Aplastic anemia
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Flashcards
Aplastic anemia
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Questions
USMLE® Step 1 style questions USMLE
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Which of the following would most likely be seen on microscopic examination of this patient’s bone marrow?
External References
First Aid
2024
2023
2022
2021
Aplastic anemia p. 427
in anemia taxonomy p. 423
chloramphenicol p. 189
as drug reaction p. 249
Fanconi anemia p. 724
neutropenia with p. 429
thionamides p. 360
Benzene
aplastic anemia p. 249, 427
Café-au-lait spots
aplastic anemia and p. 427
Carbamazepine
aplastic anemia p. 249
Chloramphenicol p. 189
aplastic anemia and p. 249, 427
Epstein-Barr virus (EBV) p. 162
aplastic anemia p. 427
Erythropoietin (EPO)
aplastic anemia p. 427
Hepatitis
aplastic anemia and p. 427
Hepatitis viruses p. 171
aplastic anemia p. 427
HIV (human immunodeficiency virus) p. 173
aplastic anemia in p. 427
Immunosuppressants
for aplastic anemia p. 427
Leukemias p. 437
aplastic anemia and p. 415
Methimazole p. 360
aplastic anemia p. 249
Nonsteroidal anti-inflammatory drugs (NSAIDs) p. 495
aplastic anemia p. 249
Pallor in aplastic anemia p. 427
Parvovirus B15
aplastic anemia p. 415
Petechiae
aplastic anemia as cause p. 427
Propylthiouracil
aplastic anemia p. 249
Purpura
aplastic anemia p. 427
Radiation exposure
aplastic anemia p. 429
Reticulocytes p. 413
in aplastic anemia p. 427
Stem cells
in aplastic anemia p. 427
Transcript
Content Reviewers
Aplastic anemia is a pancytopenia, meaning all blood cell lines are decreased - so the term aplastic anemia, which just refers to low red blood cell count, is actually a misnomer.
So with aplastic anemia, there’s actually anemia, as well as leukocytopenia, or low white blood cells, as well as thrombocytopenia, or low platelet levels.
This condition takes many forms, ranging from mild to severe depending on the cause.
Now, blood cells are produced in the bones of the body, mainly in the bones of the pelvis, ribs and sternum, through a process called hematopoiesis.
This process starts in the bone marrow, the innermost portion of bone, where the hematopoietic stem cells reside.
These serve as progenitor cells for all the different cell types found in the blood.
First, hematopoietic stem cells, also called hemocytoblasts, can become lymphoid progenitors or myeloid progenitors.
The lymphoid progenitors can develop into lymphoblasts, which can then differentiate into some white blood cells like T-lymphocytes, B-lymphocytes, or natural killer cells.
The myeloid progenitors can differentiate into erythrocytes, or red blood cells, megakaryocytes, which eventually give rise to platelets, or myeloblasts, which can then become other white blood cells like monocytes, neutrophils, basophils, and eosinophils.
The most common cause of aplastic anemia is autoimmune destruction of hematopoietic stem cells.
The details of this mechanism are not fully understood, but research shows that there are alterations in the immunologic appearance of hematopoietic stem cells because of genetic disorders, or after exposure to environmental agents, like radiation or toxins.
This means that the hematopoietic stem cells start expressing non-self antigens and the immune system subsequently targets them for destruction.
As the immune system destroys hematopoietic stem cells a whole host of complications arise.
Due to the low red blood cell count tissues cannot properly oxygenate so the heart pumps harder to circulate the red blood cells leading to chest pain and shortness of breath.
Summary
Aplastic anemia is a rare blood disorder caused by bone marrow failure to produce new blood cells. Even though it's referred to as aplastic anemia, it typically presents with pancytopenia, meaning that all three major blood cell lines - the red blood cells, white blood cells, and platelets are affected.
People with aplastic anemia may experience fatigue, shortness of breath, ecchymoses and mucosal bleeding, and frequent infections pallor Aplastic anemia can be caused by a variety of factors, including exposure to radiation or chemotherapy, viral infections, and autoimmune disorders.
Sources
- "Robbins Basic Pathology" Elsevier (2017)
- "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
- "Current concepts in the pathophysiology and treatment of aplastic anemia" Hematology (2013)
- "Aplastic anaemia" Hematology (2013)
- "Aplastic Anemia" New England Journal of Medicine (2018)
- "Harrison's Principles of Internal Medicine" McGraw-Hill (2004)
- "The complex pathophysiology of acquired aplastic anaemia" Clinical & Experimental Immunology (2015)