Skeletal muscle relaxants are drugs that relax striated muscles (those that control the skeleton). They are a separate class of drugs from the muscle relaxant drugs used during intubations and surgery to reduce the need for anesthesia and facilitate intubation. Skeletal muscle relaxants may be used for relief of spasticity in neuromuscular diseases, such as multiple sclerosis, as well as for spina…
Muscle spasms and cramps are spontaneous, often painful muscle contractions. Most people are familiar with the sudden pain of a muscle cramp. The rapid, uncontrolled contraction, or spasm, happens unexpectedly, with either no stimulation or some trivially small one. The muscle contraction and pain last for several minutes, and then slowly ease. Cramps may affect any muscle, but are most common in …
Muscular dystrophy is the name for a group of inherited disorders in which strength and muscle bulk gradually decline. Nine types of muscular dystrophies are generally recognized. The muscular dystrophies include: Several of the muscular dystrophies, including DMD, BMD, CMD, and most forms of LGMD, are due to defects in the genes for a complex of muscle proteins. This complex spans the muscle cell…
Mushroom poisoning refers to the severe and often deadly effects of various toxins that are found in certain types of mushrooms. One type known as Amanita phalloides, appropriately called "death cap," accounts for the majority of cases. The toxins initially cause severe abdominal cramping, vomiting, and watery diarrhea, and then lead to liver and kidney failure. The highest reported …
Music therapy is a technique of complementary medicine that uses music prescribed in a skilled manner by trained therapists. Programs are designed to help patients overcome physical, emotional, intellectual, and social challenges. Applications range from improving the well being of geriatric patients in nursing homes to lowering the stress level and pain of women in labor. Music therapy is used in…
Mutism is a rare childhood condition characterized by a consistent failure to speak in situations where talking is expected. The child has the ability to converse normally, and does so, for example, in the home, but consistently fails to speak in specific situations such as at school or with strangers. It is estimated that one in every 1,000 school-age children are affected. Experts believe that t…
Myasthenia gravis is an autoimmune disease that causes muscle weakness. Myasthenia gravis (MG) affects the neuromuscular junction, interrupting the communication between nerve and muscle, and thereby causing weakness. A person with MG may have difficulty moving their eyes, walking, speaking clearly, swallowing, and even breathing, depending on the severity and distribution of weakness. Increased w…
Mycetoma, or maduromycosis, is a slow-growing bacterial or fungal infection focused in one area of the body, usually the foot. For this reason—and because the first medical reports were from doctors in Madura, India—an alternate name for the disease is Madura foot. The infection is characterized by an abnormal tissue mass beneath the skin, formation of cavities within the mass, and a…
Atypical mycobacterial infections are infections caused by several types of mycobacteria similar to the germ that causes tuberculosis. These atypical mycobacterial infections are a frequent complication in patients with human immunodeficiency virus (HIV) infection or AIDS. Mycobacteria are a group of rod-shaped bacteria that cause several diseases, among them leprosy and tuberculosis. For some tim…
Mycoplasma are the smallest of the free-living organisms. (Unlike viruses, mycoplasma can reproduce outside of living cells.) Many species within the genus Mycoplasma thrive as parasites in human, bird, and animal hosts. Some species can cause disease in humans. Mycoplasma are found most often on the surfaces of mucous membranes. They can cause chronic inflammatory diseases of the respiratory syst…
Myelodysplastic syndrome (MDS) is a disease that is associated with decreased production of blood cells. Blood cells are produced in the bone marrow, and the blood cells of people with MDS do not mature normally. There are three major types of blood cells—red blood cells, white blood cells and platelets. Patients with MDS can have decreased production of one, two, or all three types of bloo…
Myelofibrosis is a rare disease of the bone marrow in which collagen builds up fibrous scar tissue inside the marrow cavity. This is caused by the uncontrolled growth of a blood cell precursor, which results in the accumulation of scar tissue in bone marrow. Myelofibrosis goes by many names including idiopathic myelofibrosis, agnogenic myeloid metaplasia, chronic myelosclerosis, aleukemic megakary…
Myelography is an x-ray examination of the spinal canal. A contrast agent is injected through a needle into the space around the spinal cord to display the spinal cord, spinal canal, and nerve roots on an x ray. The purpose of a myelogram is to evaluate the spinal cord and/or nerve roots for suspected compression. Pressure on these delicate structures causes pain or other symptoms. A myelogram is …
The Myers-Briggs Type Indicator (MBTI) is a widelyused personality inventory, or test, employed in vocational, educational, and psychotherapy settings to evaluate personality type in adolescents and adults age 14 and older. In an educational setting, the MBTI may be performed to assess student learning style. Career counselors use the test to help others determine what occupational field they migh…
Myocardial biopsy is a procedure wherein a small portion of tissue is removed from the heart muscle for testing. This test is also known as endomyocardial biopsy. The main reason for a biopsy is to secure tissue samples that will be useful in the diagnosis, treatment, and Once the catheter is threaded up into the heart, the surgeon will take several small samples of muscle for laboratory analy…
Myocardial resection is a surgical procedure in which a portion of the heart muscle is removed. Myocardial resection is done to improve the stability of the heart function or rhythm. Also known as endocardial resection, this open-heart surgery is done to destroy or remove damaged areas of the heart that cause life-threatening heart rhythms. This procedure is often performed in people who have had …
Myocarditis is an inflammatory disease of the heart muscle (myocardium) that can result from a variety of causes. While most cases are produced by a viral infection, an inflammation of the heart muscle may also be instigated by toxins, drugs, and hypersensitive immune reactions. Myocarditis is a rare but serious condition that affects both males and females of any age. Most cases of myocarditis in…
Myoglobin is a protein found in muscle. Myoglobin tests are done to evaluate a person who has symptoms of a heart attack (myocardial infarction) or other muscle damage. Myoglobin holds oxygen inside heart and skeletal muscle (muscles that attach to and move bones). It is continually released into the blood in small amounts due to normal turnover of muscle cells. Kidneys discard the myoglobin into …
Myomectomy is the removal of fibroids (noncancerous tumors) from the wall of the uterus. Myomectomy is the preferred treatment for symptomatic fibroids in women who want to keep their uterus. Larger fibroids must be removed with an abdominal incision, but small fibroids can be taken out using laparoscopy or hysteroscopy. A myomectomy can remove uterine fibroids that are causing symptoms. It is an …
Myopathies are diseases of skeletal muscle which are not caused by nerve disorders. These diseases cause the skeletal or voluntary muscles to become weak or wasted. There are many different types of myopathies, some of which are inherited, some inflammatory, and some caused by endocrine problems. Myopathies are rare and not usually fatal. Typically, effects are mild, largely causing muscle weaknes…
Myopia is the medical term for nearsightedness. People with myopia see objects more clearly when they are close to the eye, while distant objects appear blurred or fuzzy. Reading and close-up work may be clear, but distance vision is blurry. To understand myopia it is necessary to have a basic knowledge of the main parts of the eye's focusing system: the cornea, the lens, and the retina. Th…
Myotonic dystrophy is a progressive disease in which the muscles are weak and are slow to relax after contraction. Myotonic dystrophy (DM), also called dystrophia myotonica, myotonia atrophica, or Steinert disease, is a common form of muscular dystrophy. DM is an inherited disease, affecting males and females approximately equally. About 30,000 people in the United States are affected. Symptoms ma…
Myringotomy is a surgical procedure in which a small incision is made in the eardrum (the tympanic membrane), usually in both ears. The word comes from myringa, modern Latin for drum membrane, and tomē, Greek for cutting. It is also called myringocentesis, tympanotomy, tympanostomy, or paracentesis of the tympanic membrane. Fluid in the middle ear can be sucked out through the incisio…
A myxoma is a rare, usually noncancerous, primary tumor (a new growth of tissue) of the heart. It is the most common of all benign heart tumors. Myxoma is an intracardiac tumor; it is found inside the heart. Seventy five percent of all myxomas are found in the left atrium, and almost all other myxomas are found in the right atrium. It is very rare for a myxoma to be found in either of the ventricl…
Nail-patella syndrome, is a genetic disease of the connective tissue that produces defects in the fingernails, knee caps, and kidneys. Nail-patella syndrome is also known as Fong Disease, Hereditary Onycho-Osteodysplasia (H.O.O.D.), Iliac Horn Disease, and Turner-Kieser syndrome. Patients who have nail-patella syndrome may show a variety of physical defects. The hallmark features of this syndrome …
Nail removal is a form of treatment that is sometimes necessary following traumatic injuries or recurrent infections in the area of the nail. There are nonsurgical as well as surgical methods of nail removal. Nails are removed only when necessary to allow the skin beneath the nail (the nail bed) to heal or in some cases, to remove a nail that has been partially pulled out in an accident. In the ca…
Narcolepsy is a disorder marked by excessive daytime sleepiness, uncontrollable sleep attacks, and cataplexy (a sudden loss of muscle tone, usually lasting up to half an hour). Narcolepsy is the second-leading cause of excessive daytime sleepiness (after obstructive sleep apnea). Persintent sleepiness and sleep attacks are the hallmarks of this condition. The sleepiness has been compared to the fe…
Nasal irrigation is the practice of flushing the nasal cavity with a sterile solution. The solution may contain antibiotics. Nasal irrigation is used to clear infected sinuses or may be performed after surgery to the nose region. It may be performed by adding antibiotics to the solution to treat nasal polyps, nasal septal deviation, allergic nasal inflammation, chronic sinus infection, and swollen…
Nasal packing is the application of gauze or cotton packs to the nasal chambers. The most common purpose of nasal packing is to control bleeding following surgery to the septum or nasal reconstruction and to treat chronic nosebleeds. Packing is also used to provide support to the septum after surgery. Packing is the placement of gauze or cotton into the nasal area. Packing comes in three forms, ga…
Nasal papillomas are warts located inside the nose. Two types of tumors can grow inside the nose: polyps and papillomas. By far the most common are polyps, which have smooth surfaces. On the contrary, papillomas have irregular surfaces and are, in fact, warts. Papillomas may be caused by the same viruses that cause warts elsewhere on the body. They are inside the nose, more often on the side near …
A polyp is any overgrowth of tissue from a surface. Polyps come in all shapes—round, droplet, and irregular being the most common. Nasal polyps tend to occur in people with respiratory allergies. Hay fever (allergic rhinitis) is an irritation of the membranes of the nose by airborne particles or chemicals. These membranes make mucus. When irritated, they can also grow polyps. The nose is no…
Nasal trauma is defined as any injury to the nose or related structure that may result in deformity, decreased inhalation due to obstruction, or an impaired sense of smell (olfaction). The nose is composed of bone, soft tissue, and cartilage. It functions to serve as a passageway for air from the environment to flow into the lower respiratory tract and lungs, at the same time warming and humidify …
Nasogastric suction involves removing solids, liquids, or gasses from the stomach or small intestine by inserting a tube through the nose and suctioning the gastrointestinal material through the tube. Nasogastric suction may be done in the following situations: Nasogastric intubation, the insertion of a tube through the nose into the stomach or small intestine, is also done to temporarily feed cer…
A nasopharyngeal culture is used to identify pathogenic (disease causing) organisms present in the nasal cavity that may cause upper respiratory tract symptoms. Some organisms that cause upper respiratory infections are carried primarily in the nasopharynx, or back of the nose. The person carrying these pathogenic bacteria may have no symptoms, but can still infect others with the pathogen and res…
Naturopathic medicine is a branch of medicine in which a variety of natural medicines and treatments are used to heal illness. It uses a system of medical diagnosis and therapeutics based on the patterns of chaos and organization in nature. It is founded on the premise that people are naturally healthy, and that healing can occur through removing obstacles to a cure and by stimulating the body�…
Nausea is the sensation of being about to vomit. Vomiting, or emesis, is the expelling of undigested food through the mouth. Nausea is a reaction to a number of causes that include overeating, infection, or irritation of the throat or stomach lining. Persistent or recurrent nausea and vomiting should be checked by a doctor. A doctor should be called if nausea and vomiting occur: It is important to…
Near-drowning is the term for survival after suffocation caused by submersion in water or another fluid. Some experts exclude from this definition cases of temporary survival that end in death within 24 hours, which they prefer to classify as drownings. An estimated 15, 000–70, 000 near-drownings occur in the United States each year (insufficient reporting prevents a better estimate). The t…
Necrotizing enterocolitis is a serious bacterial infection in the intestine, primarily of sick or premature newborn infants. It can cause the death (necrosis) of intestinal tissue and progress to blood poisoning (septicemia). Necrotizing enterocolitis develops in approximately 10% of newborns weighing less than 800 g (under 2 lb). It is a serious infection that can produce complications in the int…
Neonatal jaundice (or hyperbilirubinemia) is a higher-than-normal level of bilirubin in the blood. Bilirubin is a by-product of the breakdown of red blood cells. This condition can cause a yellow discoloration of the skin and the whites of the eyes called jaundice. Bilirubin, a by-product of the breakdown of hemoglobin (the oxygen-carrying substance in red blood cells), is produced when the body b…
Nephrectomy is the surgical procedure of removing a kidney or section of a kidney. Nephrectomy, or kidney removal, is performed on patients with cancer of the kidney (renal cell carcinoma); a disease in which cysts (sac-like structures) displace healthy kidney tissue (polycystic kidney disease); and serious kidney infections. It is also used to remove a healthy kidney from a donor for the purposes…
Nephritis is inflammation of the kidney. The most prevalent form of acute nephritis is glomerulonephritis. This condition affects children and teenagers far more often than it affects adults. It is inflammation of the glomeruli, or small round filters located in the kidney. Pyelonephritis affects adults more than children, and is recognized as inflammation of the kidney and upper urinary tract. A …
Nephrotic syndrome is a collection of symptoms which occur because the tiny blood vessels (the glomeruli) in the kidney become leaky. This allows protein (normally never passed out in the urine) to leave the body in large amounts. The glomeruli (a single one is called a glomerulus) are tiny tufts of capillaries (the smallest type of blood vessels). Glomeruli are located in the kidneys, where they …
Nephrotoxic injury is damage to one or both of the kidneys that results from exposure to a toxic material, usually through ingestion. The kidneys are the primary organs of the urinary system, which purifies the blood by removing wastes from it and excreting them from the body in urine. Every day, the kidneys filter about 45 gal (180 l) of blood, about four times as much as the amount that passes t…
Neuralgia is defined as an intense burning or stabbing pain caused by irritation of or damage to a nerve. The pain is usually brief but may be severe. It often feels as if it is shooting along the course of the affected nerve. Different types of neuralgia occur depending on the reason the nerve has been irritated. Neuralgia can be triggered by a variety of causes, including tooth decay, eye strain…
Neuroblastoma is a type of cancer that usually originates either in the tissues of the adrenal gland or in the ganglia of the abdomen or in the ganglia of the nervous system. (Ganglia are masses of nerve tissue or groups of nerve cells.) Tumors develop in the nerve tissue in the neck, chest, abdomen, or pelvis. Neuroblastoma is one of the few cancer types known to secrete hormones. It occurs most …
Neuroendocrine tumor refers to the type of cell that a tumor grows from rather than where that tumor is located. Neuroendocrine cells produce hormones or regulatory proteins, and so tumors of these cells usually have symptoms that are related to the specific hormones that they produce. Neuroendocrine cells have roles both in the endocrine system and the nervous system. They produce and secrete a v…
Neurofibromatosis (NF), or von Recklinghausen disease, is a genetic disease in which patients develop multiple soft tumors (neurofibromas). These tumors occur under the skin and throughout the nervous system. Neural crest cells are primitive cells which exist during fetal development. These cells eventually turn into: In neurofibromatosis, a genetic defect causes these neural crest cells to develo…
Neurogenic bladder is a dysfunction that results from interference with the normal nerve pathways associated with urination. Normal bladder function is dependent on the nerves that sense the fullness of the bladder (sensory nerves) and on those that trigger the muscle movements that either empty it or retain urine (motor nerves). The reflex to urinate is triggered when the bladder fills to 300-500…
Neurolinguistic programming (NLP) is aimed at enhancing the healing process by changing the conscious and subconscious beliefs of patients about themselves, their illnesses, and the world. These limiting beliefs are "reprogrammed" using a variety of techniques drawn from other disciplines including hypnotherapy and psychotherapy. Neurolinguistic programming has been used to change th…
A neurological examination is an essential component of a comprehensive physical examination. It is a systematic examination that surveys the functioning of nerves delivering sensory information to the brain and caring motor commands (Peripheral nervous system) and impulses back to the brain for processing and coordinating (Central nervous system). A careful neurological evaluation can help to det…
Neutropenia is an abnormally low level of neutrophils in the blood. Neutrophils are white blood cells (WBCs) produced in the bone marrow that ingest bacteria. Neutropenia is sometimes called agranulocytosis or granulocytopenia because neutrophils make up about 60% of WBCs and have granules inside their cell walls. Neutropenia is a serious disorder because it makes the body vulnerable to bacterial …
Night terrors are a sleep disorder characterized by anxiety episodes with extreme panic, often accompanied by screaming, flailing, fast breathing, and sweating and that usually occur within a few hours after going to sleep. Night terrors occur most commonly in children between the ages of four and 12 but can also occur at all ages. Affected individuals usually suffer these episodes within a few ho…
Nitrogen narcosis is a condition that occurs in divers breathing compressed air. When divers go below depths of approximately 100 ft, increase in the partial pressure of nitrogen produces an altered mental state similar to alcohol intoxication. Nitrogen narcosis, commonly referred to as "rapture of the deep, " typically becomes noticeable at 100 ft underwater and is incapacitating at…
Nocardiosis is a serious infection caused by a fungus-like bacterium that begins in the lungs and can spread to the brain. Nocardiosis is found throughout the world among people of all ages, although it is most common in older people and males. While people with poor immunity are vulnerable to this infection, it sometimes strikes individuals with no history of other diseases. Nocardiosis is rare i…
This type of drug interferes with an enzyme that is key to the replication (reproduction) of the human immunodeficiency virus (HIV). The drug is designed to help suppress the growth of HIV, but does not eliminate it. This medication is used to treat patients with the HIV virus and AIDS in combination with one or more other AIDS drugs. Combining NRTIs with older drugs improves their ability to lowe…
Any inflammation of the urethra not due to gonorrhea, almost always contracted through sexual intercourse and found far more often in men. Men between the ages of 15 and 30 who have multiple sex partners are most at risk for nongonococcal urethritis (NGU), which is believed to be the most common sexually transmitted disease in the United States. NGU is spread almost exclusively via sexual contact,…
Nonsteroidal anti-inflammatory drugs are medicines that relieve pain, swelling, stiffness, and inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs) are prescribed for a variety of painful conditions, including arthritis, bursitis, tendinitis, gout, menstrual cramps, sprains, strains, and other injuries. Nonsteroidal anti-inflammatory drugs relieve pain, stiffness, swelling, and inflammation…
A nosebleed is bleeding from the nose called epistaxis. Unexpected bleeding from anywhere is cause for alarm. Persistent bleeding should always be investigated because it may be the earliest sign of cancer. Fortunately, nosebleeds are rarely a sign of cancer. A much more common cause of nosebleeds is injury from picking or blowing or fisticuffs. People with hay fever have swollen membranes that ar…
Numbness and tingling are decreased or abnormal sensations caused by altered sensory nerve function. The feeling of having a foot "fall asleep" is a familiar one. This same combination of numbness and tingling can occur in any region of the body and may be caused by a wide variety of disorders. Sensations such as these, which occur without any associated stimulus, are called paresthe…
Sterile solutions containing some or all of the nutrients necessary to support life, are injected into the body through a tube attached to a needle, which is inserted into a vein, either temporarily or for long-term treatment. Patients who cannot consume enough nutrients or who cannot eat at all due to an illness, surgery, or accident, can be fed through an intravenous (IV) line or tube. An IV can…
