, hypocalcemia, and severe acidosis or alkalosis
- Dialyzable toxin
Peritoneal dialysis (PD) and hemodialysis are both options for pediatric patients. Advantages of PD include generally stable serum biochemistries and blood pressure, fewer dietary and fluid restrictions, able to be performed home (if chronic PD), and fewer needs for erythropoietin and blood transfusions. PD is also a good choice for patients with cardiovascular disease or that live far from a dialysis center. It is also easier to perform for small children because of their small size, high rate of thrombosis, and the need for skilled personnel. The main risks of PD are peritonitis and catheter infections.
This patient required transient PD because of oliguria, hyperkalemia, fluid overload and his nutritional needs were not being able to be met because of fluid restriction.
Questions for Further Discussion
1. What public health follow-up is necessary when E. coli 0157:H7 is identified?
2. What other infectious organisms cause HUS?
3. What are the advantages and disadvantages of hemodialysis?
4. What are other non-infectious causes of bloody diarrhea?
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Fleisher GR, Ludwig S. Synopsis of Pediatric Emergency Medicine. Williams and Wilkins. Baltimore, MD. 1996.
Rudolph CD, et.al. Rudolph’s Pediatrics 21st edit. McGraw-Hill, New York, NY. 2003.
Woodhead JC. Pediatric Clerkship Guide. Mosby., St. Louis MO, 2003.
Biega T. Prauner R. Hemolytic-Uremia Syndrome. eMedicine.org. Available from the Internet at: http://www.emedicine.com/ped/topic960.htm (rev. 3/4/2004, cited 10/8/04).
Donna M. D’Alessandro, MD
Associate Professor of Pediatrics, Children’s Hospital of Iowa
October 25, 2004