ALL (acute lymphoblastic leukemia): Acute lymphoblastic leukemia, also less often called acute lymphocytic leukemia. See: Acute lymphoblastic leukemia.
Showing posts with label acute. Show all posts
Showing posts with label acute. Show all posts
Monday, July 13, 2009
Thursday, July 2, 2009
Definition of Acute tubular necrosis
Acute tubular necrosis: A severe form of acute renal failure that develops in people with severe illnesses (such as sepsis) or with very low blood pressure. Patients may need dialysis. Kidney function often improves if the underlying disease is successfully treated. Abbreviated ATN.
Definition of Acute thrombocytopenic purpura
Acute thrombocytopenic purpura: The sudden onset of low blood platelet levels with bleeding into the skin and elsewhere. Acute thrombocytopenic purpura (ATP) can be due to many
causes. It may, for example, constitute a potentially
serious complication during the acute phase of measles.
causes. It may, for example, constitute a potentially
serious complication during the acute phase of measles.
Definition of Acute renal failure
Acute renal failure: Sudden and often temporary loss of kidney function. Also called acute kidney failure. As opposed to chronic renal failure.
Wednesday, July 1, 2009
Definition of Acute lymphocytic leukemia
Acute lymphocytic leukemia: See: Acute lymphoblastic leukemia.
Definition of Acute lymphoblastic leukemia
Acute lymphoblastic leukemia: An acute (sudden onset), rapidly progressing form of leukemia that is characterized by the presence in the blood and bone marrow of large numbers of unusually immature white blood cells destined to become lymphocytes. Acute lymphoblastic leukemia is also called acute lymphocytic leukemia and is abbreviated ALL (spoken not as the word "all", but as the three letters A-L-L). ALL is the most common cancer occurring in children, representing almost 25% of cancer among children. There is a sharp peak in the incidence of ALL incidence among children ages 2 to 3. This peak is approximately fourfold greater than that for infants and is nearly 10-fold greater than that for youths who are 19 years old.
For unexplained reasons, the incidence of ALL is substantially higher for white children than for black children, with a nearly threefold higher incidence at 2 to 3 years of age for white children compared to black children. The incidence of ALL appears to be highest in Hispanic children.
Factors associated with an increased risk of ALL have been identified. The main environmental factor is radiation, namely prenatal exposure to x-rays or postnatal exposure to high doses of radiation. Children with Down syndrome (trisomy 21) also have an increased risk for both ALL and acute myeloid leukemia (AML). About two-thirds of acute leukemia in children with Down syndrome is ALL. Increased occurrence of ALL is also associated with certain genetic conditions, including neurofibromatosis, Shwachman syndrome, Bloom syndrome, and ataxia telangiectasia.
The malignant lymphoblasts from a particular ALL patient carry antigen receptors unique to that patient. There is evidence to suggest that the specific antigen receptor may be present at birth in some patients with ALL, suggesting a prenatal origin for the leukemic clone. Similarly, some patients with ALL characterized by specific chromosome translocations have been shown to have cells containing the translocation at the time of birth.
Seventy-five to 80% of children with ALL now survive at least 5 years from diagnosis with current treatments that incorporate systemic therapy (e.g., combination chemotherapy) and specific central nervous system (CNS) preventive therapy (i.e., intrathecal chemotherapy with or without cranial irradiation). Ten-year event-free survival of multiple large prospective trials conducted in different countries for children treated primarily in the 1980s is approximately 70%.
Since nearly all children with ALL achieve an initial remission, the major obstacle to cure is bone marrow and/or extramedullary (e.g., CNS, testicular) relapse. Relapse from remission can occur during therapy or after completion of treatment. While the majority of children with recurrent ALL attain a second remission, the likelihood of cure is generally poor, particularly for those with bone marrow relapse occurring while on treatment.
For unexplained reasons, the incidence of ALL is substantially higher for white children than for black children, with a nearly threefold higher incidence at 2 to 3 years of age for white children compared to black children. The incidence of ALL appears to be highest in Hispanic children.
Factors associated with an increased risk of ALL have been identified. The main environmental factor is radiation, namely prenatal exposure to x-rays or postnatal exposure to high doses of radiation. Children with Down syndrome (trisomy 21) also have an increased risk for both ALL and acute myeloid leukemia (AML). About two-thirds of acute leukemia in children with Down syndrome is ALL. Increased occurrence of ALL is also associated with certain genetic conditions, including neurofibromatosis, Shwachman syndrome, Bloom syndrome, and ataxia telangiectasia.
The malignant lymphoblasts from a particular ALL patient carry antigen receptors unique to that patient. There is evidence to suggest that the specific antigen receptor may be present at birth in some patients with ALL, suggesting a prenatal origin for the leukemic clone. Similarly, some patients with ALL characterized by specific chromosome translocations have been shown to have cells containing the translocation at the time of birth.
Seventy-five to 80% of children with ALL now survive at least 5 years from diagnosis with current treatments that incorporate systemic therapy (e.g., combination chemotherapy) and specific central nervous system (CNS) preventive therapy (i.e., intrathecal chemotherapy with or without cranial irradiation). Ten-year event-free survival of multiple large prospective trials conducted in different countries for children treated primarily in the 1980s is approximately 70%.
Since nearly all children with ALL achieve an initial remission, the major obstacle to cure is bone marrow and/or extramedullary (e.g., CNS, testicular) relapse. Relapse from remission can occur during therapy or after completion of treatment. While the majority of children with recurrent ALL attain a second remission, the likelihood of cure is generally poor, particularly for those with bone marrow relapse occurring while on treatment.
Definition of Acute
Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
"Acute" is a measure of the time scale of a disease and is in contrast to "subacute" and "chronic." "Subacute" indicates longer duration or less rapid change. "Chronic" indicates indefinite duration or virtually no change.
The time scale depends on the particular disease. For example, an acute myocardial infarction (heart attack) may last a week while an acute sore throat may only last a day or two.
"Acute" is a measure of the time scale of a disease and is in contrast to "subacute" and "chronic." "Subacute" indicates longer duration or less rapid change. "Chronic" indicates indefinite duration or virtually no change.
The time scale depends on the particular disease. For example, an acute myocardial infarction (heart attack) may last a week while an acute sore throat may only last a day or two.
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