Aplastic Anemia

Get the day-of numbers - CBC with reticulocyte count, ANC, and platelet count. Severity is defined by reticulocytes under 1% (or under 40,000/microliter), ANC under 500/microliter, and platelets under 20,000/microliter; very severe disease adds an ANC under 200/microliter. Those three numbers set your transfusion plan, your regional decision, and your infection precautions.

Marrow biopsy tells you what to expect - The diagnosis rests on a markedly hypocellular biopsy with two or more cytopenias; aspirate often gives a dry tap. If the marrow is devoid of progenitors, the counts will not rebound on their own during your case.

Transfusion planning - Blood products should be leukoreduced, and platelets are the limiting product for any procedure with bleeding risk. ⚠ Specific hemoglobin and platelet trigger numbers are a volatile guideline call — take them from your institution's current transfusion protocol, not from a remembered threshold. Type and screen early; these patients are frequently transfused and can be difficult to match.

Protect the transplant option - Young patients in good health with severe disease go to allogeneic hematopoietic cell transplant, and repeated transfusion drives anti-HLA alloimmunization and eventual platelet refractoriness. Talk to hematology before transfusing electively rather than after.

Neutropenia changes your technique, not just your antibiotics - Strict aseptic technique for every line, block, and neuraxial procedure. Treat fever as a potential neutropenic emergency. Growth factors such as erythropoietin and G-CSF are not the rescue here — there are too few precursor cells to respond.

Airway - go oral and go gentle - With platelets this low, nasal intubation, nasal temperature probes, NG tubes, and aggressive oral suctioning all buy you mucosal bleeding — the same mucosal bleeding, ecchymoses, and petechiae that brought the patient in. Use a video laryngoscope so the first look is atraumatic.

Regional - Neuraxial and deep plexus blocks are a hard sell when thrombocytopenia and neutropenia stack hematoma risk on top of infection risk. Default to GA unless the count has been corrected and hematology agrees.

Skip the NSAIDs - Aspirin and NSAIDs add a platelet-function defect to an already low count, and salicylates appear on the list of drugs associated with pancytopenia. Build the plan around acetaminophen and opioids.

Know what they are taking - Many are on anti-thymocyte globulin, cyclosporine A, prednisone, or eltrombopag. Ask what they took and when; chronic steroid exposure changes your perioperative steroid plan, and immunosuppression compounds the neutropenic infection risk.

Look for the offending agent - If the cause was a drug, don't re-expose. Agents implicated in marrow failure include chloramphenicol, methotrexate, dapsone, carbamazepine, ticlopidine, and phenylbutazone. Check the med list against the chart before you write orders.

Aplastic anemia is chronic primary hematopoietic failure: the marrow is hypocellular, progenitors are replaced by fat and fibrotic stroma, and the patient is pancytopenic. About 65% is idiopathic. The rest follows drug or toxin exposure, seronegative hepatitis (5% to 10%), telomerase defects (5% to 10% of adult-onset disease), or an inherited syndrome such as Fanconi anemia.

Two mechanisms are described — immune-mediated destruction, in which self-reactive T cells release interferon-gamma and TNF to kill hematopoietic stem cells, and an intrinsic stem-cell defect with premature exhaustion. Either way, the three cytopenias each cost you something in the OR: anemia erases oxygen-delivery reserve, neutropenia removes the infection barrier, and thrombocytopenia turns any needle or airway instrumentation into a bleeding event. Splenomegaly is absent — if you find it, the diagnosis is something else.