Delirium

Delirium, condition common in many illnesses in which the sufferer is temporarily disoriented and incoherent and may have hallucinations and delusions. Any disease causing high fever may bring on delirium. In severe cases, the victim may be maniacal and require physical restraint. Delirium is a symptom rather than a disease, and hence is not treated by any specific measures other than those used to combat the causative disease and to reduce the patient's fever. Delirium may be due to causes other than high fever, such as exhaustion from nutritional disturbance, unusual excitement, psychosensory impairment, severe head injury, and drug addiction. See Delirium Tremens.

Deafness

Deafness, most simply defined as an inability to hear. This definition, however, gives no real impression of how deafness affects function in society for the hearing-impaired person. .

Four types of hearing loss may be described. The first, conductive hearing loss, is caused by diseases or obstruction in the outer or middle ear and usually is not severe. A person with a conductive hearing loss generally can be helped by a hearing aid. Often conductive hearing losses can also be corrected through surgical or medical treatment. The second kind of deafness, sensorineural hearing loss, results from damage to the sensory hair cells or the nerves of the inner ear and can range in severity from mild to profound deafness. Such loss occurs in certain sound frequencies more than in others, resulting in distorted sound perceptions even when the sound level is amplified. A hearing aid may not help a person with a sensorineural loss. The third kind, mixed hearing loss, is caused by problems in both the outer or middle ear and the inner ear. Finally, central hearing loss is the result of damage to or impairment of the nerves or nuclei of the central nervous system.

Deafness in general can be caused by illness or accident, or it may be inherited (see Ear: Diseases of the Ear). Continuous or frequent exposure to noise levels above 85 dB (see Sound) can cause a progressive and eventually severe sensorineural hearing loss.

Cystitis

Cystitis, in medicine, inflammation of the urinary bladder, usually from bacterial infection originating in the urethra, vagina, or, in more complicated cases, the kidneys (see Urinary System). Cystitis may also be caused by irritation from crystalline deposits in the urine or from any condition or urologic abnormality that interferes with normal bladder function. Symptoms include painful or difficult urination, urinary urgency, and, in some cases, cloudy or bloody urine. Treatment is primarily with antibiotics.

Croup

Croup, disease of the respiratory tract characterized by a harsh, barking cough and difficulty in breathing. Recurrent croup may be due to allergy; usually each episode clears spontaneously. Croup with sudden onset may be due to infection of the epiglottis by bacteria. This condition, called epiglottitis, occurs most often in children of age two to five years and must be treated by a physician. Croup may also be caused by virus infection of the lower part of the trachea. This illness is often preceded by signs of respiratory infection and more often occurs between the ages of six months and three years. Usually viral croup will respond to inhalation of warm, moist air. A crouplike cough may also signal the presence of a foreign body in the airway.

Cystic Fibrosis

Cystic Fibrosis is incurable hereditary disorder that causes the body to secrete an abnormally thick, sticky mucus that clogs the pancreas and the lungs, leading to problems with breathing and digestion, infection, and ultimately, death. Three decades ago most babies born with cystic fibrosis died in early childhood, but advances in diagnosing and treating the disease have significantly improved its prognosis.

Cystic fibrosis is caused by a defect in the gene responsible for manufacturing cystic fibrosis transmembrane conductance regulator (CFTR), a protein that controls the flow of chloride ions into and out of certain cells. In healthy people, CFTR forms a channel in the plasma membrane through which chloride ions enter and leave the cells lining the lungs, pancreas, sweat glands, and small intestine. In people with cystic fibrosis, malfunctioning (or absent) CFTR prevents chloride from entering or leaving cells, resulting in production of a thick, sticky mucus that clogs ducts or tubes in these organs. In the lungs, this mucus blocks airways and impedes natural infection-fighting mechanisms, eventually turning the body’s immune system against its own lung tissue. Similar blockage prevents crucial digestive enzymes produced in the pancreas from reaching the intestines, impairing the ability to break down certain foods. In healthy people most of the chloride in sweat is reabsorbed, but in people with cystic fibrosis, sweat glands cannot take up chloride ions, enabling excessive amounts of salt to escape in the sweat.

Depending on the disease’s severity, symptoms may be apparent soon after birth, or they may escape detection for months or years. In nearly 20 percent of all cases, the first symptom is meconium ileus, intestinal blockage in newborns. In other babies, the first evidence of cystic fibrosis is bulky stool, poor weight gain, flabby muscle tone, or slow growth, all products of low levels of digestive enzymes in the intestines.

The earlier a diagnosis is made the better so that early treatment can slow the progression of lung damage caused by infection. Prenatal tests are available to determine if a baby will be born with cystic fibrosis. In newborns, blood tests indicating high levels of digestive enzymes suggest cystic fibrosis, but a certain diagnosis requires a sweat test to determine the amount of salt in the sweat. Sweat tests provide a valid diagnosis in babies over 24 hours old, and this test is also used to confirm diagnosis in older children and adults.

Cystic fibrosis remains incurable; existing treatments aim to relieve discomfort and delay the devastating and inevitable effects of the disease. Meconium ileus, the intestinal obstruction occurring in newborns, may require surgery. Patients with pancreatic blockage must take pancreatic enzymes with meals. Even with such enzymes, people with cystic fibrosis must consume adequate amounts of protein, vitamins, and higher-than-normal amounts of fat to ensure growth. Those with respiratory infections are treated with antibiotics, often in aerosol form. When inhaled, these medicated vapors fight infection and relieve constriction of the airways. Using a procedure called chest physical therapy or postural drainage, caregivers of people with cystic fibrosis repeatedly and vigorously pound on the patient’s back and chest to dislodge mucus obstructing the airways. Increasingly, cystic fibrosis patients with severe, irreparable lung damage turn to lung transplantation surgery (see Medical Transplantation).