Pancytopenia
Pancytopenia is not equivalent with bone marrow suppression.  Pancytopenia is a lab finding that may related to either bone marrow suppression or peripheral sequestration/destruction.  For details about bone marrow suppression click here.

# Overview
Pancytopenia is the reduction in numbers of all three bone marrow cell types, including red blood cells, white blood cells, and platelets. The prefix "pan-" means "everything," "cyto" means "cell", and the suffix "penia" means "deficiency." Pancytopenia is not a disease, but rather a laboratory finding that may related to bone marrow suppression caused by either insufficient production (aplastic anemia), inability of cells to mature (myelodysplasia), replacement of normal bone marrow with fibrosis (myelofibrosis) or peripheral sequestration that is not related to the bone marrow (e.g. splenomegaly or hypersplenism). Chemotherapy is associated with pancytopenia due to drug-mediated bone marrow suppression. Pancytopenia frequently requires a bone marrow biopsy in order to distinguish among different causes.

# Historical Perspective
The history of pancytopenia relates to the history of each of its individual sub-entities, namely anemia, thrombocytopenia, and leukopenia. Pancytopenia was not recognized as a distinct clinical entity until after each of its other subcomponents were characterized. Thus, there is no specific history for pancytopenia.
- History of aplastic anemia:
The seminal discoveries for aplastic anemia were made by Bruno Speck and Georges Mathe, who noted that immunosuppression could be used to treat aplastic anemia.
In the 1970s, matched sibling donor transplant was used for severe aplastic anemia.
- The seminal discoveries for aplastic anemia were made by Bruno Speck and Georges Mathe, who noted that immunosuppression could be used to treat aplastic anemia.
- In the 1970s, matched sibling donor transplant was used for severe aplastic anemia.
- History of paroxysmal nocturnal hemoglobinuria:
In 1882, Dr. Paul Strubing reported the case of a patient with hematuria at night that occurred periodically.
He noted that hemolysis was the reason for the patient's hematuria.
In 1925, the term paroxysmal nocturnal hemaglobinuria was coined.
In the 1930s, Dr. T.H. Ham noted that acidified serum could induce hemolysis.
Thus, the Ham's acid serum test was developed.
This became the first diagnostic test for this disease.
In the 1950s, the complement pathway was discovered, and it was determined that paroxysmal nocturnal hemoglobinuria was due to activation of complement proteins on the red blood cell membrane.
In the 1980s, the genetic defect responsible for the disease was discovered, specifically, the PIG-A gene defect leading to inability to anchor complement-inhibitory proteins onto the red blood cell membrane.
- In 1882, Dr. Paul Strubing reported the case of a patient with hematuria at night that occurred periodically.
He noted that hemolysis was the reason for the patient's hematuria.
- He noted that hemolysis was the reason for the patient's hematuria.
- In 1925, the term paroxysmal nocturnal hemaglobinuria was coined.
- In the 1930s, Dr. T.H. Ham noted that acidified serum could induce hemolysis.
Thus, the Ham's acid serum test was developed.
This became the first diagnostic test for this disease.
- Thus, the Ham's acid serum test was developed.
- This became the first diagnostic test for this disease.
- In the 1950s, the complement pathway was discovered, and it was determined that paroxysmal nocturnal hemoglobinuria was due to activation of complement proteins on the red blood cell membrane.
- In the 1980s, the genetic defect responsible for the disease was discovered, specifically, the PIG-A gene defect leading to inability to anchor complement-inhibitory proteins onto the red blood cell membrane.

# Classification
There is no classification system for pancytopenia. However, some underlying disease entities that cause pancytopenia have classification. For example, aplastic anemia is classified as moderate, severe, or very severe.

# Pathophysiology
- The pathophysiology of pancytopenia relates to the underlying etiology.
- In most cases, pancytopenia is due to a disruption in trilineage hematopoiesis.
- This means that the bone marrow is not appropriately producing erythrocytes, leukocytes, and thrombocytocytes.
- The cause of the disruption in trilineage hematopoiesis is in turn due to the underlying cause of pancytopenia.
- For example, viral-mediated pancytopenia is caused by viral particles infecting hematopoietic cells and preventing normal cell division.
- Leukemia-mediated pancytopenia is typically due to marrow replacement of normal hematopoietic precursors, a process known as myelopthisis.
- Leukemic infiltration of the bone marrow creates a "crowding-out" phenomenon.

# Causes

## Life Threatening Causes
Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. There are no life-threatening causes of pancytopenia that require acute treatment within 24 hours. However, if pancytopenia is accompanied by fever, this should be treated as a hematologic emergency with prompt administration of IV antibiotics.

## Common Causes
- Aplastic anemia 
This is a condition characterized by immune-mediated reduction in all three hematopoietic cell lines with absence of hematopoietic precursors.
It is a rare condition with a prevalence of only 1-2 cases per million annually. It is most commonly diagnosed in childhood.
Epidemiologic studies have shown a greater prevalence in Southeast Asia and other countries with limited access to healthcare, as viral infection can trigger aplastic crisis.
There are three categories: moderate, severe, and very severe.
These categories are based upon the number and degree of cytopenias as well as bone marrow cellularity.
The preferred treatment of aplastic anemia is bone marrow transplantation from an HLA-matched sibling.
If there is no human leukocyte antigen (HLA)-matched sibling available, the next best option is medical management with the immunosuppressive agents anti-thymocyte globulin (ATG) and cyclosporine A.
The reason for the efficacy of immunosuppressive medications is that the pancytopenia from aplastic anemia is due to abnormal immune activation and thus destruction of hematopoietic cells.
ATG from horse has been shown to be superior compared to ATG from rabbit.
ATG is administered over 5 days, and cyclosporine A is administered orally for 6 months, after which response can be assessed.
The combination of ATG and cyclosporine A carries a response rate of 60-70%.  Eltrombopag can also be added to the regimen of ATG and cyclosporine.
- This is a condition characterized by immune-mediated reduction in all three hematopoietic cell lines with absence of hematopoietic precursors.
- It is a rare condition with a prevalence of only 1-2 cases per million annually. It is most commonly diagnosed in childhood.
- Epidemiologic studies have shown a greater prevalence in Southeast Asia and other countries with limited access to healthcare, as viral infection can trigger aplastic crisis.
- There are three categories: moderate, severe, and very severe.
- These categories are based upon the number and degree of cytopenias as well as bone marrow cellularity.
- The preferred treatment of aplastic anemia is bone marrow transplantation from an HLA-matched sibling.
- If there is no human leukocyte antigen (HLA)-matched sibling available, the next best option is medical management with the immunosuppressive agents anti-thymocyte globulin (ATG) and cyclosporine A.
- The reason for the efficacy of immunosuppressive medications is that the pancytopenia from aplastic anemia is due to abnormal immune activation and thus destruction of hematopoietic cells.
- ATG from horse has been shown to be superior compared to ATG from rabbit.
- ATG is administered over 5 days, and cyclosporine A is administered orally for 6 months, after which response can be assessed.
- The combination of ATG and cyclosporine A carries a response rate of 60-70%.  Eltrombopag can also be added to the regimen of ATG and cyclosporine.
- Folate deficiency
Folate is required for pyrimidine nucleotide synthesis, and thus folate deficiency can lead to decreased production of hematopoietic cells.
Folate deficiency occurs in persons who consume large amounts of alcohol.
Folate deficiency is accompanied by macrocytosis, or large-sized cells.
Treatment of folate deficiency is supplementation of folate in the diet.
- Folate is required for pyrimidine nucleotide synthesis, and thus folate deficiency can lead to decreased production of hematopoietic cells.
- Folate deficiency occurs in persons who consume large amounts of alcohol.
- Folate deficiency is accompanied by macrocytosis, or large-sized cells.
- Treatment of folate deficiency is supplementation of folate in the diet.
- Leishmaniasis
This is a rare infectious cause of pancytopenia.
- This is a rare infectious cause of pancytopenia.
- Leukemia
This can be myeloid or lymphoid, and each of these can be acute or chronic.
Acute leukemias typically cause pancytopenia via a crowding-out phenomenon, known as myelopthisis.
Diagnosis of acute leukemia is based by demonstration of blast count of 20% or greater in the bone marrow.
Treatment involves multiagent chemotherapy, such as cytarabine combined with anthracycline for acute myeloid leukemia, or vincristine-based and anthracycline-based regimen for acute lymphoblastic leukemia.
Treatment of the underlying leukemia can help improve pancytopenia.
- This can be myeloid or lymphoid, and each of these can be acute or chronic.
- Acute leukemias typically cause pancytopenia via a crowding-out phenomenon, known as myelopthisis.
- Diagnosis of acute leukemia is based by demonstration of blast count of 20% or greater in the bone marrow.
- Treatment involves multiagent chemotherapy, such as cytarabine combined with anthracycline for acute myeloid leukemia, or vincristine-based and anthracycline-based regimen for acute lymphoblastic leukemia.
- Treatment of the underlying leukemia can help improve pancytopenia.
- Megaloblastic anemia 
This condition is characterized by decreased red blood cell count and increased cellular size with defective maturation.
The cause is usually deficiency of vitamin B12 or folate.
The diagnosis is made with a complete blood count showing hemoglobin less than 12 g/dl, mean corpuscular volume greater than 100 femtoliter (MCV > 100 fL), and peripheral smear showing enlarged cells.
The treatment is supplementation with vitamin B12 or folate.
- This condition is characterized by decreased red blood cell count and increased cellular size with defective maturation.
- The cause is usually deficiency of vitamin B12 or folate.
- The diagnosis is made with a complete blood count showing hemoglobin less than 12 g/dl, mean corpuscular volume greater than 100 femtoliter (MCV > 100 fL), and peripheral smear showing enlarged cells.
- The treatment is supplementation with vitamin B12 or folate.
- Myelodysplastic syndrome
This is a disease characterized by ineffective erythropoiesis and peripheral cytopenias.
It is a clonal disorder of the hematopoietic stem cell.
The subtype of myelodysplastic syndrome that causes pancytopenia is termed refractory anemia with multilineage dysplasia.
The pancytopenia of myelodysplastic syndrome is due to failure of maturation of hematopoietic precursors, leading to peripheral cytopenias.
Diagnosis of myelodysplastic syndrome is made by demonstration of at least 1 cell line with 10% of greater dysplastic cells on bone marrow biopsy.
Bone marrow biopsy should also show myeloblasts less then 20% of total leukocytes.
Clinical features of myelodysplastic syndrome include manifestations of specific cytopenias, such as fatigue if there is anemia, bleeding if there is thrombocytopenia, and infections if there is leukopenia.
The prognostication of myelodysplastic syndrome is determined by the International Prognosis Scoring System-Revised (IPSS-R), which is determined by blast count, the karyotype, and cytopenia.
This clinical tool is used to estimate the time to progression to acute myeloid leukemia.
The treatment of myelodysplastic syndrome is based on the subtype. Lenalidomide is highly effective for persons with deletion of chromosome 5q.
DNA hypomethylating agents like azacitadine and decitabine are commonly used for those with symptomatic cytopenias and without chromosome 5q deletion.
In some cases, allogeneic stem cell transplantation can be done with the goal of curing myelodysplastic syndrome and preventing progression to acute myeloid leukemia.
Adjunctive therapies include transfusion support (such as red blood cell transfusions or platelet transfusions), growth factor support (such as filgrastim), and immunosuppressive therapy, which is particularly effective in persons with PNH clones, HLA-DR15 positivity, or STAT3-mutant cytotoxic T cells.
- This is a disease characterized by ineffective erythropoiesis and peripheral cytopenias.
- It is a clonal disorder of the hematopoietic stem cell.
- The subtype of myelodysplastic syndrome that causes pancytopenia is termed refractory anemia with multilineage dysplasia.
- The pancytopenia of myelodysplastic syndrome is due to failure of maturation of hematopoietic precursors, leading to peripheral cytopenias.
- Diagnosis of myelodysplastic syndrome is made by demonstration of at least 1 cell line with 10% of greater dysplastic cells on bone marrow biopsy.
- Bone marrow biopsy should also show myeloblasts less then 20% of total leukocytes.
- Clinical features of myelodysplastic syndrome include manifestations of specific cytopenias, such as fatigue if there is anemia, bleeding if there is thrombocytopenia, and infections if there is leukopenia.
- The prognostication of myelodysplastic syndrome is determined by the International Prognosis Scoring System-Revised (IPSS-R), which is determined by blast count, the karyotype, and cytopenia.
- This clinical tool is used to estimate the time to progression to acute myeloid leukemia.
- The treatment of myelodysplastic syndrome is based on the subtype. Lenalidomide is highly effective for persons with deletion of chromosome 5q.
- DNA hypomethylating agents like azacitadine and decitabine are commonly used for those with symptomatic cytopenias and without chromosome 5q deletion.
- In some cases, allogeneic stem cell transplantation can be done with the goal of curing myelodysplastic syndrome and preventing progression to acute myeloid leukemia.
- Adjunctive therapies include transfusion support (such as red blood cell transfusions or platelet transfusions), growth factor support (such as filgrastim), and immunosuppressive therapy, which is particularly effective in persons with PNH clones, HLA-DR15 positivity, or STAT3-mutant cytotoxic T cells.
- Paroxysmal nocturnal hemoglobinuria
This is a clonal disorder of the hematopoietic stem cell characterized by hemolysis due to complement activation on the red blood cell membrane.
It is cause of bone marrow failure.
The genetic defect is a deficiency in glycosylphosphatidylinositol (GPI) which is encoded by the PIG-A gene.
This protein normally serves to anchor complement regulatory and inhibitory proteins onto the red blood cell membrane.
The two major regulatory proteins are CD55 (or decay accelerating factor (DAF)), which functions to degrade complement proteins C3 and C5 convertase, and CD59 (or membrane inhibitor of reactive lysis (MIRL)), which functions to prevent complement-mediated hemolysis via preventing formation of the membrane attack complex.
The clinical manifestations include hematuria, portal venous or hepatic venous thrombosis.
Diagnosis is made by performing flow cytometry of peripheral blood and analyzing the expression fo CD55 and CD59 on red blood cell membranes.
Treatment of this condition is eculizumab, a humanized monoclonal antibody that inhibits complement protein C5.
- This is a clonal disorder of the hematopoietic stem cell characterized by hemolysis due to complement activation on the red blood cell membrane.
- It is cause of bone marrow failure.
- The genetic defect is a deficiency in glycosylphosphatidylinositol (GPI) which is encoded by the PIG-A gene.
- This protein normally serves to anchor complement regulatory and inhibitory proteins onto the red blood cell membrane.
- The two major regulatory proteins are CD55 (or decay accelerating factor (DAF)), which functions to degrade complement proteins C3 and C5 convertase, and CD59 (or membrane inhibitor of reactive lysis (MIRL)), which functions to prevent complement-mediated hemolysis via preventing formation of the membrane attack complex.
- The clinical manifestations include hematuria, portal venous or hepatic venous thrombosis.
- Diagnosis is made by performing flow cytometry of peripheral blood and analyzing the expression fo CD55 and CD59 on red blood cell membranes.
- Treatment of this condition is eculizumab, a humanized monoclonal antibody that inhibits complement protein C5.
- Viral infections
Viruses such as HIV, EBV, or CMV can cause pancytopenia.
The diagnosis can be made by checking viral loads via PCR of peripheral blood or by checking antibody titers to the viruses.
For example, EBV can be diagnosed by assessing for EBV DNA PCR, or by assessing for IgM or IgM to EBV antigens.
- Viruses such as HIV, EBV, or CMV can cause pancytopenia.
- The diagnosis can be made by checking viral loads via PCR of peripheral blood or by checking antibody titers to the viruses.
- For example, EBV can be diagnosed by assessing for EBV DNA PCR, or by assessing for IgM or IgM to EBV antigens.
- Vitamin B12 deficiency
This can cause megaloblastic anemia.
- This can cause megaloblastic anemia.
- Copper deficiency
This is a more rare cause of pancytopenia.
- This is a more rare cause of pancytopenia.
- Zinc deficiency
This is a more rare cause of pancytopenia. Treatment is supplementation with zinc.
- This is a more rare cause of pancytopenia. Treatment is supplementation with zinc.

## Causes by Organ System

## Causes in Alphabetical Order
- Acetaminophen and Oxycodone
- Aclarubicin
- Acute lymphoblastic leukemia 
- Acute myeloid leukemia 
- Aggressive NK-cell leukemia 
- Albendazole
- Albers-Schonberg disease
- Alemtuzumab
- Alkylating antineoplastic agent
- Amegakaryocytic thrombocytopenia
- Ankylosing spondylitis
- Anorexia nervosa 
- Aplastic anemia
- Arsenic poisoning
- Arsenicals
- Ataxia telangiectasia
- Auranofin
- Autoimmune lymphoproliferative syndrome type 1
- Autoimmune lymphoproliferative syndrome type 2
- Azathioprine 
- Aztreonam
- Babesiosis 
- Banti's syndrome
- Benzene solvents 
- Radioactive p32
- Bleeding (Excessive)
- Bloom syndrome
- Boceprevir
- Bone marrow tumor
- Brucellosis 
- Busulfan
- Cancer
- Carbamazepine
- Carboplatin
- Cartilage-hair hypoplasia
- Castleman's disease
- Cefadroxil
- Ceftazidime
- Certolizumab pegol
- Chediak-Higashi disease
- Chemotherapy
- Chloramphenicol
- Chlorpromazine
- Chlorpropamide
- Chondrosarcoma
- Chronic lymphocytic leukaemia
- Chronic myeloid leukaemia
- Cidofovir
- Cirrhosis
- Clomipramine
- Colchicine toxicity
- Common variable hypogammaglobulinemia
- Common variable immune deficiency 
- Copper deficiency
- Cyclical neutropenia
- Cyclophosphamide
- Cytotoxic drugs
- Dactinomycin
- Dengue
- Diamond-Blackfan anemia
- DNA repair-deficiency disorder
- Docetaxel
- Down syndrome
- Doxorubicin
- Dubowitz syndrome
- Dyskeratosis congenita 
- Eosinophilic fasciitis
- Epiphyseal tumors
- Epstein-Barr virus 
- Ethosuximide
- Ewing's sarcoma
- Familial histiocytic reticulosis
- Familial monosomy 7
- Familial myelofibrosis
- Fanconi anemia
- Febuxostat
- Felty's syndrome
- Flucytosine
- Folate deficiency 
- Gaucher's disease
- Gemcitabine
- Gemifloxacin mesylate
- Genotoxic therapy
- Germ cell tumors  
- Glue vapors
- Glutathione synthase deficiency
- Gold
- Graft versus host disease 
- Granuloma
- Hairy cell leukemia 
- Hematopoietic stem cell transplantation
- Hemoglobin E disease
- Hemoglobin H disease
- Hemoglobin SC disease
- Hemophagocytic lymphohistiocytosis 
- Hepatitis
- Hepatosplenic T-cell lymphoma
- Histiocytosis X
- Hodgkin's lymphoma
- Hoyeraal-Hreidarsson syndrome
- Human immunodeficiency virus
- Hypersplenism 
- Hypoplastic myelodysplastic syndromes 
- Idarubicin
- Idiopathic
- Auto-immune disorders
- Indomethacin
- Ineffective erythropoiesis
- Infectious mononucleosis
- Infliximab
- Interferon beta-1a
- Intestinal lymphangiectasia
- Intrinsic factor deficiency
- Iron deficiency
- Jacobsen syndrome 
- Kala-azar 
- Kikuchi disease
- Kwashiorkor
- Langerhans cell histiocytosis
- Lassa fever
- Legionella pneumophila
- Leucoerythroblastic anemia
- Leukemia
- Lincomycin hydrochloride
- Lymphoma
- Malabsorption syndrome
- Malignant histiocytosis
- Marasmus
- Megaloblastic anemia 
- Melanoma
- Metastatic neoplasm
- Minocycline hydrochloride
- Mutagen exposure
- Mutagen-detoxification (GSTq1-null)
- Mycobacterium tuberculosis
- Myelodysplastic syndrome 
- Myelofibrosis
- Myeloma
- Myelopathic anemia
- Neuroblastoma
- Neurofibromatosis 1
- Niemann-Pick disease
- Non steroidal anti-inflammatory drugs
- Non-Hodgkin lymphoma
- Obesity
- Ofatumumab
- Omacetaxine
- Osteoclastoma
- Osteopetrosis lethal
- Osteopetrosis, autosomal recessive 2
- Osteoporosis
- Osteosarcoma
- Oxaprozin
- Oxcarbazepine
- Panhypopituitarism
- Paroxysmal nocturnal hemoglobinuria 
- Parvovirus B19 infection 
- Pearson syndrome
- Penicillamine 
- Pernicious anemia 
- Phenacemide
- Phenylbutazone
- Piperacillin
- Plummer-Vinson syndrome
- Portal hypertension
- Pralatrexate
- Precursor B acute lymphoblastic leukemia/lymphoma
- Pregnancy
- Propylthiouracil
- Prostate cancer
- Pyrimethamine
- Q fever
- Rabeprazole
- Radiation therapy 
- Radium chloride
- Renal failure, chronic
- Reticular dysgenesis
- Reticulosis
- Rheumatoid disease
- Sarcoidosis 
- Schwachman-Diamond syndrome
- Severe combined immunodeficiency 
- Sickle cell disease
- Splenomegaly
- Sulfonamides
- Systemic lupus erythematosus 
- Tamoxifen
- TAR syndrome
- T-cell large granular lymphocytic leukemia 
- Temozolomide 
- Thiothixene
- Thymoma
- Thyroid carcinoma
- Tobacco use
- Tolazamide
- Tolbutamide
- Topoisomerase II interactive agents
- Toxins
- Trifluoperazine
- Trimethadione
- Trimethoprim-sulfamethoxazole
- Trisomy 8 mosaicism
- Tuberculosis 
- Valganciclovir hydrochloride
- Valproic acid poisoning 
- Viral infections
- Vitamin B12 deficiency
- Vitamin C deficiency
- Whipple's disease 
- Wiskott-Aldrich syndrome
- Xeroderma pigmentosum

## Causes by Pathophysiology

### Bone Marrow Failure
- Insufficient production (aplastic anemia)
- Inability of cells or mature (myelodysplasia)
- Replacement of normal bone marrow with fibrosis (myelofibrosis)

### Peripheral Sequestration/Destruction
- Splenomegaly
- Hypersplenism

## Causes by Mode of Inheritance
This is not applicable since there is no specific mode of inheritance for pancytopenia.

### Congenital
- Cartilage hair hypoplasia:
This is a bone marrow failure condition caused by ribosomal protein mutations.
Clinical manifestations include cartilage and hair loss.
- This is a bone marrow failure condition caused by ribosomal protein mutations.
- Clinical manifestations include cartilage and hair loss.
- Diamond-Blackfan syndrome:
This is a rare condition affecting 5-7 persons per million and is characterized by a macrocytic anemia and less than 5% erythroid precursors including reticulocytes.
It is the most common inherited erythrocyte failure syndrome, and it is inherited in an autosomal dominant pattern.
This condition is caused by mutations in ribosomal protein genes such as RPS19.
Though neutropenia and thrombocytopenia do not usually occur, moderate white blood cell and platelet count reductions have been described in some cases.
Fetal hemoglobin is typically increased in an effect to enhance delivery of oxygen to tissues in the setting of low hemoglobin.
Clinical manifestations usually include short statute, ocular abnormalities, skeletal abnormalities.
It is the most common inherited erythrocyte failure syndrome.
The only curative therapy is bone marrow transplantation.
- This is a rare condition affecting 5-7 persons per million and is characterized by a macrocytic anemia and less than 5% erythroid precursors including reticulocytes.
- It is the most common inherited erythrocyte failure syndrome, and it is inherited in an autosomal dominant pattern.
- This condition is caused by mutations in ribosomal protein genes such as RPS19.
- Though neutropenia and thrombocytopenia do not usually occur, moderate white blood cell and platelet count reductions have been described in some cases.
- Fetal hemoglobin is typically increased in an effect to enhance delivery of oxygen to tissues in the setting of low hemoglobin.
- Clinical manifestations usually include short statute, ocular abnormalities, skeletal abnormalities.
- It is the most common inherited erythrocyte failure syndrome.
- The only curative therapy is bone marrow transplantation.
- Dubowitz syndrome
This is a rare autosomal recessive disorder characterized by increased cancer susceptibility.
The exact genetic abnormality and etiology is yet to be identified.
Patients have DNA that is very sensitive to ionizing radiation and a few chemotherapy agents like anthracyclines and bleomycin.
There is some clinical overlap with Fanconi anemia.
Patients can develop bone marrow failure and cytopenias.
- This is a rare autosomal recessive disorder characterized by increased cancer susceptibility.
- The exact genetic abnormality and etiology is yet to be identified.
- Patients have DNA that is very sensitive to ionizing radiation and a few chemotherapy agents like anthracyclines and bleomycin.
- There is some clinical overlap with Fanconi anemia.
- Patients can develop bone marrow failure and cytopenias.
- Dyskeratosis congenita
This is a rare condition caused by short telomeres, which normally function to maintain the length and integrity of DNA.
It is characterized by skin abnormalities, nail abnormalities, and leukoplakia.
The genes implicated include DKC1 (dyskerin), TERT, and TERC.
Other genes implicated in this condition encode ribonucleoprotein enzymes.
By age 30, approximately 80% of patients with this condition will develop bone marrow failure.
- This is a rare condition caused by short telomeres, which normally function to maintain the length and integrity of DNA.
- It is characterized by skin abnormalities, nail abnormalities, and leukoplakia.
- The genes implicated include DKC1 (dyskerin), TERT, and TERC.
- Other genes implicated in this condition encode ribonucleoprotein enzymes.
- By age 30, approximately 80% of patients with this condition will develop bone marrow failure.
- Fanconi's anemia
This is a condition characterized by erythrocyte hypoproduction due to genomic instability and increased susceptibility to DNA damaging agents. 
Diagnosis is made by demonstration of DNA crosslinking upon exposure to diepoxybutane (DEB) and mitomycin C (MCC).
Patients with fanconi anemia have a higher risk for development of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), both of which can contribute to pancytopenia.
- This is a condition characterized by erythrocyte hypoproduction due to genomic instability and increased susceptibility to DNA damaging agents. 
- Diagnosis is made by demonstration of DNA crosslinking upon exposure to diepoxybutane (DEB) and mitomycin C (MCC).
- Patients with fanconi anemia have a higher risk for development of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), both of which can contribute to pancytopenia.
- Pearson syndrome
This is a relatively uncommon cause of refractory sideroblastic anemia, neutropenia, and thrombocytopenia.
Clinical features include proximal myopathy and weakness, ophthalmoplegia, ataxia. and peripheral neuropathy.
- This is a relatively uncommon cause of refractory sideroblastic anemia, neutropenia, and thrombocytopenia.
- Clinical features include proximal myopathy and weakness, ophthalmoplegia, ataxia. and peripheral neuropathy.
- Schwachman-Diamond syndrome
This is a condition that affects approximately 1 in 50000 persons and is characterized by bone marrow failure, pancreatic exocrine insufficiency, and skeletal abnormalities.
It is caused by a biallelic (two alleles) mutation in a ribosomal protein encoded by the Schwachman-Bodian-Diamond gene SBDS, located on chromosome 7.
Clinical manifestations in children usually include diarrhea and steatorrhea (due to pancreatic exocrine insufficiency).
However, there have been cases of pancytopenia from schwachman-diamond syndrome in the absence of diarrhea, so this condition should still be in the differential diagnosis of children with pancytopenia and bone marrow failure.
- This is a condition that affects approximately 1 in 50000 persons and is characterized by bone marrow failure, pancreatic exocrine insufficiency, and skeletal abnormalities.
- It is caused by a biallelic (two alleles) mutation in a ribosomal protein encoded by the Schwachman-Bodian-Diamond gene SBDS, located on chromosome 7.
- Clinical manifestations in children usually include diarrhea and steatorrhea (due to pancreatic exocrine insufficiency).
- However, there have been cases of pancytopenia from schwachman-diamond syndrome in the absence of diarrhea, so this condition should still be in the differential diagnosis of children with pancytopenia and bone marrow failure.
- TAR syndrome
This is a rare condition characterized by low platelet count (thrombocytopenia) and absent radius (a long bone of the lower arm).
It is thought to be caused by an interstitial deletion in chromosome 1q21.
Patients can have skeletal abnormalities (like absent radius, short ulna, and absence of other long bones of the arm).
The fingers are not affected.
- This is a rare condition characterized by low platelet count (thrombocytopenia) and absent radius (a long bone of the lower arm).
- It is thought to be caused by an interstitial deletion in chromosome 1q21.
- Patients can have skeletal abnormalities (like absent radius, short ulna, and absence of other long bones of the arm).
- The fingers are not affected.

### Acquired
- Albers-Schonberg disease
- Banti's Syndrome
- Bone marrow tumor
- Cirrhosis
- Drugs/Toxins
- Felty's Syndrome
- Gaucher's Disease
- Graft-versus-host disease
- Infections
- Kala-Azar
- Leukemia
- Lymphoma
- Lymphoproliferative Disorders
- Myelodysplastic syndrome
- Myelofibrosis
- Niemann-Pick Disease
- Osteoporosis
- Pernicious anemia
- Reticulosis
- Sarcoidosis
- Thymoma
- Tuberculosis

# Differentiating Pancytopenia from Other Diseases

# Epidemiology and Demographics
- Pancytopenia affects males and females equally.
- However, the underlying etiologies of pancytopenia can have a gender predilection.
- Please see above sections for epidemiology and demographics of the individual disease entities that cause pancytopenia.

# Risk Factors
- The risk factors of pancytopenia are related to the underlying cause.
- For example, leukemia-mediated pancytopenia can be related to risk factors such as chemical exposure, radiation, or family history.
- Please see above sections for risk factors of the individual disease entities that cause pancytopenia.

# Screening
- There are no suggested screening tests for pancytopenia.
- The United States Preventive Services Task Force (USPSTF) does not have any recommendations for screening for pancytopenia.
- However, if a person is suspected of having a particular condition that cause cause pancytopenia, such as viral infection, a diagnosis complete blood count (CBC) can be checked to assess for pancytopenia.

# Natural History, Complications, and Prognosis

## Natural History
- The natural history of pancytopenia is dictated by the pathophysiology of the under etiology.
- For example, viral-mediated pancytopenia is typically short-lived, pending clearance of the virus.
- Drug-induced pancytopenia typically resolves after discontinuing of the culprit drug and the drug has been metabolized by the body.
- Leukemia-mediated pancytopenia is usually a more long-term process, as marrow replacement by leukemia cells is difficult to overcome unless the leukemia is treated and the patient is in remission.
- Please see above sections for natural history of the individual disease entities that cause pancytopenia.

## Complications
- Complications of pancytopenia relate to deficits of the cell types that are affected.
- Decrease in erythrocytes causes fatigue, pallor, lightheadedness, and shortness of breath due to decrease in oxygen delivery to tissue beds.
- Decrease in leukocytes and leukocyte subsets causes infections, which can be viral, bacteria, fungal, or parasitic.
- The most concerning complication of decrease in leukocytes is called febrile neutropenia, which is a hematologic emergency.
- Decrease in thrombocytes causes bleeding, which is typically mucosal, given loss of the ability of platelets to create a hemostatic plug.

## Prognosis
- The prognosis of pancytopenia is related to the underlying etiology.
- For example, patients with unfavorable-risk leukemia will likely have a poor prognosis from a pancytopenia perspective.
- Patients with viral-mediated pancytopenia have a prognosis that is determined by the natural history of the virus.
- Epstein-Barr virus (EBV)-related pancytopenia can have a good prognosis if EBV resolves.
- Drug-induced pancytopenia has a favorable prognosis, as discontinuation of the offending agent can typically reverse the pancytopenia.
- Please see above sections for prognosis of the individual disease entities that cause pancytopenia.

# Diagnosis

## Diagnostic Criteria
The diagnosis of pancytopenia is made by assessing a complete blood count (CBC) when all of the following criteria are fulfilled:
- Anemia as defined by hemoglobin level < 12 grams per deciliter (g/dl)
- Leukopenia as defined by leukocyte count < 4000 per microliter
- Thrombocytopenia as defined by platelet count < 150000 per microliter

## History and Symptoms
Symptoms of pancytopenia are related to decrease in erythrocytes, leukocytes, and platelets.
- Decrease in erythrocytes causes fatigue, shortness of breath, decreased exercise tolerance, and pallor.
- Decrease in leukocytes causes infection, which can affect a multitude of organ systems including the central nervous system, lungs, abdomen, urinary tract, kidneys, and skin.
- Decrease in platelets causes mucocutaneous bleeding, typically of the nose, mouth, gastrointestinal tract, or genitourinary tract.

## Physical Examination
Key components of the physical exam include assessment of the conjunctiva, oral and nasal mucosa, lymph nodes (cervical, axillary, supraclavicular, inguinal), spleen size, liver size, and skin.
- The anemia component of pancytopenia can cause conjunctival pallor, mucosal pallor, skin pallor, and tachypnea.
- The leukopenia component of pancytopenia can cause variable findings depending on whether infection is present. Exam findings can include lymphadenopathy, egophony, coarse breath sounds, malodorous urine, suprapubic tenderness, costovertebral tenderness, abdominal tenderness, skin erythema, and/or skin purulence.
- The thrombocytopenia component of pancytopenia can cause petechiae (pinpoint hemorrhages in the skin), mucosal bleeding, or internal bleeding.

## Laboratory Findings
Laboratory findings in pancytopenia are, by definition:
- Hemoglobin level < 12 grams per deciliter (g/dl)
- Leukocyte count < 4000 per microliter
- Platelet count < 150000 per microliter
Other laboratory findings, depending on the underlying cause, can include:
- Elevated LDH
- Elevated indirect bilirubin
- Elevated reticulocyte count
- Decreased haptoglobin

## Imaging Findings
- There are no imaging findings associated with pancytopenia.

## Other Diagnostic Studies
- Viral polymerase chain reaction PCR testing can be done for viral-induced pancytopenia. This includes PCR for CMV DNA and EBV DNA.

# Treatment

## Medical Therapy
- The treatment of pancytopenia depends on the underlying cause.
- If pancytopenia is due to medication adverse effect, the offending agent should be discontinued.
- If pancytopenia is due to myelopthisis from leukemia, the underlying leukemia should be treated with cytotoxic chemotherapy.
- If pancytopenia is due to aplastic anemia, this should be treated with either immunosuppression with anti-thymocyte globulin (ATG) and cyclosporine A, or by hematopoietic stem cell transplantation from a matched related donor.
- Please see above sections for details of treatment of the individual disease entities that cause pancytopenia.

## Surgery
- The is no role for surgery for pancytopenia.
- However, for immune thrombocytopenia purpura (ITP) and autoimmune hemolytic anemia (AIHA), splenectomy can be considered.

## Prevention
- The prevention of pancytopenia focuses on prevention of the underlying etiologies.
- For example, viral-induced pancytopenia can be prevented by taking precautions against acquiring viral infections.
- This can include good hand hygiene, avoidance of exposures, anti-viral medications as prophylaxis.
- Prevention of leukemia-induced pancytopenia can be achieved via avoidance of risk factors of leukemia such as radiation exposure, chemical exposure, or benzene exposure.
- Drug-induced pancytopenia can be prevented by choosing an alternative medication in a similar class that does not cause pancytopenia.
- For example, in a patient who requires prophylaxis for PCP, atovaquone can be administered in place of trimethoprim-sulfamethoxazole, as atovaquone does not cause pancytopenia.