Management of Atypical Hemolytic Uremic Syndrome (aHUS) When a Hematologist is Not Readily Available

Diagnostic Workup and Stabilization Measures

The American Society of Hematology recommends a complete blood count with peripheral blood smear to look for schistocytes >1% and platelet count <150,000/mm³ or 25% reduction from baseline in patients with suspected aHUS/TMA 1, 2
Hemolysis markers such as LDH, haptoglobin, direct and indirect Coombs test, reticulocyte count, and bilirubin should be evaluated in patients with suspected aHUS/TMA 1, 2
Renal function should be assessed through serum creatinine and urinalysis for hematuria and/or proteinuria in patients with suspected aHUS/TMA 1, 2
ADAMTS13 activity level should be measured to distinguish aHUS from TTP, with a level >5% indicating aHUS 1, 2
Complement testing, including C3, C4, and CH50, should be performed to assess complement pathway activation in patients with suspected aHUS/TMA 2, 3

Patients with suspected aHUS/TMA should be admitted immediately for continuous monitoring 4
IV access should be established and prepared for potential transfusion support in patients with suspected aHUS/TMA 5
Type and screen for blood products should be performed, and the blood bank should be notified that transfusions may need to be irradiated and filtered depending on the final diagnosis 2, 6
Platelet transfusions should be avoided unless there is life-threatening bleeding, as they may worsen thrombotic complications 5

The American College of Physicians recommends immediate telephone or telemedicine consultation with a hematologist at a referral center while beginning diagnostic workup for patients with suspected aHUS/TMA 4
Nephrology consultation should be considered, as aHUS requires multidisciplinary management involving both hematology and nephrology 1, 7

Meningococcal vaccines, including quadrivalent A, C, W, Y conjugate vaccine and meningococcal B vaccine, should be administered immediately to patients with suspected aHUS/TMA who will receive eculizumab 1, 8
Antimicrobial prophylaxis, such as penicillin or macrolides, should be started immediately and continued throughout eculizumab treatment to prevent meningococcal infection 1, 8

Eculizumab should be initiated within 4-8 hours of diagnosis in patients with severe aHUS/TMA, even without a hematologist present 1, 5
The dosing regimen for aHUS/HUS is 900 mg IV weekly for 4 doses, followed by 1,200 mg on week 5, and then 1,200 mg every 2 weeks thereafter 5, 3

Red blood cell transfusions should be administered according to existing guidelines for symptomatic anemia in patients with aHUS/TMA receiving eculizumab 5, 3
Plasma exchange/plasmapheresis should be avoided once eculizumab is started, unless specifically treating TTP (ADAMTS13 <5%) 5, 3

Daily CBC, LDH, and creatinine should be monitored for the first week after initiating eculizumab in patients with aHUS/TMA 2, 3
Patients should be watched for signs of meningococcal infection, such as fever, headache, and neck stiffness, throughout eculizumab treatment 1