From the Guidelines
Low white blood cell (WBC) count, or leukopenia, can be caused by several factors, including bone marrow disorders, viral infections, certain medications, autoimmune disorders, nutritional deficiencies, and congenital disorders. The most recent and highest quality study on this topic is from 2021, which discusses the management of hairy cell leukemia and COVID-19 adaptation of treatment guidelines 1. According to this study, patients with hairy cell leukemia often present with varying degrees of pancytopenia, including low WBC counts. Other causes of low WBC counts include:
- Bone marrow disorders like leukemia, myelodysplastic syndrome, and aplastic anemia, which disrupt normal blood cell production
- Viral infections including HIV, hepatitis, and influenza, which can temporarily suppress bone marrow function
- Certain medications, particularly chemotherapy drugs, some antibiotics, antipsychotics, and immunosuppressants, which can cause leukopenia
- Autoimmune disorders like lupus and rheumatoid arthritis, which can attack white blood cells or their production
- Nutritional deficiencies, particularly vitamin B12, folate, and copper, which can impair proper WBC formation
- Congenital disorders like Kostmann syndrome and cyclic neutropenia, which cause chronically low WBCs from birth
- Radiation exposure, severe infections, and hypersplenism, which are additional causes of low WBC counts. Treatment depends on identifying and addressing the underlying cause, which may involve stopping problematic medications, treating infections, providing nutritional supplements, or managing autoimmune conditions. It is essential to note that the management of low WBC counts should prioritize the prevention of infections and the treatment of underlying causes, as highlighted in the 2019 study on the management of acute promyelocytic leukemia 1. In addition, the 2001 study on anemia of chronic kidney disease provides insight into the importance of evaluating iron parameters and reticulocyte count to detect the cause of anemia, which can also be relevant in the context of low WBC counts 1. However, the most recent and highest quality study 1 should be prioritized when making a definitive recommendation.
From the FDA Drug Label
Hematologic Eosinophilia (6%), thrombocytosis (5.1%) and leukopenia (2.1%). Less frequently reported (<1%) were anemia, hemolytic anemia, neutropenia, lymphopenia, thrombocytopenia and prolongation of the prothrombin time. Blood and lymphatic disorders Granulocytopenia (0.9%), coagulopathy (0.4%). Hematological changes Isolated cases of agranulocytosis (< 500/mm3) have been reported, most of them after 10 days of treatment and following total doses of 20 grams or more.
Low WBC causes associated with ceftriaxone (IV) include:
- Leukopenia (2.1%)
- Neutropenia (<1%)
- Lymphopenia (<1%)
- Granulocytopenia (0.9%)
- Agranulocytosis (<0.1%) 2
From the Research
Low WBC Causes
- Leukopenia, a condition characterized by a low white blood cell (WBC) count, can be caused by various factors, including impaired proliferation and maturation of myeloid progenitor cells in the bone marrow 3.
- Systemic lupus erythematosus (SLE) is a common cause of leukopenia, with studies showing that hematological abnormalities, including leucopenias, are common among SLE patients 4, 5, 6, 7.
- In SLE patients, leukopenia can result from immune-mediated bone marrow failure, excessive peripheral cell destruction, or certain drugs and infections 4, 5, 6.
- Other causes of low WBC count include:
- Neutropenia, defined as an absolute neutrophil count (ANC) of less than 1,500/mcL 3.
- Bone marrow abnormalities, such as hypocellularity, plasmacytosis, and hemophagocytosis, which can be found in SLE patients with peripheral cytopenia 5.
- Medications, such as cyclophosphamide, which can increase the risk of severe infections in SLE patients 7.
- The treatment of low WBC count depends on the underlying cause, with corticosteroids and immunosuppressive agents being commonly used to manage immune-mediated hemolytic anemia and severe thrombocytopenia in SLE patients 4, 6.