Diseases of Human Ear

Some diseases of the ear can cause partial or total deafness. In addition, most diseases of the inner ear are associated with a disturbance of balance. Ear problems should be evaluated by specially trained physicians called otolaryngologists, who treat conditions ranging from eardrum injuries caused by physical trauma to bony deposits in the inner ear caused by the aging process.

The auricle and the opening into the outer auditory canal may be missing at birth. Acquired malformations of the outer ear include scarring from cuts and other wounds. Othematoma, known popularly as cauliflower ear, is a common result of injury to the ear cartilage followed by internal bleeding and excessive production of ear tissue.

Inflammation of the outer ear may result from any condition that causes inflammation of the skin, such as dermatitis, burns, and frostbite. Erysipelas, a skin disease caused by bacteria, and seborrhea, a skin disease caused by the malfunction of the skin’s oil glands, are common afflictions of the auricle. In the outer auditory canal, foreign bodies such as insects, as well as abnormal buildups of cerumen, cause ear disturbances and should be removed by a physician.

See also Middle Ear Disorders; Inner Ear Diseases

Down Syndrome

Down Syndrome is a chromosomal disorder that results in mild to severe learning disabilities and physical symptoms that include a small skull, extra folds of skin under the eyes, and a flattened nose bridge. Muscle tone throughout the body is usually low. The condition was formerly known as “mongolism” because the features of people with Down syndrome were thought to resemble those of Mongolian Asians. This term is now considered offensive and inappropriate and is no longer used.

Two other chromosomal abnormalities cause Down syndrome and occur in about 2 to 3 percent of all cases. The first, translocation, takes place when a child inherits a small, extra piece of the 21st chromosome that is attached to another chromosome. If, in addition to the translocation, two normal 21st chromosomes are also present, the person will have some of the features of Down syndrome. If there is only one normal 21st chromosome, the person will not display symptoms but the children may inherit Down syndrome. Mosaic Down syndrome results from a second type of chromosomal abnormality in which only some cells in the body have an extra chromosome.

There is no cure for Down syndrome. However, prenatal tests are available to identify fetuses with the disorder. Gynecologists recommends that the so-called triple-screen blood test be offered to all pregnant women. This test measures the levels of three chemicals in the blood of the pregnant woman to indicate the baby's risk of Down syndrome. If the risk is high, amniocentesis, a procedure for removing a sample of the amniotic fluid surrounding the fetus, is administered to confirm the findings from the blood tests. Fetal cells are present in the amniotic fluid and can be checked for the presence of the chromosomal disorder.

Diphtheria

Diphtheria, an acute and highly infectious disease, affecting children particularly, characterized by the formation of a false membrane in the passages of the upper respiratory system. The cause of the disease is Corynebacterium diphtheria, a bacillus discovered in 1883.

The diphtheria bacilli enter the body through the mouth and nose and attack the mucous membranes, where they multiply and secrete a powerful toxin. The toxin damages the heart and central nervous system, and can lead to death. Beginning about five days after exposure to diphtheria, a gray-white exudate is formed where the bacteria attack the walls of the nose and throat. This exudate increases in size and thickness, becoming a grayish false membrane, and it may block the air passages. Surgery may be necessary to prevent asphyxiation.

The universal use of antitoxin in treatment has cut the mortality rate to approximately 5 percent. Even more effective has been the development of harmless forms of diphtheria toxin, called toxoids. Given to infants during the first year of life as part of a combined injection, these toxoids immunize the children against serious infection and have drastically reduced the incidence of diphtheria.

The Schick test, used to determine whether an individual is immune or susceptible to diphtheria, was developed by the Hungarian-American pediatrician Béla Schick in 1913.

Diabetes Mellitus

Diabetes Mellitus, disease in which the pancreas produces little or no insulin, a hormone that helps the body’s tissues absorb glucose (sugar) so it can be used as a source of energy. The condition may also develop if muscle, fat, and liver cells respond poorly to insulin. In people with diabetes, glucose levels build up in the blood and urine, causing excessive urination, thirst, hunger, and problems with fat and protein metabolism. Diabetes mellitus differs from the less common diabetes insipidus, which is caused by lack of the hormone vasopressin that controls the amount of urine secreted.

Diabetes is classified into two types. In Type 1 diabetes, formerly called insulin-dependent diabetes mellitus (IDDM) and juvenile-onset diabetes, the body does not produce insulin or produces it only in very small quantities. Symptoms usually appear suddenly, typically in individuals under 20 years of age. Most cases occur around puberty—around age 10 to 12 in girls and age 12 to 14 in boys.

Type 1 diabetes is considered an autoimmune disease because the immune system (system of organs, tissues, and cells that rid the body of disease-causing organisms or substances) attacks and destroys insulin-producing cells, known as beta cells, in the pancreas.

In Type 2 diabetes, formerly known as non-insulin-dependent diabetes mellitus (NIDDM) and adult-onset diabetes, the body’s delicate balance between insulin production and the ability of cells to use insulin goes awry. Symptoms characteristic of Type 2 diabetes include those found in Type 1 diabetes, as well as repeated infections or skin sores that heal slowly or not at all, generalized tiredness, and tingling or numbness in the hands or feet.

Diabetes Insipidus

Diabetes Insipidus, rare disease caused by deficiency of vasopressin, one of the hormones of the posterior pituitary gland, which controls the amount of urine secreted by the kidneys. The symptoms of diabetes insipidus are marked thirst and the excretion of large quantities of urine, as much as 4 to 10 liters a day. This urine has a low specific gravity and contains no excess sugar. In many cases, injection or nasal inhalation of vasopressin controls the symptoms of the disease.