What is neutropenia?
Neutropenia occurs when the number of circulating blood neutrophils decreases. Neutrophils are a form of white blood cells which help prevent and fight bacterial infection.
What causes neutropenia?
Neutrophils are produced inside the bone marrow, which is the spongy, fatty tissue inside bones, along with red blood cells and platelets. Millions of neutrophils every day enter the blood for a few hours and then enter body tissues (skin, mouth, intestines, lungs, etc.) where they fight bacteria and protect against infection. Neutropenia can rarely be present from birth or inherited from parents (congenital), but usually it is acquired, due to diseases that decrease production of neutrophils from the bone marrow or increase their destruction in the bloodstream.
- Decreased production can occur in leukemia (blood cancer), aplastic anemia and other conditions that affect the bone marrow. It can also be a side effect of drugs e.g. chemotherapy. Because the whole marrow is commonly affected, this is usually accompanied by decrease in other blood components, such as red blood cells and platelets
- Increased destruction can occur due to antibodies in the blood stream in SLE and autoimmune neutropenia. It can also be a side-effect of antibiotics.
- Sometimes special blood tests or a bone marrow test are needed to find out the cause of the neutropenia..
How is neutropenia diagnosed?
Neutrophils are part of the complete blood count (CBC), a blood test obtained by a fingerstick or puncture of a vein. It is a simple test that can be done in almost any medical lab. The differential white blood cell count describes the percentage and number of neutrophils in the blood. The total white blood cell (WBC) count varies but in children is between 5,000 and 15,000 cells per cubic millimeter of blood. The absolute neutrophil count (ANC) is calculated by multiplying the percentage of neutrophils and bands in the blood by the total WBC count e.g. a child with neutropenia might have a WBC count of 4,000/mm3 with 5% neutrophils and 1% percent bands (ANC is 0.06 x 4,000 = 240/mm3). The ANC is normally above 1,500/mm3 (1,000/mm3 in children less than 2 years of age) and levels that drop lower than this suggest neutropenia. It is important that the doctors know the cause neutropenia, since the treatment and outcome vary depending upon the cause.
How is neutropenia cared for?
In general, the lower the neutrophil count (ANC) is, the more likely it is to lead to serious problems. If the bone marrow is healthy then mild/moderate neutropenia (ANC 500-1,000/mm3 ) commonly seen after viral infections is usually not a problem, and recovers in a few days or weeks.