What is the immediate management for a patient diagnosed with haemolytic uraemic syndrome (HUS)?

Immediate Management of Haemolytic Uraemic Syndrome (HUS)

Patients with suspected or confirmed haemolytic uraemic syndrome (HUS) should be treated as a medical emergency with immediate transfer to a specialized reference center, prompt initiation of supportive measures, and early complement inhibition therapy for atypical HUS cases to prevent irreversible organ damage or death. 1, 2

Initial Assessment and Diagnosis

• Confirm the diagnosis through identification of the classic triad:

  • Microangiopathic hemolytic anemia (schistocytes >1%, elevated LDH, reduced haptoglobin)
  • Thrombocytopenia (<150,000/mmc or 25% reduction from baseline)
  • Acute kidney injury (elevated creatinine, hematuria/proteinuria) 2

• Immediately differentiate between types of HUS:

  • Obtain ADAMTS13 activity to rule out TTP (activity <10% indicates TTP)
  • Test for Shiga toxin-producing E. coli (STEC) to identify typical HUS
  • Consider atypical HUS (aHUS) if no STEC identified or atypical presentation 2

Emergency Management Protocol

1. Transfer to specialized center:

   • Patients with suspected HUS should be immediately transferred to a reference center with multidisciplinary expertise 1
   • For critically ill patients in ICUs without specialized HUS expertise, establish urgent teleconsultation with reference centers 1

2. Supportive care measures:

   • Fluid and electrolyte management
   • Blood pressure control
   • Initiate renal replacement therapy if indicated by severe kidney injury
   • Management of hematological complications 2, 3

3. For atypical HUS:

   • Initiate complement inhibition therapy within 4-8 hours of diagnosis
   • First-line options:
     • Eculizumab (anti-C5 monoclonal antibody)
     • Ravulizumab (longer-acting C5 inhibitor) 1, 2, 4

4. For typical HUS (STEC-associated):

   • Supportive care is the mainstay of treatment
   • Avoid antibiotics and antidiarrheal medications which may worsen toxin release 2, 3

5. For TTP:

   • Plasma exchange (PEX) and high-dose corticosteroids 2

Critical Preventive Measures with Complement Inhibitors

• Mandatory meningococcal vaccination prior to or concurrent with initiation of complement inhibitor therapy
• Antimicrobial prophylaxis with penicillin (or macrolides if allergic) during treatment 1, 2
• Monitor complement parameters (C3, C4, CH50, AP50) during treatment 1

Monitoring and Follow-up

• Regular assessment of:
  • Platelet count
  • Hemoglobin
  • LDH levels
  • Renal function
  • Neurological status (10-20% of aHUS cases have neurological involvement) 1, 2

Special Considerations

• Pediatric patients: Create a multidisciplinary team including neurologist, emergency physician, psychologist, pediatrician, hematologist, and nephrologist 1

• Genetic testing: Should be performed for suspected aHUS cases, with results ideally available within months to guide long-term management 1, 5

• Discontinuation of complement inhibitors: Should be approached with caution as there is a 10-20% risk of relapse after discontinuation; patients must be thoroughly assessed for risk factors before considering discontinuation 1

Treatment Outcomes and Expectations

• With complement inhibition therapy for aHUS:

  • Complete thrombotic microangiopathic response in 54-65% of patients
  • Significant reduction in dialysis requirement
  • Substantial improvement in renal function and quality of life 4

• Without appropriate treatment, aHUS historically led to high rates of kidney failure and death 4, 6

Common Pitfalls to Avoid

• Delaying transfer to specialized centers
• Missing the diagnosis due to incomplete presentation (not all three clinical signs may be present initially)
• Administering antibiotics or antidiarrheal medications in STEC-HUS
• Failing to provide meningococcal vaccination and prophylactic antibiotics with complement inhibitor therapy
• Overlooking neurological complications 1, 2, 3

The immediate and decisive management of HUS is critical to patient outcomes, with early recognition and appropriate treatment significantly reducing the risk of irreversible organ damage or death.