An 89-year-old male presents to the ED with significant fatigue. His initial blood pressure is 90/50 mmHg with a GCS of 15. His CBC is below.
- Is this patient’s anemia secondary to bone marrow failure or red cell destruction?
- What is the next best test to identify the cause of this patient’s anemia?
- What is your immediate management?
Click for answer:
Diagnosis: autoimmune hemolytic anemia (AIHA) secondary to chronic lymphocytic leukemia (CLL)
CBC findings suggestive of diagnosis:
(1) Reticulocytosis – suggests appropriate bone marrow response and RBC destruction
(2) Spherocytes – suggests a hemolytic process, particularly extravascular hemolysis
(3) Smudge cells – classically associated with CLL
Q1: Is this patient’s anemia secondary to bone marrow failure or red cell destruction?
Red cell destruction.
Q2: What is the next best test to identify the cause of this patient’s anemia?
Hemolysis panel (see box). If positive, the next best test is direct antiglobulin test (DAT).
Q3: What is your immediate management?
Transfusion given severe/symptomatic anemia
Hemolysis Panel
• Lactate dehydrogenase (LDH)
• D-dimer
• Fibrinogen
• Reticulocytes
• Haptoglobin
• Peripheral blood smear
• +/- DAT
AIHA is an autoimmune process involving antibody-mediated destruction of red blood cells. It can be idiopathic/primary or secondary to underlying disease. In this case, the patient has CLL (see Case 12) that can lead to AIHA in up to 10% of cases.
The first step in diagnosis requires ordering a hemolysis panel (see Box). If positive, the next best test is a direct antiglobulin test (DAT). The DAT identifies if red cell lysis is secondary to antibody and/or complement binding. A positive DAT is therefore suggestive of autoimmune hemolysis.
CBC Pearls
• Reticulocytosis suggests a hemolytic process with bone marrow response
• Transfuse “best-compatible blood” in AIHA
Transfusion is indicated for severe/symptomatic anemia. However, transfusion decisions should take into account the patient’s volume status and co-morbidities. In this patient, his blood pressure and perfusion are compensated by increased plasma volume. Therefore, rapid administration of multiple blood products could risk adverse effects, such as transfusion associated cardiac overload.
It is important to contact the hematologist on-call or blood laboratory technician to discuss blood product compatibility. The antibody in AIHA will make complete cross-matching near impossible, so best compatible products should be identified and provided.