Myelofibrosis 1525923 226109612 2008-07-16T21:27:00Z 70.171.239.148 Reverting vandalism {{DiseaseDisorder infobox | Name = Myelofibrosis | ICD10 = {{ICD10|C|94|5|c|81}}, {{ICD10|D|47|1|d|37}} | ICD9 = {{ICD9|289.89}} | Image = | Caption = | ICDO = 9932, 9961 | OMIM = | DiseasesDB = 8616 | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D009191 | }} '''Myelofibrosis''', also known as '''myeloid metaplasia''', '''chronic idiopathic myelofibrosis''', and '''primary myelofibrosis''',<ref>Older terms include "myelofibrosis with myeloid metaplasia" and "agnogenic myeloid metaplasia". The [[World Health Organization]] utilizes the name "chronic idiopathic myelofibrosis", while the International Working Group on Myelofibrosis Research and Treatment calls the disease "primary myelofibrosis". Eponyms for the disease are Heuck-Assmann disease, or Assmann's Disease.</ref>, is a disorder of the [[bone marrow]], in which the marrow is replaced by fibrous (scar) tissue ([[collagen]]). Myelofibrosis was first described in 1879 and is currently classified as a [[myeloproliferative disease]] caused by the growth and proliferation of an abnormal [[bone marrow]] stem cell, resulting in the [[fibrosis|replacement of the bone marrow with fibrous connective tissue]]. == Signs and symptoms == *Abdominal fullness related to an [[splenomegaly|enlarged spleen]] *Bone pain *Bruising and easy bleeding due to inadequate numbers of [[platelets]] *Fatigue *Increased susceptibility to infection, such as [[pneumonia]] or [[diarrhea]] *Pallor and shortness of breath while doing physical work due to [[anemia]] ==Pathophysiology== The bone marrow is replaced by collagen fibrosis, impairing the patient's ability to generate new blood cells resulting in a progressive [[pancytopenia]]. It is usually reactive following other [[myeloproliferative disorders]], such as [[polycythemia rubra vera]] or [[essential thrombocytosis]]. [[Extramedullary haematopoeisis]] occurs as the haemopoetic cells migrate away from the bone marrow, to the liver and spleen. Patients often have [[hepatosplenomegaly]] and [[poikilocytosis]]. In primary myelofibrosis, a progressive scarring ([[fibrosis]]) of the bone marrow occurs. As a result, blood forms in sites other than the bone marrow, such as the [[liver]] and [[spleen]]. This causes an enlargement of these organs. The cause and risk factors are unknown. It commonly occurs in the spent phase of [[Polycythemia rubra vera]], possibly in response to the medication [[hydroxyurea]] poisoning the marrow. ==Diagnosis== Diagnosis is based upon: # [[Normochromic]] [[normocytic]] [[anaemia]] # Red cell [[poikilocytosis]] on blood film (tear-drop shaped RBCs) # JAK 2 mutation on Val 617 Phe locus in 50% # Raised levels of lactate dehydrogenase # Raised [[neutrophil]] alkaline phosphatase score # [[Bone marrow biopsy]] may show increased cellularity and fibrosis ==Treatment== {{expand|date=May 2008}} Myleofibrosis has no known cure. Treatment is often challenging and is largely supportive. This may include regular [[folic acid]], [[allopurinol]] or [[blood transfusion]]s. [[Dexamethasone]], alpha-[[interferon]] and [[hydroxycarbamide]] may play a role. [[Lenalidomide]] and [[Thalidomide]] may be used in its treatment, though they can cause [[gout]] and leave the patient susceptible to diseases such as [[pneumonia]]. Frequent [[blood transfusions]] may also be required. ==Prognosis== Myelofibrosis leads to progressive bone marrow failure. The mean survival is five years and causes of death include infection, bleeding, organ failure, portal hypertension, and leukemic transformation. ==Epidemiology== The disorder usually develops slowly, in people over 50 years old. == Notes and references== {{reflist}} {{Hematology}} {{Hematological malignancy histology}} [[Category:Hematology]] [[Category:Blood disorders]] [[bn:মজ্জাকাঠিন্য]] [[de:Osteomyelofibrose]] [[fr:Splénomégalie myéloïde]] [[it:Mielofibrosi]] [[pl:Mielofibroza]] [[fi:Myelofibroosi]]