Page 1 of 1: hematology;thalassemia intermedia

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what are d clinical manifestations of thalassemia intermedia.reliable info about its lab diagnosis would be helpful!

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luk 4 d ans in de gruchi

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harrison can also help

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Thalassemia (British spelling, "thalassaemia") is an inherited autosomal recessive blood disease. In thalassemia, the genetic defect results in reduced rate of synthesis of one of the globin chains that make up hemoglobin. Reduced synthesis of one of the globin chains causes the formation of abnormal hemoglobin molecules, and this in turn causes the anemia which is the characteristic presenting symptom of the thalassemias. Thus thalassemia is one of the hemoglobinopathies, like sickle-cell disease, which it resembles

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Thalassemia intermedia is a condition intermediate between the major and minor forms. Affected individuals can often manage a normal life but may need occasional transfusions e.g. at times of illness or pregnancy, depending on the severity of their anemia.
The genetic mutations present in β thalassemias are very diverse, and a number of different mutations can cause reduced or absent β globin synthesis. Two major groups of mutations can be distinguished:

Nondeletion forms: These defects generally involve a single base substitution or small deletion or inserts near or upstream of the β globin gene. Most commonly, mutations occur in the promoter regions preceding the beta-globin genes. Less often, abnormal splice variants are believed to contribute to the disease.
Deletion forms: Deletions of different sizes involving the β globin gene produce different syndromes such as (βo) or hereditary persistence of fetal hemoglobin syndromes

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Lab Studies:

Severe forms of thalassemia intermedia must be differentiated from beta thalassemia major; this is mainly a clinical differentiation based on close monitoring to determine whether the patient's Hb level can be maintained at 6-7 g/dL without blood transfusions. The severe anemia, if associated with thrombocytopenia, hypersplenism, and the immature leukocytes often observed on peripheral blood films, raises the question of acute leukemia or metastatic lymphoma. Milder cases, on the other hand, must be differentiated from thalassemia trait or even anemias related to iron deficiency or chronic inflammation. Unlike the intermedia forms, beta thalassemia trait rarely produces an Hb level less than 9 g/dL. Iron deficiency anemia is characterized by a normal Hb electrophoresis pattern and abnormal iron study results.
The following tests are usually adequate to suggest a diagnosis of thalassemia major or intermedia:
CBC and differential reveal anemia with marked hypochromasia and microcytosis. An Hb level below 7-8 g/dL indicates a severe case; whether it is thalassemia major or intermedia can be determined only after adequate monitoring.
Hb electrophoresis shows an abnormal pattern. An elevated Hb A2 fraction up to 7% indicates a beta thalassemia, typically beta thalassemia trait or certain forms of thalassemia intermedia. However, absence of Hb A2 does not exclude the diagnosis of beta thalassemia; in fact, an Hb A2 of 0% frequently arises from a homozygous deletion of both the beta and the delta chain genes because delta chains are needed to produce Hb A2. In the intermedia type overall, Hb F ranges from 20-100%, Hb A from 0-80%, and A2 up to 7% of total.
Peripheral blood film examination usually reveals marked hypochromasia and microcytosis, polychromasia, target cells, and significant variation in the size of the red blood cells (see Image 1).
Iron studies should be obtained, either as baseline in anticipation of iron overload in the future or for diagnosis and management of this condition when suspected.
Ferritin level is an adequate tool for screening, but it is not the perfect test for a precise evaluation of the progress of iron overload and the development of tissue damage as a complication. It is a noninvasive test that is easy to obtain and is of value in the early stages of iron overload process; however, it becomes inaccurate when iron accumulates heavily, it lacks sensitivity and specificity, and it correlates poorly with hepatic iron concentration. It is also known to be a positive plasma reactant, which rises in association with inflammation.

Serum transferrin saturation may provide some information about the patient's iron status; it lacks sensitivity, however. Twenty-four–hour deferoxamine-induced urinary iron excretion is a beneficial test in deciding when chelation therapy should be started (presence of adequate iron available for chelation); it is not a practical test to evaluate iron overload, however. Urine aliquots are not usually collected correctly, the ratio of stool-to-urine iron is variable, and furthermore, it correlates poorly with hepatic iron deposits.
Either bone marrow grading of iron stores or monitoring the numbers of nucleated red blood cells in the peripheral blood may reflect the stage of iron overload. Patients with thalassemia intermedia tend to develop iron overload somewhat later than those with thalassemia major regardless of whether they are on a transfusion schedule.
Once the patient is started on blood transfusions, the onset of iron overload should be expected earlier than in nontransfused patients, and closer follow-up is required.
Tests to identify endocrine disturbances such as diabetes mellitus or thyroid, adrenal, or other gland dysfunction are also required.
Liver function tests are needed at diagnosis and during follow-up, especially in those patients who are receiving blood transfusions.
Imaging Studies:

Chest radiography should be obtained to evaluate the size of the heart.
A skeletal survey should be conducted to evaluate the status of the bones and to monitor bone changes that are due to the chronic hyperactivity of the marrow.
CT scanning or even MRI of the liver to evaluate iron deposition has been very helpful for monitoring patients on transfusion regimens and chelation therapy. Variable correlation results were reported for both. However, MRI appears to be more informative than CT scanning and is the only modality available to evaluate cardiac and pituitary iron stores.
Echocardiography should be performed to evaluate the function of the heart.
Other Tests:

With iron overload, an ECG is necessary to monitor for cardiac conduction defects (eg, atrioventricular block).

Genetic counseling and DNA studies using DNA probes from known thalassemia intermedia genotypes are very useful in prenatal diagnosis and identification of new cases in selected patients at risk.
Study of the genotype yields no advantage and is not warranted to differentiate between thalassemia major and intermedia when, for example, a previously stable Hb level in a patient assumed to have thalassemia intermedia suddenly drops and the patient becomes transfusion dependent.
Genotype testing is beneficial when deciding whether to terminate a pregnancy when the fetus is affected. A thalassemia intermedia genotype probably indicates a milder disease, and parents may decide to continue the pregnancy.
Procedures:

Examination of liver tissues obtained by ultrasonographically guided biopsy is an optimal way to evaluate body iron burden and the status of the liver itself (eg, fibrosis, inflammation). Cardiac biopsy is not sensitive because the distribution of iron in the heart is not homogeneous. A noninvasive method that correlates precisely with biopsy-determined hepatic iron levels is the superconducting susceptometry SQUID (superconducting quantum interference device).
Once chelation therapy is deemed necessary, evaluation of liver tissue damage from iron deposition is required. Some have suggested that liver histologic studies for iron status be obtained every 2 years.
Histologic Findings: Erythroid hyperplasia is the major finding in the bone marrow. In addition, excessive iron deposition is observed in later stages in both marrow and liver. Osteopenia and osteoporosis are also observed in untreated patients with relatively low Hb levels.
Quantitative assessment of liver iron deposition can be used as a guideline for starting chelation: an iron concentration of 1.5 mg/g of liver (dry weight) has been suggested as an appropriate threshold.

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emdicine.com
nice site
all the info from that

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uk

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uk ?

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