very important to diagnose childhood leukemia as soon as possible and determine the type of leukemia, so that treatment can be tailored to the child so as to obtain the best chance of success. The examinations and tests described below are used to diagnose the disease, to help determine the type of leukemia and to measure their forward.
Signs and symptoms of leukemia in children
Many of the signs and symptoms of childhood leukemia are caused by a lack of normal blood cells, which occurs when cells producing leukemia cells crowd out normal blood cells in the bone marrow. As a result, a child may not have enough red blood cells, white cells or platelets. These deficiencies are manifested in the blood tests, but can also cause symptoms. Leukemia cells can also invade other body areas, which can cause symptoms.
addition, many these symptoms have other causes, and most often not caused by leukemia. Still, it is important to tell your child's doctor about these symptoms so that you are and treat the cause, if necessary.
tiredness, pale skin, anemia (a shortage of red blood cells) can cause a child to feel tired, weak, dizzy or breathless. It can also cause the skin to look pale.
infections and fever: a child with leukemia may develop a fever. It is often caused by an infection that can not improve even with antibiotics. The cause is the lack of normal white blood cells, which normally help fight infection. Although children with leukemia may have have very high white blood cells, leukemia cells do not protect against infection as they do normal white blood cells. Sometimes the leukemic cells themselves also cause fever by releasing certain chemicals in the body.
Bleeding and bruising easily: a child with leukemia may have bruising and frequent bleeding of the gums or nose, or bleeding from small cuts. You may appear in the skin red dots the size of a pin caused by bleeding from small blood vessels. This is due to lack of platelets, which normally stop bleeding by plugging the holes in damaged blood vessels.
Bone pain or joint: about one in three children with leukemia presented bone pain. A smaller number will have joint pain. This is due to the accumulation of leukemia cells near the bone surface or within the joint. Swelling of the abdomen
: leukemic cells can accumulate in the liver and spleen, causing these organs increase in size. This can be seen as a fullness or swelling of the stomach. Generally lower ribs cover these organs, but when enlarged is possible that the doctor to feel.
Loss of appetite and weight loss: if the spleen and / or liver are enlarged too, may pressure other organs such as the stomach. This may limit the amount of food that can be ingested, resulting in loss of appetite and weight loss over time.
Swollen lymph nodes: some leukemias can spread to lymph nodes. The child, parent, or a medical professional may notice swollen glands and lumps under the skin in certain areas of the body (sides of the neck, underarm areas, above the collarbone or in the groin). You can also occur swollen lymph nodes located inside the chest or abdomen, but this can only be detected by imaging tests such as CT or MRI.
often lymph nodes are enlarged when they are fighting an infection, especially in infants and children. Lymph nodes that grow as a reaction to infection
are called reactive nodes or hyperplastic nodes. An enlarged lymph node in a child more often is a sign of infection of leukemia, but a doctor should review and make a close follow-up.
cough or difficulty breathing: frequently acute lymphocytic leukemia T cells involves the thymus gland located in the chest behind the breastbone and in front of the trachea. The enlarged thymus or lymph nodes inside the chest can press the trachea, which can cause coughing or shortness of breath.
Swelling in the face and arms: the superior vena cava (superior vena cava
, SVC), a large vein that carries blood from the head and arms back to the heart, passes near the thymus. The growth of the thymus due to an excessive number of cells SVC can press leukemia causing blood to back up into the veins. This is called SVC syndrome, and may cause swelling of the face, neck, arms and upper chest (sometimes with a bluish red color of the skin). It can also cause headaches, dizziness and, if it affects the brain, a change in knowledge. This syndrome can be life threatening and requires immediate treatment.
headaches, convulsions and vomiting: Leukemia can spread outside the bone marrow. Can spread to the central nervous system (brain and spinal cord), testicles, ovaries, kidneys, lungs, heart, intestines or other organs. Approximately 5 to 10% of children have leukemia that has spread to the central nervous system when they receive the diagnosis. Symptoms of leukemia that has spread to the central nervous system including headaches, trouble concentrating, weakness, seizures, vomiting, balance problems and blurred vision.
rash, gum problems: in children with AML, the leukemia cells can spread to the gums, causing inflammation, pain and bleeding. Spread to the skin can cause small patches of dark color similar to a rash Common skin. An accumulation of AML cells beneath the skin or other parts of the body is called
chloroma or granulocytic sarcoma
.
extreme tiredness and weakness: a consequence rare but very serious AML is fatigue, weakness and slurred speech. This can happen when a large number of leukemia cells "thicken" the blood too much and interfere with circulation in small blood vessels in the brain.
medical history and physical examination
If any of the signs and symptoms suggesting the possibility of leukemia, the doctor will perform a history thorough clinical examination, including how long they have experienced symptoms and whether or not there is a history of exposure to risk factors. They can also be significant family history of cancer, especially leukemia.
During the physical exam, the doctor will focus on any enlarged lymph nodes, areas of bleeding or bruising or possible signs of infection. Probably will carefully examine the eyes, mouth and skin, and can conduct a review of the nervous system. It will feel your abdomen to try to detect signs of a swollen spleen or liver.
If there is any reason to believe that there may be problems caused by abnormal numbers of blood cells (anemia, infection, bleeding or bruising, etc..), your doctor may ask you to obtain blood samples to analyze your child's blood counts. If results are abnormal, your doctor may refer a child cancer doctor who can perform one or more of the tests described below.
Types of samples to be used in screening of leukemia in children
If symptoms, signs and / or physical findings suggest that a child may have leukemia, the doctor will need to analyze samples of blood and marrow cells child's bone to be sure of this diagnosis. You can also take other tests of tissues and cells to help guide treatment.
Blood samples Blood samples for screening of leukemia are taken in the same way as for other tests, usually from a vein in your arm. In infants and young children can be taken from other veins (such as the feet or scalp) or a finger prick.
The tests done on these samples are generally blood counts and smear. There is a complete blood count or complete blood count (complete blood count
, CBC) to determine the number of each type blood cell present in blood. A blood smear involves spreading of a small blood sample on a glass slide and observing it under a microscope. Abnormal numbers of different types of blood cells and changes in the way these cells look can make the doctor suspects the presence of leukemia.
Most children with acute leukemia (ALL or AML) have too many white blood cells and not enough red blood cells or platelets adequate. Many of the white blood cells will
blasts, a type of primitive cells that are normally found only in bone marrow. Although these findings may make a doctor suspects the presence of leukemia, the disease usually can not be diagnosed with certainty without observing a sample of bone marrow cells.
bone marrow samples Bone marrow samples are obtained by aspiration and bone marrow biopsy, two tests are usually done at the same time. The samples are usually taken from the back bone of the pelvis (hip), although in some cases can take the sternum or other bones. The
aspiration of bone marrow, the skin covering the hip bone and the surface is cleaned and numbed with a local anesthetic. In most cases, the child also receives other medicines to reduce pain or even to sleep during the procedure. Then insert a thin, hollow needle into the bone, and used a syringe to aspirate a small amount of liquid bone marrow.
usually performed a bone marrow biopsy immediately after aspiration. Remove a small piece of bone and marrow with a slightly larger needle is rotated to push into the bone. Once the biopsy is done, pressure is applied on site to help prevent any bleeding.
These tests are used to diagnose leukemia and may be repeated later to see if the leukemia is responding to treatment.
lumbar puncture test is used to detect leukemic cells in cerebrospinal fluid (cerebrospinal fluid
CSF), which is the liquid that bathes the brain and spinal cord. A lumbar puncture can also be used to administer chemotherapy drugs in the CSF to prevent or treat the spread of leukemia to the spinal cord and brain.
For this test, the doctor first numbs an area on the lower back on the spine. Usually, the doctor also administers medicines your child to sleep during the procedure. Then introduced a small hollow needle between the bones of the spine to remove some fluid.
This test is done routinely in children with leukemia, but it is important for carrying out an expert. Doctors have found that lumbar puncture is not done by an expert and some blood enters the spinal fluid, in some cases the leukemia cells can enter and grow in this fluid.
lymph node biopsy
This procedure is important in diagnosing lymphomas, but rarely needed in children with leukemia.
For this biopsy, a surgeon cuts skin to remove an entire lymph node (excisional biopsy). If the node is located near the surface of the skin, this is a simple operation. However, it may be more complex if the node is inside the chest or abdomen. Most often, the child will need general anesthesia (the child is asleep).
laboratory tests used to diagnose and classify leukemia
routine microscopic examinations
As mentioned earlier, accounts and blood smears are usually the first tests done when the leukemia is a possible diagnosis. A pathologist (a doctor specializes in laboratory tests) notice any other sample taken (bone marrow, lymph node tissue or CSF) with a microscope, and hematologist / oncologist (a doctor who specializes in treating diseases and cancer blood) the patient may be reviewed.
The doctors look at the size, shape and staining patterns of blood cells of samples to classify them into specific types (see "How do you classify
leukemia in children? " for more information on the types of leukemia).
A basic factor is whether the cells look mature (like normal blood cells) or immature (lacking the characteristics of normal cells). The most immature cells are called blasts
.
An important feature of a sample of bone marrow cellularity is your
. Normal bone marrow contains a number of blood-forming cells and fat cells. It is said that a bone that has too many blood-producing cells
hypercellular. If there are very few blood-forming cells, it is considered that the marrow is hypocellular
. Cytochemistry
The cytochemical tests, Sample cells are exposed to stains (dyes) chemicals that react only with certain types of leukemia cells. These colors cause color changes that can see through the microscope. This can help the doctor determine the types of cells. For example, one stain causes the granules of most AML cells appear as black spots under the microscope, but does not cause ALL cells to change colors.
flow cytometry and immunohistochemistry
The
flow cytometry is sometimes used to analyze cells from the bone marrow, lymph nodes and blood. It is very useful to determine the exact type of leukemia.
The test analyzes certain substances on the cell surface, which helps identify the type to which they belong. The sample cells are treated with special antibodies (synthetic versions of immune system proteins) that only attach to these substances. The cells are then passed in front of a laser beam. If the cells now have antibodies attached to the laser beam causes the light, which is then measured and analyzed by a computer.
Flow cytometry can also be used to calculate the amount of DNA in leukemic cells. It is important to know, especially in ALL, and that cells with high DNA index
(over 16% of normal value) are often more sensitive to chemotherapy, and these leukemias have a better prognosis (outlook). For testing
immunohistochemistry, the bone marrow cells or other samples are treated with special synthetic antibodies. But instead of using a laser and a computer for analysis, the sample is treated so that certain types of cells change color. The color change is visible under a microscope. Like flow cytometry, this procedure is useful to distinguish different types of leukemia among themselves and other diseases.
These tests are used to determine the
cell immunophenotype, ie, the classification of leukemic cells according to the substances (antigens) on their surface. The different types of cells have different antigens on their surface. These antigens also change as each mature cell. Each patient's leukemic cells must have the same antigen because they all derive from the same cell. Laboratory tests of the antigens are a very sensitive way to diagnose and classify leukemia. Cytogenetics
For this chromosomes observed test (sections of DNA) with a high-powered microscope to detect any changes. Normal human cells contain 23 pairs of chromosomes, each of which is a certain size and stained in some way. In some types of leukemia is possible to observe changes in the chromosomes.
For example, sometimes two chromosomes exchange some of their DNA, so that part of a chromosome attaches to part of a different chromosome. This change, called translocation
, usually can be seen under a microscope. Recognition of these changes can help identify certain types of ALL and AML and may help determine the prognosis (outlook).
Some types of leukemia have cells with an abnormal number of chromosomes (instead of the normal 46), we may be missing chromosomes or extra copies of others. This can also affect the prognosis of a patient. For example, it is more likely that chemotherapy works in ALL cases where the cells have more than 50 chromosomes and is less likely to be effective if the cells are less than 46 chromosomes. (The count of the number of chromosomes by cytogenetics provides information similar to that obtained by measuring the DNA index by flow cytometry, as described above).
cytogenetic tests usually take two to three weeks, this is because the leukemic cells must grow in petri dishes for a couple of weeks before their chromosomes can be seen with a microscope.
Not all chromosomal changes can be seen under a microscope. Often, other laboratory tests can help detect these changes.
fluorescent in situ hybridization (FISH)
This is a procedure similar to cytogenetic testing. It uses special fluorescent dyes that only attach to certain parts of particular chromosomes. The FISH test can find most of the chromosomal changes (such as translocations) that are visible under a microscope in cytogenetic tests conventional as well as some changes that are too small to be seen with usual cytogenetic testing.
FISH test can be used to detect specific changes in chromosomes. Can be used on samples of blood and bone marrow. It is very accurate and can usually provide results within a couple of days, reason why this test is now used in many medical centers.
chain reaction (PCR) test
This is a highly sensitive DNA can also find some chromosomal changes too small to be seen with a microscope, although the sample has very few leukemia cells.
also This test can be used after treatment to try to detect small numbers of leukemia cells that may not be visible under the microscope.
Other blood
Children with leukemia, shall be tested to measure the amount of certain chemicals in blood to assess the functioning of body systems.
These tests are not used to diagnose leukemia, but children who already know they have it, can help detect damage to the liver, kidneys and other organs caused by the spread of leukemia cells or side effects certain chemotherapy drugs. With frequency tests are done to measure levels of certain important minerals in the blood, and to ensure that the process of blood clotting is normal.
can also be tested for infections in the blood of children. It is important to diagnose and quickly treat infections in children with leukemia, as their weakened immune system can allow this infection to spread quickly.
Imaging Studies Imaging studies using sound waves, X rays, radioactive particles and magnetic fields to produce images inside the body. Because leukemia is usually not visible tumors, imaging studies are of limited value. However, if you suspect the presence of leukemia, or have already been diagnosed, your child's doctor may ask you to do some of the following imaging tests to get a better idea of \u200b\u200bthe extent of disease. Chest x-ray
chest X-rays can help detect a thymus gland or lymph nodes enlarged breast. If test results are abnormal, a CT scan can make for a more detailed image.
chest X-rays can also help detect pneumonia if you think your child has an infection.
CT
CT (computed tomography scan
, CT) is a type of x-ray that produces detailed cross-sectional images of the body. Unlike a regular x-rays, CT scans can show the detail in soft tissues such as internal organs.
This test can help tell if any lymph nodes or organs in the body are enlarged. Not usually needed to diagnose leukemia, but can be done if the doctor suspects the leukemia is being developed in the chest lymph nodes or organs like the spleen or liver. Sometimes also used to view the brain and spinal cord, although this also MRI can be used.
Instead of taking one picture, like a regular X-rays, a CT scanner takes many pictures as it rotates around the body of his son. A computer then combines these pictures into detailed images of the body part under study.
Before the study, you may ask your child to make a contrast solution and / or receive intravenous (IV) contrast dye helps better outline abnormal areas in the body. He or she may need an intravenous line (IV) to inject contrast material.
IV injection of contrast dye can cause a feeling of embarrassment or heat on the face or other areas of the body. Some people are allergic and get hives or rarely more serious reactions like trouble breathing and low blood pressure. Be sure to tell your doctor if your child has any allergies or have ever had any reaction to any contrast material used for x-rays
CT scans take longer than x-rays. Your child will need to lie still on a table while the test is performed. During the test, the table moves in and out of the scanner, a ring-shaped machine that completely surrounds the table. Some children may need a sedative before the test.
Currently, spiral CT
(also known as helical CT) is available at many medical centers. This type of CT scan uses a faster machine. The scanner part of the machine rotates around the body continuously, allowing doctors to collect the images much faster than with conventional CT. This reduces the chance of blurred images as a result of body movement. It also reduces the radiation dose during the study. Moreover, the images are more detailed. Study
PET / CT: In recent years, have developed new devices that combine CT with a positron emission tomography (
positron emission tomography, PET). For positron emission tomography injected glucose (a form of sugar), which contains a radioactive atom, in the blood. Because cancer cells grow rapidly in the body, they absorb large amounts of radioactive sugar. A special camera can then create a picture of areas of radioactivity in the body. The PET / CT allows the doctor to compare areas of higher radioactivity on the PET with the detailed appearance of the area in CT.
MRI
As the CT images MRI (magnetic resonance imaging
, MRI) provides detailed images of soft tissues of the body. However, MRI uses radio waves and strong magnets instead of x-ray The radio wave energy is absorbed by the body and then released in a pattern formed by the type of body tissue and by certain diseases. A computer translates the pattern into a very detailed image of parts of the body.
often inject a contrast material called gadolinium into a vein before the scan to better see the details. The contrast material usually does not cause allergic reactions.
MRI scans are very useful for the brain and spinal cord.
Compared with CT, MRI study takes longer, often up to an hour. Your child needs to lie inside a narrow tube, which is confining and can be distressing, so it is sometimes necessary to sedate the child. The new, more open MRI machines may be another option. The MRI machine makes loud buzzing and clicking noises that may find disturbing your child. Some places provide headphones or earplugs to help block the noise.
Ultrasound Ultrasound uses sound waves and their echoes to produce an image of internal organs or masses. For this test, skin is placed on a small instrument that looks like a microphone, called a transducer (which is first lubricated with gel), which emits sound waves and picks up the echoes bouncing from the organs. A computer converts the echoes into an image that appears on the screen.
Ultrasound can be used to look at lymph nodes near the surface of the body or to look within their bodies swollen abdomen, including kidneys, liver and spleen.
This test is easy to make and it does not use radiation. Just your child lies on a stretcher, and a technician moves the transducer over the area of \u200b\u200bthe body being examined.
Gallium scan and bone scan
These tests can be useful if your child has bone pain may be due to either an infection or cancer involving bones. If your child has been diagnosed with leukemia or if there was a PET (described above), usually no need for these studies.
For these tests, the doctor or nurse injects a small amount of slightly radioactive chemical into the bloodstream, which accumulates in the body areas with cancer or infections. Then observe these areas with a special type of camera. Images of these studies are as radioactive spots " in the body, but do not provide many details. If an area lights up in the studio, you can do other imaging tests such as X rays, CT or MRI to get a more detailed picture. If there is the possibility of leukemia, you may need to be confirmed with a biopsy of the area.
