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Iron deficiency anemia
Anemia of chronic disease
Hemolytic disease of the newborn
Glucose-6-phosphate dehydrogenase (G6PD) deficiency
Autoimmune hemolytic anemia
Pyruvate kinase deficiency
Paroxysmal nocturnal hemoglobinuria
Sickle cell disease (NORD)
Anemia of chronic disease
Folate (Vitamin B9) deficiency
Vitamin B12 deficiency
Acute intermittent porphyria
Porphyria cutanea tarda
Vitamin K deficiency
Immune thrombocytopenic purpura
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Von Willebrand disease
Disseminated intravascular coagulation
Antithrombin III deficiency
Factor V Leiden
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Polycythemia vera (NORD)
Essential thrombocythemia (NORD)
Langerhans cell histiocytosis
Monoclonal gammopathy of undetermined significance
Microcytic anemia: Pathology review
Non-hemolytic normocytic anemia: Pathology review
Intrinsic hemolytic normocytic anemia: Pathology review
Extrinsic hemolytic normocytic anemia: Pathology review
Macrocytic anemia: Pathology review
Heme synthesis disorders: Pathology review
Coagulation disorders: Pathology review
Platelet disorders: Pathology review
Mixed platelet and coagulation disorders: Pathology review
Thrombosis syndromes (hypercoagulability): Pathology review
Lymphomas: Pathology review
Leukemias: Pathology review
Plasma cell disorders: Pathology review
Myeloproliferative disorders: Pathology review
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dacrocytes in p. 422
myelofibrosis p. 441
Stefan Stoisavljevic, MD
Myelofibrosis is a disease in which the bone marrow within a bone gets replaced by connective tissue in a process called fibrosis.
Since the bone marrow’s main role is to produce erythrocytes or red blood cells, leukocytes or white blood cells, and thrombocytes or platelets, the process of fibrosis interferes with production of these cell types.
Now, normally, the vast majority of bone marrow is made of hematopoietic cells which are the early progenitor cells that can differentiate into other cell types.
In addition to these cells there are fibroblasts, which are connective tissue cells.
Now, myelofibrosis can be primary or secondary.
Primary myelofibrosis is caused by a gene mutation within hematopoietic cells, which activates a set of enzymes that together are called the JAK-STAT pathway.
The mutation specifically causes the enzymes in the JAK-STAT pathway to go into overdrive so that the cells begin to mature and divide rapidly, quickly filling up the bone marrow.
A large majority of these cells turn into megakaryocytes which go on to make platelets.
These megakaryocytes release cytokines, which are molecules that create inflammation.
And one of these cytokines is fibroblast growth factor which activates fibroblasts.
The activated fibroblasts engage in the process of fibrosis - they make lots of connective tissue that ultimately begins to fill up and scar the bone marrow and replaces hematopoietic cells.
In response, the hematopoietic cells migrate to liver, spleen, and lungs - a process called extramedullary hematopoiesis.
These tissues enlarge and sometimes become dysfunctional.
The extramedullary hematopoiesis is often not able to fully compensate for the loss of bone marrow hematopoiesis, and it can lead to a shortage of all blood cell lines - called pancytopenia.
Myelofibrosis is a type of bone marrow disorder that affects the production of blood cells. In Myelofibrosis, the bone marrow tissue is replaced with fibrotic tissue, which interferes with blood cell production. Symptoms include anemia, fatigue, bone pain, itching, fever, and weight loss. Treatment options may include medications like ruxolitinib, bone marrow transplants, and blood transfusion.
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