Approach to Pancytopenia
Pancytopenia is the simultaneous reduction of hemoglobin, absolute neutrophil count (ANC), and platelets below the reference range, a sign of marrow failure, infiltration, or peripheral destruction rather than a diagnosis. The reticulocyte count and bone marrow biopsy separate the causes, and treatment combines transfusion or empiric antibiotics for the acute cytopenias with disease-specific therapy such as immunosuppression or transplantation for aplastic anemia.
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What this article covers
- Overview
Definition: pancytopenia is a fall in all three peripheral blood lineages, hemoglobin, absolute neutrophil count (ANC), and platelets, below the reference range on a complete blood count (CBC).
- Epidemiology
Medication-induced neutropenia: most common after age 50 years, within the first 3 months of starting the offending drug, resolving within 1 to 3 weeks of stopping it.
- Risk factors
Marrow-toxic medications: thionamides (methimazole, propylthiouracil), sulfonamides, gold salts, NSAIDs, anticonvulsants, and cytotoxic chemotherapy, usually within the first 3 months of exposure.
- Pathophysiology
Autoimmune stem cell destruction: T-cell-mediated attack on hematopoietic stem cells produces the marrow hypocellularity of aplastic anemia; withdrawing an offending drug reverses it over 1 to 3 weeks.
- Clinical features
Anemia symptoms: fatigue, exertional dyspnea, and pallor developing over weeks in production-failure states, more abruptly when destruction dominates.
- Differential diagnosis
Myelodysplastic syndrome: the near-identical sibling; unlike aplastic anemia, the marrow is normocellular or hypercellular with dysplastic cells and often an abnormal karyotype, not empty.
- Diagnosis
What establishes the diagnosis: pancytopenia is confirmed by a CBC with differential and smear showing hemoglobin, ANC, and platelets all below the reference range on at least two occasions; it is a…
- Management
First, stabilize and remove the trigger: stop any medication linked to the cytopenias and address active bleeding or instability before extending the workup.
- Complications
Invasive infection: bacterial sepsis and, once neutropenia exceeds 7 to 10 days, invasive fungal infection (Aspergillus, Candida) are the leading causes of death in marrow failure.
- Prognosis
Untreated severe aplastic anemia: without treatment, 80% of patients with severe aplastic anemia die within 2 years of diagnosis.
- Prevention
Serial CBC monitoring for high-risk drugs: for agents such as clozapine, obtain a baseline ANC of at least 1000 cells/microL before starting, then weekly for 6 months, every 2 weeks for months 7 to…
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Related articles
- Aplastic anemia
Aplastic anemia is an acquired or inherited hematopoietic stem cell disorder that produces pancytopenia with a hypocellular, fatty bone marrow and no dysplasia, blasts, or fibrosis. Diagnosis rests on marrow biopsy showing less than 25% cellularity with severity graded by the Camitta criteria, and treatment is allogeneic stem cell transplantation for young fit patients with a matched donor or antithymocyte globulin plus cyclosporine and eltrombopag for everyone else.
- Myelodysplastic syndromes
Myelodysplastic syndromes are clonal stem cell disorders producing ineffective hematopoiesis: a dysplastic, usually hypercellular bone marrow with peripheral cytopenias and a variable risk of transformation to acute myeloid leukemia. Diagnosis requires bone marrow biopsy showing dysplasia after excluding reversible mimics, risk is stratified with the IPSS-R, and treatment ranges from supportive transfusions and lenalidomide in lower-risk disease to hypomethylating agents and allogeneic transplant, the only cure, in higher-risk disease.
- Neutropenic fever
Neutropenic fever is an oncologic emergency defined as a single oral temperature of 38.3 C or higher, or 38.0 C sustained for 1 hour, with an ANC of 500/microL or lower, most often during the chemotherapy nadir. Management is empiric antipseudomonal beta-lactam therapy within 60 minutes, with vancomycin, antifungal therapy, and growth factors added only for specific indications.
- Thrombocytopenia: an overview
Thrombocytopenia, a platelet count below 150,000/microL, is a laboratory finding rather than a single disease, so evaluation starts with the smear to exclude pseudothrombocytopenia and identify the can't-miss consumptive emergencies TTP, HIT, and DIC before working through production, destructive, and sequestration causes. Management treats the underlying cause, reserves platelet transfusion for bleeding or procedural thresholds, and specifically avoids platelet transfusion in TTP and HIT except for life-threatening hemorrhage.
- Pernicious anemia
Pernicious anemia is autoimmune atrophic gastritis that destroys gastric parietal cells and abolishes intrinsic factor production, causing vitamin B12 malabsorption, megaloblastic macrocytic anemia, and a potentially irreversible myelopathy and neuropathy. Diagnosis rests on a low or borderline B12 with an elevated methylmalonic acid, confirmed by anti-intrinsic factor antibody, and treatment is lifelong vitamin B12 replacement.
- Approach to Anemia
Anemia is a hemoglobin below 12 g/dL in women or 13 g/dL in men, from underproduction, destruction, or loss of erythrocytes, never a final diagnosis in itself. The mean corpuscular volume (MCV) and reticulocyte count sort the differential, and management means treating the identified cause, iron or vitamin repletion, immunosuppression, or transfusion for symptomatic or severe disease.
- Paroxysmal nocturnal hemoglobinuria
Paroxysmal nocturnal hemoglobinuria is an acquired clonal stem cell disorder caused by a somatic PIGA mutation that leaves blood cells unprotected from complement, producing intravascular hemolysis, unusual-site venous thrombosis, and cytopenias. Diagnosis rests on flow cytometry showing loss of the GPI-anchored proteins CD55 and CD59, and eculizumab or ravulizumab is used to block terminal complement and reduce both hemolysis and thrombotic risk, while allogeneic stem cell transplant remains the only cure.