Management Guide for Hemolytic Uremic Syndrome (HUS)

He Hemolytic Uremic Syndrome (HUS) It is a serious disease characterized by thrombotic microangiopathy. This means that small blood clots form in the smallest blood vessels in the body.

These clots can cause:

Hemolytic anemia: Red blood cells are destroyed as they pass through clogged vessels.
Thrombocytopenia: Platelets are consumed in the formation of clots, leading to a low count.
Acute Kidney Injury: Clots damage the small vessels in the kidneys, affecting their ability to filter blood.

Most common cause: Most cases in children (more than 90%) are caused by infection with a strain of the bacteria Escherichia coli which produces Shiga toxin (STEC), often after an episode of bloody diarrhea. This is known as typical SHU or D+.

Clinical Suspicion Criteria

HUS should be suspected in any child who presents the classic triad, especially after an episode of diarrhea (usually bloody).

Microangiopathic Hemolytic Anemia

(Paleness, jaundice, schistocytes)

Thrombocytopenia

(Petechiae, ecchymosis)

Acute Kidney Injury

(Oliguria, anuria, edema, HBP)

Initial Studies Panel

Study	Expected Finding in SHU
Complete Blood Biometry	Anemia (Hb < 10 g/dL), Thrombocytopenia (< 150,000/µL)
Peripheral Blood Smear	Presence of schistocytes ("bitten" cells)
Blood Chemistry	Elevation of Creatinine and BUN
Hemolysis Tests	Elevated LDH, Decreased Haptoglobin, Elevated indirect bilirubin
Serum electrolytes	Hyperkalemia, hyponatremia, metabolic acidosis
General Urine Examination	Hematuria, proteinuria
Coproparasitoscopic and Shiga toxin in feces	STEC-HUS confirmation

Key Principle

The mainstay of treatment is support management. There is no specific curative therapy for typical HUS (Shiga toxin-associated).

1. Fluid and Electrolyte Management

It is crucial to maintain euvolemia. Avoid water overload.

Initial solution: Saline 0.9%.
Aim: Maintain urine output > 1 ml/kg/hr.
Strict monitoring: Water balance, daily weight, vital signs.

2. Management of Arterial Hypertension (HTN)

1st Line Medication	Presentation	Dose
Amlodipine	Tablets 5 mg	0.1 - 0.2 mg/kg/day, divided into 1-2 doses. Max 0.6 mg/kg/day.
Labetalol IV (HBP Crisis)	Sol. Injectable 5 mg/ml	Bolus: 0.2-1 mg/kg/dose. Infusion: 0.25-3 mg/kg/hour.

3. Re-evaluation and Monitoring Criteria

Re-evaluation must be continuous.

Every 4-6 hours: Vital signs, neurological status.
Every 12-24 hours: BH, kidney function, electrolytes.

Indications for Referring to the Pediatric Nephrologist

The reference must be IMMEDIATE before any of the following data:

Severe anuria or oliguria (>24h).
Volume overload refractory to diuretics.
Severe or difficult to control arterial hypertension.
Severe electrolyte alterations (Hyperkalemia > 6.5 mEq/L, severe acidosis).
Neurological compromise (seizures, lethargy, focusing).
Imminent need for dialysis.
Suspected atypical HUS (aHUS): no previous diarrhea, recurrences, family history.

Management by Nephrology

The nephrologist will evaluate the need for renal replacement therapies and specific treatments.

Therapeutic Option	Main Indications
Peritoneal Dialysis / Hemodialysis	Refractory anuria, fluid overload, symptomatic uremia, hyperkalemia or acidosis.

Management of Atypical HUS (aHUS)

aHUS requires a different approach, focusing on complement inhibition.

Medicine	Presentation	Dosage (example)
Eculizumab	Sol. Injectable 300 mg/30 ml	Dose by weight. Ex: 5-10 kg: 300 mg initial, then maintenance.

*Eculizumab is a highly specialized drug and its use is exclusive to pediatric nephrologist/hematologist.

Reference to Other Specialties

Hematology: Severe thrombocytopenia, need for plasmapheresis.
Gastroenterology: Severe colitis, rectal prolapse.
Pediatric Neurology: Any manifestation in the CNS.
Pediatric Cardiology: If there is evidence of cardiomyopathy or pericardial effusion.

What YES to do

Wash hands, fruits and vegetables well.
Thoroughly cook meat, especially ground meat.
Consult the doctor immediately if your child has bloody diarrhea.
Follow medical instructions regarding liquids and medications to the letter.
Monitor the amount of urine the child produces.
Ask all your questions to the health team.

What NOT to do

NEVER give antibiotics or medications to stop diarrhea (antimotility) without medical indication, as they may increase the risk or severity of HUS.
Do not consume unpasteurized milk or juices.
Do not self-medicate the child with anti-inflammatories (such as ibuprofen) if HUS is suspected, as they can further damage the kidney.
Do not ignore symptoms such as decreased urination, swelling or bruising.

Joseph C, et al. A clinical approach to the child with bloody diarrhea. Pediatr Rev. 2020;41(1):19-29.
Loirat C, Fakhouri F, Ariceta G, et al. An international consensus approach to the management of atypical hemolytic uremic syndrome in children. Pediatr Nephrol. 2016;31(1):15-39.
Mele C, Remuzzi G, Noris M. Hemolytic uremic syndrome. Buy Physiol. 2014;4(2):611-645.
Nelson Textbook of Pediatrics, 21st Edition. Kliegman RM, St. Geme JW, Blum NJ, et al. Elsevier, 2020.
UpToDate®. Overview of hemolytic uremic syndrome in children. (Consulted in 2024).