What is Neutrophilia? Simple Answers to Basic Questions

Neutrophilia (aka neutrophilic leukocytosis) is a white blood cell disorder. The term neutrophilia means that the number of neutrophils (a type of white cells) in the blood is too high. (When the neutrophil count is too low, the condition is called neutropenia.)

2) What are neutrophils and what do they do?

Neutrophils are the most numerous white cells (leukocytes) in our bodies. They constitute up to 70% of all circulating white cells. They are also called polymorphonuclear leukocytes (PMNs) because they have a multi-lobed nucleus with various shapes. Neutrophils (together with basophils and eosinophils) are granulocytes, i.e. they have granules in their cytoplasm. These granules contain ammunition, so to speak, against all sorts of pathogens that invade the body and cause infection. Neutrophils are the swiftest and fiercest fighters of the body's immune system against bacteria and fungi. Their response to infection is immediate (less than one hour) and deadly. Neutrophils are cell eaters, phagocytes: They engulf and ingest infectious agents and dead cells. When their mission is accomplished, they die. Pus is mostly made up of dead neutrophils.

3) Where are neutrophils produced?

Neutrophils are produced in the bone marrow.

4) What is a normal neutrophil count?

In the adult, a normal neutrophil count (called the absolute neutrophil count, ANC), ranges from 1500 to 8000 neutrophils per microL of blood.

5) What is an abnormally high neutrophil count?

A neutrophil count over 8000 neutrophils per microL of whole blood is considered elevated.

6) What causes neutrophilia?

Neutrophilia generally occurs in response to other conditions. Chronic idiopathic (i.e. appearing spontaneously and of unknown cause) neutrophilia is very rare. The most common cause of neutrophilia is infection (mostly bacterial or fungal). Other causes of neutrophilia include inflammation (as in rheumatoid arthritis and other inflammatory autoimmune diseases), tissue damage (as in trauma, burns, surgery, or a heart attack), hemolysis (as in sickle cell anemia), certain medications (e.g. corticosteroids, epinephrine, lithium), certain cancers (e.g. bone marrow disorders), acute pain, and strenuous physical activity.

7) What are the symptoms of neutrophilia?

The symptoms of neutrophilia are essentially the symptoms of the underlying condition that causes the neutrophilia. Common symptoms (as in the case of underlying infection) can be fatigue, persistent fever, and weight loss.

8) How is neutrophilia diagnosed?

The most common diagnostic test for neutrophilia is the CBC (complete blood count) test, which includes a white blood cell (WBC) count and a WBC differential. The WBC differential will show the percentage of neutrophils (and other WBC types) in the blood. If the cause of neutrophilia remains uncertain, the physician will review a blood sample (blood smear) for possible abnormalities in the blood cells. Blood cell abnormalities (e.g. the presence of immature neutrophils in the circulation) usually call for a bone marrow aspirate and biopsy.

9) How is neutrophilia treated?

Since neutrophilia mostly occurs as a reaction to another condition, treatment targets the underlying condition. With successful treatment, the neutrophil count is expected to revert to normal levels.

Sources:
http://emedicine.medscape.com/article/208576-overview
http://emedicine.medscape.com/article/956278-overview