Health A-Z

Macular Degeneration

Clinical Definition Macular degeneration, or age-related macular degeneration (AMD), is an ophthalmic disease that slowly destroys sharp central vision.  About 90 percent of patients have atrophic AMD, usually beginning when drusen appear in the macula. Others have neovascular or exudative AMD, triggered by abnormal blood vessel growth beneath the macula that can leak fluid and

Magnetic Resonance Imaging

Clinical Definition Magnetic resonance imaging is a scan that employs a powerful magnetic field, radio frequency pulses and a computer to create detailed pictures of bone, soft tissues, organs and other structures. Functional MRI or fMRI is newer, using the scan to measure tiny metabolic changes taking place in an active neurological area to help


Clinical Definition Malaria is a disease caused by parasitic protozoa, which are transmitted into the bloodstream by certain types of mosquitos. Once this type of parasite moves to the liver, it multiplies and infects red blood cells. The disease can be fatal if untreated, especially in children. In Our Own Words Malaria is a parasitic


Clinical Definition Abnormally growing cells can become cancerous, or malignant. Malignant cells may travel from their point of origin and can be fatal if left untreated. In Our Own Words Cancer generally describes a group of abnormal cells that tend to divide more rapidly than most healthy cells or lack the natural life cycle that

Manic Depressive Disorder

Clinical Definition Manic depression, known clinically as bipolar disorder, is a major mood disorder marked by episodes of depression, mixed episodes or mania. Symptoms vary but may include depressive symptoms as well as episodes with exaggerated assessment of self-importance, insomnia, pressured speech, impaired judgment, and engaging in risky activities. The disorder is managed with medication


Clinical Definition Mastitis, an inflammation of the breast, is most prevalent in lactating women but can affect others. The etiology is typically an infection and the condition is typically unilateral. Pain, edema and a burning sensation while breastfeeding are reported, as well as fatigue and chills. Treatments include antibiotics and over-the-counter pain medicine. In Our


Clinical Definition Measles, or rubeola, is a highly contagious vaccine-preventable viral respiratory disease caused by the virus rubeola. Droplets from the nose, mouth or throat of an infected person transmit the virus, with symptoms (e.g., red rash, fever and runny nose) typically appearing eight to 12 days after exposure. There is no cure, but bed


Clinical Definition Meaning “black tumor” in Latin, melanoma is the most serious form of skin cancer and can affect any part of the body. Risk of melanoma is increased through exposure to UV radiation and time spent outdoors, in tanning beds or under sun lamps. Because it affects the melanocytes (i.e. pigment cells), melanomas are


Clinical Definition Meningitis is an infection of the meninges, the protective membranes that surround the brain and spinal cord. Meningitis may develop in response to a number of causes, usually bacteria or a virus, but it can also be caused by certain physical injuries, cancers or drugs. In Our Own Words Although relatively rare, meningitis is


Clinical Definition When a woman’s ovaries no longer release eggs and she hasn’t menstrated in one year, she has entered menopause. It marks the end of a woman’s reproductive period, when her body begins to produce less estrogen and progesterone. In Our Own Words A women officially enters menopause when she hasn’t had a menstrual


Clinical Definition Menstruation is the monthly shedding of the uterine lining that happens if a pregnancy does not occur. The typical menstrual cycle is 28 days long but can range from 21 to 35 or even 45. To menstruate three to five days is typical, but as few as two and as many as seven

Mental Breakdown

Clinical Definition Mental breakdown is a term used to describe an acute psychiatric condition  precipitated by intense stressors. Mental breakdown is not defined by the American Psychiatric Association, but is a common euphemism used to describe a reactive psychiatric condition causing impaired concentration and normal functioning. In Our Own Words A mental breakdown is a

Metabolic Syndrome

Clinical Definition Metabolic syndrome is a term used to describe a cluster of risk factors for coronary artery disease, peripheral vascular disease and diabetes. There are five characteristics of the syndrome including elevated triglyceride levels, hypertension and central obesity. Additional characteristics include insulin resistance and low high density lipoprotein cholesterol levels. In Our Own Words


Clinical Definition Metabolism is the chemical process occurring in the cells, which involves releasing energy from nutrients. Metabolism is an ongoing process and necessary in order to maintain life. The process of metabolism not only involves the digestion of foods but also involves processes which use energy, such as the contracting of muscles, temperature regulation,

Microvascular Coronary Dysfunction

Clinical Definition Microvascular coronary dysfunction is a cardiovascular condition that affects the capillaries and arterioles connected to the myocardium. Microvascular dysfunction interferes with proper dilation of the small vessels carrying oxygen to the myocardium. Ischemia and angina may develop as a result of microvascular coronary dysfunction. In Our Own Words The heart pumps blood to


Clinical Definition A migraine is a headache disorder that impacts more than one in ten people. Migraines tend to be recurrent and can be moderate to severe. Pain occurs when excited brain cells trigger the trigeminal nerve to release chemicals that cause the blood vessels on the surface of the brain become dilate and become

Mitral Valve Prolapse

Clinical Definition Mitral valve prolapse is a condition in which one or both of the mitral valve flaps collapse backwards into the left atrium of the heart. As a result of the valve abnormality, a small amount of blood may regurgitate through the valve. Treatment depends on severity and symptoms, but typically ranges from monitoring

Mitral Valve Stenosis

Clinical Definition Mitral valve stenosis is a narrowing of the mitral valve orifice, impeding the filling of the left ventricle. Rheumatic heart disease is typically the cause, but the stenosis can also be linked to calcifications, infection, lupus, rheumatoid arthritis or heart disease. Those affected may have abnormal heart rhythms, chest pain and fatigue. Treatment

Mold Allergy

Clinical Definition Mold is a type of fungus that produces airborne spores. People with mold allergies have an abnormal immune response after exposure to mold spores. After inhalation of mold spores, some individuals develop an antigen-antibody reactions leading to symptoms of hypersensitivity. The most common types of molds that induce allergic reactions include Cladosporium, Penicillium


Clinical Definition A mole, or pigmented nevus, is a dermatological growth, typically unicolor, most often brown but sometimes other hues or colorless. Most moles are benign, but changes in color, height, size or shape demands evaluation, as do nevi that bleed, ooze, itch, have a scaly appearance or become tender or painful. Some types of


Clinical Definition Mononucleosis is an acute infectious disease that can cause lymphadenopathy, splenomegaly and pharyngitis. The most common causative agent is the Epstein-Barr Virus (EBV), which is a gamma-type herpes virus. Once infected with EBV, the virus remains dormant in the body and may reactivate. It is often transmitted through contact with oral secretions from

Morning Sickness

Clinical Definition Morning sickness is charactered by episodes of nausea and vomiting that occur during the first trimester of pregnancy. It is a common condition that is thought to be caused by increased levels of human chorionic gonadotropin (HGC) hormone released by the placenta into a pregnant woman’s blood system. In Our Own Words During


Clinical Definition MRSA, or methicillin-resistant Staphylococcus Aureus, is a staph bacterium and the cause of certain skin infections in the community and serious hospital-acquired infections as well. S. aureus is common on the skin and in the nose and may be resistant to beta-lactam antibiotics (e.g., methicillin). Serious MRSA infections occur most frequently among patients in hospital settings. In

Mucous Membranes

Clinical Definition The mucous membranes, or mucosae, are moist tissues that line parts of the nose, mouth, lungs and urinary and digestive tracts. Special cells in the mucous membranes release mucus. In Our Own Words Mucous membranes, also called mucosae, are the moist tissue layers that line many structures and cavities in the body, including

Muscle Cramp

Clinical Definition A muscle cramp is the involuntary and acute contraction of a muscle. The contraction causes sudden pain for varyingdurations. Mineral depletion, nerve compression, heat and inadequate circulation can lead to muscle cramps. Muscle cramps can affect any muscle, but most commonly occur in the gastrocnemius, quadriceps and hamstrings. In Our Own Words Muscle

Myocardial Infarction

Clinical Definition Myocardial infarction, commonly called a heart attack, usually occurs when a coronary artery becomes blocked. Coronary arteries form a network of blood vessels that surround the heart and nourish it with oxygen-rich blood, which is crucial for the heart muscle to function effectively. In Our Own Words Myocardial infarction, or heart attack, happens


Clinical Definition The myocardium is the thick middle layer of cardiac tissue, sandwiched between the epicardium and endocardium. In Our Own Words The myocardium is the heart’s thick muscular middle layer, located between the outer layer (i.e., epicardium) and the inner layer (i.e., endocardium). The myocardium is made up of highly specialized heart muscle cells


Clinical Definition Myopia is a refractive error, with incoming light focusing in front of the retina, rather than directly on the retina, resulting in blurred vision with objects at a distance, but not close up. Myopia runs in families, with the typical onset in childhood. Myopia progresses with age, but typically plateaus. Eyeglasses, contact lenses

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