Monocytosis is an increase in the number of

monocyte Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and monocyte-derived dendritic cells. As a part of the vertebrate innate immune system monocytes also ...

s circulating in the blood. Monocytes are white blood cells that give rise to macrophages and dendritic cells in the immune system. In humans, monocytosis occurs when there is a sustained rise in monocyte counts greater than 800/mm³ to 1000/mm³. Monocytosis has sometimes been called mononucleosis, but that name is usually reserved specifically for

infectious mononucleosis Infectious mononucleosis (IM, mono), also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adu ...

Causes

Monocytosis often occurs during chronic inflammation. Diseases that produce such a chronic inflammatory state: * Infections:

tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

brucellosis Brucellosis is a zoonosis spread primarily via ingestion of raw milk, unpasteurized milk from infected animals. It is also known as undulant fever, Malta fever, and Mediterranean fever. The bacteria causing this disease, ''Brucella'', are small ...

listeriosis Listeriosis is a bacterial infection most commonly caused by '' Listeria monocytogenes'', although '' L. ivanovii'' and '' L. grayi'' have been reported in certain cases. Listeriosis can cause severe illness, including severe sepsis, me ...

, subacute bacterial endocarditis,

syphilis Syphilis () is a sexually transmitted infection caused by the bacterium ''Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms depend on the stage it presents: primary, secondary, latent syphilis, latent or tertiary. The prim ...

, and other viral infections and many

protozoa Protozoa (: protozoan or protozoon; alternative plural: protozoans) are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically ...

l and

rickettsia ''Rickettsia'' is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci (0.1 μm in diameter), bacilli (1–4 μm long), or threads (up to about 10 μm long). The genus was n ...

l infections (e.g.

kala azar Visceral leishmaniasis (VL), also known as kala-azar (Hindi: kālā āzār, "black sickness") or "black fever", is the most severe form of leishmaniasis and, without proper diagnosis and treatment, is associated with high fatality. Leishmaniasi ...

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

Rocky Mountain spotted fever Rocky Mountain spotted fever (RMSF) is a bacterial disease spread by ticks. It typically begins with a fever and headache, which is followed a few days later with the development of a rash. The rash is generally Petechial rash, made up of small s ...

). * Blood and immune causes: chronic

neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...

and myeloproliferative disorders. *

Autoimmune disease An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated tha ...

s and

vasculitis Vasculitis is a group of disorders that destroy blood vessels by inflammation. Both artery, arteries and veins are affected. Lymphangitis (inflammation of lymphatic vessels) is sometimes considered a type of vasculitis. Vasculitis is primarily c ...

systemic lupus erythematosus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

and

inflammatory bowel disease Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, with Crohn's disease and ulcerative colitis (UC) being the principal types. Crohn's disease affects the small intestine and large intestine ...

. * Malignancies:

Hodgkin's disease Hodgkin lymphoma (HL) is a type of lymphoma in which cancer originates from a specific type of white blood cell called lymphocytes, where multinucleated Reed–Sternberg cells (RS cells) are present in the lymph nodes. The condition was named a ...

and certain

leukaemia Leukemia ( also spelled leukaemia; pronounced ) is a group of blood cancers that usually begin in the bone marrow and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called ''blasts'' or '' ...

s, 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 Sarcoidosis (; also known as Besnier–Boeck–Schaumann disease) is a disease involving abnormal collections of White blood cell, inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph n ...

, drug overdose, lipid storage disease an
ZNFX1 deficiency
During these stages of extreme inflammation, monocytosis can damage tissues because it increases the activation of the immune response and prevents the inflammation from subsiding which is seen in cases where sepsis occurs.

Diagnosis

* Blood Test (CBC) (Normal range of Monocytes: 1-10%) (Normal range in males: 0.2-0.8 x 10³/microliter) * Blood test checking for monocytosis (Abnormal ranges: >10%) (Abnormal range in males: >0.8 x 10³/microliter)

Treatment

Ceftriaxone Ceftriaxone, sold under the brand name Rocephin, is a third-generation cephalosporin antibiotic used for the treatment of a number of bacterial infections. These include middle ear infections, endocarditis, meningitis, pneumonia, bone and joi ...

if there is typhoid fever and

levofloxacin Levofloxacin, sold under the brand name Levaquin among others, is a broad-spectrum antibiotic of the fluoroquinolone drug class. It is the left-handed isomer of the medication ofloxacin. It is used to treat a number of bacterial infections ...

moxifloxacin Moxifloxacin is an antibiotic, used to treat bacterial infections, including pneumonia, conjunctivitis, endocarditis, tuberculosis, and sinusitis. It can be given by mouth, by injection into a vein, and as an eye drop. Common side effec ...

Gentamicin Gentamicin is an aminoglycoside antibiotic used to treat several types of bacterial infections. This may include bone infections, endocarditis, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis amo ...

and doxycyclin if

References

External links

{{Monocyte and granulocyte disease Monocyte and granulocyte disorders