Monocytosis

Monocytosis
Classification and external resources
Specialty	hematology
ICD-10	D72.8
ICD-9-CM	288.8
DiseasesDB	22713

Monocytosis is an increase in the number of monocytes circulating in the blood.^[1] Monocytes are white blood cells that give rise to macrophages and dendritic cells in the immune system.

In humans, 950/μL is regarded as at the upper limit of normal; monocyte counts above this level are regarded as monocytosis.

Monocytosis has sometimes been called mononucleosis,^[2] but that name is usually reserved specifically for infectious mononucleosis.

Causes

Monocytosis often occurs during. **chronic inflammation. **Diseases that produce this state:

• Infections: tuberculosis, brucellosis, listeriosis, subacute bacterial endocarditis, syphilis, and other viral infections and many protozoal and rickettsial infections (e.g. kala azar, malaria, Rocky Mountain spotted fever).
  • Blood and immune causes: chronic neutropenia and myeloproliferative disorders.
  • Autoimmune diseases and vasculitis: systemic lupus erythematosus, rheumatoid arthritis and inflammatory bowel disease.
  • Malignancies: Hodgkin's disease and certain leukaemias, such as chronic myelomonocytic leukaemia (CMML) and monocytic leukemia.
  • Recovery phase of neutropenia or an acute infection.
  • Obesity (cf. Nagareddy et al. (2014), Cell Metabolism, Vol. 19, pp 821-835)
  • Miscellaneous causes: sarcoidosis and lipid storage disease.

References

1. "monocytosis" at Dorland's Medical Dictionary
2. Elsevier, Dorland's Illustrated Medical Dictionary, Elsevier.