Articles on Medical Diseases and Conditions

Entries for the ‘White Blood Cells’ Category


Leukoerythroblastosis can be defined as the presence of both immature WBCs (metamyelocytes or earlier cells) and nucleated RBCs in the peripheral blood smear. Although the relative frequency of etiologies is different in different reports, approximately 25%-30% of patients with leukoerythroblastosis have metastatic tumor in the bone marrow, about 20% have leukemia, about 10% have myeloid […]

Neutropenia (Granulocytopenia)

Neutropenia is usually defined as a WBC count less than 4,000/mm3. Some conditions associated with neutropenia include (1) conditions associated with pancytopenia, such as megaloblastic anemia, aplastic anemia, acute or aleukemic leukemia, hypersplenism of varying etiology (e.g., cirrhosis, systemic lupus, Gaucher’s disease), and paroxysmal nocturnal hemoglobinuria, (2) drug-induced neutropenia (agranulocytosis), (3) certain infections, such as […]


Lymphocytosis is most commonly associated with a normal or a decreased total WBC count. The most common etiology is viral infection. The lymphocytosis seen in the majority of viral infections is actually a relative type due to a decrease in granulocytes while total (absolute) lymphocyte numbers remain constant. The same phenomenon is found in Addison’s […]

Leukemoid Reaction

Leukemoid reaction is usually defined as a nonleukemic WBC count more than 50,000/mm3 (50 х 109/L) or a differential count with more than 5% metamyelocytes or earlier cells. It is basically a more severe or pronounced form of ordinary nonneoplastic granulocyte reaction. Some conditions associated with leukemoid reaction are severe bacterial infections, severe toxic states […]


Basophilia is most frequently found in chronic myelogenous leukemia. Basophils may be increased in the other “myeloproliferative” diseases and occasionally in certain nonmalignant conditions.


Parasites. Eosinophilia is most often associated with roundworms and infestation by various flukes. In the United States, roundworms predominate, such as Ascaris, Strongyloides, and Trichinella (Trichina). The condition known as visceral larva migrans, caused by the nematode Toxocara canis (common in dogs) is sometimes seen in humans. In Trichinella infection an almost diagnostic triad is […]


Monocytosis may occur in the absence of leukocytosis. Monocytosis is most frequently found in subacute bacterial endocarditis (about 15%-20% of patients), disseminated TB (15%-20% of patients), during the recovery phase of various acute infections, in many types of hematologic disorders (including nonmonocytic leukemias, myeloma, and hemolytic anemias), in malignant lymphomas and carcinomas, in rheumatoid-collagen diseases, […]

Neutrophilic Leukocytosis Due To Infection and Inflammation

Inflammation is the most frequent condition associated with neutrophilic leukocytosis. Besides an increase in total neutrophil count, there often is some degree of immaturity (“shift to the left”*). Usually a shift to the left involves an increase in the early segmented and the band neutrophil stages. Occasionally even some earlier cells (metamyelocytes or even myelocytes) […]

Neonatal Leukocytosis

At birth, there is a leukocytosis of 18,000-22,000/ mm3 (18-22 Ч 109/L) for the first 1-3 days. This drops sharply at 3-4 days to levels between 8,000 and 16,000/mm3. At roughly 6 months, approximately adult levels are reached, although the upper limit of normal is more flexible. Although the postnatal period is associated with neutrophilia, […]

Pelger-Hu?t Anomaly

Of various hereditary abnormalities of WBC morphology, the most important is the Pelger-Huлt nuclear anomaly. This is manifested by WBC nuclear hyposegmentation. In the neutrophil series, many of the segmented cells appear to have bilobed nuclei shaped like a dumbbell or a pair of eyeglasses. There is also an increase in bandlike forms and forms […]