leucopenia

Leucopenia is a reduction in the number of white blood cells (WBCs) in the blood, which can impair the body's ability to fight infections. In adults, a typical reference range for WBCs is about 4,000 to 11,000 cells per microliter; leucopenia is usually defined as a count below 4,000/µL (4.0 x 10^9/L), though exact cutoffs can vary by laboratory reference values. The condition may involve any white blood cell type but is often used when there is a general decrease rather than a specific deficiency of neutrophils.

Causes of leucopenia include decreased production in the bone marrow (for example, bone marrow suppression from chemotherapy or radiation therapy, aplastic anemia, myelodysplastic syndromes, certain nutritional deficiencies such as vitamin B12 or folate deficiency), increased destruction or sequestration (hypersplenism), and redistribution due to acute illness or steroids. Other contributors include autoimmune diseases (such as systemic lupus erythematosus), severe infections, chronic liver disease, and certain medications (chemotherapy agents, antipsychotics like clozapine, antiepileptics, methotrexate, and other drugs that suppress marrow function). Infections, particularly viral ones, can transiently lower WBC counts.

Diagnosis relies on a complete blood count with differential, with attention to the absolute neutrophil count (ANC). Management targets the underlying cause and may involve infection prevention, supportive care, and, in selected cases of severe neutropenia or chemotherapy-related neutropenia, growth factor therapies such as granulocyte colony-stimulating factor (G-CSF). Prognosis varies with etiology and the presence of infections; protection against infection is a central concern in care.