Our patient had mild neutropenia. Neutropenia has a number of causes and the finidning of neutriopenia should prompt clinical evaluation.
Causes of neutropenia include
- Sepsis secondary to exhausting neutrophil pool
- Nutritional deficiency – B12, folate, copper, anorexia
- Viral infections – HIV, VZV, measles, rubella, CMV, EBV, hepatitis, parvovirus, influenza
- Thyroid dysfunction
- Bone marrow failure
- Aplastic anaemia
- Bone marrow infiltration
- Haematological malignancy
- Non-haematological malignancy
- Liver disease/alcohol
- Co-trimoxazole, chloramphenicol, beta lactams, linezolid, vancomycin
- Phenytoin, carbamazepine
- Monoclonal antibodies
- Furosemide, bumetanide
- Any chemotherapy or radiotherapy
- Ethnicity – African and Arabic
- 10% have neutrophils less than 1.5×109/l
- Due to reduction of neutrophils in marrow storage pool
- Polymorphism in Duffy antigen chemokine receptor (DARC) gene
- Reduced DARC expression on red cells
- Advantageous as P vivax uses DARC to enter red cell
- Reduced DARC leads to neutropenia
- No clinical consequence
- Autoimmune neutropenia
- ELAINE-associated neutropenia e.g. cyclical neutropenia
- T-large granulocytic leukaemia
- Felty syndrome
Although some of these causes can appear frightening most can be excluded on clinical grounds. Usually the simplest thing to do is repeat the test as it will usually resolve and represent transient causes. Safety netting is important so to retrun if somthing worse is happening.
In our case her neutrophils were mildly low and we found that she is black with African heritage where benign ethnic neutropenia is common. Depending on clinical suspicion other causes should be ruled out before coming to this conclusion. There is no specific guidance on how much investigation should be done. A blood film, biochemistry and viral studies would seem reasonable and a clinical assessment for autoimmune disease.
In this case on looking back her neutrophil count has always been on the lower side of normal and she has not had hig rates of infection. This is all very reassuring.
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