What is the treatment for dengue fever?
Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue, the treatment is purely concerned with relief of the symptoms. Rest and fluid intake for adequate hydration is important. Aspirin and nonsteroidal anti-inflammatory drugs should only be taken under a doctor's supervision because of the possibility of worsening bleeding complications. Acetaminophen (Tylenol) and codeine may be given for severe headache and for joint and muscle pain (myalgia).What is the prognosis for typical dengue fever?
Typical dengue is fatal in less than 1% of cases. The acute phase of the illness with fever and myalgias lasts about one to two weeks. Convalescence is accompanied by a feeling of weakness (asthenia), and full recovery often takes several weeks.DENGUE FEVER:
What is dengue hemorrhagic fever?
Dengue hemorrhagic fever (DHF) is a specific syndrome that tends to affect children under 10 years of age. It causes abdominal pain, hemorrhage (bleeding), and circulatory collapse (shock). DHF is also called Philippine, Thai, or Southeast Asian hemorrhagic fever and dengue shock syndrome.DHF starts abruptly with high continuous fever and headache. There are respiratory and intestinal symptoms with sore throat, cough, nausea, vomiting, and abdominal pain. Shock occurs two to six days after the start of symptoms with sudden collapse, cool, clammy extremities (the trunk is often warm), weak pulse, and blueness around the mouth (circumoral cyanosis).
In DHF, there is bleeding with easy bruising, blood spots in the skin (petechiae), spitting up blood (hematemesis), blood in the stool (melena), bleeding gums, and nosebleeds (epistaxis). Pneumonia is common, and inflammation of the heart (myocarditis) may be present.
Patients with DHF must be monitored closely for the first few days since shock may occur or recur precipitously (dengue shock syndrome). Cyanotic (bluish) patients are given oxygen. Vascular collapse (shock) requires immediate fluid replacement. Blood transfusions may be needed to control bleeding.
The mortality (death) rate with DHF is significant. With proper treatment, the World Health Organization estimates a 2.5% mortality rate. However, without proper treatment, the mortality rate rises to 20%. Most deaths occur in children. Infants under a year of age are especially at risk of dying from DHF.
What geographic areas are at high risk for contracting dengue fever?
Dengue is prevalent throughout the tropics and subtropics. Outbreaks have occurred recently in the Caribbean, including Puerto Rico, the U.S. Virgin Islands, Cuba, and Central America. Cases have also been imported via tourists returning from areas with widespread dengue, including Tahiti, Singapore, the South Pacific, Southeast Asia, the West Indies, India, and the Middle East (similar in distribution to the areas of the world that harbor malaria and yellow fever). Dengue is now the leading cause of acute febrile illness in U.S. travelers returning from the Caribbean, South America, and Asia.In 2011, Bolivia, Brazil, Columbia, Costa Rica, El Salvador, Honduras, Mexico, Peru, Puerto Rico, and Venezuela reported a large number of dengue cases. Paraguay reported a dengue fever outbreak in 2011, the worst since 2007. Hospitals were overcrowded, and patients had elective surgeries canceled due to the outbreak.
The U.S. Centers for Disease Control and Prevention (CDC) reports that from 1946 to 1980, no cases of dengue acquired in the continental United States were reported. Since 1980, a few locally acquired U.S. cases have been confirmed along the Texas-Mexico border, temporally associated with large outbreaks in neighboring Mexican cities.
A 2009 outbreak of dengue fever in Key West, Fla., showed that three patients who did not travel outside of the U.S. contracted the virus. Subsequent testing of the population of Key West has shown that up to 55 of the people living in the area have antibodies to dengue. In total, 28 people were diagnosed with dengue fever in this outbreak.
Dengue fever is common, in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean. Thailand, Vietnam, Singapore, and Malaysia have all reported an increase in cases.
According to the CDC, there are an estimated 100 million cases of dengue fever with several hundred thousand cases of dengue hemorrhagic fever requiring hospitalization each year. Nearly 40% of the world's population lives in an area endemic with dengue. The World Health Organization (WHO) estimates that 22,000 deaths occur yearly, mostly among children.
How is dengue fever contracted?
The virus is contracted from the bite of a striped Aedes aegypti mosquito that has previously bitten an infected person. The mosquito flourishes during rainy seasons but can breed in water-filled flower pots, plastic bags, and cans year-round. One mosquito bite can cause the disease.The virus is not contagious and cannot be spread directly from person to person. There must be a person-to-mosquito-to-another-person pathway.
Dengue fever facts
- Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes.
- Symptoms such as headache, fever, exhaustion, severe joint and muscle pain, swollen glands (lymphadenopathy), and rash. The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue fever.
- Dengue is prevalent throughout the tropics and subtropics. Outbreaks have occurred recently in the Caribbean, including Puerto Rico, the U.S. Virgin Islands, Cuba, and in Paraguay in South America, and Costa Rica in Central America.
- Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue fever, the treatment is purely concerned with relief of the symptoms (symptomatic).
- The acute phase of the illness with fever and myalgias lasts about one to two weeks.
- Dengue hemorrhagic fever (DHF) is a specific syndrome that tends to affect children under 10 years of age. It causes abdominal pain, hemorrhage (bleeding), and circulatory collapse (shock).
- The prevention of dengue fever requires control or eradication of the mosquitoes carrying the virus that causes dengue.
- There is currently no vaccine available for dengue fever.
What is dengue fever?
Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes. It is an acute illness of sudden onset that usually follows a benign course with symptoms such as headache, fever, exhaustion, severe muscle and joint pain, swollen glands (lymphadenopathy), and rash. The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue. Other signs of dengue fever include bleeding gums, severe pain behind the eyes, and red palms and soles.Dengue (pronounced DENG-gay) can affect anyone but tends to be more severe in people with compromised immune systems. Because it is caused by one of four serotypes of virus, it is possible to get dengue fever multiple times. However, an attack of dengue produces immunity for a lifetime to that particular serotype to which the patient was exposed.
Dengue goes by other names, including "breakbone" or "dandy fever." Victims of dengue often have contortions due to the intense joint and muscle pain, hence the name breakbone fever. Slaves in the West Indies who contracted dengue were said to have dandy fever because of their postures and gait.
Dengue hemorrhagic fever is a more severe form of the viral illness. Symptoms include headache, fever, rash, and evidence of hemorrhage in the body. Petechiae (small red or purple splotches or blisters under the skin), bleeding in the nose or gums, black stools, or easy bruising are all possible signs of hemorrhage. This form of dengue fever can be life-threatening and can progress to the most severe form of the illness, dengue shock syndrome.
CATARACT:
Facts about cataracts
- A cataract is a clouding of the lens of the eye.
- Cataracts are extremely common, and most cataracts are a result of the aging process.
- Although many cataracts are not significant enough to require treatment, surgical removal of cataracts is usually safe and effective, resulting in improvement of vision.
- Cataract surgery should be performed when the visual loss from the cataract significantly impacts the lifestyle of the individual patient.
What is a cataract?
A cataract is an eye disease in which the clear lens of the eye becomes cloudy opaque, causing decrease in vision. Although the word cataract to describe this condition has been part of the English language only since the middle of the 16th century, the eye disease has been recognized and surgically treated since ancient times.
The lens is a portion of the eye that is normally clear. It assists in focusing rays of light entering the eye onto the retina, the light-sensitive tissue at the back of the eye. In order to get a clear image onto the retina, the portions of the eye in front of the retina, including the lens, must be clear and transparent. Once light reaches the retina, the light initiates a chemical reaction within the retina. The chemical reaction, in turn, initiates an electrical response which is carried to the brain through the optic nerve. The brain then interprets what the eye sees.
In a normal eye, light passes through the transparent lens to the retina. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image striking the retina will be blurry and the vision will be blurry. The extent of the visual disturbance is dependent upon the degree of cloudiness of the lens.
Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans either have some degree of cataract or have already undergone cataract surgery in one or both eyes. By age 95, this percentage increases to almost 100%. A cataract can occur in either or both eyes. Individuals with a cataract in one eye usually go on to develop a cataract in the other eye as well. A cataract is not contagious and cannot spread from one eye to the other or from person to person. Cataracts do not cause the eye to tear abnormally. They are neither painful nor make the eye itchy or red.
Although vision can be restored in most people with cataracts, age-related cataracts are still the most common cause of blindness in the world, primarily because many third-world nations lack appropriate surgical services.
As life span increases in the developed world due to modern technology and new methods of treatment of acute and chronic disease, the incidence of age-related cataracts will continue to increase.
What are the different types of cataracts?
Cataracts can be classified by anatomical location within the lens, degree of clouding of the lens, or by the cause of the cataract.The lens of the human eye is shaped similar to an M&M's candy. It has a front (anterior) part and a back (posterior) part. The central portion of the lens is called the lens nucleus, and the outer portion is called the lens capsule. Between the inner nucleus and the outer capsule is a portion of the lens called the cortex. Clouding of the lens can occur only in the nucleus, in which case the term nuclear cataract or nuclear sclerosis is used. If the clouding occurs in the lens cortex only, the cataract is termed a cortical cataract. If the loss of clarity of the lens is primarily in the capsule, the term subcapsular cataract is used. The location of the clouding can also be defined as being anterior or posterior, central, or peripheral. Often the clouding of the lens may affect multiple portions of the lens. The most common type of cataract that is related to age is sometimes termed a senile cataract. This type of cataract primarily involves the nucleus of the lens. Cataracts that develop in the posterior subcapsular area (in the rear region of the lens capsule) are more common in a younger age group.
Any degree of loss of the normal transparency of the lens is called a cataract. The more cloudy the, lens the more advanced the degree of cataract. A cataract may be mild, moderate, or severe. It may be early or advanced. If the lens is totally opaque it is termed a "mature" cataract. Any cataract that is not opaque is therefore termed an "immature" cataract. Most mature cataracts are white in color.
What are causes of cataracts?
The lens is made of mostly water and protein. The protein is arranged in a specific way that keeps the lens clear and allows light to pass through it to focus a clear image onto the retinal surface. As we age, some of the protein may clump together and start to cloud a small area of the lens. This is our understanding of the cause of an age-related cataract. Over time, the cataract may become more dense or cloud more of the lens, making it more difficult to see through. A cataract is not a growth or tumor.There are many causes of non age-related cataracts or secondary cataracts. Secondary cataracts are a result of similar changes to the protein of the lens, also resulting in visual blurring or visual loss.
Blunt or penetrating injury to the eye may cause secondary cataracts, either immediately after the injury or some weeks to years afterward. A cataract following an injury may appear and then not increase in density (be stationary) or be progressive. Eye surgery for other conditions can also cause cataracts. Excessive exposure to ionizing radiation (X-ray), infrared radiation (as in glass blowers), or ultraviolet radiation cause secondary cataracts.
Diabetes is associated with the development of secondary cataracts. Inflammatory disease of the eye, such as iritis or uveitis, may cause or accelerate the development of cataract in the involved eye.
There are many genetic illnesses that are associated with the development of secondary cataracts. These include myotonic dystrophy, galactosemia, homocystinuria, Wilson's disease and Down syndrome, plus many others. Congenital infections with herpes simplex, rubella, toxoplasmosis, syphilis, and cytomegalic inclusion disease may also result in cataracts.
There are many medications which, when taken over a long period of time, can cause secondary cataracts. The most common of these are oral corticosteroids, such as prednisone, which are used for a wide variety of medical conditions.
The term "congenital cataract" is used when a baby is born with any clouding of the lens. This may be present in one or both eyes, be stationary or be progressive. Causes include genetic disorders or intrauterine developmental disorders, both often associated with other physical abnormalities of the baby.
Atopic dermatitis, other diseases of the skin and mucous membranes, hypothyroidism, and hyperparathyroidism are associated with the early development of cataracts.
Patients who develop cataracts in both eyes at an early age often have family members who have also developed cataracts prematurely, implying a genetic cause, even in the absence of a recognized underlying disease.
How are cataracts diagnosed?
Cataracts are relatively simple to diagnose by an ophthalmologist or an optometrist during a routine eye examination. It is important, when making the diagnosis of cataract, to also examine the entire eye for evidence of any other eye disease which may be compromising the vision. In addition to taking a medical and ocular history and visual acuity test, the ophthalmologist will check eye movements and pupillary responses, measure the pressure inside the eyes and examine the front and back of the eyes after the pupils have been dilated with drops.What is the treatment for cataracts?
People with early cataract will find that changing their glasses, using sunglasses to decrease glare and having better lighting to read can significantly alleviate their symptoms. Magnifying lenses for close work and reading fine print may also be helpful.Many cataracts are not bothersome, causing few symptoms. In that situation, no surgical treatment is necessary. However, the only true treatment for cataract is surgical removal of the cloudy lens. Surgery is suggested if the patient loses the ability to perform necessary activities of everyday life, such as driving, reading, or looking at computer or video screens, even with glasses, and there is the expectation that vision will improve as a result of the surgery.
Depending on a patient's specific visual needs, surgery is sometimes done on cataracts that are not very dense or surgery can wait until the cataract and the vision gets more cloudy. Patients' responses to cataracts vary. A cataract in only one eye may be disturbing to a particular patient and may not cause significant symptoms in another patient.
Cataracts usually do not harm your eye, so you can have surgery when it is convenient for you. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult.
If the eye has other diseases that have caused visual loss such as glaucoma, macular degeneration, diabetic retinopathy, or optic nerve damage from glaucoma, cataract surgery may not improve the vision.
Occasionally, your doctor may recommend removal of a cataract if it prevents diagnosis or treatment of another eye problem, such as macular degeneration or diabetic retinopathy.
If both eyes have cataracts and surgery is agreed upon, the surgery on the second eye is generally planned at least a week after the first eye. There is usually no harm in waiting a much longer period of time between the two eye operations.
Since the lens of the eye is necessary to accurately focus light onto the retinal surface and removal of the cataract involves removal of the lens, modern cataract surgery combines removal of the lens with placement of a new artificial lens into the eye. Measurements for the size, shape, and power of this lens will be taken at least a week prior to the surgery so that the lens can be ordered and available at the time of surgery.
More than 2 million cataract surgeries are performed annually in the United States. It is extremely safe and effective, improving vision in the vast majority of patients.
CANCER:
What is cancer?
Cancer is the uncontrolled growth of abnormal cells anywhere in a body. The abnormal cells are termed cancer cells, malignant cells, or tumor cells. Many cancers and the abnormal cells that compose the cancer tissue are further identified by the name of the tissue that the abnormal cells originated from (for example, breast cancer, lung cancer, colon cancer). Cancer is not confined to humans; animals and other living organisms can get cancer. Below is a schematic that shows normal cell division and how when a cell is damaged or altered without repair to its system, the cell usually dies. Also shown is what can occur when such damaged or unrepaired cells do not die and become cancer cells and proliferate with uncontrolled growth; a mass of cancer cells develop. Frequently, cancer cells can break away from this original mass of cells, travel through the blood and lymph systems, and lodge in other organs where they can again repeat the uncontrolled growth cycle. This process of cancer cells leaving an area and growing in another body area is termed metastatic spread or metastatic disease. For example, if breast cancer cells spread to a bone (or anywhere else), it means that the individual has metastatic breast cancer.There are over 200 types of cancers; most can fit into the following categories according to the National Cancer Institute:
- Carcinoma: Cancer that begins in the skin or in tissues that line or cover internal organs
- Sarcoma: Cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue
- Leukemia: Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood
- Lymphoma and myeloma: Cancers that begin in the cells of the immune system
- Central nervous system cancers: Cancers that begin in the tissues of the brain and spinal cord
| Cancer type | Estimated new cases | Estimated deaths |
| Bladder | 70,530 | 14,680 |
| Breast (female-male) | 207,090-1,970 | 39,840-390 |
| Colon and rectal (combined) | 142,570 | 51,370 |
| Endometrial | 43,470 | 7,950 |
| Kidney (renal cell) | 53,581 | 11,997 |
| Leukemia | 43,050 | 21,840 |
| Lung (including bronchus) | 222,520 | 157,300 |
| Melanoma | 68,130 | 8,700 |
| Non-Hodgkin lymphoma | 65,540 | 20,210 |
| Pancreatic | 43,140 | 36,800 |
| Prostate | 217,730 | 32,050 |
| Thyroid | 44,670 | 1,690 |
- Men: Prostate, lung, and colorectal
- Women: Breast, colorectal, and lung
- Children: Leukemia, brain tumors, and lymphoma
- Cancer is a leading cause of death worldwide. It accounted for 7.4 million deaths (around 13% of all deaths) in 2004 (statistics published in 2009).
- Lung, stomach, liver, colon, and breast cancer cause the most cancer deaths each year.
- Deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030.
The objective of this article is to introduce the reader to general aspects of cancers. It is designed to be an overview of cancer and cannot cover every cancer type. This article will also attempt to help guide the reader to more detailed sources about specific cancer types.
What causes cancer?
Anything that may cause a normal body cell to develop abnormally potentially can cause cancer. Many things can cause cell abnormalities and have been linked to cancer development. Some cancer causes remain unknown while other cancers may develop from more than one known cause. Some may be developmentally influenced by a person's genetic makeup. Many patients develop cancer due to a combination of these factors. Although it is often difficult or impossible to determine the initiating event(s) that cause a cancer to develop in a specific person, research has provided clinicians with a number of likely causes that alone or in concert with other causes, are the likely candidates for initiating cancer. The following is a listing of major causes and is not all-inclusive as specific causes are routinely added as research advances:Chemical or toxic compound exposures: Benzene, asbestos, nickel, cadmium, vinyl chloride, benzidine, N-nitrosamines, tobacco or cigarette smoke (contains at least 66 known potential carcinogenic chemicals and toxins), and aflatoxin
Ionizing radiation: Uranium, radon, ultraviolet rays from sunlight, radiation from alpha, beta, gamma, and X-ray-emitting sources
Pathogens: Human papillomavirus (HPV), EBV or Epstein-Barr virus, hepatitis viruses B and C, Kaposi's sarcoma-associated herpesvirus (KSHV), Merkel cell polyomavirus, Schistosoma spp., and Helicobacter pylori; other bacteria are being researched as possible agents
Genetics: A number of specific cancers have been linked to human genes and are as follows: breast, ovarian, colorectal, prostate, skin and melanoma; the specific genes and other details are beyond the scope of this general article so the reader is referred to http://www.cancer.gov/cancertopics/genetics for more details about genetics and cancer.
It is important to point out that most everyone is exposed to cancer-causing substances (for example, sunlight, cigarette smoke, and X-rays) during their lifetime but many individuals do not develop cancer. In addition, many people have the genes that are linked to cancer but do not develop it. Why? Although researchers may not be able give a satisfactory answer for every individual, it is clear that the higher the amount or level of cancer-causing materials a person is exposed to, the higher the chance the person will develop cancer. In addition, the people with genetic links to cancer may not develop it for similar reasons (lack of enough stimulus to make the genes function). In addition, some people may have a heightened immune response that controls or eliminates cells that are or potentially may become cancer cells. There is evidence that even certain dietary lifestyles may play a significant role in conjunction with the immune system to allow or prevent cancer cell survival. For these reasons, it is difficult to assign a specific cause of cancer to many individuals.
Proving that a substance does not cause or is not related to increased cancer risk is difficult. For example, antiperspirants are considered to possibly be related to breast cancer by some investigators and not by others. The official stance by the NCI is "additional research is needed to investigate this relationship and other factors that may be involved." This unsatisfying conclusion is presented because the data collected so far is contradictive. Other claims that are similar require intense and expensive research which may never be done. Reasonable advice might be to avoid large amounts of any compounds even remotely linked to cancer, although it may be difficult to do in complex, technologically advanced modern societies.
What is the treatment for cancer?
The treatment for cancer is usually designed by a team of doctors or by the patient's oncologist and is based on the type of cancer and the stage of the cancer. Most treatments are designed specifically for each individual. In some people, diagnosis and treatment may occur at the same time if the cancer is entirely surgically removed when the surgeon removes the tissue for biopsy.Although patients may obtain a unique treatment protocol for their cancer, most treatments have one or more of the following components: surgery, chemotherapy, radiation therapy, or combination treatments (a combination of two or all three treatments).
Individuals obtain variations of these treatments for cancer. Patients with cancers that cannot be cured (completely removed) by surgery usually will get combination therapy, the composition determined by the cancer type and stage.
Palliative therapy (medical care or treatment used to reduce disease symptoms but unable to cure the patient) utilizes the same treatments described above. It is done with the intent to extend and improve the quality of life of the terminally ill cancer patient. There are many other palliative treatments to reduce symptoms such as pain medications and antinausea medications.
What is the prognosis for cancer?
The prognosis (outcome) for cancer patients may range from excellent to poor. The prognosis is directly related to both the type and stage of the cancer. For example, many skin cancers can be completely cured by removing the skin cancer tissue; similarly, even a patient with a large tumor may be cured after surgery and other treatments like chemotherapy (note that a cure is often defined by many clinicians as a five-year period with no reoccurrence of the cancer). However, as the cancer type either is or becomes aggressive, with spread to lymph nodes or is metastatic to other organs, the prognosis decreases. For example, cancers that have higher numbers in their staging (for example, stage III or T3N2M1; see staging section above) have a worse prognosis than those with low (or 0) numbers. As the staging numbers increase, the prognosis worsens.There are many complications that may occur with cancer; many are specific to the cancer type and stage and are too numerous to list here. However, some general complications that may occur with both cancer and its treatment protocols are listed below:
- Fatigue (both cancer and treatments)
- Anemia (both)
- Loss of appetite (both)
- Insomnia (both)
- Hair loss (treatments mainly)
- Nausea (both)
- Lymphedema (both)
- Pain (both)
- Immune system depression (both)
HEMOPHILIA:
What is hemophilia?
Hemophilia is not one disease but rather one of a group of inherited bleeding disorders that cause abnormal or exaggerated bleeding and poor blood clotting. The term is most commonly used to refer to two specific conditions known as hemophilia A and hemophilia B, which will be the main subjects of this article. Hemophilia A and B are distinguished by the specific gene that is mutated (altered to become defective) and codes for a defective clotting factor (protein) in each disease. Rarely, hemophilia C is encountered, but its effect on clotting is far less pronounced than A or B.Hemophilia A and B are inherited in an X-linked recessive genetic pattern and are therefore much more common in males. This pattern of inheritance means that a given gene on the X chromosome expresses itself only when there is no normal gene present. For example, a boy has only one X chromosome, so a boy with hemophilia has the defective gene on his sole X chromosome (and so is said to be hemizygous for hemophilia). Hemophilia is the most common X-linked genetic disease.
Although it is much rarer, a girl can have hemophilia, but she would have to have the defective gene on both of her X chromosomes or have one hemophilia gene plus a lost or defective copy of the second X chromosome that should be carrying the normal genes. If a girl has one copy of the defective gene on one of her X chromosomes and a normal second X chromosome, she does not have hemophilia but is said to be heterozygous for hemophilia (a carrier). Her male children have a 50% chance of inheriting the one mutated X gene and thus has a 50% chance of inheriting hemophilia from their carrier mother.
Hemophilia A occurs in about 1 out of every 5000 live male births. Hemoplilia A and B occurs in all racial groups. Hemophilia A is about four times more common than B; B occurs in about 1 out of 20- 34,000 live male births.
Hemophilia has been called the Royal Disease because Queen Victoria, Queen of England from 1837 to 1901, was a carrier. Her daughters passed the mutated gene on to members of the royal families of Germany, Spain, and Russia. Alexandra, Queen Victoria's granddaughter, who became Tsarina of Russia in the early 20th century when she married Tsar Nicholas II, was a carrier. Their son, the Tsarevich Alexei, suffered from hemophilia.
What causes hemophilia?
As mentioned above, hemophilia is caused by a genetic mutation. The mutations involve genes that code for proteins that are essential in the blood clotting process. The bleeding symptoms arise because blood clotting is impaired.The process of blood clotting involves a series of complex mechanisms, usually involving 13 different proteins classically termed I through XIII and written with Roman numerals. If the lining of the blood vessels becomes damaged, platelets are recruited to the injured area to form an initial plug. These activated platelets release chemicals that start the clotting cascade, activating a series of 13 proteins known as clotting factors. Ultimately, fibrin is formed, the protein that crosslinks with itself to form a mesh that makes up the final blood clot. The protein involved with hemophilia A is factor VIII (factor 8) and with hemophilia B is factor IX (factor 9).
A condition referred to as hemophilia C involves a deficiency of clotting factor XI. This condition is much rarer than hemophilia A and B and typically leads to mild symptoms. It is also not inherited in an X-linked manner and affects persons of both sexes.
Hemophilia A is more common than hemophilia B. About 80% of people with hemophilia have hemophilia A. Hemophilia B occurs in about 1 out of every 25,000 to 30,000 people. A subgroup of those with hemophilia B has the so-called Leyden phenotype, which is characterized by a severe hemophilia in childhood that improves at puberty.
What are treatments for hemophilia?
The mainstay of treatment is replacement of the blood clotting factors. Clotting factor concentrates can be purified from human donor blood or made in the laboratory using methods that do not use donor blood. This type of therapy is known as replacement therapy. Clotting factor replacement therapy is carried out by infusing the clotting factor concentrates into a vein, much like a blood transfusion. This type of therapy can be administered at home with proper instruction and training.Depending upon the severity of the condition, replacement therapy may be carried out on an as-needed basis (called demand therapy) or on a regular basis to prevent bleeding episodes (known as prophylactic therapy).
People who have mild cases of hemophilia A are sometimes treated with the drug desmopressin, also known as DDAVP. This drug stimulates release of more clotting factor by the body. It is administered either slowly through the intravenous route (IV) or occasionally, in nasal spray form.
Pain relievers may be prescribed for symptom relief, but pain relievers other than aspirin or non-steroidal anti-inflammatory medications (such as naproxen, ibuprofen) must be used, since these types of drugs further inhibit the blood's ability to clot. Acetaminophen (Tylenol and others) is often given for pain relief.
What are complications of treatment?
Inhibitors
A major complication of treatment is the development of so-called inhibitors to the clotting factors. Inhibitors (antibodies) are produced because the body sees the factor concentrates used to treat patients to reduce or prevent bleeding, as foreign and activates an immune response in the patient to destroy the foreign substances (factor VIII or factor IX).Inhibitors to factor VIII are the most common and occur in about one-third of those with severe hemophilia A and about 1 out of every 50 people with mild or moderate hemophilia A. They typically develop in childhood in those with severe hemophilia A and later in life in milder cases. Inhibitors destroy both the replacement factor VIII concentrates as well as any factor VIII that is present in the body. This is a serious complication of treatment because the factor concentrates are no longer effective in treating the condition. The action of inhibitors to destroy factor VIII concentrates shows different degrees of severity among individuals and can even vary over time in the same individual.
In about two-thirds of cases, the inhibitors disappear on their own or with treatment known as immune tolerance therapy (ITT) or immune tolerance induction (ITI). In cases of severe hemophilia A with persistence of inhibitors, other factor concentrates, such as activated prothrombin complex concentrate or recombinant factor VIIa, are administered to attempt to help control bleeding.
The development of inhibitors to factor IX is much less common and occurs in about 1% of those with hemophilia B. However, these can cause a very serious allergic reaction when factor IX concentrates are given. Immune tolerance therapy to eliminate inhibitors is less successful than with hemophilia A.
