What is the appropriate management for a patient with Mycoplasma pneumonia, severe anemia, elevated reticulocyte count, elevated LDH, and low haptoglobin?

Management of Mycoplasma-Induced Autoimmune Hemolytic Anemia

Stop the antibiotics immediately and start corticosteroids with prednisone 1-2 mg/kg/day. This patient has Grade 3 autoimmune hemolytic anemia (AIHA) triggered by Mycoplasma pneumoniae, evidenced by severe anemia (Hb 60 g/L), elevated reticulocytes, elevated LDH, and undetectable haptoglobin with normal platelets and liver function 1.

Clinical Reasoning

This presentation is classic for Mycoplasma-induced cold agglutinin disease, which causes immune-mediated hemolysis rather than direct infection-related anemia 1, 2, 3. The key distinguishing features are:

• Severe hemolysis without thrombocytopenia rules out thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS), which would show platelet consumption 4
• Normal liver function tests exclude hepatic causes of jaundice 1
• High reticulocyte count confirms appropriate bone marrow response, excluding aplastic anemia 1
• Temporal relationship (2 days after starting antibiotics) suggests drug-triggered autoimmune phenomenon 1, 2

Immediate Management Algorithm

Step 1: Discontinue Antibiotics

• Stop all antibiotics immediately, as they can trigger or exacerbate immune-mediated hemolysis 5, 1
• The Mycoplasma infection itself triggers cold agglutinins, but continuing antibiotics may worsen the autoimmune response 1, 2

Step 2: Initiate Corticosteroid Therapy

• Administer prednisone 1-2 mg/kg/day orally for Grade 3 hemolytic anemia 5, 1
• This dosing is based on the severity: Hb 60 g/L represents life-threatening anemia requiring aggressive immunosuppression 1
• Add folic acid 1 mg daily to support erythropoiesis during active hemolysis 5, 1

Step 3: Transfusion Decision

• Consider RBC transfusion only if symptomatic (severe dyspnea, chest pain, altered mental status) or hemodynamically unstable 5, 1
• Target hemoglobin 70-80 g/L in stable patients; transfuse minimum units necessary 5, 1
• Coordinate with blood bank before transfusion, as cold agglutinins can interfere with crossmatching 5, 3

Step 4: Monitoring Protocol

• Daily monitoring during acute phase: hemoglobin, reticulocyte count, LDH, haptoglobin, bilirubin 5, 1
• Weekly hemoglobin checks during corticosteroid tapering phase 1, 4
• Reassess at 1-2 weeks for response to therapy 1

When to Escalate Therapy

Rituximab is NOT first-line for Mycoplasma-induced AIHA 1. Reserve rituximab for:

• No improvement or worsening after 1-2 weeks of high-dose corticosteroids 5, 1
• Grade 4 severity with life-threatening complications despite corticosteroids 5
• Refractory cases requiring additional immunosuppression 5

Alternative second-line agents include IVIG, cyclosporine, or mycophenolate mofetil if corticosteroids fail 5.

Critical Pitfalls to Avoid

• Do not delay corticosteroids while awaiting additional testing (e.g., direct antiglobulin test results) 1, 6
• Do not continue antibiotics thinking you need to "finish the course"—the immune response is now the primary problem 1
• Do not transfuse unnecessarily—transfusion can worsen hemolysis in cold agglutinin disease if blood is not warmed 3
• Do not start with observation alone at this severity level (Hb 60 g/L is Grade 3-4) 1
• Do not jump to rituximab as first-line therapy—corticosteroids are the established initial treatment 1, 6

Expected Clinical Course

Most patients with Mycoplasma-induced AIHA respond well to corticosteroids within 1-2 weeks, with gradual improvement in hemoglobin and resolution of hemolysis markers 1, 2, 3. The cold agglutinins typically resolve as the infection clears 2, 3. Corticosteroid taper should occur over 4-6 weeks after hemoglobin stabilizes 6.