Text B. Drugs That Affect Clotting.

Certain types of drugs can help people who have conditions that put them at high risk of de­veloping dangerous blood clots. In severe coro­nary artery disease, small accumulations of plate­lets may block an already narrowed coronary artery and cut off blood flow to the heart, result­ing in a heart attack. Low doses of aspirin, as well as several other drugs, can reduce the stickiness of platelets so they won't clump together to block the artery.

Another type of drug, an anticoagulant, reduces the blood's tendency to clot by inhibiting the action of the clotting factors. Though often called blood thinners, anticoagulants don't really thin the blood. Commonly used anticoagulants are warfarin, given by mouth, and heparin, given by injection. People who have artificial heart valves or who are confined to bed for long periods are often given anticoagulants as a precaution against clot formation. People taking anticoagulants must be under close medical supervision. Doctors monitor the effects of these drugs with blood tests that measure clotting time, and they adjust the dose on the basis of test results. Doses that are too low may not prevent clots, while doses that are too high may cause severe bleeding. Fibrinolytic drugs help dissolve clots that have already formed. Dissolving clots quickly may prevent the death of heart tissue deprived of its blood supply because of blocked blood vessels. Three fibrinolytic drugs commonly used for dissolving clots in people who have had a heart attack are streptokinase, urokinase, and tissue plasminogen activator. These drugs may save lives when used during the first few hours after a heart attack or when given for other clotting disorders, but they can also put people at risk of severe bleeding.

 

Notes:

clot accumulation clump inhibiting precaution

сгусток, тромб скопление слипшаяся масса, тромб задерживающий, тормозящий предосторожность; предусмотрительность

Text C. Allergic Purpura.

Allergic purpura (Henoch-Schönlein purpura) is an inflammation of the small blood vessels that may be caused by an abnormal immune (autoimmune) reaction.

Allergic purpura, an uncommon disease, affects mainly young children but can affect older children and adults. Usually, it develops just after a respiratory tract infection, but it can be caused by drugs. The disease may develop suddenly and last a short time, or it may develop gradually and last a long time. Blood vessels in the skin, joints, gastrointestinal tract, or kidneys may become inflamed and leak.

Symptoms and Diagnosis

The disease may begin with the appearance of small areas of purplish spots (purpura)—most often on the feet, legs, arms, and buttocks—as blood leaks from vessels in the skin. Over several days, the purpuric spots may become raised and hard; crops of new spots may break out for sev­eral weeks after the first one appears. Swollen ankles, hips, knees, wrists, and elbows are com­mon, usually accompanied by a fever and achy joints. Bleeding in the gastrointestinal tract may cause abdominal cramps and tenderness; nearly half the people who have allergic purpura have blood in the urine (hematuria). Most people recover completely within a month, but symptoms may appear and disappear several times. Sometimes the kidneys are permanently damaged.

The diagnosis is based on the symptoms. If blood or urine tests show changes in kidney function, a doctor may remove a small sample of tissue from the kidney with a needle for examination under a microscope (needle biopsy) to determine the extent of damage and to ensure that the cause is allergic purpura.

Prognosis and Treatment

If a doctor suspects that the allergic reaction is caused by a drug, the drug is discontinued immediately. Corticosteroids such as prednisone may help relieve swelling, joint pain, and abdominal pain, but they don't prevent kidney damage. Drugs that reduce the activity of the immune system (immunosuppressive drugs), such as azathioprine or cyclophosphamide, are sometimes used if kidney damage develops, but whether they help is not known.

 

Notes:

gradually joint leak achy

постепенно сочленение, сустав течь, протечка; утечка больной, нездоровый, слабый

Text D. Hemophilia.

Hemophilia is a bleeding disorder caused by a deficiency in one of the blood clotting factors.

Hemophilia A (classic hemophilia), which accounts for about 80 percent of all cases, is a deficiency in clotting factor VIII. Hemophilia B (Christmas disease) is a deficiency in clotting factor IX. The bleeding patterns and consequences of these types of hemophilia are similar. Both are inherited through the mother (sex-linked inheritance) but affect male children almost exclusively.

Symptoms

Hemophilia is caused by several different gene abnormalities. The severity of the symptoms depends on how a particular gene abnormality affects the activity of factors VIII and IX. When the activity is less than 1 percent of normal, episodes of severe bleeding occur and recur for no apparent reason.

People whose clotting activity is 5 percent of normal may have only mild hemophilia. They rarely have unprovoked bleeding episodes, but surgery or injury may cause uncontrolled bleeding, which can be fatal. Milder hemophilia may not be diagnosed at all, although some people whose clotting activity is 10 to 25 percent of normal may bleed excessively after surgery, dental extractions, or a major injury.

Generally, the first bleeding episode occurs before 18 months of age, often after a minor injury. A child who has hemophilia bruises easily. Even an injection into a muscle can cause bleeding that results in a large bruise (hematoma). Recurring bleeding into the joints and muscles can ultimately lead to crippling deformities. Bleeding can swell the base of the tongue until it blocks the airway, making breathing difficult. A slight bump on the head can trigger substantial bleeding in the skull, causing brain damage and death.

Diagnosis

A doctor may suspect hemophilia in a young boy whose bleeding is unusual. A laboratory analysis of blood samples can determine whether the boy's clotting is abnormally slow. If it is, the doctor can confirm the diagnosis of hemophilia and can determine the type and severity by testing the activity of factors VIII and IX.

Treatment

People who have hemophilia should avoid situations that might provoke bleeding. They should be conscientious about dental care so they won't need to have teeth extracted. If people who have milder forms of hemophilia need to have dental or other surgery, the drug desmopressin may be given to improve clotting temporarily so that transfusions can be avoided. People who have hemophilia should also avoid certain drugs— aspirin, heparin, warfarin, and certain analgesics such as nonsteroidal anti-inflammatory drugs— that can aggravate bleeding problems.

Usually, treatment involves transfusions to replace the deficient clotting factor. These factors are found in plasma and, to a greater extent, in plasma concentrates. Some plasma concentrates are intended for home use and can be self-administered, either on a regular basis to prevent bleeding or at the first sign of bleeding. More often, they are administered three times a day, but both the dose and frequency depend on the severity of the bleeding problem. The dose is adjusted according to the results of periodic blood tests. During a bleeding episode, more clotting factors are needed, and treatment must be coordinated by a health care practitioner who is an expert in this disease.

In the past, the plasma concentrates carried the risk of transmitting blood-borne diseases such as hepatitis and AIDS. About 60 percent of the hemophiliacs who were treated with plasma concentrates in the early 1980s have been infected with HIV. However, the risk of transmitting HIV infection through plasma concentrates has been virtually eliminated by today's use of screened and processed blood and a genetically engineered factor VIII.

Some hemophiliacs develop antibodies to transfused factors VIII and IX. As a result, the transfusions are ineffective. If antibodies are detected in blood samples, the dosage of the plasma concentrates may be increased, or different types of clotting factors or drugs to reduce the antibody levels may be used.

 

Notes:

pattern consequences inherited gene abnormalities unprovoked bruise bump aggravate

образец, модель последствия унаследованный генетические нарушения неспровоцированный, ничем не вызванный гематома столкновение, тяжелый удар; ударять(ся) отягчать, усугублять

White Blood Cell Disorders

 

White blood cells (leukocytes) are the body's defense against infective organisms and foreign substances. To defend the body adequately, a suf­ficient number of white blood cells must stimulate the right responses, get to where they are needed, and then kill and digest the harmful organisms and substances.

Like all blood cells, white blood cells are pro­duced in the bone marrow. They develop from precursor (stem) cells that mature over time into one of the five major types of white blood cells— neutrophils, lymphocytes, monocytes, eosino-phils, and basophils. Normally, a person pro­duces about 100 billion white blood cells a day.

Usually, the number of white blood cells in a given volume of blood is determined automati­cally by a computerized cell-counting instrument. These instruments provide the total white blood cell count, expressed as cells per microliter of blood, as well as the proportion of each of the five major types of white blood cells. Too few or too many white blood cells indicates a disorder.

 

Text A. Neutropenia.

Neutropenia is an abnormally low number of neutrophils in the blood. Neutrophils are the body's primary cellular defense system against bacteria and fungi. They also help heal wounds and ingest foreign debris, such as embedded splinters.

Neutrophils mature in the bone marrow in about 2 weeks. After entering the bloodstream, they circulate for about 6 hours, searching for infective organisms and other intruders. When they find one, they migrate into the tissues, attach themselves to the intruders, and produce toxic substances that kill and digest the intruders. This reaction may damage healthy tissue in the area of the infection. The entire process produces an in­flammatory response in the infected area, which appears on the body's surface as redness, swell­ing, and heat.

Because neutrophils generally make up over 70 percent of the white blood cells, a decrease in the number of white blood cells usually means a de­crease in the total number of neutrophils. When the neutrophil count falls below 1,000 cells per microliter, the risk of infections increases some­what; when it falls below 500 cells per microliter, the risk of infections increases greatly. Without the key neutrophil defense, a person could die of an infection.

Causes

Neutropenia has a number of causes. The num­ber of neutrophils can decrease because bone marrow production isn't adequate or because large numbers of white blood cells are destroyed in the circulation.

Aplastic anemia causes neutropenia as well as deficiencies in other types of blood cells. Certain rare hereditary diseases, such as infantile genetic agranulocytosis and familial neutropenia, also cause decreases in the number of white blood cells.

In cyclic neutropenia, a rare disorder, the num­ber of neutrophils fluctuates between normal and low every 21 to 28 days; the neutrophil count may fall to almost zero and then spontaneously return to normal after 3 to 4 days. People who have cyclic neutropenia are prone to infections when the number of neutrophils is low.

Some people who have cancer, tuberculosis, myelofibrosis, vitamin B₁₂ deficiency, or folic acid deficiency develop neutropenia. Certain drugs, especially those used in cancer treatment (chemotherapy) impair the bone marrow's ability to produce neutrophils.

Neutrophils are destroyed faster than they're produced in some bacterial infections, some al­lergic disorders, some autoimmune diseases, and some drug treatments. People with an enlarged spleen—for instance, those who have Felty's syndrome, malaria, or sarcoidosis—may have a low neutrophil count because the enlarged spleen traps and destroys neutrophils.

Symptoms and Diagnosis

Neutropenia can develop suddenly over a few hours or days (acute neutropenia), or it can last for months or years (chronic neutropenia). Because neutropenia has no specific symptoms, it's likely to go unnoticed until an infection occurs. In acute neutropenia, a person can develop fever and painful sores (ulcers) around the mouth and anus. Bacterial pneumonia and other severe infections follow. In chronic neutropenia, the course may be less severe if the number of neutrophils isn't extremely low.

When a person has frequent or unusual infections, a doctor suspects neutropenia and orders a complete blood cell count to make the diagnosis. A low neutrophil count indicates neutropenia.

Next, the cause of the neutropenia is determined. A doctor usually takes a sample of bone marrow through a needle (bone marrow aspiration and biopsy). Although this procedure can be uncomfortable, it's usually not dangerous. The bone marrow sample is examined under a microscope to determine whether it looks normal, has a normal number of neutrophil precursor cells, and is producing a normal number of white blood cells. By determining whether the number of precursor cells is decreased and whether these cells are maturing normally, the doctor may be able to estimate the time needed for the neutrophil count to return to normal. If the number of precursor cells is decreased, new neutrophils will not appear in the bloodstream for 2 weeks or more; if the number is adequate and the cells are maturing normally, new neutrophils may appear in the bloodstream within days. Sometimes, bone marrow examination also reveals that other disease such as leukemia or other blood cell cancers, are affecting the bone marrow.

Treatment

The treatment of neutropenia depends on its cause and severity. Drugs that may cause neutropenia are discontinued whenever possible. Sometimes the bone marrow recovers by itself without treatment. People who have mild neutropenia (more than 500 neutrophils per microliter of blood) generally have no symptoms and may not need treatment.

People who have severe neutropenia (fewer than 500 cells per microliter) can rapidly succumb to infection because their bodies lack the means to fight the invading organisms. When these people develop infections, they are generally hospitalized and immediately given strong antibiotics, even before the cause and exact location of the infection are identified. Fever, the symptom that usually indicates infection in a person who has neutropenia, is an important sign that immediate medical attention is needed

Growth factors that stimulate the production of white blood cells, particularly granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM CSF), are sometimes helpful. This form of treatment can eliminate neutropenic episodes in cyclic neutropenia. Corticosteroids may help if the neutropenia is caused by an allergic or autoimmune reaction. Antithymocyte globulin or some other type of immunosuppressive therapy (therapy that suppresses the activity of the im­mune system) may be used when an autoimmune disease – such as certain cases of aplastic ane­mia – is suspected. Removing an enlarged spleen may increase the neutrophil count if the spleen is trapping white blood cells.

People who have aplastic anemia may need to undergo bone marrow transplantation if immunosuppressive therapy fails. Bone marrow transplantation can have significant toxic effects, requires a lengthy hospitalization, and can be per­formed only in certain situations. Generally, it isn't used to treat neutropenia alone.

 

primary cellular defense system myelofibrosis ingest foreign debris painful sores bone marrow

основная система клеточного иммунитета миелосклероз, миелофиброз глотать инородное тело болезненные язвы костный мозг

Notes:

Text B. Lymphocytopenia.

Lymphocytopenia is an abnormally low lymphocyte count – below 1,500 cells per microliter of blood in adults or below 3,000 cells per microliter in children.

Normally, lymphocytes constitute 15 to 40 per­cent of all white blood cells in the bloodstream. Lymphocytes are central to the immune system. They protect the body against viral infection; they help other cells protect the body against bacterial and fungal infections; they develop into cells that produce antibodies (plasma cells); they fight can­cer; and they help coordinate the activities of other cells in the immune system.

Lymphocytopenia can be caused by a variety of diseases and conditions. The number of lym­phocytes can decrease briefly during severe stress and during treatment involving corticosteroids such as prednisone, chemotherapy for can­cer; and radiation therapy. People who have low T-lymphocyte counts usually have more severe lymphocytopenia and generally suffer more severe consequences than people who have low B-lymphocyte counts, but either deficiency can be fatal.

Symptoms and Diagnosis

Because lymphocytes make up a relatively small proportion of the white blood cells, a re­duction in their number may not cause a signifi­cant decrease in the total number of white blood cells. Lymphocytopenia itself may cause no symptoms and is usually detected in a complete blood cell count that was ordered to diagnose other illnesses. Drastically reduced numbers of lymphocytes lead to infections with viruses, fungi and parasites.

With current laboratory technology, changes in numbers of specific types of lymphocytes can be detected. For instance, decreases in a type of T-lymphocyte known as T4 cells are one way to measure the progression of AIDS.

Treatment

Treatment depends mainly on the cause. Lymphocytopenia caused by a drug usually resolves within days after a person stops taking the drug. When the cause is AIDS, generally little can be done to increase the number of lymphocytes, although certain drugs such as zidovudine and didanosine may increase the number of helper T cells.

When lymphocytopenia is a deficiency of B lymphocytes, the concentration of antibodies in the blood may fall below normal. In these cases, gamma globulin (a substance rich in antibodies) may be given to help prevent infections. If an infection does develop, specific antibiotic, antifungal, or antiviral drugs directed against the infective organism are given.

 

Notes:

chemotherapy signifi­cant relatively

химиотерапия значительный относительно, сравнительно

 

 

Diseases That Cause Lymphocytopenia 1. Cancer (leukemias, lymphomas, Hodgkin’s disease) 2. Rheumatoid arthritis 3. Systemic lupus erythematosus 4. Chronic infections 5. Rare hereditary disorders (certain agammaglobulinemias, DiGeorge syndrome, Wiskott-Aldrich syndrome, severe combined immunodeficiency syndrome, and ataxia-telangiectasia) 6. Acquired immunodeficiency syndrome (AIDS) 7. Some viral infections

 

Leukemias

Leukemias are cancers of the blood cells.

Leukemias usually affect the white blood cells. The cause of most types of leukemia isn't known. Viruses cause some leukemias in animals, such as cats. A virus known as HTLV-I (human T-cell lymphotropic virus type I), which is similar to the virus that causes AIDS, is strongly suspected to be the cause of a rare type of leukemia in people, adult T-cell leukemia. Exposure to radiation and certain chemicals, such as benzene, and use of some anticancer drugs increase the risk of devel­oping leukemia. Also, people who have certain genetic disorders, such as Down syndrome and Fanconi's syndrome, are more likely to develop leukemia.

Leukemia results when the process of maturation from stem cell to white blood cell goes away and produces a cancerous change. The change often involves a rearrangement of pieces of chromosomes—the cell's complex genetic material. Because the chromosomal rearrangements (chromosomal translocation) disturb the normal control of cell division, the affected cells multiply without restraint, becoming cancerous. They ultimately occupy the bone marrow, replacing the cells that produce normal blood cells. These leukemic (cancer) cells may also invade other organs, including the liver, spleen, lymph nodes, kidneys, and brain.

There are four major types of leukemia, named for how quickly they progress and which kind of white blood cell they affect. Acute leukemias progress rapidly; chronic leukemias progress slowly.

Lymphocytic leukemias affect lymphocytes; myeloid (myelocytic) leukemias affect myelocytes. Myelocytes develop into granulocytes, another term for neutrophils.