Acute myeloid leukemia
Synonym: AML
Acute myeloid leukemia
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| acute myeloid |
Acute myeloid leukemia is a malignant disease of the hematopoietic system. The acute onset of myelocytic leukemia is more likely to occur in adults over 60 years of age. It runs untreated infaust.
Acute myeloid leukemia (blood smear)
Acute myeloid leukemia (blood smear)
2 epidemiology
The AML has its peak in adulthood (about 80% of cases). Their incidence is 2.5-3 / 100,000 a year.
3 etiology
The causes include genetic factors such as trisomy 21 (about 20-fold increased risk), the Fanconi anemia or translocations such. t (15,17) -translocation in question. Environmental factors also play a role in the development of AML. Thus, chronic exposure to benzene or ionizing radiation can increase the risk.
AML can also be the result of another hematological disease such as chronic myeloid leukemia or osteomyelofibrosis.
4 morphology
Acute myeloid leukemia is characterized by a so-called differentiation block at the level of the myeloid multipotent progenitor cell - erythropoiesis is displaced (anemia) and the bone marrow releases the immature myeloblasts into the blood due to a lack of capacity.
The blood contains precursors of granulocytopoiesis (promyelocytes, myeloblasts, monocytes). These usually impress as cells with a large nucleus and little cytoplasm. In the cytoplasm of the granulocytes so-called Auerstäbchen (lysosomal degradation products) are detectable, which are peroxidase-positive. The differentiated, functional granulocytes are missing in the peripheral blood.
In the bone marrow one sees a repression of erythropoiesis and megakaryopoiesis; leukemic infiltrates are macroscopically gray-red. To diagnose, about 25% precursors (blasts) must be present in the bone marrow or blood.
5 clinic
AML is an acute disease, which is why general symptoms (weakness, fever, night sweats) typically show a short history. As the leukemic cells spread into bone marrow and blood, symptoms of disturbed hematopoiesis develop:
Susceptibility to infection due to the absence of mature and functional leukocytes (for example oral thrush)
Coagulation disorders (petechiae, epistaxis, hematoma)Some subtypes of AML can cause specific symptoms. For example, mucosal infiltration by blasts may cause gingival hyperplasia in myelomonocytic (M4) and monocytic (M5) leukemia.
6 Diagnostics
The basic diagnosis of AML includes a history and physical examination (signs of disturbed hematopoiesis, organ enlargements) a blood test including differential blood picture. Typical findings are:
Anemia, thrombocytopenia and granulocytopenia (white blood cell count is not a reliable marker of acute leukemia)
leukemic blasts, missing intermediates (hiatus leucaemicus)
BSG increased
Uric acid and LDH increased (due to increased cell turnover)
A backup of the diagnosis follows by a subsequent bone marrow puncture.
By definition, the proportion of immature blasts in the bone marrow must be> 20% or> 30% in the blood for diagnosis.
For detailed classification into the FAB classification, further studies, e.g. Immunophenotyping, cytogenetics and molecular genetics (NPM1, CEBPA, FLT3).
If the patient is scheduled for stem cell transplantation, HLA typing and CMV status verification are also performed.
6.1 Complementary diagnostics
chest x-ray
ECG
echocardiography
7 classification
7.1 FAB classification
The classification is based on the proposals of the French American British Cooperative Group (FAB, FAB classification):
M0: AML with minimal differentiation
M1: AML without maturation (about 20%)
M2: AML with maturation (about 30%)
M3: promyelocytic leukemia (about 5%)
M4: myelomonocytic leukemia (about 30%)
M5: Monocytic leukemia (about 10%)
M6: erythroleukemia (rare)
M7: megakarocytic leukemia (rare)
A more detailed presentation with cytochemistry and aberrations can be found on the FAB classification's own page.
7.2 WHO classification
The WHO divides the AML into four subgroups:
Type 1: AML with specific cytogenetic translocations
Type 2: AML with multilinarian dysplasia (2-3 lines) with / without previous myelodysplastic syndrome
Type 3: Therapy-induced AML with myelodysplastic syndrome
Type 4: other AML forms
8 therapy
The therapy of AML consists of intensified chemotherapy, which is divided into several phases.
In the induction phase, high dose chemotherapeutic agents (e.g., daunorubicin, cytosine arabinoside) are targeted for massive reduction of tumor cells and full remission for several weeks.
The consolidation phase refers to the subsequent cytostatic therapy with medium-high-dose therapeutics over several months.
This is followed by maintenance therapy for up to two years with low dosage.
For the treatment of promyelocytic leukemia (M3), vitamin A supplements (e.g., ATRA) can also be used.
Another therapy option with a curative approach is allogeneic stem cell transplantation.
9 forecast
Induction therapy achieves complete remission (complete normalization of the blood count, complete absence of extramedullary manifestations) in approximately 70% of patients.
Unfortunately, in many patients not all leukemic cells can be destroyed, which is why the 5-year survival rate is about 30% and only about 20% of patients experience a long-term remission.
Prognostically unfavorable factors for the course and therapy of AML include:Age> 60 years
initial leucocyte counts> 100,000 / μl
Complex chromosomal aberrations
Tags: acute leukemia, acute myeloid leukemia, leukemia, myelopoiesis
Anemia with paleness, weakness and dyspnea
Other organ-specific symptoms include splenomegaly, hepatomegaly and, rarely, lymphadenopathy.
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