Monocytosis

# Overview
Monocytosis is an increase in the number of circulating monocytes. In humans, 950/L is regarded as at the upper limit of normal; monocyte counts above this level are regarded as monocytosis.  Monocytes are white blood cells that give rise to macrophages and dendritic cells in the immune system.

# Historical Perspective
- Monocytosis was first discovered by Federica Sallusto an Italian Biologist and Immunologist and and Antonio Lanzavecchia an Italian and Swiss Immunologist in 1994 when they paved the way by formulating different culture conditions starting from monocytes.
- The association between Multiple gene mutations and Clonal hematopoiesis in monocytosis was made in 2022.

# Classification
- monocytosis has various causes and in can be classified to reactive or clonal monocytosis.

# Pathophysiology
- The pathogenesis of  is characterized by , , and .
- The  gene/Mutation in  has been associated with the development of , involving the  pathway.
- On gross pathology, , , and  are characteristic findings of .
- On microscopic histopathological analysis, , , and  are characteristic findings of .

# Causes

## By Organ System

## In Alphabetical Order
- Acute lymphocytic leukemia
- Bacterial Endocarditis
- Benign familial neutropenia
- Brucellosis
- Carcinoma
- Chronic myeloid leukaemia
- Chronic neutropenia
- Cirrhosis
- Crohn's disease
- Cyclical neutropenia
- Cytomegalovirus
- Drugs
- Gaucher's Disease
- Granulocyte-macrophage colony stimulating factor
- Herpes Zoster Virus
- Hodgkin lymphoma
- Infectious Endocarditis
- Infectious hepatitis
- Inflammatory bowel disease
- Irritable Bowel Syndrome
- Kala-azar
- Kostmann syndrome
- Lipid storage disease
- listeriosis
- Lymphoproliferative disease
- Malaria
- Mononeucleosis
- Mycobacterium tuberculosis
- Myelodysplastic syndrome
- Myeloma
- Myeloproliferative disease
- Non-Hodgkin lymphoma
- Other malignant lymphomas
- Polyarteritis nodosa
- Recovery from neutropenia
- Relapsing fever
- Rheumatoid arthritis
- Rocky Mountain spotted fever
- Sarcoidosis
- Syphillis
- Systemic lupus erythematosus
- Trypanosomiasis
- Tuberculosis
- Ulcerative colitis
- Visceral leishmaniasis
- Whooping cough

# Differentiating  from other Diseases
-  must be differentiated from other diseases that cause , , and , such as:

# Epidemiology and Demographics
- The prevalence of  is approximately  per 100,000 individuals worldwide.
- In , the incidence of  was estimated to be  cases per 100,000 individuals in .

## Age
- Patients of all age groups may develop .
-  is more commonly observed among patients aged  years old.
-  is more commonly observed among .

## Gender
-  affects men and women equally.
-  are more commonly affected with  than .
- The  to  ratio is approximately  to 1.

## Race
- There is no racial predilection for .
-  usually affects individuals of the  race.
-  individuals are less likely to develop .

# Risk Factors
- Common risk factors in the development of  are , , , and .

# Natural History, Complications and Prognosis
- The majority of patients with  remain asymptomatic for .
- Early clinical features include , , and .
- If left untreated,  of patients with  may progress to develop , , and .
- Common complications of  include , , and .
- Prognosis is generally , and the  of patients with  is approximately .

# Diagnosis

## Diagnostic Criteria
- The diagnosis of  is made when at least  of the following  diagnostic criteria are met:

## Symptoms
-  is usually asymptomatic.
- Symptoms of  may include the following:

## Physical Examination
- Patients with  usually appear .
- Physical examination may be remarkable for:

## Laboratory Findings
- There are no specific laboratory findings associated with .
- A    is diagnostic of .
- An  concentration of   is diagnostic of .
- Other laboratory findings consistent with the diagnosis of  include , , and .

## Imaging Findings
- There are no  findings associated with .
-  is the imaging modality of choice for .
- On ,  is characterized by , , and .
-  may demonstrate , , and .

## Other Diagnostic Studies
-  may also be diagnosed using .
- Findings on  include , , and .

# Treatment

## Medical Therapy
- There is no treatment for ; the mainstay of therapy is supportive care.
- The mainstay of therapy for  is  and .
-  acts by .
- Response to  can be monitored with  every .

## Surgery
- Surgery is the mainstay of therapy for .
-  in conjunction with  is the most common approach to the treatment of .
-  can only be performed for patients with  .

## Prevention
- There are no primary preventive measures available for .
- Effective measures for the primary prevention of  include , , and .
- Once diagnosed and successfully treated, patients with  are followed-up every . Follow-up testing includes , , and .