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]]