Neutropenia

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Neutropenia is "a decrease in the number of neutrophilic leukocytes in the blood."[1]

The half-life of a neutrophil is less than one-half of a day. [2]

Diagnosis

Grading

Grading is:[3]

  • Grade 1: < 2.0 x 109/L (< 2000/mm3) and > 1.1 x 109/L (> 1500/mm3)
  • Grade 2: < 1.5 x 109/L (< 1500/mm3) and > 1.0 x 109/L (> 1000/mm3)
  • Grade 3: < 1.0 x 109/L (< 1000/mm3) and > 0.5 x 109/L (> 500/mm3)
  • Grade 4: < 0.5 x 109/L (< 500/mm3)

Simple Definitions

There are three general guidelines used to classify the severity of neutropenia based on the absolute neutrophil count (ANC) measured in cells permicro liter of blood:

  • Mild neutropenia (1000 < ANC < 1500) — minimal risk of infection
  • Moderate neutropenia (500 < ANC < 1000) — moderate risk of infection
  • Severe neutropenia (ANC < 500) — severe risk of infection.

NOTE: These are ranges for Caucasians. Neutropenia in black individuals is defined as ANC < 1200. The following information is from WikiDoc.

For ease of reading the following measurements can be written as:

  • Mild neutropenia ranges between 1,000 to 1,500 absolute neutrophil count (ANC) measured in cells per micro liter of blood. There is a minimal risk of infection.
  • Moderate neutropenia ranges between 500 to 1,000 absolute neutrophil count (ANC) measured in cells per micro liter of blood. There is a moderate risk of infection.
  • Severe neutropenia is less than absolute neutrophil count (ANC) measured in cells per micro liter of blood. There is a severe risk of infection.

Neutropenia is more commonly found in women and the elderly.

Benign ethnic neutropenia has been observed in Africans, African-Caribbean persons, West Indians Ethiopians, Yemenite Jews and certainArabs, according to the Annals of Internal Medicine.


Determining Absolute Neutrophil Count (ANC)

Neutropenia is a subset of a leukopenia.Leukopenia means a low white blood cell count while Neutropenia represents a lowered neutrophil count. Neutropenia has many causes and can be temporary. The Absolute Neutrophil Count (ANC) is the determining factor when it comes to evaluating neutropenia counts.

Absolute Neutrophil Count (ANC) is determined by using the results of your blood test, normally the differential white blood cell count (WBC). Neutrophils make up 50 to 70 percent of the white blood cell count. To determine your ANC use the following formula:

(% of neutrophils + % of bands) X WBC count = ANC.

Note: Neutrophils are sometimes called “segs” or “polys” while young while blood cells are referred to as bands.

An example of this formula at work is illustrated here:

If the WBC is 1,000 and the percentage of neutrophils is 70 percent, and there are no young white blood cells (bands) present, the ANC would be 700, according to the American Cancer Society.



Causes

There are many causes of neutropenia. Some causes are caused by infections while others are not. Some causes of neutropenia may include Acquired Immune Deficiency Syndrome (AIDS), influenza, typhus, malaria, tuberculosis, dengue, Rickettsial infections, systemic lupus erythematosus, Sjogren’s Syndrome, Felty’s Syndrome, Kostmann Syndrome, enlargement of the spleen, folate deficiencies and sepsis, according to WikiDoc.


Types

Kostmann Syndrome, Cyclic Neutropenia, Idiopathic Neutropenia and autoimmune neutropenia are considered rare medical disorders of the blood. Patients may register with the Severe Chronic Neutropenia Registry (SCNIR) founded in 1994 to monitor the clinical course, treatment and disease outcomes of registered patients.


The following information is from SCNIR:

Kostmann Syndrome, known as Congential neutropenia, is rare neutropenia found at birth. It is an inherited disease and can affect more than one family member. Congenital neutropenia, often also called Kostmann syndrome is a rare type of neutropenia that is present at birth. It is an inherited disease and therefore, more than one family member can be affected, but sporadic occurrence with only one patient in a family may occur. There is no prenatal testing available to check for Kostmann Syndrome. Children affected by Kostmann Syndrome are usually severe and children may have no neutrophils present in the blood. Neutrophils typically are in an arrested state of development or maturation arrest in the bone marrow. The neutrophils rarely mature to full stage development leaving the patient incapable of fighting off infection. Diagnosis is usually made during infancy.

Cyclic neutropenia is another inherited blood disorder. Neutrophil activity runs in cycles, typically 21 days, and range from normal blood counts to low blood counts. It is common for the ANC to drop to less than 200 cells/µl) (0.2 x 109/l). Common symptoms during the low period of the cycle may include mouth ulcers and inflammation. Severe infections such as otitis media (ear infections), pneumonia and bacteraemia (bacterial blood infections) are less likely to be seen.

Patients suspected of Cyclic neutropenia go through a specific type of testing to determine if they have Cyclic neutropenia.

“Cyclic neutropenia occurs because of fluctuating rates of cell production by the bone marrow stem cells”

Idiopathic neutropenia includes many types of neutropenia and can happen at any point in life for unknown reasons. It can occur in both adults and children and the effects are variable based on disease severity.

Autoimmune neutropenia is found in children between six months and four-years-old that have not been diagnosed with congenital neutropenia. This is the most common cause of neutropenia for children in this age group. Severe bacterial infections are rare. Autoimmune neutropenia may also be found in adults, who are usually between the ages of 20 to 40, and most commonly women. This condition is usually associated with other medical conditions.

Other medical conditions or medicines may cause neutropenia. Cancer patients undergoing chemotherapy could develop neutropenia.

Febrile neutropenia

Clinical practice guidelines define febrile neutropenia as "a single oral temperature of >=38.3°C (101°F) or a temperature of >=38.0°C (100.4°F) for >= 1 h. Neutropenia is defined as a neutrophil count of <500 cells/mm3, or a count of <1000 cells/mm3 with a predicted decrease to <500 cells/mm3"[4]

A clinical prediction rule can estimate the risk of morbidity in the febrile patient with neutropenia.[5] A score of >=21 indicates low risk.

Prevention

Hematopoietic colony-stimulating factors for primary prevention of febrile neutropenia may not decrease mortality but do decrease infections in patients undergoing cancer chemotherapy or stem cell transplantation according to a systematic review.[6]

Granulocyte colony-stimulating factor is indicated in selected settings[7][8] if the projected chance of febrile neutropenia is at least 20%.[9]

References

  1. ↑ Anonymous (2024), Neutropenia (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. ↑ Carneiro, José; Junqueira, Luiz Carlos Uchôa (2005). Basic histology: text & atlas. New York: McGraw-Hill, Medical Pub. Division. ISBN 0-07-144091-7. 
  3. ↑ Anonymous (1999). Common Toxicity Criteria (CTC). Cancer Therapy Evaluation Program. Retrieved on 2008-01-06.
  4. ↑ Hughes WT, Armstrong D, Bodey GP, et al (2002). "2002 guidelines for the use of antimicrobial agents in neutropenic patients with cancer". Clin. Infect. Dis. 34 (6): 730–51. DOI:10.1086/339215. PMID 11850858. Research Blogging.
  5. ↑ Klastersky J, Paesmans M, Rubenstein EB, et al (2000). "The Multinational Association for Supportive Care in Cancer risk index: A multinational scoring system for identifying low-risk febrile neutropenic cancer patients". J. Clin. Oncol. 18 (16): 3038–51. PMID 10944139. [e] (See Table 4 for the prediction rule)
  6. ↑ Sung L, Nathan PC, Alibhai SM, Tomlinson GA, Beyene J (September 2007). "Meta-analysis: effect of prophylactic hematopoietic colony-stimulating factors on mortality and outcomes of infection". Ann. Intern. Med. 147 (6): 400–11. PMID 17876022. [e]
  7. ↑ Kuderer NM, Dale DC, Crawford J, Lyman GH (2007). "Impact of primary prophylaxis with granulocyte colony-stimulating factor on febrile neutropenia and mortality in adult cancer patients receiving chemotherapy: a systematic review". J. Clin. Oncol. 25 (21): 3158–67. DOI:10.1200/JCO.2006.08.8823. PMID 17634496. Research Blogging. ACP JC Review
  8. ↑ Frei, Emil; Kufe, Donald W.; Holland, James F. (2003). Cancer medicine 6: Granulocyte colony-stimulating factor. Hamilton, Ont: BC Decker. ISBN 1-55009-213-8. Full text
  9. ↑ Smith TJ, Khatcheressian J, Lyman GH, et al (2006). "2006 update of recommendations for the use of white blood cell growth factors: an evidence-based clinical practice guideline". J. Clin. Oncol. 24 (19): 3187–205. DOI:10.1200/JCO.2006.06.4451. PMID 16682719. Research Blogging.
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