acute lymphoblastic leukemia in the elderly
Introduction
Introduction to elderly acute lymphoblastic leukemia Acute lymphoblastic leukemia (ALL) is a type of acute leukemia. ALL is the most common type of leukemia in children. The incidence rate of adults is low, accounting for 15% to 25% of adult acute leukemia, and the prevalence rate of the elderly is lower. About 14% of acute lymphoblastic leukemia. basic knowledge The proportion of illness: 0.0003%-0.0005% Susceptible people: the elderly Mode of infection: non-infectious Complications: respiratory failure
Cause
The cause of acute lymphoblastic leukemia in the elderly
(1) Causes of the disease
The etiology of leukemia has not yet been fully elucidated. The more recognized factors are:
Genetic factors (10%):
Familial leukemia accounts for 0.7% of leukemia, and the incidence of leukemia in the same twin is three times higher than that of other people. B-cell chronic lymphocytic leukemia is familial, congenital diseases such as Fanconi anemia, Down syndrome, Bloom syndrome, etc. The incidence of leukemia is high.
Other blood diseases (30%):
Such as chronic myeloid leukemia, MDS, myeloproliferative diseases such as essential thrombocytosis, myelofibrosis and polycythemia vera, paroxysmal hemoglobinuria, multiple myeloma, lymphoma and other blood diseases may eventually develop into acute Leukemia, especially ANLL.
Ionizing radiation (18%):
X-ray diagnosis and treatment, 32P treatment, the incidence of leukemia in the population of atomic bombs is high.
Chemical factors (18%):
Benzene and its derivatives, antineoplastic agents such as alkylating agents and etoposide, and bis-morpholine for the treatment of psoriasis can cause leukemia, especially ANLL.
Virus (10%):
For example, a type C retrovirus, human T lymphocyte virus-I, can cause adult T cell leukemia.
(two) pathogenesis
The pathogenesis has not yet been elucidated.
Prevention
Elderly acute lymphoblastic leukemia prevention
Improve the body's immunity and prevent infection.
Complication
Elderly patients with acute lymphoblastic leukemia Complications, respiratory failure
There are bleeding, serious infections and respiratory failure.
Symptom
Symptoms of acute lymphoblastic leukemia in the elderly Common symptoms thrombocytopenic leukemia cell infiltration bone pain hyperthermia intravascular coagulation skin infiltration bacteria mixed infection chills gingivitis secondary infection
There are 4 aspects of clinical manifestations, namely anemia, fever, hemorrhage and infiltration, the onset symptoms can be hidden, slow, or sudden.
Anemia
It is because the proliferation of bone marrow erythroid cells is inhibited, and the shortening of red blood cell life in some cases, as well as bleeding, is also the cause of anemia. Of course, after the application of chemotherapy, the drug inhibits the proliferation of erythroid cells and can aggravate the symptoms of anemia. .
2. fever
Half of the patients with early fever, can be low fever, can be as high as 39 ~ 40 ° C or more, with chills, sweating, etc., although leukemia itself can be fever, but higher heat often suggests secondary infection, the cause of infection is Low immune function, including inhibition of normal leukocyte proliferation, neutropenia, and low cellular immune function. When patients undergo chemotherapy, including corticosteroids, they are more susceptible to infection. The common infection is upper respiratory tract infection. The most common form of stomatitis, gingivitis or angina, can occur ulcers or even necrosis in severe cases, in addition, pneumonia, enteritis, pyelonephritis, perianal inflammation, carbuncle is also more common, severe infection can be complicated by bacteremia or sepsis, Some patients may have fever and can not find the infection. Most of the infections at the beginning of leukemia are bacterial infections, especially Gram-negative bacilli infections. Late cases are often mixed with fungal infections or mixed infections of bacteria. Pneumocystis can be seen in later cases. Infection and cytomegalovirus infection.
3. Bleeding
The main cause of bleeding is thrombocytopenia. The reason for thrombocytopenia is that the proliferation of bone marrow megakaryocytes is inhibited, followed by the infiltration of blood vessel walls of leukemia cells, and some patients with diffuse intravascular coagulation have obvious bleeding symptoms. Inhibition of megakaryocyte proliferation will aggravate bleeding symptoms. The most serious bleeding is intracranial hemorrhage. Intracranial hemorrhage is often accompanied by intracranial leukemia cell infiltration, which is often one of the causes of leukemia death. There are data indicating that acute leukemia died of bleeding. 62.24%, of which 87% were intracranial hemorrhage.
4. Performance of organ and tissue infiltration
Leukemia cells can be infiltrated with multiple organs and have different infiltration symptoms:
(1) It is more common that the infiltration of bone marrow causes sternal tenderness, and the infiltration of bones and joints has painful symptoms. In a few cases, the symptoms of bone pain are caused by bone marrow necrosis of leukemia.
(2) Infiltration of lymph nodes, liver and spleen may occur in different degrees of swelling, more common than acute non-leaching, each accounted for 75%, 85%, 78%.
(3) About 10% of cases have headache, nausea, vomiting, and manifestations of central nervous system leukemia at the onset of the disease. Meningeal leukemia is a common type of central nervous system leukemia infiltration. Central nervous system Leukemia (CNS-L) can also be manifested as infiltration of the brain parenchyma and infiltration of the spinal cord. Corresponding localization signs may appear according to different parts.
(4) Skin infiltration is rare in acute showers. If there is skin involvement, many early B cell phenotypes.
(5) The testicles are infiltrated, and there is painless swelling, mostly one side, although the other side is not swollen, but there is often leukemia cell infiltration during biopsy. Testicular leukemia is more common in male children after acute leukemia chemotherapy Or youth, is the root cause of extramedullary recurrence of leukemia after CNS-L.
5. Classification
The classification of leukemia has evolved from the FAB classification in the 1970s to today's MICM classification (morphology, immunity, cytogenetics and molecular biology):
(1) FAB morphology classification: acute drench is divided into three subtypes L1, L2, L3.
(2) Immunology classification:
Immunohistochemical expression of 1B cells Early pre-B cells showed HLA-DR, TdT (terminal deoxynucleotidyl transferase), CD34, CD19, CD24, CD10 (CALLA) and other positive; pre-B cells showed HLA-DR, CD19, CD24, CD10, CD20, C (cytoplasmic heavy chain) positive, B cells showed HLA-DR, CD19, CD24, CD10, C20, CIg, C21 positive.
The T cell antigen CD7 of 2T cells is the most sensitive, but some T cells are negative, so CD5 and CD2 must be added. Children's T cells are rarely expressed HLA-DR positive, CD3 is often Cytoplasmic positive and surface negative.
(3) cytogenetic classification: chromosomal changes in acute lymphoblastic: pre-B cell acute lymphoblast t (1; 19); B cell acute lymphoblast t (8; 14), t (2; 8), t (8; 22) ; T cell acute lymphoblast t (11; 14), t (1; 14), t (8; 14), t (10; 14), t (7; 9), t (7; 14), INV (14) In addition, there is still t (9; 22) in the acute shower, often a poor prognosis of chromosome changes.
(4) Molecular biology: With the continuous development of molecular biology techniques, such as PCR, FISH and in situ PCR gene diagnosis techniques, some leukemia patients have not found chromosomal abnormalities, but genetic diagnostic techniques can find abnormal fusion genes; The myc of t(8;14)(q24;q32) is fused with the immunoglobulin (Ig) gene, and the E2A of t(1;19)(q23;p13) is fused with the PBX gene, t(1;14)(p32; Q11) SCL (TAL-1) is fused to TCR gene, t(10;14)(q24;q11) HOX-11 is fused to TCR gene, t(11;14)(q13;q32)BCL-1 Ig gene fusion and t(14;18)(q32;q21) BCL-2 are fused to the Ig gene, and these fusion genes are often associated with acute lymphoblastic.
Examine
Examination of acute lymphoblastic leukemia in the elderly
Peripheral blood
When the white blood cell count is on the onset, about 60% of the cases are increased, >10×109/L, and more than 50×109/L account for nearly 1/4 of the cases. The higher the white blood cell count, the higher the proportion of primordial lymphocytes. High; white blood cell count is not high, some less primordial cells or no primordial cells, so-called sub-leukemia leukemia and non-leukemia leukemia, if the peripheral blood leukocyte count> 50 × 109 / L (50,000 / mm3 ), often with obvious lymph nodes, liver, splenomegaly, and often T cell immunophenotype, red blood cell count is common, most cases (2 / 3 cases) showed moderate anemia, hematocrit <30%, genus Positive cells, positive pigmented anemia, decreased platelet count, about 60% of cases <50 × 109 / L (50,000 / mm3).
2. Bone marrow examination
In addition to morphological examination of Wright's stain, bone marrow fluid puncture can also be used for immunophenotypic, histochemical and cytogenetic tests. When the density of bone marrow cells is very high, and reticular fibrosis is proliferated, it is difficult to extract bone marrow fluid. "dry pumping" phenomenon, you must do bone marrow biopsy, bone marrow examination showed increased cell proliferation, and see a large number of lymphoid leukemia cells, but the morphology of myeloid and erythroid precursor cells is normal, but the number is reduced, megakaryocytes often Poor proliferation.
3. Cell chemistry
Peroxidase negative; glycogen PAS reaction positive block or granular; non-specific esterase negative; neutrophil alkaline phosphatase increased.
4. Blood biochemistry
(1) Determination of blood uric acid Because of the high cell turnover rate of leukemia cells, metabolic disorders occur, showing an increase in blood uric acid, but gout symptoms are rare, but attention should be paid to whether uric acid nephropathy occurs, even in the absence of excessively high leukemia cells. At the same time, there will be an increase in blood uric acid. It is also important to note that when the patient has severe dehydration at the same time, uric acid nephropathy may occur more and may even cause severe renal dysfunction.
(2) Blood lactate dehydrogenase is increased due to an increase in the conversion of leukemia cells.
5. Cerebrospinal fluid (CSF) examination
About 3% of children with acute effusion have central nervous system invasion. In addition to routine CSF routine examination, CSF centrifugal sedimentation and concentration to find leukemia cells is helpful for diagnosis. It should be noted that when peripheral blood cells are high, leukemia When the proportion of cells is very high, the bleeding caused by lumbar puncture will lead to the "input" of peripheral blood leukemia cells. Therefore, there are some cases that the lumbar puncture is delayed for a few days. After the chemotherapy, the peripheral blood leukocytes have decreased significantly and it is difficult to find leukemia cells. It is better to have a lumbar puncture. When the central nervous system (brain and spinal cord membrane) is infiltrated, it shows an increase in CSF pressure, increased protein, decreased sugar, and leukemia cells.
6. X-ray examination: chest radiograph shows anterior mediastinal mass accounted for 5% to 10% of cases, thymus enlargement often accompanied by pleural effusion, such cases are common in T cell acute shower.
Diagnosis
Diagnosis and differential diagnosis of acute lymphoblastic leukemia
diagnosis
The diagnosis of emergency department mainly depends on bone marrow examination, see a large number of primitive lymphocytes, at least 25%, but the proportion of bone marrow in the acute lymph node is far more than 25%.
Differential diagnosis
1. Identification of bone marrow metastasis of solid tumors, such as bone marrow metastasis of neuroblastoma. These cells often appear in a pile of rosettes and are differentiated by electron microscopy if necessary.
2. Due to the clinical non-specific symptoms such as fever, joint symptoms, mild anemia should be differentiated from juvenile rheumatoid arthritis or lupus erythematosus, should not abuse the adrenal cortex hormone when the diagnosis is unknown, or it will lead to symptoms Relieve, delay diagnosis.
3. Certain infectious diseases such as infectious mononucleosis, toxoplasmosis, cytomegalovirus infection may have fever, lymphadenopathy and hepatosplenomegaly, and atypical lymphocytes can be seen in peripheral blood. Morphological examination.
4. In addition, the non-leukemia leukemia type in acute drenching should be differentiated from the aplastic anemia, but the bone marrow examination is helpful for the identification of these two types of diseases. The blood uric acid and lactate dehydrogenase in the biochemical aplastic anemia cases are all reduced. And can rise in leukemia.
