Gastrointestinal Tract

Gastrointestinal (GI) tract refers to a tubular passage from mouth to anus that releases hormones to aid the digestion process. Extending about 8.3 meters, GI tract may be divided into three divisions: foregut, midgut, and hindgut.

1,849 Questions
Gastrointestinal Tract

How does the digestive system interact with other organ systems in the body?

The digestive system can work with other systems in different ways. Lets give the example of the liver. The liver does send nutrients around the body after the small intestines absorb the nutrients and give it to the liver. The liver needs the help of the circulatory system do it. So the blood vessels of the liver help the liver give the nutrients to the body. So that's an example of how the circulatory system works with the digestive system.

Frank <censored> is the best!

252627
Gastrointestinal Tract

What three substances make up gastric juice?

but hole

001
Human Anatomy and Physiology
Digestive System
Gastrointestinal Tract

Name two lower gastrointestinal system procedures that involve and endoscope?

Colonoscopy - The direct visual examination of the inner surface of the entire colon from the rectum to the cecum.

Sigmoidoscopy - The endoscopic examination of the interior of the rectum, sigmoid colon, and possible a portion of the descending colon.

234
Intestinal Health
Gastrointestinal Tract

How long can a person go without a bowel movement?

Month

567
Periodic Table
Genetics
Gastrointestinal Tract

What is a molecule called when it contains carbon?

An organic molecule generally contains carbon, though it should be noted that there are carbon containing molecules (such as carbon monoxide, carbon dioxide, metal carbonates, metal bicarbonates and metal carbides) which are considered to be inorganic.

001
Intestinal Health
Gastrointestinal Tract
Stomach

What is erythematous mucosa in the antrum?

Mucosa is the lining of cavities that are exposed to the outside environment, such as the nasal cavities, and internal organs. Antrum is a general term for a cavity or chamber which may have specific meaning in reference to certain organs or sites in the body. Erythematous means unnaturally reddened.

So, erythematous mucosa in the antrum means that the lining at a site in your body is unnaturally reddened.

100101102
Gastrointestinal Tract

Name the enzyme present in gastric juice?

pepsinozene

192021
Gastrointestinal Tract
Stomach

What is irregular z line in esophagus?

Irregular Z line is the connection where the oesaphagus meets the stomach. when the endoscopist means Irregular Z line- They take a sample tissue and send it for biposy.

Irregular Z line does not mean that something is wrong.

343536
Colorectal and Colon Cancer
Medical Technologies
Gastrointestinal Tract

Can you eat mash potatoes before a colonoscopy?

Yes

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Gastrointestinal Tract

To neutralize gastric juices in your stomach antacids contain?

Base salts

345
Gastrointestinal Tract
Intestines
Pancreas

Digestion needs the help of two more systems in the body to provide energy from food. Which are these systems and how do they help?

It’s very simple ok hope you have confidence

91011
Gastrointestinal Tract

Jaundice causes?

Definition

Jaundice is a yellow color in the skin, mucus membranes, or eyes. The yellow color comes from bilirubin, a byproduct of old red blood cells. Jaundice is a sign of other diseases.

This article discusses the possible causes of jaundice in children and adults. For information on jaundice in very young infants, see: Newborn jaundice

Alternative Names

Causes of jaundice

Information

Common causes of jaundice in older children and adults include:

Other causes of jaundice include:

  • Cancer of the pancreas
  • Disorders present since birth that makes it hard for the body to breakdown bilirubin (such as Gilbert syndrome, Dubin-Johnson syndrome, Rotor syndrome, or Crigler-Najjar syndrome)
  • Eating poisonous mushrooms or other poisons
  • Immune disorder that mistakenly attacks healthy liver tissue (autoimmune hepatitis)
  • Liver damage caused by reduced oxygen or blood flow to the liver
  • The body destroys too many blood cells and the liver cannot handle them (hemolytic anemia)
  • Use of certain drugs, including an overdose of acetaminophen

Gallbladder and bile duct disorders that can cause jaundice include:

  • Blocked or narrowed bile ducts (by infection, tumor, stricture, or gallstones)
  • Primary biliary cirrhosis
  • Bile build up in the gallbladder because of pressure in the belly area during pregnancy (jaundice of pregnancy)

See also:

References

Lidofsky SD. Jaundice. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 20.

Reviewed By

Review Date: 04/17/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Chromium - blood test?

Definition

Chromium is a mineral that affects insulin, carbohydrate, fat, and protein levels in the body. This article discusses the test to check the amount of chromium in your blood.

Alternative Names

Serum chromium

How the test is performed

A blood sample is needed. For information on how this is done, see: Venipuncture

How to prepare for the test

No special preparation is necessary for this test.

How the test will feel

When the needle is inserted to draw blood, you feel moderate pain, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

This test may be done to diagnose chromium poisoning or deficiency.

Normal Values

Serum chromium levels normally range from less than 0.05 up to 0.5 micrograms/milliliter (mcg/mL).

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

What abnormal results mean

Increased chromium levels may result if you are overexposed to the substance when you work in the following industries:

  • Leather tanning
  • Electroplating
  • Steel manufacturing

Decreased chromium levels only occurs in people who receive all of their nutrition by vein (total parenteral nutrition or TPN) whose nutritional fluids do not contain enough chromium.

What the risks are

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)
Special considerations

Test results may be altered if the sample is collected in a metal tube.

References

Mason JB. Nutritional assessment and management of the malnourished patient. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 4.

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 237.

National Institutes of Health. Chromium. Dietary Supplement Fact Sheet. Available at: http://ods.od.nih.gov/factsheets/chromium/Accessed June 24, 2011.

Reviewed By

Review Date: 05/30/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Intestinal pseudo-obstruction?

Definition

Intestinal pseudo-obstruction is a condition in which there are symptoms of intestinal blockage without any physical signs of a blockage.

Alternative Names

Primary intestinal pseudo-obstruction; Acute colonic ileus; Colonic pseudo-obstruction; Idiopathic intestinal pseudo-obstruction; Ogilvie's syndrome; Chronic intestinal pseudo-obstruction

Causes, incidence, and risk factors

In primary intestinal pseudo-obstruction, the small or large intestines lose their ability to contract and push food, stool, and air through the gastrointestinal tract.

The condition can occur suddenly (acute) or over time (chronic). It may occur at any age, but is most common in children and the elderly. Because the cause is unknown, it is also called idiopathic intestinal pseudo-obstruction (idiopathic means occurring without reason).

Risk factors include:

  • Having cerebral palsy or other nervous system (neurologic) disorders
  • Staying in bed for long periods of time (bedridden)
  • Taking narcotic (pain) medications
SymptomsSigns and tests

Signs include:

  • Nutritional deficiency

Tests include:

Treatment
  • Colonoscopy may be used to remove air from the large intestine.
  • Fluids given through a vein (intravenous fluids) will replace fluids lost from vomiting or diarrhea.
  • Neostigmine may be used to treat intestinal pseudo-obstruction that is only in the large bowel (Ogilvie's syndrome)
  • Nasogastric suction -- a nasogastric (NG) tube is placed through the nose into the stomach to remove air from (decompress) the bowel.
  • Special diets usually do not work, although vitamin B12 and other vitamin supplements should be used for patients with vitamin deficiency.

In severe cases, surgery may be needed.

Expectations (prognosis)

Most cases of acute pseudo-obstruction get better in a few days with treatment. In chronic forms of the disease, symptoms can return and worsen for many years.

ComplicationsCalling your health care provider

Call your health care provider if you have persistent abdominal pain or other symptoms of this disorder.

References

Batke M, Cappell MS. Adynamic ileus and acute colonic pseudo-obstruction. Med Clin North Am.2008;92:649-670.

Camilleri M. Disorders of gastrointestinal motility. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 138.

Reviewed By

Review Date: 07/07/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Jaundice?

Definition

Jaundice is a yellow color of the skin, mucus membranes, or eyes. The yellow coloring comes from bilirubin, a byproduct of old red blood cells. Jaundice can be a symptom of other health problems.

See newborn jaundice for information about jaundice in infants.

Alternative Names

Conditions associated with jaundice; Yellow skin and eyes; Skin - yellow; Icterus; Eyes - yellow

Causes, incidence, and risk factors

Everyday, a small number of red blood cells in your body die, and are replaced by new ones. The liver removes the old blood cells, forming bilirubin. The liver helps break down bilirubin so that it can be removed by the body in the stool.

When too much bilirubin builds up in the body, jaundice may result.

Jaundice can occur if:

  • Too many red blood cells are dying or breaking down and going to the liver
  • The liver is overloaded or damaged
  • The bilirubin from the liver is unable to move through the digestive tract properly

Jaundice is often a sign of a problem with the liver, gallbladder, or pancreas. Infections, use of certain drugs, cancer, blood disorders, gallstones, birth defects and a number of other medical conditions can lead to jaundice. For more information on the causes of jaundice see: Jaundice causes

Symptoms

Jaundice may appear suddenly or develop slowly over time. Symptoms of jaundice commonly include:

  • Yellow skin and the white part of the eyes (sclera) -- when jaundice is more severe, these areas may look brown
  • Yellow color inside the mouth
  • Dark or brown-colored urine
  • Pale or clay-colored stools

Note: If the whites of your eyes are not yellow, you may not have jaundice. Your skin can turn a yellow-to-orange color if you eat too much beta carotene, the orange pigment in carrots.

Other symptoms depend on the disorder causing the jaundice:

  • Cancers may produce no symptoms, or there may be fatigue, weight loss, or other symptoms
  • Hepatitis may produce nausea, vomiting, fatigue, or other symptoms
Signs and tests

The health care provider will perform a physical exam. This may reveal liver swelling.

A bilirubin blood test will be done. Other tests vary, but may include:

Treatment

Treatment depends on the cause of the jaundice.

Calling your health care provider

Contact your health care provider if you develop symptoms of jaundice.

References

Lidofsky SD. Jaundice. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 20.

Reviewed By

Review Date: 04/17/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Transjugular intrahepatic portosystemic shunt (TIPS)?

Alternative Names

TIPS

Definition

Transjugular intrahepatic portosystemic shunt (TIPS) is a procedure to create new connections between two blood vessels in your liver. You may need this procedure if you have very bad liver problems.

Description

This is not a surgical procedure. It is done by a radiologist using x-ray. A radiologist is a doctor who uses imaging techniques to diagnose and treat diseases.

You will be asked to lie on your back. You will be connected to monitors that will check your heart rate and blood pressure.

You will probably receive local anesthesia and medicine to relax you. This will make you pain-free and sleepy. Or, you may have general anesthesia(asleep and pain-free).

Your radiologist will insert a catheter (a flexible tube) through your skin into a vein in your neck.

  • On the end of the catheter is a balloon and a metal mesh stent (tube).
  • Using x-ray equipment, the surgeon will guide the catheter into a vein in your liver.
  • The balloon will be blown up to place the stent. You may feel a little pain when this happens.
  • Your radiologist will use the stent to connect your portal vein to one of your hepatic veins.
  • At the end of the procedure, your pressures will be measured to make sure portal pressure has gone down.
  • After the procedure, a small bandage is placed over the neck area. There are no stitches.
  • The procedure takes about 60 - 90 minutes to complete.

This new pathway will allow blood to flow better. It will ease pressure on the veins of your stomach, esophagus, intestines, and liver.

Why the Procedure Is Performed

Normally, blood coming from your esophagus, stomach, and intestines first flows through the liver. When your liver has a lot of damage and there are blockages, blood cannot flow through it very easily. This is called portal hypertension (increased pressure and backup at the portal vein).

When this problem happens, you may have:

  • Bleeding from veins of the stomach, esophagus, or intestines (variceal bleeding)
  • Buildup of fluid in the belly (ascites)
  • Buildup of fluid in the chest (hydrothorax)
  • Clotting in a vein that carries blood from the liver to the heart (Budd-Chiari syndrome)

This procedure allows your blood to flow better in your liver, stomach, esophagus, and intestines, and then back to your heart.

Risks

Potential risks for this procedure are:

  • Damage to blood vessels
  • Fever
  • Infection, bruising, or bleeding
  • Reactions to medicines or the contrast dye
  • Stiffness, bruising, or soreness in the neck

Rare risks are:

  • Bleeding in the belly
  • Blockage in the stent
  • Cutting of the blood vessels of the liver
  • Heart problems or abnormal heart rhythms
  • Infection of the stent
Before the Procedure

Your doctor may ask you to have these tests:

Always tell your doctor or nurse:

  • If you are or could be pregnant
  • Any drugs you are taking, even drugs, supplements, or herbs you bought without a prescription (your doctor may ask you to stop taking blood thinners like aspirin, heparin, or warfarin a few days before the procedure)

On the day of your surgery:

  • Do not eat or drink anything after midnight the night before surgery.
  • Ask your doctor which medications you should still take on the day of surgery. Take these drugs with a small sip of water.
  • Take a shower the night before or the morning of surgery.
  • Your doctor or nurse will tell you when to arrive at the hospital.
  • You should plan to stay overnight at the hospital.
After the Procedure

After the procedure, you will recover in your hospital room. You will be monitored for bleeding. You will have to keep your head raised.

There is usually no pain after the procedure.

You will be able to go home when you feel better. This may be the day after surgery.

Many people get back to their everyday activities in 7 to 10 days.

Your doctor will probably do ultrasounds after surgery to make sure the stent is working correctly.

You will be asked to have a repeat ultrasound in a few weeks to make sure that the TIPS procedure is working.

Outlook (Prognosis)

Your radiologist can tell you right away how well the procedure worked. Most patients recover well.

TIPS works in about 80% - 90% of portal hypertension cases.

The procedure is much safer than surgery and does not involve any cutting or stitches.

References

Rikkers LF. Surgical complications of cirrhosis and portal hypertension. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 53.

Shah VH, Kamath PS. Portal hypertension and gastrointestinal bleeding. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010: chap 90.

Reviewed By

Review Date: 09/10/2010

Shabir Bhimji, MD, PhD, Specializing in Cardiothoracic and Vascular Surgery, Midland, TX. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Digital rectal exam?

Definition

A digital rectal exam is an examination of the lower rectum. The doctor uses a gloved, lubricated finger to check for abnormalities.

Alternative Names

DRE

How the test is performed

The doctor will first examine the outside of the anus for hemorrhoids or fissures. Then the doctor will put on a latex glove and insert a lubricated finger into the rectum. In female patients, this exam may be done together with a pelvic exam.

How to prepare for the test

The doctor will ask you to try to relax before the test and to take a deep breath during the actual insertion of the finger into the rectum.

How the test will feel

You may feel mild discomfort during this test.

Why the test is performed

This test is performed for various reasons. It is sometimes done as part of a routine yearly physical examination in both men and women.

In men, the test is used to examine the prostate, looking for abnormal enlargement or other signs of prostate cancer.

In women, a digital rectal exam may be performed during a routine gynecologic examination.

A digital rectal exam is also done to collect stool for testing for fecal occult (hidden) blood as part of screening for colorectal cancer.

This procedure is also done before other tests, such as a colonoscopy, to make sure nothing is blocking the rectum before inserting an instrument.

Normal Values

A normal finding means the doctor did not detect any problem during the exam. However, this test does not completely rule out all possible problems.

What abnormal results mean

An abnormal result may be due to:

  • A prostate problem, including prostate enlargement or prostate cancer
  • Bleeding in the gastrointestinal tract
  • Tumor of the rectum
  • Other problems within the rectum
References

Marcello PW. Diseases of the anorectum. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 125.

Reviewed By

Review Date: 02/02/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Flushable reagent stool blood test?

Definition

Flushable reagent stool blood test is an at-home test to detect hidden blood in the stool.

Alternative Names

Stool occult blood test - flushable home test; Fecal occult blood test - flushable home test

How the test is performed

This test is performed at home with disposable pads. The pads are available at pharmacies without a prescription. Brand names include EZ-Detect and ColoCARE.

There is no direct handling of stool with this test. You simply note any changes on a card and then mail the results card to your health care provider.

Urinate if you need to, then flush the toilet before you have a bowel movement. After the bowel movement, place the disposable pad in the toilet. Watch for a change of color on the test area of the pad. Results usually appear within 2 minutes. Note the results on the card provided, then flush the pad away. Repeat for the next two bowel movements.

The different tests have different methods to check for water quality. Check the package for instructions.

How to prepare for the test

Some drugs may interfere with this test.

Check with your health care provider regarding medication changes that may be necessary. Never discontinue or decrease any medication without consulting your health care provider.

Check package instructions to see if you need to stop eating certain foods before doing the test.

How the test will feel

This test involves only normal bowel functions, and there is no discomfort.

Why the test is performed

This test is mainly performed for colorectal cancer screening. It may also be recommended in the evaluation of low levels of red blood cells (anemia).

Normal Values

A negative result is normal.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Abnormal results of the flushable test may indicate the following problems (which are the same as with the guaiac smear test):

Additional causes of a positive test, which do not indicate a problem in the gastrointestinal tract, include:

  • Coughing up and then swallowing blood
  • Nose bleed

Abnormal test results require follow-up with your doctor.

What the risks are

There can be false-positive (the test indicates a problem when there actually is none) or false-negative (the test indicates there is NOT a problem, but there is) results. This is similar to the traditional stool smear tests, which also can have false-positive or false-negative results.

References

Bresalier RS. Colorectal cancer. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 123.

Reviewed By

Review Date: 02/16/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Aging changes in organs - tissue - cells?

Information

All vital organs begin to lose some function as you age. Aging changes have been found in all of the body's cells, tissues, and organs, and these changes affect the functioning of all body systems.

Living tissue is made up of cells. There are many different types of cells, but all have the same basic structure. Tissues are layers of similar cells that perform a specific function. The different kinds of tissues group together to form organs.

There are four basic types of tissue:

  • Connective tissue supports other tissues and binds them together. This includes bone, blood, and lymph tissues, as well as the tissues that give support and structure to the skin and internal organs.
  • Epithelial tissue provides a covering for deeper body layers. The skin and the linings of the passages inside the body, such as the gastrointestinal system, are made of epithelial tissue.
  • Muscle tissue includes three types of tissue:
    • Striated muscles, such as those that that move the skeleton (also called voluntary muscle)
    • Smooth muscles (also called involuntary muscle), such as the muscles contained in the stomach and other internal organs
    • Cardiac muscle, which makes up most of the heart wall (also an involuntary muscle)
  • Nerve tissue is made up of nerve cells (neurons) and is used to carry messages to and from various parts of the body. The brain, spinal cord, and peripheral nerves are made of nerve tissue.

AGING CHANGES

Cells are the basic building blocks of tissues. All cells experience changes with aging. They become larger and are less able to divide and multiply. Among other changes, there is an increase in pigments and fatty substances inside the cell (lipids). Many cells lose their ability to function, or they begin to function abnormally.

Waste products build up in tissue with aging. A fatty brown pigment called lipofuscin collects in many tissues, as do other fatty substances.

Connective tissue changes, becoming more stiff. This makes the organs, blood vessels, and airways more rigid. Cell membranes change, so many tissues have more trouble getting oxygen and nutrients and removing carbon dioxide and wastes.

Many tissues lose mass. This process is called atrophy. Some tissues become lumpy (nodular) or more rigid.

Because of cell and tissue changes, your organs also change as you age. Aging organs slowly lose function. Most people do not notice this loss, because you rarely need to use your organs to their fullest ability.

Organs have a reserve ability to function beyond the usual needs. For example, the heart of a 20-year-old is capable of pumping about 10 times the amount of blood that is actually needed to keep the body alive. After age 30, an average of 1% of this reserve is lost each year.

The biggest changes in organ reserve occur in the heart, lungs, and kidneys. The amount of reserve lost varies between people and between different organs in a single person.

These changes appear slowly and over a long period of time. When an organ is worked harder than usual it may not be able to increase function. Sudden heart failure or other problems can develop when the body is worked harder than usual. Things that produce an extra workload (body stressors) include the following:

  • Illness
  • Medications
  • Significant life changes
  • Suddenly increased physical demands on the body, for example:
    • A sudden change in activity
    • Exposure to a higher altitude

Loss of reserve also makes it harder to restore balance (equilibrium) in the body. Drugs are removed from the body at a slower rate. Lower doses of medications may be needed, and side effects become more common.

Medication side effects can mimic the symptoms of many diseases, so it is easy to mistake a drug reaction for an illness. Some medications have entirely different side effects in the elderly than in younger people.

AGING THEORY

No one really knows how and why people change as they get older. Some theories claim that aging is caused by injuries from ultraviolet light over time, wear and tear on the body, or byproducts of metabolism. Other theories view aging as a predetermined process controlled by genes.

However, no single process can explain all the changes of aging. Aging is a complex process that varies in how it affects different people and even different organs. Most gerontologists (people who study aging) feel that aging is due to the interaction of many lifelong influences. These influences include heredity, environment, culture, diet, exercise and leisure, past illnesses, and many other factors.

Unlike the changes of adolescence, which are predictable to within a few years, each person ages at a unique rate. Some systems begin aging as early as age 30. Other aging processes are not common until much later in life.

Although some changes always occur with aging, they occur at different rates and to different extents. There is no way to predict exactly how you will age.

TERMS

  • ATROPHY
    • Cells shrink. If enough cells decrease in size, the entire organ atrophies. This is often a normal aging change and can occur in any tissue. It is most common in skeletal muscle, the heart, the brain, and the sex organs (such as the breasts).
    • The cause of atrophy is unknown, but may include reduced use, decreased workload, decreased blood supply or nutrition to the cells, and reduced stimulation by nerves or hormones.
  • HYPERTROPHY
    • Cells enlarge. This is caused by an increase of proteins in the cell wall and cell structures, not an increase in the cell's fluid.
    • When some cells atrophy, others may hypertrophy to make up for the loss of cell mass.
  • HYPERPLASIA
    • The number of cells increases. There is an increased rate of cell division.
    • Hyperplasia usually occurs to compensate a for loss of cells. It allows some organs and tissues to regenerate, including the skin, lining of the intestines, liver, and bone marrow. The liver is especially good at regeneration. It can replace up to 70% of its structure within 2 weeks after an injury.
    • Tissues that have limited ability to regenerate include bone, cartilage, and smooth muscle (such as the muscles around the intestines). Tissues that rarely or never regenerate include the nerves, skeletal muscle, heart muscle, and the lens of the eye. When injured, these tissues are replaced with scar tissue.
  • DYSPLASIA
    • The size, shape, or organization of mature cells becomes abnormal. This is also called atypical hyperplasia.
    • Dysplasia is fairly common in the cells of the cervix and the lining of the respiratory tract.
  • NEOPLASIA
    • The formation of tumors, either cancerous (malignant) or noncancerous (benign).
    • Neoplastic cells often reproduce quickly. They may have unusual shapes and abnormal function.

RELATED TOPICS

References

Martin GM. Biology of aging. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 22.

Reviewed By

Review Date: 05/22/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

001
Gastrointestinal Tract

Aging changes in the heart and blood vessels?

Alternative Names

Heart disease - aging; Atherosclerosis - aging

Information

Some changes in the heart and blood vessels normally occur with age, but many other changes that are common with aging are due to modifiable factors that, if not treated, can lead to heart disease.

BACKGROUND

The heart has two sides. The right side pumps blood to the lungs to receive oxygen and get rid of carbon dioxide. The left side pumps oxygen-rich blood to the body.

Blood flows out of the heart through arteries, which branch out and get smaller and smaller as they go into the tissues. In the tissues, they become tiny capillaries.

Capillaries are where the blood gives up oxygen and nutrients to the tissues, and receives carbon dioxide and wastes back from the tissues. Then, the vessels begin to collect together into larger and larger veins, which return blood to the heart.

AGING CHANGES

Heart

  • The heart has a natural pacemaker system that controls the heartbeat. Some of the pathways of this system may develop fibrous tissue and fat deposits. The natural pacemaker (the SA node) loses some of its cells. These changes may result in a slightly slower heart rate.
  • A slight increase in the size of the heart, especially the left ventricle, is not uncommon. The heart wall thickens, so the amount of blood that the chamber can hold may actually decrease despite the increased overall heart size. The heart may fill more slowly.
  • Heart changes cause the ECG of a normal, healthy older person to be slightly different than the ECG of a healthy younger adult. Abnormal rhythms (arrhythmias) such as atrial fibrillationare more common in older people. They may be caused by heart disease.
  • Normal changes in the heart include deposits of the "aging pigment," lipofuscin. The heart muscle cells degenerate slightly. The valves inside the heart, which control the direction of blood flow, thicken and become stiffer. A heart murmur caused by valve stiffness is fairly common in the elderly.

Blood vessels

  • Receptors called baroreceptors monitor the blood pressure and make changes to help maintain a fairly constant blood pressure when a person changes positions or activities. The baroreceptors become less sensitive with aging. This may explain why many older people have orthostatic hypotension, a condition in which the blood pressure falls when a person goes from lying or sitting to standing. This causes dizziness because there is less blood flow to the brain.
  • The capillary walls thicken slightly. This may cause a slightly slower rate of exchange of nutrients and wastes.
  • The main artery from the heart (aorta) becomes thicker, stiffer, and less flexible. This is probably related to changes in the connective tissue of the blood vessel wall. This makes the blood pressure higher and makes the heart work harder, which may lead to thickening of the heart muscle (hypertrophy). The other arteries also thicken and stiffen. In general, most elderly people experience a moderate increase in blood pressure.

Blood

  • The blood itself changes slightly with age. Normal aging causes a reduction in total body water. As part of this, there is less fluid in the bloodstream, so blood volume decreases.
  • The number of red blood cells (and correspondingly, the hemoglobin and hematocrit levels) are reduced. This contributes to fatigue. Most of the white blood cells stay at the same levels, although certain white blood cells important to immunity (lymphocytes) decrease in their number and ability to fight off bacteria. This reduces the ability to resist infection.

EFFECT OF CHANGES

Under normal circumstances, the heart continues to adequately supply all parts of the body. However, an aging heart may be slightly less able to tolerate increased workloads, because changes reduce this extra pumping ability (reserve heart function).

Some of the things that can increase heart workload include:

  • Certain medications
  • Emotional stress
  • Extreme physical exertion
  • Illness
  • Infections
  • Injuries

COMMON PROBLEMS

  • Angina (chest pain caused by temporarily reduced blood flow to the heart muscle), shortness of breath with exertion, and heart attack can result from coronary artery disease.
  • Abnormal heart rhythms (arrhythmias) of various types can occur.
  • Anemia may occur, possibly related to malnutrition, chronic infections, blood loss from the gastrointestinal tract, or as a complication of other diseases or medications.
  • Arteriosclerosis (hardening of the arteries) is very common. Fatty plaque deposits inside the blood vessels cause them to narrow and can totally block blood vessels.
  • Congestive heart failure is also very common in the elderly. In people older than 75, congestive heart failure occurs 10 times more often than in younger adults.
  • Coronary artery disease is fairly common. It is often a result of arteriosclerosis.
  • Heart and blood vessel diseases are fairly common in older people. Common disorders include high blood pressure and orthostatic hypotension.
  • Heart valve diseases are fairly common. Aortic stenosis, or narrowing of the aortic valve, is the most common valve disease in the elderly.
  • Transient ischemic attacks (TIA) or strokes can occur if blood flow to the brain is disrupted.

Other problems with the heart and blood vessels include the following:

PREVENTION

You can help your circulatory system (heart and blood vessels). Heart disease risk factors that you have some control over include high blood pressure, cholesterol levels, diabetes, obesity, and smoking.

  • Eat a heart-healthy diet with reduced amounts of saturated fat and cholesterol, and control your weight. Follow your health care provider's recommendations for treating high blood pressure, high cholesterol, or diabetes. Minimize or stop smoking.
  • Exercise may help prevent obesity, and it helps people with diabetes control their blood sugar.
  • Exercise may help you maintain your abilities as much as possible and it reduces stress.
  • Have regular check-ups for your heart:
    • Have your blood pressure checked every year. If you have diabetes, heart disease, kidney problems, or certain other conditions, your blood pressure may need to be monitored more closely.
    • If your cholesterol level is normal, heave it rechecked every 5 years. If you have diabetes, heart disease, kidney problems, or certain other conditions, your cholesterol may need to be monitored more closely.
  • Moderate exercise is one of the best things you can do to keep your heart, and the rest of your body, healthy. Consult with your health care provider before beginning a new exercise program. Exercise moderately and within your capabilities, but do it regularly.
  • People who exercise usually have less body fat and smoke less than people who do not exercise. They also tend to have fewer blood pressure problems and less heart disease.

RELATED TOPICS

References

Minaker KL. Common clinical sequelae of aging. In: Goldman L, Ausielo D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 23.

Schwartz JB, Zipes DP. Cardiovascular disease in the elderly. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa; Saunders Elsevier; 2007: chap 75.

Reviewed By

Review Date: 08/15/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Liver biopsy?

Definition

A liver biopsyis a test that takes a sample of tissue from the liver for examination.

Alternative Names

Biopsy - liver; Percutaneous biopsy

How the test is performed

The test is usually done in the hospital. Before the test is done, you may be given a medicine to prevent pain or to calm you (sedative).

If the biopsy is done through the abdominal wall, you will be lying on your back with your right hand under your head. It is important to be as still as possible.

The health care provider will determine the correct spot for the biopsy needle to be inserted into the liver. The skin will be cleansed, and a small needle will be used to to inject medicine to numb the area. A small cut is made, and the biopsy needle is inserted. Ultrasound is usually used to guide the needle.You will be told to hold your breath while the biopsy is taken. This is to reduce the chance of puncturing the lung or tearing the liver.

The needle is removed quickly. Pressure will be applied to stop the bleeding. A bandage is placed over the insertion site.

The procedure can also be done by inserting a needle into the jugular vein. If the procedure is performed this way, you will lie on your back. X-rays will be used to guide the health care provider to the vein. A special needle and cathether (thin tube) is used to take the biopsy sample.

If you receive sedation for this test, you will need someone to drive you home.

How to prepare for the test

Tell your health care provider about:

  • Bleeding problems
  • Drug allergies
  • Medications you are taking
  • Whether you are pregnant

You must sign a consent form. Blood tests are sometimes done to test your blood's ability to clot. You will be told not eat or drink anything for the 8 hours before the test.

For infants and children:

The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following:

How the test will feel

You will feel a stinging pain from the anesthetic needle and when the anesthetic is injected. The biopsy needle may feel like deep pressure and dull pain. Some people feel this pain in the shoulder.

Why the test is performed

The biopsy helps diagnose many liver diseases. The procedure also helps assess the stage (early, advanced) of liver disease. This is especially important in hepatitis C infection.

The biopsy also helps detect:

  • Cancer
  • Infections
  • The cause of abnormal levels of liver enzymes that have been found in blood tests
  • The cause of an unexplained liver enlargement
Normal Values

The liver tissue is normal.

What abnormal results mean

The biopsy may reveal a number of liver diseases, including cirrhosis, hepatitis, or infections such as tuberculosis. It may also indicate cancer.

This test also may be performed for:

What the risks are
  • Collapsed lung
  • Complications from the sedation
  • Injury to the gallbladder or kidney
  • Internal bleeding
References

Lomas DJ. The liver. In: Adam A, Dixon AK, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 35.

Liver. Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:section IX.

Reviewed By

Review Date: 01/10/2011

Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Enteroscopy?

Definition

Enteroscopy is a procedure used to examine the small intestine (small bowel).

Alternative Names

Small bowel biopsy; Push enteroscopy; Double-balloon enteroscopy; Capsule enteroscopy; Sonde enteroscopy

How the test is performed

A thin, flexible tube (endoscope) is inserted through the mouth or nose and into the upper gastrointestinal tract. During a double-balloon enteroscopy, balloons attached to the endoscope can be inflated to allow the doctor to view a large part of the small intestine.

In a colonoscopy, a flexible tube is inserted through your rectum and colon. The tube usually can reach into the end part of the small intestine (ileum). See also: Colonoscopy

Tissue samples removed during enteroscopy are sent to the laboratory for examination.

How to prepare for the test

Do not take products containing aspirin for 1 week before the procedure. Tell your doctor if you take blood thinners such as warfarin (Coumadin) or clopidogrel (Plavix), because these may interfere with the test. Do NOT stop taking any medication unless told to do so by your health care provider.

Do not eat any solid foods or milk products after midnight the day of your procedure. You may have clear liquids until 4 hours before your exam.

You must sign a consent form.

How the test will feel

When the tube is put into your mouth and down your esophagus (food pipe), you may feel like gagging. You will get a numbing medicine to reduce this feeling.

You may get a mild sedative, but only in small doses because you must stay alert enough to help with the procedure (by doing such things as swallowing and turning). The biopsy sampling causes little or no pain, although you may have some mild cramping.

Why the test is performed

This test is most often performed to help diagnose diseases of the small intestines. It may be done if you have:

  • Abnormal x-ray results
  • Tumors in the small intestines
  • Unexplained diarrhea
  • Unexplained gastrointestinal bleeding
Normal Values

In a normal test result, the health care provider will not find sources of bleeding in the small bowel, and will not find any tumors or other abnormal tissue.

What abnormal results mean

Abnormal findings may include:

  • Abnormalities of the tissue lining the small intestine (mucosa) or the tiny, finger-like projections on the surface of the small intestine (villi)
  • Immune cells called PAS-positive macrophages
  • Polyps or cancer
  • Radiation enteritis
  • Swollen or enlarged lymph nodes or lymphatic vessels
  • Ulcers

Changes found on enteroscopy may be signs of disorders and conditions including:

What the risks are

Complications are rare but may include:

  • Excessive bleeding from the biopsy site
  • Hole in the bowel (bowel perforation)
  • Infection of the biopsy site leading to bacteremia
  • Vomiting, followed by aspiration into the lungs
Special considerations

Factors that prohibit use of this test may include:

  • Uncooperative or confused patients
  • Untreated blood clotting (coagulation) disorders
  • Use of aspirin or other medicines that prevent the blood from clotting normally (anticoagulants)

The greatest risk is bleeding. Signs include:

References

Bjorkman DJ. Gastrointestinal hemorrhage and occult gastrointestinal bleeding. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 137.

Sidhu R, Sanders DS, Morris AJ, McAlindon ME. Guidelines on small bowel enteroscopy and capsule endoscopy in adults. Gut. 2008;57:125-136.

Reviewed By

Review Date: 01/20/2010

David C. Dugdale III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

Gastric suction?

Definition

Gastric suction is a procedure to empty the contents of your stomach.

Alternative Names

Gastric lavage; Stomach pumping; Nasogastric tube suction

How the test is performed

A tube is inserted through the nose or mouth, down the food pipe (esophagus), and into the stomach. Sometimes you may be given a numbing medicine to reduce irritation and gagging caused by the tube.

Stomach contents can be removed using suction right away or after spraying water through the tube.

How to prepare for the test

In an emergency, such as when a patient has swallowed poison or is vomiting blood, no preparation is needed for gastric suction.

If gastric suction is being done for testing, your doctor may ask you not to eat overnight or to stop taking certain medications.

How the test will feel

You may feel a gagging sensation as the tube is passed.

Why the test is performed

This test may be done to:

  • Remove poisons, harmful materials, or excess medications from the stomach
  • Clean the stomach before an upper endoscopy (EGD) if you have been vomiting blood
  • Collect stomach acid
  • Relieve pressure if you have a blockage in the intestines
What the risks are

Risks may include:

  • Breathing in contents from the stomach (this is called aspiration)
  • Hole (perforation) in the esophagus
  • Tube may be placed into the airway instead of the esophagus
  • Minor bleeding
References

Greene S, Harris C, Singer J. Gastrointestinal decontamination of the poisoned patient. Pediatr Emerg Care. 2008;24:176-178.

Reviewed By

Review Date: 11/01/2010

Todd Eisner, MD, Private practice specializing in Gastroenterology, Boca Raton, FL. Clinical Instructor, Florida Atlantic University School of Medicine. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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Gastrointestinal Tract

RBC nuclear scan?

Definition

An RBC nuclear scan uses small amounts of radioactive material to mark (tag) red blood cells (RBCs). Your body is then scanned to determine the location of the cells and to see how they move through the body.

See: Nuclear ventriculography

How the test is performed

The exact procedure may vary slightly depending on the reason for the scan.

The RBCs are tagged with radioisotope in 1 of 2 ways.

The first method involves removing blood from a vein. The red blood cells are separated from the rest of the blood sample and then mixed with the radioactive material. The cells with the radioactive material are considered "tagged." A short time later the tagged RBCs are injected into one of your veins.

The second method involves an injection of medicine that will allow the radioactive material to attach to your red blood cells. The radioactive material is injected into a vein 15 or 20 minutes after you receive this medicine.

Scanning may be done immediately or after a delay. You will lie on a table underneath a special camera that detects the location and amount of radiation given off by the tagged cells.

A series of scans may be performed. The specific areas scanned depend on the reason for the test.

How to prepare for the test

You must sign a consent form. You will wear a hospital gown. Remove jewelry or metallic objects before the scan.

How the test will feel

When the needle is inserted to draw blood or to give the injection, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

The x-rays and radioactive material are painless. Some people may have discomfort from lying on the hard table.

Why the test is performed

This test is most often done to locate the site of bleeding in patients who have blood loss from the colon or other parts of the gastrointestinal tract.

A variation on this test, called a ventriculogram, may be performed to check heart function.

Normal Values

A normal exam shows the patient is not bleeding rapidly from the gastrointestinal tract.

What abnormal results mean

Your health care provider will determine abnormalities based on the scan findings. This scan is most commonly used to determine the site of bleeding, particularly bleeding within the gastrointestinal tract.

What the risks are

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

Extremely rarely, a person may experience an allergic reaction to the radioisotope. This may include anaphylaxis if the person is extremely sensitive to the substance.

There is a very slight exposure to radiation from the radioisotope. The radiation is minimal, and the materials "decompose" (are no longer radioactive) in a very short time. Virtually all radioactivity is gone within about 12 hours. There are no documented cases of injury from exposure to radioisotopes. The scanner only detects radiation -- it does not give off radiation.

Most nuclear scans (including an RBC scan) are not recommended for women who are pregnant or breastfeeding.

Special considerations

Scans may need to be repeated over 1 or 2 days to detect gastrointestinal bleeding.

References

Bjorkman DJ. Gastrointestinal hemorrhage and occult gastrointestinal bleeding. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2007:chap 137.

Segerman D, Miles KA. Radionuclide imaging: general principles. In: Adam A, Dixon AK, eds. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging. 5th ed. New York, NY: Churchill Livingstone; 2008:chap 7.

Reviewed By

Review Date: 11/21/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

001
Gastrointestinal Tract

Percutaneous transhepatic cholangiogram?

Definition

A percutaneous transhepatic cholangiogram (PTCA) is an x-ray of the bile ducts, the tubes that carry bile from the liver to the gallbladder and small intestine.

Alternative Names

PTCA; Cholangiogram - PTCA

How the test is performed

The test is performed in a radiology department by a radiologist.

You will be asked to lie on your back on the x-ray table. The health care provider will clean the upper right side of your belly area and then apply a numbing medicine.

X-rays are used to help the health care provider locate your liver and bile ducts. A long, thin, flexible needle is then inserted through the skin into the liver. The health care provider injects dye, called contrast medium, into the bile ducts. Contrast helps highlight certain areas they can be seen better. More x-rays are taken as the dye flows through the bile ducts into the small intestine. This can be seen on a nearby video monitor.

How to prepare for the test

Inform the health care provider if you are pregnant. You will be given a hospital gown to wear and will be asked to remove all jewelry.

You will be asked not to eat or drink anything for 6 hours prior to the exam.

Tell your health care provider if you are taking any blood thinners such as warfarin (coumadin) or Plavix (clopidrogrel).

How the test will feel

There will be a sting as the anesthetic is given and some discomfort as the needle is advanced into the liver. You may be given medication for sedation and/or pain control. Generally, the x-ray itself causes little or no discomfort.

Why the test is performed

This test can help diagnose the cause of a bile duct blockage.

Bile a liquid released by the liver. It contains cholesterol, bile salts, and waste products. Bile salts help your body break down (digest) fats. A blockage of the bile duct can lead to swelling of the gallbladder or pancreas.

This results of this test may help your doctor plan treatments for a bile duct blockage. For example, it can help determine where a drainage tube or stent can be placed.

Normal Values

The bile ducts are normal in size and appearance for the age of the patient.

What abnormal results mean

The results may show that the ducts are enlarged, which may indicate the ducts are blocked. The blockage may be caused by scarring or stones. It may also indicate cancer in the bile ducts, liver, pancreas, or region of the gallbladder.

See also:

What the risks are

There is a slight chance of an allergic reaction to the contrast medium (iodine).

There is a slight chance of damage to nearby organs, excessive blood loss, blood poisoning (sepsis), and inflammation of the bile ducts.

Special considerations

This test has been mostly replaced by an endoscopic retrograde cholangiopancreatography (ERCP) test, which can also treat the blockage. This test may be done if an ERCP test cannot be performed or has failed.

A magnetic resonance cholangiopancreatography (MRCP) is a newer, noninvasive imaging method, based on MRI. It provides similar views of the bile ducts, but is not always possible to perform. It cannot be used to treat the blockage.

References

Lidofsky S. Jaundice. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 20.

Wael E.A. Saad, Michael J. Wallace, Joan C. Wojak, Sanjoy Kundu. Quality Improvement Guidelines for Percutaneous Transhepatic Cholangiography, Biliary Drainage, and Percutaneous Cholecystostomy. Journal of Vascular and Interventional Radiology Vol. 21, Issue 6, Pages June 2010. 789-795.

Reviewed By

Review Date: 01/31/2011

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Jason Levy, MD, Northside Radiology Associates, Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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