Flashcards in Stem Cell Disorders Deck (33)
What is aplastic anemia?
A condition in which there are a reduced number of RBCs, WBCs, and platelets due to bone marrow aplasia/hypoplasia.
Differentiate between aplastic anemia and aplastic crisis.
Aplastic anemia is a misnomer and actually refers to the presence of pancytopenia. Aplastic crisis involves a decrease in the red cell line only.
What are some known causes of aplastic anemia?
The cause is unknown in >50% of cases, with the remainder due to certain drugs, toxins, infections, or radiation exposure.
What are some dose-related causes of aplastic anemia?
Benzene and radiation.
What are some drugs/toxins which can be implicated in the development of aplastic anemia?
Sulfa drugs, gold, chloramphenicol, and insectisides.
What are some infections for which testing should be included in the initial evaluation of aplastic anemia?
Hepatitis, CMV, EBV, HIV, and parvovirus.
What genetic workup should be performed in patients with aplastic anemia?
These patients should be evaluated for inherited bone marrow failure syndromes in addition to the rest of the recommended workup.
What hemotologic disorder can develop in patients with paroxysmal nocturnal hemoglobinuria?
About 20% of patients with PNH eventually develop aplastic anemia as well.
List 6 potential etiologies for pancytopenia.
Aplastic anemia, HLH, primary hematologic malignancies, folic acid deficiency, B12 deficiency, and fibrosis or infiltration with neoplastic cells, such as in neuroblastoma.
What physical exam findings would be concerning for a hematologic disorder affecting >1 cell line?
The combination of bruising and pallor.
What procedure is required as part of the evaluation of pancytopenia?
Bone marrow biopsy/aspiration
What would be the typical bone marrow finding in a patient with aplastic anemia?
Hypocellular or acellular bone marrow.
What are the treatment options for children with aplastic anemia?
Immunosuppressive therapy with antithymocyte globulin (ATG), cyclosporine, and prednisone offers a complete response rate of 65%, although relapses are common. Matched bone marrow transplant, if available, has a 10-year survival rate of >80%.
Which medically treated patients with aplastic anemia are at higher risk for a secondary malignancy?
Patients with inherited bone marrow failure syndromes are at higher risk for secondary malignancy if treated medically.
Why should blood products be leukoreduced and irradiated in patients with aplastic anemia?
To prevent pretransplant alloimmunization, minimize the number of transfusions if possible. If transfusions are required: do not use family members as donors, use single-donor platelets, and use leukocyte-filtered and irradiated blood components.
What is the inheritance pattern associated with Fanconi anemia?
What is the underlying defect that leads to the clinical manifestations of Fanconi anemia?
It is due to the presence of poor DNA repair mechanisms.
Describe some congenital anomalies which can be seen in children with Fanconi anemia.
Short stature, absent or abnormal thumbs, abnormal radii, microcephaly, café-au-lait spots, dark pigmentation, and renal anomalies.
What is the typical presentation of Fanconi anemia?
It can present with congenital anomalies, but they are not required for diagnosis. Most children are diagnosed around 8-9 years of age when they are found to have pancytopenia or an isolated macrocytic anemia.
What is the average lifespan of patients with Fanconi anemia?
On average, patients live into their mid-30s. Most deaths are due to infection (neutropenia), or bleeding (thrombocytopenia), but aerodigestive cancers are also common.
Children with Fanconi anemia are at risk for which malignancies?
They have a 15% risk for developing AML. Hepatic malignancy, aerodigestive cancers, and squamous cell carcinomas are also more common in patients with Fanconi anemia than in the general population.
How is red cell aplasia defined?
Red cell aplasia is defined by the presence of anemia in the setting of reticulocytopenia.
What are (6) known causes of red cell aplasia in the pediatric population?
Most common: parvovirus B19-associated RBC aplasia, transient erythroblastopenia of childhood (TEC), and congenital hypoplastic anemia (Diamond-Blackfan anemia). Can also be: idiopathic, secondary to drugs (phenytoin and chloramphenicol), or secondary to immune disorders (thymoma, SLE, chronic lymphocytic leukemia).
Which virus infects RBCs and results in aplastic crisis in children with congenital hemolytic anemias?
How does parvovirus B19 cause red cell aplasia?
It infects the erythroid progenitors, causing an acute or chronic red cell aplasia.
What clinical features, in conjunction with red cell aplasia, should point one toward the diagnosis of Parvovirus B19?
Fever, rash, and/or arthropathy. Rash can have the "slapped cheek" appearance classically associated with parvovirus B19.
What is the typical treatment for red cell aplasia caused by infection with parvovirus B19?
Treatment is usually supportive, but IVIG can be given for complicated cases in immunocompromised patients.
Describe the typical presentation of transient erythroblastopenia of childhood (TEC).
Affected children are usually 1-3 years of age and present with pallor and decreased activity without petechiae or organomegaly. Labs will reveal a normocytic anemia with isolated reticulocytopenia.
What is the typical treatment for transienct erythroblastopenia of childhood (TEC)?
Treatment includes supportive care, with transfusion for symptomatic anemia. In most cases, the anemia resolves within 1-2 months without need for transfusion.