Diseases & conditions A-Z List
Diseases & Conditions A-Z List - «R»:
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Rash - child under 2 years
A rash is a change in the color or texture of the skin. A skin rash can be flat, bumpy, scaly, red, skin-colored, or slightly lighter or darker than skin color.
Considerations
Most bumps and blotches on a newborn baby are harmless and clear up by themselves.
By far the most common skin problem in ...
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Rashes
Rashes involve changes in the color or texture of your skin.
Considerations
Often, the cause of a rash can be determined from its visible characteristics and other symptoms.
Causes
A simple rash is called dermatitis, meaning inflammation of the skin. Contact dermatitis is caused by things your skin ...
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Rat-bite fever
Rat-bite fever is a rare disease spread by infected rodents.
Causes
Rat-bite fever can be caused by the bacteria, Actinobacillus muris (formerly called Streptobacillus moniliformis) and Spirillum minus. Most cases of rat-bite fever occur in Japan, where it is called sodoku.
The disease has also bee...
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Raynaud’s phenomenon
Raynaud’s phenomenon is a condition in which cold temperatures or strong emotions cause blood vessel spasms that block blood flow to the fingers, toes, ears, and nose.
Causes
Raynaud's phenomenon can be associated with other conditions. This is called secondary Reynaud's phenomenon. Most peo...
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RBC - urine
The RBC urine test measures the number of red blood cells in a urine sample.
How the Test is Performed
A clean-catch urine sample is needed.
To obtain a sample, boys and men should wipe the head of the penis clean. Girls and women need to wipe between the vaginal "lips" (labia) with soapy water and...
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RBC count
An RBC count is a blood test that tells how many red blood cells (RBCs) you have.
RBCs contain hemoglobin, which carries oxygen. How much oxygen your body tissues get depends on how many RBCs you have and how well they work.
How the Test is Performed
Blood is typically drawn from a vein, usually f...
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RBC indices
Red blood cell (RBC) indices are part of the complete blood count (CBC) test. They are used to help diagnose the cause of anemia, a condition in which there are too few red blood cells.
The indices include:
Average red blood cell size (MCV)
Hemoglobin amount per red blood cell (MCH)
The amount of ...
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RBC nuclear scan
An RBC nuclear scan is a group of tests using small amounts of radioactive material to mark (tag) red blood cells (RBCs). The body is then scanned to detect the location and flow of the tagged RBCs.
See: Nuclear ventriculography
How the Test is Performed
The exact procedure may vary slightly depen...
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Reactive arthritis
Reactive arthritis is a group of inflammatory conditions that involves the joints, urethra, and eyes. There may also be sores (lesions) on the skin and mucus membranes.
Causes
The exact cause of reactive arthritis is unknown. It occurs most commonly in men before the age of 40. It may follow an inf...
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Reactive attachment disorder of infancy or early childhood
Reactive attachment disorder is a problem with social interaction that occurs when a child's basic physical and emotional needs are neglected, particularly when the child is an infant.
Causes
Reactive attachment disorder is caused by abuse or neglect of an infant's needs for:
Emotional bonds with ...
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Recognizing medical emergencies
According to the American College of Emergency Physicians, the following are warning signs of a medical emergency:
Bleeding that will not stop
Breathing problems (difficulty breathing, shortness of breath)
Change in mental status (such as unusual behavior, confusion, difficulty arousing)
Chest p...
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Rectal biopsy
A rectal biopsy is a procedure to remove a small piece of rectal tissue for examination.
How the Test is Performed
A rectal biopsy is usually part of anoscopy or sigmoidoscopy.
A digital rectal exam is done first. Then, a lubricated instrument (anoscope or proctoscope) is placed into the rectum. Yo...
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Rectal culture
Rectal culture is a laboratory test to identify organisms in the rectum that can cause gastrointestinal symptoms and disease.
How the Test is Performed
A cotton swab is inserted into the rectum, rotated gently, and removed. A smear of the swab is placed in culture media to encourage the growth of b...
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Rectal prolapse
Rectal prolapse occurs when the tissue that lines the rectum falls down into or sticks through the anal opening.
Causes
Rectal prolapse occurs most often in children under age 6 and in the elderly. It is often associated with the following conditions:
Constipation
Cystic fibrosis
Malnutrition ...
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Rectal prolapse repair
Rectal prolapse repair is surgery to fix a rectal prolapse, in which the rectum (the last part of the colon) protrudes through the anus.
Description
Rectal prolapse may be partial, involving only the mucosa. Or it may be complete, involving the entire wall of the rectum. It can occur in children bu...