Health A-Z

Radiation Therapy

Clinical Definition Radiation therapy uses high-energy radiation to damage or alter cellular DNA in order to treat malignancies or disease. Once genetic material in cancer cells is damaged, cells are unable to divide, and tumors shrink or may be eradicated. The dose of radiation given will vary based on the malignancy and specific site treated.


Clinical Definition Radon is a colorless, radioactive gas that occurs from the breakdown of uranium. It is classified as a carcinogen and can be found in rocks, soil and ground water. In Our Own Words Radon is a colorless, odorless and tasteless gas that naturally occurs as the radioactive element uranium decays in rocks and

Rebound Headache

Clinical Definition Rebound headaches are the escalation of headache pain after the discontinuation of analgesics. Rebound headaches often occur frequently, even daily. The exact physiology of what causes rebound headaches is not completely understood. It is theorized that headache medication may alter or interfere with a particular individual’s brain chemistry and affect how pain pathways

Renal Failure

Clinical Definition Renal failure is either a level of glomerular filtration rate of less than 15 mL/min/1.73m2, or a need to initiate kidney replacement therapy, either dialysis or transplantation, for complications of decreased GFR.  GRF levels used in defining renal failure are viewed as arbitrary in potential need of modification based on kidney replacement therapy

Respiratory infection

Clinical Definition A respiratory infection is considered an infectious disease, such as pneumonia, influenza and the common cold, which affects the respiratory tract. Respiratory infections may affect the upper respiratory tract, lower respiratory tract, or both.  A respiratory infection may be caused by a viral or bacterial pathogen and may range from mild to severe.

Respiratory Syncytial Virus

Clinical Definition Respiratory syncytial virus is an infection caused by the virus from the Pneumovirus genus. Although healthy adults can become infected, it usually results in a mild respiratory infection. In young children, it tends to cause inflammation of the bronchioles. In some cases, it may also lead to bronchopneumonia and respiratory failure. The infection

Restless legs syndrome

Clinical Definition Restless legs syndrome is a neurological disorder characterized by intense urges to move the legs, typically in supine positions and accompanied by uncomfortable periodic prickling sensations. Exact cause is unknown, but several underlying conditions are thought to be associated with restless leg syndrome, including iron deficiency, kidney failure and peripheral nerve disease. In


Clinical Definition Rett syndrome is a pediatric neurodevelopmental disorder predominantly affecting females.  The nervous system disorder leads to developmental reversals, especially in expressive language and use of the hands. Breathing problems, floppy limbs and seizures may occur In Our Own Words Rett syndrome is a genetic disorder affecting the nervous system. The gene thought to


Clinical Definition Reyes syndrome is a rare, acute illness that produces a buildup of fat in the body’s organ systems. It primarily causes encephalopathy and brain damage, along with fatty degenerative liver failure. Typically, it affects children under the age of 15. The specific cause is not known, but an association with ingestion of salicylates

Rh factor blood test

Clinical Definition Rh factor blood test detects a protein, Rh factor, which can be present on the surface of erythrocytes. The majority of the population have the Rh factor and so test ”Rh positive.”  When the blood test does not detect Rh factor, the result is Rh negative. Pregnant women are tested not only for


Clinical Definition Rheumatism is defined as the pain and stiffness of soft tissues in and around the joints. It refers to more than 100 collective conditions affecting the musculoskeletal system (which consists of the joints, muscles, bones and tendons). Among the most common rheumatic conditions are osteoporosis, rheumatoid arthritis, fibromyalgia, osteoarthritis and scleroderma. In Our


Clinical Definition Rhinitis is an inflammation of the nasal mucosa. Rhinitis is usually classified as either infectious, allergic or non-allergic. The mucus membranes may become irritated and inflamed due to allergies, viruses and bacteria. Allergic rhinitis is the most common type of rhinitis. In Our Own Words Rhinitis is an inflammation and irritation of the mucus


Clinical Definition Rhinophyma is a condition, which is thought to be a severe form of rosacea. It is characterized by hypertrophy and redness of the lower portion of the nose. It is a result of hyperplasia of the sebaceous glands in the nose. The condition may also spread to the adjacent cheeks. In Our Own


Clinical Definition Rickets is a deficiency disease resulting from a lack of vitamin D, calcium, or phosphorus, all crucial for normal growth and development of bones. Stooped posture may be a symptom; contributing factors include poor diet, lactose intolerance, low calcium intake, lack of sun exposure and long-term breastfeeding, as breast milk has low levels


Clinical Definition Ringworm, known medically as tinea, refers to a highly contagious skin infection that is not caused by a worm but by several types of fungi. Tinea corporis is ringworm on the body, for example, and tinea capitis targets only the scalp. These fungi specially thrive on the skin between the toes and in the groin because


Clinical Definition Rosacea is a common skin disorder that most often affects facial skin. Some experts believe that rosacea may be related to a vascular disorder because of its association with flushing, redness and visible blood vessels. Sometimes called adult acne, rosacea causes redness that appears on the chin, nose, cheeks and forehead. As the

Rotator Cuff

Clinical Definition The rotator cuff refers to parts of the capsule of the shoulder joint, reinforced by four tendons that connect to the supraspinatus, infraspinatus, teres minor and subscapularis muscles. The rotator cuff helps keep the upper arm (humerus) stable in the shoulder socket. In Our Own Words The rotator cuff is made of four


Clinical Definition Rotavirus is caused by a group of RNA viruses in the reoviridae family. It is a common cause of gastroenteritis. It is highly contagious and found in the stool of infected individuals. Although anyone can become infected with rotavirus, it is the leading cause of severe diarrhea in children. Vaccines are available to


Clinical Definition Rubella is an infectious, exanthematous disease caused by the rubivirus, a member of the togavirus family. It is characterized by a red rash and mild flu-like symptoms. The disease is usually mild in children and adults; in pregnant women, however, it can lead to fetal birth defects. Immunization is available to prevent rubella.

Ruptured Disc

Clinical Definition Family practice, Orthopedics, Physical medicine & rehab In Our Own Words In between each vertebra in the spine is a disc that acts as a cushion. Each disc is made up of two parts. The outer ring of the disc is a ligament connecting the vertebrae called the annulus. The center of each

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