Blood

Blood is a red liquid that is vital to life. Blood is composed of water as well as a multitude of different proteins, including antibodies and important hormones and transport molecules; nutritional products, such as sugars, fats, and amino acids; and most importantly - living cells. The major types of blood cells are leukocytes (also known as white blood cells), red blood cells (cells that contain hemoglobin and carry oxygen to the tissues), and platelets (cells necessary for blood clotting and formed in the blood marrow). All blood cells are manufactured in the bone marrow, growing from a cell known as the hematopoietic stem cell. Leukemia is a malignancy (cancer) of the white blood cell.

Plasma

Plasma is a citrin liquid used as a support mechanism for millions of cells that are suspended in it. However, it is more than a carrier; plasma also contains a number of products that ensure the proper functioning of our bodies, such as glucose, minerals (calcium, sodium, potassium, chlorine, etc.), proteins (albumin, antibodies, proteins needed for blood coagulation, etc. ), soluble fats (cholesterol, triglycerides) , and a number of products resulting from organ activity (urea, lactic acid, creatine, etc.).

Types of blood cells

Red blood cells

Red blood cells look like small sacs with a flat center; they have no nucleus and their main role is to transport hemoglobin, which in turn transports the oxygen picked up from the lungs.
As they travel through the arteries, red blood cells distribute oxygen to all of the organs in our body (brain, heart, muscles, etc.). At the same time, they pick up the carbon dioxide (CO2) from these organs and, through the veins, transport it to the lungs.
When red blood cells are filled with oxygen, they are bright red. When they are transporting carbon dioxide they are a bluish color. This explains the bright red color of arterial blood and the bluish color of venous blood. There are a very high number of red blood cells: approximately five million per cubic millimeter of blood; their average lifespan is 120 days. They are manufactured mainly in bone marrow.
If their number decreases or if the quantity of hemoglobin they carry decreases, the resulting condition is known as anemia. Anemia has several causes, the most common being loss of blood (heavy menstruation, giving birth, intestinal bleeding, or a secondary hemorrhage due to a wound); it can also be caused by a lack of iron or vitamins (folic acid and vitamin B12). In some instances, anemia can be the warning sign of more serious illnesses that decrease the number of red blood cells the body produces: certain cases of aplasia, leukemia, and lymphoma.
On their surface, red blood cells carry the antigens of the ABO and Rh blood types.

White blood cells

White cells are true cells: they have a nucleus, an intracellular space (cytoplasm), and a membrane.
The nucleus can have several shapes; for example, it can be round and formed of a single lobe, or it can have several lobes and appear to be multiple. The intracellular space (cytoplasm) contains enzymes, substances used to digest foreign bodies. The membrane carries the HLA tissue groups; HLAs (H for human, L for leucocytes, and A for antigens) are groups that define each human being, and their role is vital in the transplant rejection reaction.
There are two large families of white cells: lymphocytes and myelocytes. These two classes of white cells are differentiated by their nucleus and the color of their intracellular space.

Myelocytes

This class accounts for 55 to 65 percent of all white cells.
Early researchers believed that these cells had several nuclei, which is why they referred to them as "polynuclears.' Today, we know that these cells have only one nucleus, composed of several lobes that are linked together by a system of fine threads.
The intracellular space contains small grains (granules) that pick up colorants and take on bluish or reddish tints. These granules are what give these corpuscles their alternate name: granulocytes. The color of grains can differentiate neutrophilic (slightly bluish) polynuclears, eosinophilic (red) polynuclears, and basophilic (very bluish) polynuclears.
Polynuclears have several functions:

• Neutrophilic polynuclears, specialized in bacteria phagocytosis (digestion), play an important role in the anti-infection battle. Their number increases when infections are present.
• Eosinophilic polynuclears play a role in allergic reactions and in the body's defense against parasites.

The terms granulocytes and polynuclears are accurate, and both commonly used to designate the myelocytes "families".

Lymphocytes

Lymphocytes make up the remaining 35 to 45 percent of white blood cells. They have a large, oval nucleus, but no grains. These blood cells are manufactured mainly by the lymph nodes.
Because they are specialized in the manufacture of antibodies, lymphocytes play an important part in the fight against infections and transplant rejections. Antibodies attack viruses, bacteria, and foreign bodies.
Lymphocytes can also "remember" some viruses, preventing subsequent infections. This phenomenon is known as immunization.

Platelets

Platelets look like minuscule sacs and have the property of sticking to one another to form a blood clot. Blood clots seal off the walls of veins and arteries, which prevents bleeding (hemorrhages). When the number of platelets decreases, the patient is more susceptible to bruises and hemorrhages.

Bone marrow

Bone marrow constitutes the major industrial center in our bodies - it has the major task of manufacturing blood. In fact, it replaces all of our blood once every twenty days. This change is progressive: each second, bone marrow produces more than ten million blood cells, which flow into the blood. At the same time, ten million other blood cells die; thus, equilibrium exists at all times.

Bone marrow works according to very precise rules; it adjusts to the rules of supply and demand by increasing or decreasing its production. It adapts quickly to all of the conditions that can prevail in our bodies; when an infection is present, it produces more white blood cells so that the body is better equipped to fight germs. Once the infection is under control, the number of white blood cells produced drops to its normal level. In situations where there is hemorrhaging, the production of red blood cells increases until their number returns to its normal level.

Bone marrow also reacts to certain natural phenomena; for example, at high altitudes, where oxygen is less plentiful, bone marrow manufactures more red blood cells, which results in better oxygenation of the body's organs. Athletes who are aware of this process often train at high altitudes a few weeks before competing. When they return to sea level, they benefit from better muscle oxygenation and their performance levels are higher.

Bone marrow has a liquid consistency and is found in the center of all of the bones in the body. It contains stem cells (cells with the ability to multiply and to produce blood cells), which it uses to renew our blood supply throughout our lifetimes. We call this the hemopoietic system. The stem cells can move into the blood stream by using the hormone named colony stimulating factor.

The bone marrow found in the sternum and hip bone contains the highest number of stem cells. This is where doctors do bone marrow puncture and bone marrow biopsies. These two tests are essential to arrive at a diagnosis.

Blood clot formation

We could not survive without the presence of mechanisms through which our bodies seal the breaks in our arteries and our veins-at all times, we are exposed to accidents (traumas, cuts, fractures) that can lead to lesions in our blood vessels. Without the formation of blood clots, these lesions would cause an uncontrollable loss of blood that would quickly jeopardize our lives. Several malignant blood diseases weaken the body's ability to form blood clots.

Hemorrhages can be external (breaks in vessels located in the skin) or internal (breaks in vessels located inside certain organs, such as the stomach, intestine, kidney, and brain). Minor hemorrhages are quickly brought under control through the formation of a blood clot, but serious hemorrhages sometimes require surgical intervention; if, for example, a large blood vessel is torn, a stitch is needed to bring the two vessel walls together, which stops the bleeding.

The formation of a blood clot is also called blood coagulation or hemostasis. It requires the presence of platelets and substances known as coagulation factors that are found in blood plasma. Numbers are assigned to each of these factors. Coagulation factors react to one another in a sequential series and form a trellis that incorporates platelets: a blood clot.

The causes of increased bleeding

Usually, blood clots form quickly and all minor bleeding stops within a few minutes. But several causes can slow the formation of a blood clot; in addition to a decrease in the number of platelets, referred to previously, some forms of medication, some illnesses, and a vitamin deficiency sometimes slow down the process leading to blood clot formation, thus increasing the risk of severe hemorrhage.

Medications that delay the formation of blood clots

The most common medication known to have an effect on coagulation is aspirin. Aspirin decreases the efficiency of platelets, which slows the formation of blood clots. The effect of aspirin can last for more than two weeks following the ingestion of a single tablet.
Anti-inflammatories and antibiotics can also have a negative effect on coagulation.
Because they can result in severe hemorrhaging, medications that decrease the efficiency of platelets should never be used by patients under treatment for malignant blood diseases without prior consultation with a physician.
Other medications are intentionally used to slow the formation of blood clots, or to "thin the blood," as some patients say. These anticoagulants are used to treat patients who have artificial heart valves or who have suffered from phlebitis or pulmonary embolisms in the past.

Diseases that slow the formation of blood clots

Among congenital diseases that affect coagulation factors and slow the formation of blood clots, the most common are Type A hemophilia and Type B hemophilia.
Severe liver diseases decrease the formation of coagulation factors and increase the risk of severe hemorrhage.
All malignant blood diseases and all kidney diseases lead to renal failure. Serious infections and certain inflammatory diseases can affect the formation of blood clots.

Vitamin deficiencies

Due either to malnutrition or to poor digestive absorption, vitamin deficiencies can increase bleeding.
Vitamin K is crucial to the formation of II, VII, IX, and X blood coagulation factors; a lack of vitamin K leads to a decrease in these factors, which slows down the chain reaction leading to the formation of a blood clot.
Deficiencies in vitamin C, vitamin B12, and folic acid can lead to increased bleeding.

Symptoms suggesting coagulation problems

The appearance of small red dots (petechia) or larger blotches (purpura and bruises) on the skin often indicates problems that can be traced to platelets. Bleeding in the stomach or in other regions of the intestine and bleeding within joints (hemarthrosis) is more likely linked to a problem with coagulation factors.

Some types of bleeding are perfectly normal among people in good health; for example, menstruation or the type of bleeding associated with superficial cuts. But any increase in the duration or the quantity of such bleeding should be discussed with a physician, who will decide whether to evaluate blood clot formation. Evaluating coagulation factors and platelets is part of the basic blood testing procedure.

Blood and the body's main systems

Blood, a vital liquid essential to all of our organs, carries the nutrients and oxygen our bodies need. Blood also plays a role in eliminating waste, since it carries toxic materials to the organs that excrete them from the body.

The study of anatomy and the functioning of the human body is very complex. The body consists of several systems. These systems do not constitute all of the human body's anatomy, but they are closely linked to blood and, consequently, they are often affected by malignant blood diseases.

The hemopoietic system

The hemopoietic system groups together bone marrow, the spleen, and lymph nodes, which are all linked by small vessels knows as lymphatic ducts.

Lymph node system

Lymph nodes are the organs in which white lymphocyte-type blood cells multiply; their function is to fight infections. Lymph nodes increase in volume as a reaction to certain cancers, infections, or inflammatory diseases. We call this lymphadenopathy. Nodes can also be a site for cancers, the most frequent of which is lymphoma. Lymph nodes are found everywhere in the body and are designated based on the anatomical region in which they are found; the principal types of nodes are cervical, inguinal, abdominal, and thoracic.

Lymphatic ducts

Lymphatic ducts are the small vessels that link nodes together. When an infection is present, the white cells travel through these ducts to reach the nodes, where they multiply to better fight the infection. When a cancer is present, this circuit often serves as a way for the malignant tumor to spread. Cancerous cells can detach from the tumor and use the lymphatic ducts to invade regional nodes, thus forming node metastases.

Spleen

The spleen resembles a small blood-filled bag and is approximately the same size as a tomato. It is located on the left side of the abdomen and, like a tomato, is very fragile.
Its main role is eliminating "old red blood cells," those that have carried oxygen for more than 120 days and are beginning to age. The spleen recognizes them and picks them out of the blood supply.
It also plays an important part in the fight against infections by eliminating bacteria and particulate antigens from the bloodstream. Several diseases can cause the spleen to increase in volume (splenomegaly); the most common are viral infections, liver diseases, inflammatory diseases, and malignant diseases such as leukemia and lymphoma. Under such circumstances, the spleen can swell to the size of a football; when it does, it is extremely vulnerable to the slightest trauma.

The cardio-respiratory system

The cardio-respiratory system is composed mainly of the heart, the lungs, and the large blood vessels.
The heart is an organ whose role is to ensure good blood circulation to all parts of our bodies. It is divided into two parts: the right heart and the left heart.
The right heart receives non-oxygenated blood from our muscles and our organs; this blood travels through the venous system and ends up in the superior and inferior vena cava. The right heart pumps this blood to the lungs.
The lungs ensure that gases are exchanged and that the blood is re-oxygenated, turning bright red in the process.
The left heart pumps the oxygenated blood to all organs in our body. The heart beats more than 100,000 times in one day; it adjusts its rhythm and the strength of its contractions constantly, reflecting changes in the demand for oxygen.
Some hematological conditions can increase cardiac rhythm, such as a patient suffering from anemia or an infection.

The central nervous system

The central nervous system is a series of organs composed of nervous tissues, all of them closely linked to each other. It includes the brain, the cerebellum, the brain stem, and the spinal cord.

The brain, the cerebellum, and the brain stem group together millions of cells called neurons. These cells cannot multiply and they communicate with one another through a system of branching parts whose total length can go to beyond one meter.

The spinal cord is formed by this system of branching parts, which travels through the center of vertebra in a canal known as the vertebral canal. The spinal cord is divided into several sections, which are known as nerves. A break in the spinal cord results in irreversible paralysis. The central nervous system is enveloped in cerebrospinal fluid, which circulates constantly while protecting and nourishing it. When a physician proceeds with a lumbar puncture, he removes several milliliters of cerebrospinal fluid.

Several malignant blood diseases tend to spread to the central nervous system, in particular, childhood leukemia. Analysis of the cerebrospinal fluid makes it possible to detect the presence of leukemic cells and, consequently, to modify treatment programs; if cancerous cells are present or to prevent certain types of leukemia, the central nervous system will be treated with radiation, and chemotherapy medications will be injected directly into the cerebrospinal fluid (intrathecal injection).

The digestive system

The digestive system includes the digestive tract and several organs, each of which has a specific part to play in food digestion.

The digestive tract

The digestive tract extends from the mouth to the anus and its main role is to digest and absorb food. In this complex process, each part of the digestive tract has a very specific function.
The inside of the digestive tract is lined with a thin layer of cells, called intestinal mucous membrane. These cells characteristically multiply very quickly; therefore, they are very sensitive to cancer-fighting treatments.
In the mouth, food is chewed and mixed with saliva from the salivary glands. The food is then swallowed, passing through the esophagus on its way to the stomach. Chemotherapy and radiation therapy can affect the salivary glands and the taste buds (small glands located on the tongue and used to taste food); patients will have difficulty tasting foods and will have dry mouths. A mucositis (red blotches and a burning sensation in the mouth) and an esophagitis (irritation of the esophagus caused by burning when food is swallowed) can sometimes occur.
The stomach is a reservoir where food is stored for a few hours. The food is mixed with a very acidic liquid that breaks it down and prepares it for absorption. The stomach is sensitive to certain medications (aspirin, cortisone) and can react to stress by increasing its acid level; this reaction can degenerate into gastritis (irritation of the stomach, causing heartburn, which can be relieved temporarily by drinking milk or water) and sometimes even ulcers (deep erosion of the stomach wall). If not treated quickly, gastritis and ulcers can lead to stomach hemorrhages. In response to certain medications, to stress, and to inflammation, the stomach's movements may be upset and the person will experience nausea and, on occasion, vomiting.
The duodenum, the small intestine, and the large intestine form a tube approximately 21 feet (seven meters) long. Solid food is absorbed in the small intestine, and liquids are absorbed in the large intestine.
During anticancer treatment, the mucous membrane in this region commonly stops its absorption activities; as a result, the patient may experience severe diarrhea. The physician can sometimes counter this lack of food absorption by feeding the patient intravenously.
All of the side effects that chemotherapy can have on the digestive tract are reversible as soon as the treatment program ends.

The pancreas

This organ has two different functions. The first is to take part in the digestive process by producing pancreatic juices, which are emptied into the duodenum. These juices contain enzymes essential to the digestion of meats, sugars, and fats. Its second function consists of secreting hormones, the most well known of which is insulin (which maintains proper glucose levels in the blood; a decrease in the secretion of insulin leads to diabetes).
The pancreas can be damaged by certain substances, such as alcohol or medications, or by stones that block its opening and cause congestion and inflammation of the pancreas (pancreatitis). Cases of pancreatitis are rare during anticancer treatment programs.

The liver

The liver is the organ with the highest number of functions to provide. First, it participates in the digestion of food by secreting bile. Essential for the digestion of fats, bile is stored in the gallbladder before emptying into the duodenum. The liver also manufactures a number of proteins, the most important of which are albumin and blood coagulation proteins, vital to the formation of blood clots. In addition, it helps to eliminate organic wastes and medications from the body; its role in anticancer treatment programs is extremely important.
The liver is sensitive to several medications, to toxic substances, and even to some viruses. An obstruction in the bile ducts, often caused by gallbladder stones and, more rarely, by tumors (lymphoma or cancer of the pancreas), creates congestion of the liver. When the liver is inflamed by one of the previously mentioned causes, the condition is known as hepatitis.
During chemotherapy, the liver is kept under close watch since medication-related hepatitis is frequent; blood tests are taken regularly, and at the first sign of damage, treatment is modified or stopped.
The liver can be affected by certain malignant blood diseases, such as various forms of leukemia and lymphoma, and at times, in instances of bone marrow transplants, by the graft versus host reaction. The physician proceeds with a biopsy to confirm or invalidate the diagnosis.

The urinary system

The urinary system mainly includes the kidneys, the urethra, and the bladder. The kidneys play a key role in the elimination of medications and biological wastes produced from our various organs.

The kidneys

Among other functions, the kidneys balance arterial pressure and adjust the quantity of liquid and the level of minerals (sodium, potassium, calcium, chlorides, etc.) present in our bodies and essential for the proper functioning of our organs. They are also involved in the elimination of organic wastes (urea) and medications, which they concentrate and eliminate in the urine.
The kidneys are rarely affected by malignant blood diseases, but they are very sensitive to certain anticancer or anti-rejection medications. During anticancer treatment programs the kidneys are monitored closely (for example, through regular blood tests and urine analyses).
If a medication changes kidney functions, its dosage is immediately decreased; at times, the physician may stop administering the medication completely, replacing it with an alternative that is less toxic for the kidneys.

The bladder

Urine that is synthesized in the kidneys travels through the urethra to the bladder. The latter acts as a reservoir; when its maximum storage capacity is reached, sensors located along its wall send a message to the central nervous system, which warns us that urination is imminent.
As we have seen, urine can contain several medication residues; occasionally. some of these can cause an irritation of the bladder (medication-related cystitis). Sometimes, bacteria and viruses infect the bladder (infectious cystitis) and can even travel backward through the urethra to infect the kidneys (pyelonephritis). Infectious cystitis and pyelonephritis can be treated quickly with antibiotics.

Hemophilia

Hemophilia is a disorder of blood clotting. Normally when somebody injures themselves the blood clots in a few minutes and wound healing can begin. In hemophilia this does not happen. This is because one of the ingredients needed for making a blood clot does not work properly. This deficiency in the activity of the ingredient may be complete or partial. When the deficiency is complete the person is said to have severe hemophilia.

Even in severe haemophilia clotting is not prevented altogether. Instead it is much slower than normal. The result is a friable clot that cannot withstand the pressure of escaping blood. Body tissues involved become disrupted, and wounds do not heal up properly. In severe hemophilia most bleeds are internal, into joints and muscles. With modern treatment given early there is often nothing to see, and no interference with everyday life.

There are a number of blood clotting ingredients. Most are proteins. We make them continuously so that the body is always prepared for action should injury occur. As fresh ingredients are made and delivered to the bloodstream, so the older ingredients die and are either recycled or eliminated from the body. Normally, low levels of active ingredients circulate. Injury triggers a rapid increase in manufacture, and the bloodstream then delivers them to the site where they are needed. Here the clotting ingredients contain the damage and start the process of wound healing.

Most of the ingredients are called factors. There are 12 factors. One of them is called factor VIII, and another factor IX. It is the failure of the body to produce either normal factor VIII or normal factor IX that results in hemophilia.

• When factor VIII is not normal (abnormal), the disorder is called - hemophilia A.
• When factor IX is abnormal, the disorder is called - hemophilia B.

Hemophilia A is five times more common than hemophilia B. It is also referred to as factor VIII deficiency, as classical hemophilia, or sometimes just as 'hemophilia'. This last, generic term can be dangerous when it comes to giving treatment because factor VIII is no good to someone with hemophilia B. Hemophilia B is also called factor IX deficiency or, especially in the United Kingdom where the first patient was identified, as Christmas disease. Christmas was the name of the patient.

Like factors VIII and IX, all the factors are identified by international agreement with Roman numerals.

Severity

When all a clotting factor is abnormal the resulting disorder is called severe. Conversely, when some of the factor is normal the disorder is only of moderate or even mild severity. In terms of figures someone with severe hemophilia A has a level of factor VIII in his blood of zero international units or, expressed as a percentage of average normal, 0 per cent. Someone with mild hemophilia A has over 0.05 international units per milliliter of blood.

Knowing the level of the affected factor is important for three reasons:

• The level usually, but not always, indicates what to expect in terms of physical problems.
• The level indicates the sort of treatment that is likely to be successful.
• The level runs true to form in a family. So a baby with a family history of mild hemophilia will have mild hemophilia.

Inheritance

Hemophilia is an inherited disorder. This means that it can be passed down a family from one generation to the next. The instructions for making proteins such as factor VIII or factor IX are called genes. All the genes together form the blueprint for the life and the characteristics of an individual. There are 100 000 genes, collectively called the genome.

Half of a baby's genome comes from his father and half from his mother. The genes are carried in his father's sperm and in his mother's egg on structures called chromosomes. When sperm and egg fuse at the moment of conception the complete blueprint for the future individual is present.

Humans have 46 chromosomes. Two of these chromosomes determine the sex of an individual. They are called X and Y. Someone inheriting two X chromosomes (XX) will be female. Someone inheriting an X and a Y (XY) will be male.

The genes for hemophilia A and B are on an X chromosome. So they are said to be 'sex-linked'.

Because females have two X chromosomes they have two sets of instructions for making factors VIII and IX. If one set is faulty, the other set makes up for the deficit. That is why women do not usually have hemophilia. The inactive abnormal gene is masked by the normal activity of the other gene on the second X chromosome. The abnormality is hidden. Someone with an abnormal gene like this is called a carrier. Carriers 'carry' the abnormal gene and can pass it on to their children. Very rarely a women may inherit two abnormal factor VIII, or factor IX, genes, and have hemophilia. This can only happen when someone with hemophilia mates with a carrier of hemophilia.

Carriers may pass their hemophilia gene to their daughters or to their sons. The chances of this happening are 50:50.

If the X chromosome with the normal gene is in the fertilized egg the child will not inherit the hemophilia gene. If the X chromosome with the abnormal gene is in the fertilized egg the child will inherit the hemophilia gene. If the child is female she will be a carrier like her mom. If the child is male he will have hemophilia because his Y chromosome does not have a duplicate set of instructions for making factor VIII, or factor IX.

A father with hemophilia may fertilize an egg (X) with a sperm containing either an X chromosome or a Y chromosome. His X chromosome results in a daughter (XX). Because his X chromosome bears the abnormal gene all his daughters must be carriers of hemophilia. His Y chromosome results in a son (XY). Because his Y chromosome is normal all his sons must be normal. They cannot inherit a hemophilia gene and, therefore, cannot pass hemophilia to any of their children. The line of inheritance ends.

About one third of all genetic disorders seem to come out of the blue. There is no family history. This is because our genetic make-up undergoes changes, and one of these changes can result in hemophilia. A change like this is called a mutation. In the family history of someone with hemophilia there is no way of telling (except occasionally with specialized testing) the timing of this mutation. It may have just happened to the fertilized egg, or it may have happened generations beforehand and have been unknowingly passed down the female line where, of course, it would have been masked by normal X chromosomes.

How do I know when treatment is necessary?

It takes a little time to get used to living with a child who has just been diagnosed as having hemophilia. The label hemophilia constantly gets in the way. It is easy to think of nothing else, and to start to imagine a disrupted and difficult future for him and the family. In fact nasty bleeds are very rare in early childhood and there is nearly always plenty of time to learn how to cope with everyday knocks and bruising before more serious bleeds begin.

Diagnosis from cord blood or in the newborn period is followed by several quiet months in which hemophilia produces few, if any, visible signs. As the boy with severe hemophilia becomes more mobile bruising appears. Although unsightly these bruises do not hurt him. Unless there has been a big knock they are superficial. Try moving them around in the skin with your fingers. They feel nubbly and move easily over underlying tissues. If you can do this no treatment is necessary. If you cannot, seek help. Fixed bruises suggest bleeding into deep tissues and probably need treatment.

Bleeds over or very near joints should also be looked at by someone with experience of hemophilia, unless they are very small. Bleeds into joints, causing swelling of the joint, are uncommon before the age of 2 years but they do occur. When they do early treatment is very important if long-term damage is to be avoided. This is why some doctors are recommending that prophylaxis, in which regular shots of factor VIII or IX are given, be started in the second year of life if the boy's hemophilia is severe.

Apart from joint or deep muscle bleeds the one time that advice must always be sought is in the case of head injury. All toddlers fall and bump their heads, and it can be very difficult to decide whether or not a bruised head should be seen.

Tests and immunizations

Screening tests on the newborn, like the Guthrie test for phenyl-ketonuria, often involve taking a small specimen of blood from a heel prick. This only hurts for an instant and does no harm to a baby with hemophilia. What should not happen, except in real emergency, is an attempt to take blood from a blood vessel in the neck (an external jugular vein) or the groin (a femoral vein) in order to make a diagnosis of hemophilia. These vessels are relatively large and bruising around them can be very dangerous. If blood is taken from a neck or groin vein make sure pressure is kept on the site for at least five minutes, and that the area is then checked regularly for several hours. Untoward swelling requires further pressure and sometimes special treatment. If the diagnosis has not been made on a specimen from the umbilical cord it is best to wait until a good vein in the hand, wrist or crease of the elbow, or on the top of the foot becomes available. Veins show up better as babies grow and start to move around more. Unless a baby is very fat access to one of these peripheral veins should be relatively easy before his tenth month of life.

Immunizations are fine before this time. The injections are of small volume and, provided finger pressure is kept over the injection site for five minutes, do not cause untoward bruising. Other than immunization all intramuscular injections are banned in people with hemophilia. Medicines must be given via another route, usually intravenously (into a vein). This is because medicines, especially antibiotics, are often of large volume and can easily provoke extensive bleeding into muscles.

Treatment

Nowadays treatment is easy, at least in developed countries where access to quality blood products is available. Treatment consists of replacing the missing clotting activity of factor VIII or IX.

In the case of hemophilia A this can be done either by using a product made from blood plasma provided by human donors or, in some cases by pigs, or by using a factor VIII preparation made synthetically by bioengineering. In all cases the product will have undergone stringent testing and measures to remove viral contamination. In the case of hemophilia B the preparation available is likely to be a factor IX concentrate made from human plasma.

These concentrated forms of factors VIII and IX are expensive and must be used wisely. They are very effective and their introduction has revolutionized the management of hemophilia. Before they were available in large quantities treatment was with unrefined blood plasma in the form of fresh frozen plasma or cryoprecipitate, both of which had to be stored in a deep freeze. These simple products are very effective but are less safe from viral contamination than the concentrates, and are harder to store and administer.