What aspects of autism are being studied?
The NINDS is the Federal Government's leading supporter of biomedical research on brain and nervous system disorders, including autism. The NINDS conducts research in its laboratories at the National Institutes of Health, in Bethesda, Maryland, and supports research at other institutions through grants.
NINDS-supported research includes studies aimed at identifying the underlying brain abnormalities of autism through new methods of brain imaging and other innovative techniques. Some scientists hope to identify genes that increase the risk of autism. Others are studying specific aspects of behavior, information processing, and other characteristics to learn precisely how children with autism differ from other people and how these characteristics change over time. The findings may lead to improved strategies for early diagnosis and intervention. Related studies are examining how the cerebellum develops and processes information, how different brain regions function in relation to each other, and how alterations in this relationship during development may result in the signs and symptoms of autism. Researchers hope this research will provide new clues about how autism develops and how brain abnormalities affect behavior.
Chickenpox
Chickenpox is a very common and highly contagious disease. Although the symptoms can be annoying and uncomfortable and limit normal activities, the disease is usually mild and rarely serious. In otherwise healthy children, chickenpox lasts two weeks or less and does not cause complications. In adults, newborn babies, and children with weakened immune systems, however, it can be a serious, long-lasting disease.
Chickenpox is caused by a type of herpesvirus called varicella-zoster virus (VZV). After the initial chickenpox infection, VZV hides in nerve cells and is sometimes reactivated later in life. This reactivated, often very painful, disease is called herpes zoster or shingles. Researchers are trying to learn what causes the virus to become active again after being dormant for many years.
Chickenpox epidemics can occur anytime of the year, but are most common in late winter and early spring. Doctors estimate that each year 3.5 to 4 million people, mostly children, get chickenpox. Ninety percent of cases are in people under 15 years of age. The U.S. Centers for Disease Control and Prevention (CDC) reports that there are approximately 100 deaths and 9,300 hospitalizations due to the complications of chickenpox each year. A vaccine to prevent chickenpox became available in 1995. The numbers of cases should decline as more people get immunized with this vaccine.
Symptoms and Diagnosis
The most common signs and symptoms of chickenpox include a rash, fever, tiredness, and loss of appetite. The fever begins a day or two before the rash in about half of patients and is usually less than 101.5�F, but may be as high as 106�F. The rash consists of many (usually less than 300) fluid-filled vesicles surrounded by red sores. Although the rash can involve the entire body, it typically is found on the back, chest, face, and abdomen. The effects of the rash may be mild and barely noticeable or severe and accompanied by intense itching. As the disease spreads from child to child within a family, the intensity and extent of the rash may increase.
A doctor can easily diagnose chickenpox by examining the characteristic rash, with healed and unhealed sores on the body, and by noting the presence of other symptoms mentioned above.
Transmission
It is virtually impossible for a susceptible person to avoid getting chickenpox. It is highly contagious and spreads quickly in settings like day-care facilities and schools and within families. The virus is transmitted by direct contact with the rash on an infected person or by droplets dispersed into the air by coughing or sneezing.
The time between exposure to the virus and the development of symptoms is usually about two weeks, but can range from 10 to 21 days. A person can transmit the disease for up to 48 hours before the telltale rash of chickenpox appears. The period of transmission lasts for four to five days after the rash begins until the sores have crusted over. Therefore, staying away from someone only after they have visible signs of chickenpox is probably too late to prevent transmission.
Rarely, a susceptible person can get chickenpox from someone who has a reactivated VZV infection (shingles).
Treatment
Unless the infection is severe, children with chickenpox usually are not treated.
Scratching can make the lesions harder to heal, cause scarring and increase the risk of bacterial skin infections. The doctor may recommend anti-itch drugs, such as over-the-counter antihistamines, to control this troublesome symptom. Warm baths with uncooked oatmeal or cornstarch added also can help relieve the itching. Fingernails should be kept clean and cut short.
Fever can be reduced with acetaminophen. Aspirin should not be taken by anyone with chickenpox because it can lead to a serious disease called Reye's syndrome. Cool baths also can help bring down a fever.
Acyclovir (Zovirax(r)) is an antiviral drug that attacks the virus. When treatment is started very soon after the first sores appear, it shortens the duration of rash formation by about one day and reduces the number of new sores. The American Academy of Pediatrics recommends it for use in premature babies, adolescents, adults, and other high-risk populations.
Complications
Because chickenpox most often is an uncomplicated infection, it ordinarily does not require a visit to the doctor.
It is wise, however, to visit a doctor if symptoms other than the rash, low fever, and fatigue are present. Symptoms that require immediate medical attention are fever of more than 103�F, dizziness, rapid heartbeat, shortness of breath, tremors, loss of muscle coordination, vomiting, and/or stiff neck.
If the lesions become infected with bacteria such as staphylococcus or streptococcus, a doctor can prescribe an appropriate antibiotic.
In children and adults whose immune systems are impaired by disease or suppressed by drugs (including steroids), chickenpox can affect internal organs. Also, people with impaired immune systems are more likely to develop bacterial skin infections, and their sores take longer to heal. In children with leukemia, chickenpox can be life-threatening.
Infrequently, chickenpox can cause central nervous system complications of which the most serious is encephalitis (inflammation of the brain). Encephalitis can be life-threatening in adults and usually lasts for a minimum of two weeks. Of those patients who survive, 15 percent continue to have neurologic symptoms after the initial infection has cleared. Other nervous system complications include meningitis and Reye's syndrome.
Another serious complication, which occurs mainly in adults, is varicella pneumonitis (inflammation of the lungs). This complication can be life-threatening to women during the second or third trimester of pregnancy.
If a pregnant woman develops chickenpox five days before or up to 48 hours after delivery, the baby can be born with complications from the infection. Serious disease in the newborn, however, is uncommon. A pregnant woman who is not immune to chickenpox and has a prolonged exposure to a person with the disease should consult with her physician about the risk to herself and her unborn child.
Prevention
The use of varicella vaccine (Varivax(r)) is the best way to prevent chickenpox. According to CDC, the vaccine protects about 70 to 90 percent of people who receive it. CDC's Advisory Committee on Immunization Practices recommends that a single dose of the vaccine be given routinely to children ages 12 months to 12 years old who have not had chickenpox and who have not been vaccinated. It also recommends that persons older than 13 years of age who have not had chickenpox receive two injections of the vaccine, especially those in high-risk groups such as:
· Teachers of young children, day care employees and residents and staff in institutional settings.
· College students and military personnel.
· Nonpregnant women of childbearing age.
· Family and health care workers who have not had chickenpox and who are in close contact with persons who may suffer serious complications if infected with chickenpox.
· International travelers, especially if they expect to have close contact with local populations.
Consult your doctor for more information about varicella vaccine.
A question remains about how long the vaccine's protection will last. Recent studies show that protection should last at least ten years, but it is still not known if a booster will be needed later in life.
McCune-Albright Syndrome
Introduction
The McCune-Albright syndrome is named for the two physicians who described it over 50 years ago. They reported a group of children, most of them girls, with an unusual pattern of associated abnormalities: bone disease, with fractures, asymmetry and deformity of the legs, arms, and skull; endocrine disease, including early puberty with menstrual bleeding, development of breasts and pubic hair and an increased rate of growth; and skin changes, with areas of increased pigment distributed in an asymmetric and irregular pattern. Today, the term "McCune-Albright syndrome" is used to describe patients who have some or all of these bone, endocrine, and skin abnormalities. In the years since it was first identified, however, researchers have studied many additional patients, and have learned that the condition has a broad spectrum of severity. Sometimes, children are diagnosed in early infancy with obvious bone disease and markedly increased endocrine secretions from several glands; a very few of these severely affected children have died. At the opposite end of the spectrum, many children are entirely healthy, and have little or no outward evidence of bone or endocrine involvement. They may enter puberty close to the normal age, and have no unusual skin pigment at all. Because of this marked variability among patients, the components of this complicated syndrome are described separately below.
Endocrine Abnormalities
Precocious Puberty
When the signs of puberty (development of breasts, testes, pubic and underarm hair, body odor, menstrual bleeding, and increased growth rate) appear before the age of 8 years in a girl or 9 1/2 years in a boy, it is termed "precocious puberty." In the most common form of precocious puberty, there is early activation of the regions in the brain which control the maturation of the gonads (ovaries in a girl and testes in a boy). One brain center, the hypothalamus, secretes a substance called gonadotropin-releasing-hormone or "GnRH." This acts, in turn, on another part of the brain, the pituitary gland, to cause increased secretion of hormones called "gonadotropins" (LH and FSH) that travel through the bloodstream, and act on the ovaries or testes to stimulate secretion of estrogen or testosterone. Endocrinologists determine if a child with precocious puberty has early activation of the hypothalamus and pituitary by measuring the levels of LH and FSH in the blood after an injection of a synthetic preparation of GnRH.
After studying many girls with McCune-Albright syndrome, however, researchers have learned that most do not appear to have early activation of the hypothalamus and pituitary, because the levels of LH and FSH are usually low, or similar to those of prepubertal children. The precocious puberty in McCune-Albright girls is caused by estrogens which are secreted into the bloodstream by ovarian cysts, which enlarge, and then decrease in size over periods of weeks to days. The cysts can be visualized and measured by ultrasonography, in which sound waves are used to outline the dimensions of the ovaries. The cysts may become quite big, occasionally over 50 cc in volume (about the size of a golf ball). Frequently, menstrual bleeding and breast enlargement accompany the growth of a cyst. In fact, menstrual bleeding under 2 years of age has been the first symptom of McCune-Albright syndrome in 85 percent of patients. Although ovarian cysts and irregular menstrual bleeding may continue into adolescence and adulthood, many adult women with McCune-Albright syndrome are fertile, and can bear normal children.
The precocious puberty in McCune-Albright syndrome has been difficult to treat. After surgical removal of the cyst or of the entire affected ovary, cysts usually recur in the remaining ovary. A progesterone-like hormone called Provera can be given to suppress the menstrual bleeding, but does not appear to slow the rapid rates of growth and bone development, and may have unwanted effects on adrenal functioning. The synthetic forms of GnRH (Deslorelin, Histerelin, and Lupron) which suppress LH and FSH, and are used to treat the common, gonadotropin-dependent form of precocious puberty, are not effective in most girls with McCune-Albright syndrome. An investigational form of treatment, using oral medications which block estrogen synthesis, (testolactone and fadrozole) is now being tested in girls with McCune-Albright syndrome, and has been beneficial in many patients.
Thyroid Function
Almost 50 percent of patients with McCune-Albright syndrome have thyroid gland abnormalities; these include generalized enlargement called goiter, and irregular masses called nodules and cysts. Some patients have subtle structural changes detected only by ultrasonography. Pituitary thyroid-stimulating-hormone (TSH) levels are low in these patients, and thyroid hormone levels may be normal or elevated. Therapy with drugs which block thyroid hormone synthesis (Propylthiouracil or Methimazole), can be given if thyroid hormone levels are excessively high.
Growth Hormone
Excessive secretion of pituitary growth hormone has been seen in a few patients with McCune-Albright syndrome. Most of these have been diagnosed as young adults, when they developed the coarsening of facial features, enlargement of hands and feet, and arthritis characteristic of the condition termed "acromegaly." Therapy has included surgical removal of the area of the pituitary which is secreting the hormone, and use of new, synthetic analogs of the hormone somatostatin, which suppress growth hormone secretion.