Disease Description (Causes and Symptoms)
- Definition summary: Microangiopathic hemolytic anemia (MAHA) is a condition in which hemolysis occurs because red blood cells are fragmented (fragmented RBCs, schistocytes) by fibrin and platelet thrombi formed in small blood vessels or by mechanical stress.
- Main pathophysiology: Red blood cells are mechanically destroyed by thrombi (or damaged endothelium) in small blood vessels, causing hemolytic anemia. Thrombocytopenia and organ damage (kidneys, brain) may also occur.
- Common causes (representative)
- Thrombotic thrombocytopenic purpura (TTP): markedly reduced ADAMTS13 activity (hereditary/autoimmune) → platelet hyperaggregation caused by ultra-large VWF
- Hemolytic uremic syndrome (HUS): mainly Shiga toxin-related (e.g., E. coli O157) or atypical (complement-mediated) HUS
- Disseminated intravascular coagulation (DIC), severe infection/sepsis
- Cancer-related microangiopathy, severe hypertension (e.g., malignant hypertension), mechanical damage from prosthetic plates/artificial heart valves
- Drug-induced (quinine, some anticancer drugs, immunosuppressants, etc.)
- Main symptoms
- Symptoms of hemolytic anemia: fatigue, dizziness, shortness of breath, pallor, jaundice (yellowing of the skin/sclera)
- Urinary abnormalities: hematuria, proteinuria, decreased urine output (when kidney function is impaired)
- Bleeding and purpura: bruising/purpura when thrombocytopenia is present
- Vary depending on the cause, including fever, neurological symptoms (headache, confusion, focal neurological symptoms), and symptoms of kidney failure (edema, hypertension)
Treatment Methods and Precautions
- General principles: Identifying the cause and promptly providing cause-specific treatment are important. In an emergency, immediately coordinate care with hematology, emergency medicine, and nephrology.
- TTP (when suspected or confirmed)
- First-line treatment: urgent plasma exchange (PEX) + fresh frozen plasma (FFP) replacement
- Additional medications: high-dose steroids (e.g., prednisone), immunosuppressants (rituximab) — in cases of relapse or inadequate response
- Recently used medication: caplacizumab (anti-vWF Nanobody) — promotes platelet recovery during the acute phase and helps reduce complications
- Contraindication/precaution: Avoid repeated platelet transfusions based solely on the platelet count (except in cases of severe bleeding).
- HUS
- Typical (STEC) HUS: mainly supportive care (fluid management, electrolyte correction, and dialysis when necessary)
- Atypical (complement-mediated) HUS: eculizumab (anti-C5 monoclonal antibody) is the first-line standard treatment
- Antibiotic use is controversial in STEC infection (some studies suggest a possible increased risk of HUS)
- DIC and other causes: Treat the underlying cause (infection, cancer, etc.); provide transfusions (red blood cells, platelets, fresh frozen plasma) and correct coagulation factors when necessary
- Transfusion and supportive care: Red blood cell transfusion for symptomatic anemia; platelet and plasma replacement for severe bleeding (however, use platelet transfusions cautiously in TTP)
- Removal of drugs/triggers: Discontinue suspected causative drugs (e.g., quinine, certain anticancer drugs, immunosuppressants)
- Lifestyle management and follow-up: Regularly monitor kidney function and blood tests (CBC, liver and kidney function, hemolysis markers LDH and bilirubin, reticulocytes). When there is a risk of relapse, early recognition of symptoms and an emergency contact system are necessary.
- Special precautions
- Meningococcal vaccination is recommended before administering eculizumab (increased risk of infection)
- TTP/HUS during pregnancy is a high-risk condition requiring multidisciplinary management
- Delayed treatment increases the risk of mortality and permanent kidney or neurological sequelae
Checklist Before an Outpatient Visit (Including Items to Prepare and Sample Questions)
- Items to bring
- List of currently used medications (including prescription drugs, OTC drugs, and health supplements)
- Recent test results (if available): CBC, peripheral blood smear images, kidney function (creatinine), electrolytes, coagulation tests (PT/aPTT/fibrinogen), LDH, total/direct bilirubin, and urinalysis results
- Record of when symptoms began and how they have progressed (fever, diarrhea, neurological symptoms, changes in urination, etc.)
- Recent history of infection (diarrhea/respiratory symptoms), recent transfusions, surgery, or treatment (chemotherapy, immunosuppressants, transplantation, etc.), and whether you are pregnant
- Items useful to record during the outpatient visit
- Patterns of worsening/improvement of symptoms, whether bleeding or bruising has occurred, and changes in urine volume
- Sample questions (for asking yourself or submitting to the doctor during the visit)
- Could any of the medications I recently took have caused this condition?
- If I have an ADAMTS13 test result, what does it mean?
- What is the expected schedule and what are the side effects of treatment (plasma exchange/medications)?
Sample General Questions to Ask the Doctor
- What appears to be the cause of this condition, and what additional tests are needed?
- What are the advantages, disadvantages, and side effects of my treatment options (plasma exchange, rituximab, caplacizumab, eculizumab, etc.)?
- How high is the risk of relapse, and how might the symptoms differ if it recurs?
- If I am planning a pregnancy or am pregnant, how will this affect treatment?
Examples of condition-specific questions
- What is my ADAMTS13 activity (%) and how should this value be interpreted in relation to a diagnosis of TTP?
- In my current situation, should plasma exchange be started immediately, or can we wait for the results of additional tests (ADAMTS13 and tests for accompanying infections)?