Reticulocytopenia

Last updated
Reticulocytopenia
Other namesAplastic crisis, Marrow failure
Specialty Hematology
CausesParvovirus B19 (Aplastic Crisis)

Pure Red Cell Aplasia

Aplastic Anemia

Reticulocytopenia is the medical term for an abnormal decrease in circulating red blood cell precursors (reticulocytes) that can lead to anemia due to resulting low red blood cell (erythrocyte) production. [1] Reticulocytopenia may be an isolated finding or it may not be associated with abnormalities in other hematopoietic cell lineages such as those that produce white blood cells (leukocytes) or platelets (thrombocytes), a decrease in all three of these lineages is referred to as pancytopenia. [1]

Contents

With isolated reticulocytopenia, the main cause is Parvovirus B19 infection of reticulocytes leading to transient anemia. [2] In patients who rely on frequent red cell regeneration e.g. sickle cell disease, a reticulocytopenia can lead to a severe anemia due to the cessation in red cell production (erythropoiesis), referred to as aplastic crisis. [3] If pancytopenia is present, bone marrow failure [4] must be considered and evaluation for bone marrow failure syndromes or aplastic anemia must be pursued. Treatment is dependent on the etiology and may include replacement of blood products as patients can develop severe anemia. [3]

Differential Diagnosis

Reticulocytopenia may be associated with abnormalities in other hematopoietic cell lineages. The following is a differential diagnosis for patients in which reticulocytopenia is the most marked cytopenia. For conditions that lead to significant reduction in all three cell lineages, see pancytopenia or aplastic anemia.

Pathophysiology

The specific pathophysiology differs with each etiology. For conditions that lead to pancytopenia, see aplastic anemia.

Parvovirus B-19 Infection

Parvovirus is able to infiltrate the bone marrow and enter and replicate in red blood cell precursors such as reticulocytes. [2] Viral replication in reticulocytes causes apoptosis (cell death) of affected cells. [2] The reduction in living reticulocytes leads to a decrease in red blood cell production. This transient cessation in red cell production results in a decrease in hemoglobin that is often asymptomatic in people without underlying hematologic disorders. Reticulocyte production often recovers within one week. Parvovirus infection in people reliant on frequent red cell production due to low baseline production or high turnover rates are at risk of developing a life-threatening condition called aplastic crisis (see below).

Bone Marrow Failure Syndromes

Bone marrow failure syndromes may be acquired or inherited. These conditions lead to a decrease in one or more cell lineages. Diamond-Blackfan Anemia is an example of a congenital bone marrow failure syndrome that primarily affects red blood cell production. In DBA, the erythroid cell lineage is more susceptible to cell death due to abnormal ribosome function. [4] This leads to a reduced population of red blood cell precursors and a resulting reticulocytopenia and anemia.

Evaluation

For the patient with isolated reticulocytopenia and anemia without significant disturbances in other cell lineages, the initial evaluation may include some of the following studies: [7]

Further Evaluation

Depending on findings on initial evaluation, may consider investigating the cause of low reticulocyte count with some of the following studies depending on patient presentation and differential diagnoses:

Management

The goal is to treat the underlying condition if it can be identified and provide supportive care. If symptomatic anemia develops, blood products may be replaced. Disease specific management may include glucocorticoids, IVIG, immunosuppressive agents, stem cell transplant, or other treatments depending on the etiology of reticulocytopenia. [7]

Complications

Anemia

Severe anemia can lead to complications such as heart failure due to volume overload, bone marrow necrosis, etc. See anemia for further details.

Aplastic Crisis

Transient decrease in erythropoiesis resulting in low reticulocyte count with decrease in hemoglobin >/= 3 g/dL is considered to be aplastic crisis. [8] For the decrease in all cell lineages (pancytopenia), see aplastic anemia. The majority of cases of aplastic crisis are seen in people with hematologic disorders and superimposed infection with Parvovirus B19. [3] [8]

Predisposing Conditions

Patients who rely on frequent regeneration of RBCs due to shorter RBC lifespan or decreased production are at risk of developing aplastic crisis when erythropoiesis is affected as they cannot compensate for the lapse in red cell production. A typical erythrocyte has a lifespan of about 120 days while an erythrocyte in a sickle cell patient has an average lifespan of 12–15 days. Listed below are some of the conditions that may put a patient at risk of developing aplastic crisis if there is a disruption in erythropoiesis. [2]

Parvovirus B19 Infection and Transient Aplastic Crisis [5]

The majority of TAC are triggered by Parvovirus B19 in patients with hematologic disorders. These patients often present with high viral titers during profound anemia and are found to have reticulocytopenia upon further evaluation. Children are more affected than adults, and immunity appears to last several years after infection. [7] Patients with TAC due to Parvovirus B19 are less likely to have the typical slapped-cheek rash (erythema infectiosum) characteristic of this infection. Infections with Salmonella, S. pneumoniae, and other pathogens may also lead to TAC. With Parvovirus infection, bone marrow recovery typically occurs within 10 days and erythropoiesis resumes. [8] Parvovirus IgG/IgM may be obtained to assess for active infection. Patients may require IVIG or replacement of blood products during this transient bone marrow failure to reduce the chance of serious complications from the severe anemia. [7]

See also

Related Research Articles

<span class="mw-page-title-main">Anemia</span> Medical condition

Anemia or anaemia is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin or hemoglobin abnormalities. The name is derived from Ancient Greek: ἀναιμία anaimia, meaning 'lack of blood', from ἀν- an-, 'not' and αἷμα haima, 'blood'. When anemia comes on slowly, the symptoms are often vague, such as tiredness, weakness, shortness of breath, headaches, and a reduced ability to exercise. When anemia is acute, symptoms may include confusion, feeling like one is going to pass out, loss of consciousness, and increased thirst. Anemia must be significant before a person becomes noticeably pale. Symptoms of anemia depend on how quickly hemoglobin decreases. Additional symptoms may occur depending on the underlying cause. Preoperative anemia can increase the risk of needing a blood transfusion following surgery. Anemia can be temporary or long term and can range from mild to severe.

<span class="mw-page-title-main">Myelodysplastic syndrome</span> Diverse collection of blood-related cancers

A myelodysplastic syndrome (MDS) is one of a group of cancers in which immature blood cells in the bone marrow do not mature, and as a result, do not develop into healthy blood cells. Early on, no symptoms typically are seen. Later, symptoms may include fatigue, shortness of breath, bleeding disorders, anemia, or frequent infections. Some types may develop into acute myeloid leukemia.

Aplastic anemia (AA) is a severe hematologic condition in which the body fails to make blood cells in sufficient numbers. Aplastic anemia is associated with cancer and various cancer syndromes. Blood cells are produced in the bone marrow by stem cells that reside there. Aplastic anemia causes a deficiency of all blood cell types: red blood cells, white blood cells, and platelets.

<span class="mw-page-title-main">Reticulocyte</span> Blood cells

Reticulocytes are immature red blood cells (RBCs). In the process of erythropoiesis, reticulocytes develop and mature in the bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. Like mature red blood cells, in mammals, reticulocytes do not have a cell nucleus. They are called reticulocytes because of a reticular (mesh-like) network of ribosomal RNA that becomes visible under a microscope with certain stains such as new methylene blue and Romanowsky stain.

<span class="mw-page-title-main">Fifth disease</span> Medical condition

Erythema infectiosum, fifth disease, or slapped cheek syndrome is one of several possible manifestations of infection by parvovirus B19. Fifth disease typically presents as a rash and is more common in children. While parvovirus B19 can affect humans of all ages, only two out of ten individuals will present with physical symptoms.

<span class="mw-page-title-main">Hereditary spherocytosis</span> Medical condition

Hereditary spherocytosis (HS) is a congenital hemolytic disorder, wherein a genetic mutation coding for a structural membrane protein phenotype leads to a spherical shaping of erythrocytic cellular morphology. As erythrocytes are sphere-shaped (spherocytosis), rather than the normal biconcave disk-shaped, their morphology interferes with these cells' abilities to be flexible during circulation throughout the entirety of the body - arteries, arterioles, capillaries, venules, veins, and organs. This difference in shape also makes the red blood cells more prone to rupture under osmotic and/or mechanical stress. Cells with these dysfunctional proteins are degraded in the spleen, which leads to a shortage of erythrocytes resulting in hemolytic anemia.

<span class="mw-page-title-main">Paroxysmal nocturnal hemoglobinuria</span> Medical condition

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired, life-threatening disease of the blood characterized by destruction of red blood cells by the complement system, a part of the body's innate immune system. This destructive process occurs due to deficiency of the red blood cell surface protein DAF, which normally inhibits such immune reactions. Since the complement cascade attacks the red blood cells within the blood vessels of the circulatory system, the red blood cell destruction (hemolysis) is considered an intravascular hemolytic anemia. There is ongoing research into other key features of the disease, such as the high incidence of venous blood clot formation. Research suggests that PNH thrombosis is caused by both the absence of GPI-anchored complement regulatory proteins on PNH platelets and the excessive consumption of nitric oxide (NO).

Bone marrow suppression also known as myelotoxicity or myelosuppression, is the decrease in production of cells responsible for providing immunity (leukocytes), carrying oxygen (erythrocytes), and/or those responsible for normal blood clotting (thrombocytes). Bone marrow suppression is a serious side effect of chemotherapy and certain drugs affecting the immune system such as azathioprine. The risk is especially high in cytotoxic chemotherapy for leukemia.

<span class="mw-page-title-main">Parvovirus B19</span> Human virus that infects RBC precursors.

Primate erythroparvovirus 1, generally referred to as B19 virus(B19V),parvovirus B19 or sometimes erythrovirus B19, is the first known human virus in the family Parvoviridae, genus Erythroparvovirus; it measures only 23–26 nm in diameter. The name is derived from Latin parvum, meaning small, reflecting the fact that B19 ranks among the smallest DNA viruses. B19 virus is most known for causing disease in the pediatric population; however, it can also affect adults. It is the classic cause of the childhood rash called fifth disease or erythema infectiosum, or "slapped cheek syndrome".

Pancytopenia is a medical condition in which there is significant reduction in the number of almost all blood cells.

Anemia of chronic disease (ACD) or anemia of chronic inflammation is a form of anemia seen in chronic infection, chronic immune activation, and malignancy. These conditions all produce elevation of interleukin-6, which stimulates hepcidin production and release from the liver. Hepcidin production and release shuts down ferroportin, a protein that controls export of iron from the gut and from iron storing cells. As a consequence, circulating iron levels are reduced. Other mechanisms may also play a role, such as reduced erythropoiesis. It is also known as anemia of inflammation, or anemia of inflammatory response.

<span class="mw-page-title-main">Pure red cell aplasia</span> Medical condition

Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of aplastic anemia affecting the precursors to red blood cells but usually not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. There are multiple etiologies that can cause PRCA. The condition has been first described by Paul Kaznelson in 1922.

Transient erythroblastopenia of childhood (TEC) is a slowly developing anemia of early childhood characterized by gradual onset of pallor.

Aplasia is a birth defect where an organ or tissue is wholly or largely absent. It is caused by a defect in a developmental process.

Myelophthisic anemia is a severe type of anemia found in some people with diseases that affect the bone marrow. Myelophthisis refers to the displacement of hemopoietic bone-marrow tissue by fibrosis, tumors, or granulomas. The word comes from the roots myelo-, which refers to bone marrow, and phthysis, shrinkage or atrophy.

Hematologic diseases are disorders which primarily affect the blood & blood-forming organs. Hematologic diseases include rare genetic disorders, anemia, HIV, sickle cell disease & complications from chemotherapy or transfusions.

Normocytic anemia is a type of anemia and is a common issue that occurs for men and women typically over 85 years old. Its prevalence increases with age, reaching 44 percent in men older than 85 years. The most common type of normocytic anemia is anemia of chronic disease.

<span class="mw-page-title-main">Congenital amegakaryocytic thrombocytopenia</span> Medical condition

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare autosomal recessive bone marrow failure syndrome characterized by severe thrombocytopenia, which can progress to aplastic anemia and leukemia. CAMT usually manifests as thrombocytopenia in the initial month of life or in the fetal phase. Typically CAMPT presents with petechiae, cerebral bleeds, recurrent rectal bleeding, or pulmonary hemorrhage.

Non-sideropenic hypochromic anemia also known as Normochromic Normocytic Anemia is a kind of anemia in which the red blood cells in circulation have a normal red color (normochromic) and the same size (normocytic). Normocytic normochromic anemia is most commonly caused by a variety of chronic infections and systemic diseases.

Neal Stuart Young is an American physician and researcher, chief of the Hematology Branch of the National Institutes of Health (NIH), and Director of the Center for Human Immunology at the NIH in Bethesda, Maryland. He is primarily known for his work in the pathophysiology and treatment of aplastic anemia, and is also known for his contributions to the pathophysiology of parvovirus B19 infection.

References

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