Definition Emergency contraception Definition Emergency contraception or emergency birth control uses either emergency contraceptive pills (ECPs) or a Copper-T intrauterine device (IUD) to help prevent pregnancy following unprotected vaginal intercourse. Purpose Emergency contraception may be used to prevent pregnancy after vaginal intercourse when:  A birth control method was not used. Young people, in particular,...

Definition An embolism is an obstruction in a blood vessel due to a blood clot or other foreign matter that gets stuck while traveling through the bloodstream. The plural of embolism is emboli. Description Emboli have moved from the place where they were formed through the bloodstream to another part of the body, where they obstruct an artery and block the flow of blood. The emboli are usually formed from...

Definition The word elephantiasis is a vivid and accurate term for the syndrome it describes: the gross (visible) enlargement of the arms, legs, or genitals to elephantoid size. Description True elephantiasis is the result of a parasitic infection caused by three specific kinds of round worms. The long, threadlike worms block the body’s lymphatic system–a network of channels, lymph nodes, and organs...

Definition An electrophysiology (EP) study of the heart is a nonsurgical analysis of the electrical conduction system (normal or abnormal) of the heart. The test employs cardiac catheters and sophisticated computers to generate electrocardiogram (EKG) tracings and electrical measurements with exquisite precision from within the heart chambers. The EP study can be performed solely for diagnostic purposes....

Definition Electronic fetal monitoring (EFM) is a method for examining the condition of a baby in the uterus by noting any unusual changes in its heart rate. Electronic fetal monitoring is performed late in pregnancy or continuously during labor to ensure normal delivery of a healthy baby. EFM can be utilized either externally or internally in the womb. Electronic fetal monitoring (EFM) is performed late in...

Definition Electromyography (EMG) is an electrical recording of muscle activity that aids in the diagnosis of neuromuscular disease. Purpose Muscles are stimulated by signals from nerve cells called motor neurons. This stimulation causes electrical activity in the muscle, which in turn causes contraction. This electrical activity is detected by a needle electrode inserted into the muscle and connected...

Definition Electrolytes are positively and negatively charged molecules, called ions, that are found within cells, between cells, in the bloodstream, and in other fluids throughout the body. Electrolytes with a positive charge include sodium, potassium, calcium, and magnesium; the negative ions are chloride, bicarbonate, and phosphate. The concentrations of these ions in the bloodstream remain fairly constant...

Definition Electrolyte supplements are a varied group of prescription and nonprescription preparations used to correct imbalances in the body’s electrolyte levels. Electrolytes themselves are substances that dissociate into ions (electrically charged atoms or atom groups) when they melt or are dissolved, thus serving to conduct electricity. In the human body, electrolytes are thus critical to the proper...

Definition An electrolyte disorder is an imbalance of certain ionized salts (i.e., bicarbonate, calcium, chloride, magnesium, phosphate, potassium, and sodium) in the blood. Description Electrolytes are ionized molecules found throughout the blood, tissues, and cells of the body. These molecules, which are either positive (cations) or negative (anions), conduct an electric current and help to balance pH and...

Definition Electroencephalography, or EEG, is a neurological test that uses an electronic monitoring device to measure and record electrical activity in the brain.       This woman is undergoing an electroencephalogram (EEG) to diagnose Alzheimer’s disease. On the computer screen at the right are the colored scans of the electrical activity in her brain. Alzheimer’s patients show...

Definition Electroconvulsive therapy (ECT) is a medical treatment for severe mental illness in which a small, carefully controlled amount of electricity is introduced into the brain. This electrical stimulation, used in conjunction with anesthesia and muscle relaxant medications, produces a mild generalized seizure or convulsion.While used to treat a variety of psychiatric disorders, it is most effective...

Definition Electrocardiography is a commonly used, noninvasive procedure for recording electrical changes in the heart. The record, which is called an electrocardiogram (ECG or EKG), shows the series of waves that relate to the electrical impulses which occur during each beat of the heart. The results are printed on paper or displayed on a monitor. The waves in a normal record are named P, Q, R, S, and T and...

Definition Electrical stimulation of the brain (ESB) is a relatively new technique used to treat chronic pain and tremors associated with Parkinson disease. ESB is administered by passing an electrical current through an electrode implanted in the brain. Purpose While the implantation of electrodes in the brain is used to treat or diagnose several disorders, the term ESB is limited here to the treatment of...

Definition Electrical nerve stimulation, also called transcutaneous electrical nerve stimulation (TENS), is a noninvasive, drug-free pain management technique. By sending electrical signals to underlying nerves, the battery-powered TENS device can relieve a wide range of chronic and acute pain. Purpose TENS is used to relieve pain caused by a variety of chronic conditions, including:  neck and lower...

Definition Electric shock injuries are caused by lightning or electric current from a mechanical source passing through the body. Description Electric shocks are responsible for about 1,000 deaths in the United States each year, or about 1% of all accidental deaths. Causes and symptoms The severity of injury depends on the current’s pressure (voltage), the amount of current (amperage), the type of current...

Definition  Elder abuse is a general term used to describe harmful acts toward an elderly adult, such as physical abuse, sexual abuse, emotional or psychological abuse, financial exploitation, and neglect, including self-neglect. Description  Results from the National Elder Abuse Incidence Study, funded in part by the Administration on Aging, suggest that over 500,000 people 60 years of age and older...

Definition Ehrlichiosis is a bacterial infection that is spread by ticks. Symptoms include fever, chills, headache, muscle aches, and tiredness. Description Ehrlichiosis is a tick-borne disease caused by infection with Ehrlichia bacteria. Ticks are small, blood-sucking arachnids. Although some ticks carry disease-causing organisms, most do not. When an animal or person is bitten by a tick that carries bacteria,...

Definition The Ehlers-Danlos syndromes (EDS) refer to a group of inherited disorders that affect collagen structure and function. Genetic abnormalities in the manufacturing of collagen within the body affect connective tissues, causing them to be abnormally weak.     Description Collagen is a strong, fibrous protein that lends strength and elasticity to connective tissues such as the skin, tendons,...

Definition Edwards’ syndrome is caused by an extra copy of chromosome 18. For this reason, it is also called trisomy 18 syndrome. The extra chromosome is lethal for most babies born with this condition. It causes major physical abnormalities and severe mental retardation, and very few children afflicted with this disease survive beyond a year. Description Humans normally have 23 pairs of chromosomes....

Definition Echocardiography is a diagnostic test that uses ultrasound waves to create an image of the heart muscle. Ultrasound waves that rebound or echo off the heart can show the size, shape, and movement of the heart’s valves and chambers as well as the flow of blood through the heart. Echocardiography may show such abnormalities as poorly functioning heart valves or damage to the heart tissue from...

Definition Echinococcosis (Hydatid disease) refers to human infection by the immature (larval) form of tapeworm, Echinococcus. One of three forms of the Echinococcus spp., E. granulosus, lives on dogs and livestock, and infects humans through contact with these animals. Allergic reactions and damage to various organs from cyst formation are the most common forms of disease in humans. Infection with the larva...

Definition Echinacea, or purple coneflower, is a perennial herb of the Composite family, commonly known as the daisy family. Most often referred to as the purple coneflower, this hardy plant also known as Sampson root, Missouri snakeroot, and rudbeckia. The prominent, bristly seed head inspired the generic name of the plant, taken from the Greek word echinos meaning hedgehog.         Description Echinacea...

Definition Ear surgery is the treatment of diseases, injuries, or deformations of the ear by operation with instruments. Purpose Ear surgery is performed to correct certain types of hearing loss, and to treat diseases of, injuries to, or deformities of the ear’s auditory tube, middle ear, inner ear, and auditory and vestibular systems. Ear surgery is commonly performed to treat conductive hearing loss,...

Definition An otoscope is a hand-held instrument with a tiny light and a cone-shaped attachment called an ear speculum, which is used to examine the ear canal. An ear examination is a normal part of most physical examinations by a doctor or nurse. It is also done when an ear infection or other type of ear problem is suspected.     Purpose An otoscope is used to look into the ear canal to see the ear...

ENCEPHALITIS, EPIDEMIC Encephalitis causes a serious inflammation of the brain tissue. In the epidemic type, sometimes called sleeping sickness. The causative agent is probably a virus. It typically affects persons between the ages of ten and forty-five. The virus is probably carried from one person to another by the minute droplets of moisture discharged by a sneeze or by way of contact with articles soiled...

Emotional tensions occur in persons ill at ease or baffled by problems seemingly too difficult to solve. In some cases the person knows, at the level of intellect, what he should do but is deterred by his emotions (fear, love, hate) from acting. In other cases moving in the sensible direction would require him to forfeit some cherished desire; so emotional pressures build up while the solving of the problem...

Edema is an accumulation of excess fluid in the body's tissues or cavities. The extra fluid accumulates outside of the capillaries in the spaces between the cells, and the tissues become soggy and swollen. Normally, there is a continual exchange of fluid between the blood within the capillaries and the tissue spaces outside the capillaries. The capillary walls permit water and small molecules to pass through....

The soft tissues of the external ear and middle ear are attached firmly to the cartilage or bone which forms their foundation. There is not much room to allow for swelling when these tissues become inflamed. When inflammation occurs, therefore, the pain is intense. One form of earache is caused by an inflammation of the delicate skin lining the canal of the external ear. This becomes most painful when the...