Management of Edema Causes

Source#1 www.medicalnewstoday.com

What is EDEMA?

Edema, is swelling caused by fluid retention - excess fluid is trapped in the body's tissues. In the UK/Ireland/Australasia and some other countries the word is spelled oedema. Swelling caused by edema commonly occurs in the hands, arms, ankles, legs and feet. It is usually linked to the venous or lymphatic systems. Edema was formerly known as dropsy or hydropsy.

Edema may be generalized or local. It can appear suddenly, but usually develops subtly - the patient may first gain weight, or wake up with puffy eyes. Many patients wait until symptoms are well advanced before seeking medical help.

According to Medilexicon's medical dictionary, edema is:"1. An accumulation of an excessive amount of watery fluid in cells or intercellular tissues.2. At the gross level, used to describe the physical sign commonly likened to swelling or increased girth that often accompanies the accumulation of fluid in a body part, most often a limb."

The English word "edema" comes from the Greek word oidema, meaning "a swelling tumor", which is derived from the Greek verb oidein meaning "to swell".

It is estimated that approximately 4.4 million people in USA have edema.

There are many types of edema. The most common ones are:

Peripheral edema - in the feet (pedal edema), ankles, legs, hands and arms.

Cerebral edema - in and around the brain (cerebral edema).

Eye edema - in and around the eyes, e.g. macular edema, corneal edema, periorbital edema (puffiness around the eys. Macular edema is a serious complication of diabetic retinopathy. The CDC (Centers for Disease Control and Prevention) estimates that the number of cases of diabetic retinopathy will triple from 5.5 million in 2005 to 16 million in 2050.

What causes edema? If the capillaries (tiny blood vessels) leak fluid into the surrounding tissue the area will start to swell. This could be due to capillary damage or increased pressure.

Leaking capillaries will cause the kidneys to accumulate higher than normal quantities of sodium (salt) and water in order to compensate for the capillary fluid loss. This results in more blood circulating in the body, which in turn causes even more capillary leakage into the surrounding tissue, which produces additional swelling - a vicious cycle.

Edema is most commonly caused by:

Physical inactivity - edema is more prevalent among people who do not exercise at all, and walk very little.

Standing or sitting still for long - if you stand or sit still for a long time there is a much higher chance of swelling.

Genes - researchers in Spain identified the genes that cause blindness produced by corneal edema. Surgery - there is usually some swelling after a surgical procedure.

High altitudes - especially when combined with physical exertion. Acute mountain sickness can lead to high altitude pulmonary edema or high altitude cerebral edema.

Heat - especially when combined with physical exertion. During high temperatures the body is less efficient at removing fluid from tissues, especially around the ankles.

Burns - the skin reacts to a burn by retaining fluid, causing localized swelling.

Pregnancy - during pregnancy the woman releases hormones which encourage the body to retain fluids. Pregnant women tend to retain much more sodium and water than women who are not pregnant. When a woman is pregnant her face will typically swell, as will her hands, lower limbs and feet.

When the woman is resting in a reclined position the enlarged uterus occasionally compresses the inferior vena cava, causing obstruction of both femoral veins, leading to edema.

A pregnant woman's blood is hypercoaguble (clots more easily), raising the risk of deep venous thrombosis (DVT), a cause of edema. Eclampsia, which results from pregnancy-induced hypertension (high blood pressure), can also cause edema.

Menstruation and pre-menstruation - hormone levels fluctuate during the menstrual cycle. During the days before menstrual bleeding there will be a reduction in the levels of the hormone progesterone, which may cause fluid retention.

The contraceptive pill - any medication that includes estrogen can cause fluid retention. It is not uncommon for women to put on weight when they first go on the pill.

Menopause - around the period of the menopause as well as after it, hormone fluctuations can cause fluid retention. Hormone replacement therapy after the menopause can also cause edema.

Certain medications - such as vasodilators (drugs that open blood vessels), calcium channel blockers, NSAIDs (non-steroidal anti-inflammatory drugs), estrogens, several chemotherapy drugs, and some diabetes drugs, such as thiazolidinediones. Scientists in the University of Utah discovered why thiazolidinediones cause edema .

Excessive salt intake - this is especially the case for people who are susceptible to developing edema.

Malnutrition and/or bad diet - dietitians say low consumption of thiamine (vitamin B1), as well as insufficient vitamins B6 and B5 may contribute toward fluid retention. Low levels of albumin levels may also play a part - low albumin levels can also be caused by kidney disease.

Edema can also be caused by the following diseases: Kidney disease/damage - patients with kidney disease may not be able to eliminate enough fluid and

sodium from the blood. This results in more pressure on the blood vessels, which causes some of the liquid to leak out. Kidney disease patients with edema will generally have swelling around their legs and eyes.

Damage to the capillaries in the kidneys (glomeruli) that filter waste and excess fluids from the blood can result in nephrotic syndrome. Among the many symptoms of nephrotic syndrome is an insufficient level of blood albumin, which leads to edema.

Heart failure - this is when the heart cannot pump blood properly to all parts of the body. If one or both of the lower chambers of the heart lose the ability to pump blood effectively, the blood can accumulate in the limbs, causing edema.

Chronic lung disease - this includes many lung diseases, such as asthma, chronic bronchitis, COPD, emphysema, pulmonary fibrosis and sarcoidosis. Some patients may experience an accumulation of fluids in the lungs - pulmonary edema.

Liver disease - such as cirrhosis, which causes scarring of the liver. This affects liver function, which causes the secretion of hormones and fluid-regulating chemicals to change. People with cirrhosis of the liver also have increased pressure within the portal vein - a large vein that carries blood from the intestines, spleen and pancreas into the liver. The problems can lead to fluid retention in the legs and ascites (abdominal cavity).

Diabetes - a patient with diabetes may have edema for several different reasons, including cardiovascular disease and its complications, acute renal failure, acute liver failure, protein losing enteropathy (disease of the intestine causing protein loss), and some medications. Diabetic macular edema is the swelling of the retina in diabetes.

Allergies - some foods and insect bites may cause edema in susceptible people.

Arthritis - people with arthritis most commonly have swelling in the ankles, feet, legs, and calves - peripheral edema. Arthritis may cause swelling for many reasons, for example, sporadic ankle swelling in rheumatoid arthritis is common and occurs mainly as a result of active inflammatory synovitis (inflammation of the synovial membrane, the lining of the joint).

Thyroid disease - people with a disorder of the thyroid gland commonly experience edema.

Brain tumor - a brain tumor will accumulate water around itself, especially as it builds new blood vessels.

Head injury - a blow to the head may result in an accumulation of fluids in the brain or between the brain and the skull.

Edema in the leg is most commonly caused by: A blood clot - any blockage, such as a clot in one of the veins can impede the flow of blood. This causes an

increase in pressure in the vein, which may result in leakage of fluids into the surrounding tissue, causing edema.

Varicose veins - these often accompany symptoms of edema. Varicose veins usually occur because valves become damaged; static pressure increases, resulting in the bulging veins. The static pressure also increases the risk of leakage of fluids into the surrounding tissue.

Infection/inflammation - the lymph nodes may swell in response to infection.

A cyst/growth/tumor - edema can causes cysts, which can then cause more edema. Any lump can cause edema for a number of reasons. The lump may press against a vein causing a build-up of pressure in that vein, which may result in fluids leaking into surrounding tissue. The lymph nodes may react to a tumor and swell.

Lymphedema - the lymphatic system helps get rid of excess fluid from tissues. If this system is damaged the lymph nodes and lymph vessels which continually drain an area may not work as they should, it could result in edema.

If the damage is due to lymphedema it is called primary lymphedema, if it is caused by a disease or medical condition, such as an infection or cancer, it is caused secondary lymphedema.

What are the symptoms of edema? Symptoms will mainly depend on the underlying cause. The following refer to generalized edema:

Swelling of the skin. Skin may be stretched and shiny. The skin may retain a dimple after being pressed for about ten seconds. Puffiness of the ankles, face or eyes. Aching body parts. Stiff joints. Weight gain. Weight loss. Hand and neck veins are fuller. Raised pulse rate. Hypertension - raised blood pressure. Ascites - increased abdominal size.

What is the diagnosis of edema? A GP (general practitioner, primary care physician) will want to determine what the underlying cause of the edema is. The patient will be asked questions about his/her:

Medical history. Current state of health. How long the signs and symptoms have existed. How permanent or intermittent the signs and symptoms are. Whether the patient has had edema before.

The physician will also carry out a physical exam. If there are indications that there may be an underlying medical condition causing the edema the doctor may order some tests, these may include:

A chest X-ray Blood tests Urine tests Liver function tests Heart function tests

What is the treatment for edema? In order to treat the edema the doctor has to diagnose the condition that is causing it first.

Diuretics

These are drugs that raise the rate of urination, providing a means of forced dieresis. Diuresis is the increased production of urine by the kidney. There are several types of diuretics - they increase the excretion of water from the body in various different ways. Diuretics are not suitable if the patient is

pregnant, or has chronic venous insufficiency (weakened valves in the veins of the legs).

Many medications appear to cause pedal edema (foot edema), especially estrogens, vasodilators, NSAIDS, and calcium channel blockers. Most edemas caused by medications are the types that are caused by high blood pressure in the capillaries. For these patients diuretics are not an effective treatment. Physicians report that angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers give better results.

Antiangiogenesis therapy (controlling blood vessel growth)

The beneficial effects of anti-angiogenesis drugs in the treatment of the glioblastomas (deadly brain tumors) appear to result primarily from reduction of edema, researchers at the Massachusetts General Hospital reported.

Oxygen therapy

Oxygen delivered through the nose may improve poor vision caused by diabetic macular edema, say researchers at Johns Hopkins.

A good GP will also recommend the following self-care techniques which may help resolve the fluid retention problem:

Cut down salt consumption.

If the patient is overweight, to lose weight.

Do regular exercise.

Raise the legs several times per day to improve circulation.

Wear supporting stockings.

Not to sit/stand still for too long.

Get up and walk about regularly when travelling by car, train, boat or plane.

Avoid extremes of temperature, such as hot baths, showers, and saunas. Dress warmly if it is cold.

Massage - if the affected area is stroked firmly in the direction of the heart it may help move the fluid. It is important that the hand movements do not cause pain. A qualified masseuse or physical therapist will know how to do this more effectively.

What are the complications of edema? Edema is usually caused by an underlying disease or condition. If that condition is not treated, the health consequences could be serious. Untreated edema can cause:

Painful swelling. The pain can gradually get worse.

Walking difficulty.

Stiffness.

Awkward gait.

Skin can become stretched, itchy and bothersome.

The swollen area is more likely to become infected.

Scarring may occur between the layers of tissue.

Poor blood circulation.

Arteries, veins, and joints may lose their elasticity.

Ulcerations of the skin.

Written by Christian Nordqvist Copyright: Medical News Today

Source#2 www.mayoclinic.com

Definition

Edema is swelling caused by excess fluid trapped in your body's tissues. Although edema can affect any part of your body, it's most commonly noticed in your hands, arms, feet, ankles and legs.

Edema can be the result of underlying medical conditions, certain medications or pregnancy.

Identifying and treating the underlying cause of edema is key to effectively controlling it. Self-care measures coupled with medication that removes excess fluid usually can effectively treat edema.

Symptoms

Signs and symptoms of edema include:

Swelling or puffiness of the tissue under your skin (subcutaneous tissue) Stretched or shiny skin Skin that retains a dimple after being pressed for several seconds Increased abdominal size

When to see a doctor Make an appointment to see your doctor if you have any of the signs or symptoms of edema, such as swelling, stretched or shiny skin, or skin that retains a dimple after being pressed.

Seek immediate medical attention if you experience any signs or symptoms of edema in your lungs (pulmonary edema), including:

Shortness of breath Difficulty breathing Chest pain

Pulmonary edema is a potentially life-threatening condition. Diagnosis and treatment of pulmonary edema differ from other forms of edema.

Causes

Edema occurs when tiny blood vessels in your body (capillaries) leak fluid. This leakage can result from damage to or increased pressure in the capillaries, or from lowered levels of serum albumin, a protein in your blood. When your body senses the capillaries are leaking, your kidneys begin to retain more sodium and water than normal to compensate for the lost fluid from your blood vessels. This increases the amount of fluid circulating through your body, which causes the capillaries to leak more. The fluid from the capillaries leaks into the surrounding tissue, causing the tissue to swell.

Mild cases of edema may result from:

Sitting or staying in one position for too long Eating too much salty food Premenstrual signs and symptoms Pregnancy, which can cause swelling in your hands, feet and face from excess fluid retention

Edema can be a side effect of some medications, including:

Drugs that open blood vessels (vasodilators) Calcium channel blockers (calcium antagonists) Nonsteroidal anti-inflammatory drugs (NSAIDs) Estrogens Certain diabetes medications called thiazolidinediones

In some cases, however, edema may be a sign of a more serious underlying medical condition. Diseases and conditions that may cause edema include:

Congestive heart failure. When one or both of your heart's lower chambers loses its ability to pump blood effectively — as happens in congestive heart failure — the blood can back up in your legs, ankles and feet, causing edema.

Cirrhosis. This disease causes scarring of your liver, which interferes with liver function, causing changes in the hormones and chemicals that regulate fluids in your body, as well as increasing pressure within the large blood vessel (portal vein) that carries blood from your intestine, spleen and pancreas into your liver. These problems can result in fluid accumulating in your legs and your abdominal cavity (ascites).

Kidney disease. When you have kidney disease, your kidneys may not be able to eliminate enough fluid and sodium from your blood. The extra fluid and sodium increases pressure in your blood vessels, causing edema. Edema associated with kidney disease usually occurs in your legs and around your eyes.

Kidney damage. Damage to the tiny blood vessels in your kidneys (glomeruli) that filter waste and excess water from your blood can result in nephrotic syndrome. One result of nephrotic syndrome is low levels of protein (albumin) in your blood, which can lead to fluid accumulation and edema.

Weakness or damage to veins in your legs. Chronic venous insufficiency (CVI) is a condition in which the veins and valves in the veins in your legs are weakened or damaged and can't pump enough blood back to your heart. The remaining blood increases pressure in the veins, causing swelling.

Inadequate lymphatic system. Your body's lymphatic system helps clear excess fluid from tissues. If this system is damaged — either due to lymphedema that occurs on its own (primary lymphedema) or because of a disease or medical condition, such as cancer or an infection (secondary lymphedema) — the lymph nodes and lymph vessels draining an area may not work correctly and edema results.

Risk Factors

The following diseases and conditions can increase the risk of developing edema:

Congestive heart failure Cirrhosis Kidney disease Nephrotic syndrome Chronic venous insufficiency (CVI) Deep vein thrombosis Lymphedema

Due to the fluid needed by the fetus and placenta, a pregnant woman's body retains more sodium and water than usual, increasing the risk of edema.

Taking some medications — such as drugs that open blood vessels (vasodilators), calcium channel blockers (calcium antagonists), nonsteroidal anti-inflammatory drugs (NSAIDs), estrogens and certain diabetes medications called thiazolidinediones — can increase your risk of edema.

Complications

If left untreated, edema can cause:

Increasingly painful swelling Difficulty walking Stiffness Stretched skin, which can become itchy and uncomfortable Increased risk of infection in the swollen area Scarring between layers of tissue Fibrous deposits in tissues Decreased blood circulation Decreased elasticity of arteries, veins, joints and muscles Increased risk of skin breakdown (ulceration)

Preparing for your appointment

Unless you're already under a specialist's care for a current medical condition, you'll probably start by seeing your family doctor or regular health care provider to begin evaluation for what could be causing your symptoms.

Here's some information to help you prepare for your appointment, and what to expect from your doctor.

What you can do

Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance to prepare for common diagnostic tests.

Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.

Make a list of your key medical information, including any other conditions for which you're being treated, and the names of any medications, vitamins or supplements you're taking.

Consider questions to ask your doctor and write them down. Bring along notepaper and a pen to jot down information as your doctor addresses your questions.

For edema, some basic questions to ask your doctor include:

What are the possible causes of my symptoms? What kinds of tests do I need? Do these tests require any special preparation? Is my condition temporary? Will I need treatment? What treatments are available? I have other medical problems; will this treatment interfere with them? Do you have any brochures or other printed material that I can take home with me? What Web sites do

you recommend visiting?

In addition to the questions that you've prepared, don't hesitate to ask questions during your appointment at any time if you don't understand something.

What to expect from your doctor Your doctor or health care provider is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on.

Questions your doctor might ask include:

What symptoms are you experiencing? How long have you been experiencing these symptoms? Do your symptoms seem to come and go or are they persistent? Have you had edema before? Does anything seem to make your symptoms better? Does anything seem to make your symptoms worse? What kinds of foods do you regularly eat? Do you restrict your intake of salt and salty foods? Do you drink alcohol? Do you seem to be urinating normally? Do you notice swelling all over your body, or does it seem to be localized to one area, such as an arm or

leg? Does swelling diminish if you raise the swollen limb above heart level for an hour or so?

Test and Diagnosis

To understand what might be causing your edema, your doctor will perform a physical exam and ask you questions about your medical history.

If your doctor suspects an underlying condition as the cause of your edema, he or she may recommend certain tests to help identify the cause. Tests might include:

A urine test (urinalysis) Blood tests Measuring or estimating the pressure in certain blood vessels, such as in your jugular vein A chest X-ray

Treatments and Drugs

Treating edema usually involves:

Treating the underlying cause of edema Taking medication to increase your kidneys' output of water and sodium (diuretics), including thiazide

diuretics, furosemide (Lasix) or spironolactone (Aldactone) Limiting salt in your diet to decrease fluid retention, as recommended by your doctor

In some cases, diuretics may not be appropriate to treat edema, such as in some people who have chronic venous insufficiency or in most pregnant women.

Lifestyle and Home Remedies

The following may help decrease edema and keep it from coming back. Before trying these self-care techniques, talk to your doctor about which ones are right for you.

Movement. Moving and using the muscles in the part of your body that's affected by edema may help pump the excess fluid back to your heart. Ask your doctor about exercises you can do that may reduce swelling.

Elevation. Hold the swollen part of your body above the level of your heart for at least 30 minutes, three or four times a day. In some cases, elevating the affected body part while you sleep may be helpful.

Massage. Stroking the affected area toward your heart using firm, but not painful, pressure may help move the excess fluid out of that area.

Compression. If one of your limbs is affected by edema, your doctor may recommend you wear compression stockings, sleeves or gloves. These garments keep pressure on your limbs to prevent fluid from collecting in the tissue.

Reduce salt intake. Follow your doctor's suggestions about limiting how much salt you consume. Avoid temperature extremes. Sudden temperature changes and very hot and very cold temperatures can

make edema worse. Avoid hot baths, hot showers, hot tubs and saunas. Protect yourself from sunburn. Dress warmly when going out in cold temperatures and take precautions to protect yourself from frostbite.

Source#3: www.medicinenet.com

What is edema?

Edema is observable swelling from fluid accumulation in body tissues. Edema most commonly occurs in the feet and legs, where it is referred to as peripheral edema. The swelling is the result of the accumulation of excess fluid under the skin in the spaces within the tissues. All tissues of the body are made up of cells and connective tissues that hold the cells together. This connective tissue around the cells and blood vessels is known as the interstitium. Most of the body's fluids that are found outside of the cells are normally stored in two spaces; the blood vessels (as the "liquid" or serum portion of your blood) and the interstitial spaces (not within the cells). In various diseases, excess fluid can accumulate in either one or both of these compartments.

The body's organs have interstitial spaces where fluid can accumulate. An accumulation of fluid in the interstitial air spaces (alveoli) in the lungs occurs in a disorder called pulmonary edema. In addition, excess fluid sometimes collects in what is called the third space, which includes cavities in the abdomen (abdominal or peritoneal cavity - called "ascites") or in the chest (lung or pleural cavity - called "pleural effusion"). Anasarca refers to the severe, widespread accumulation of fluid in the all of the tissues and cavities of the body at the same time.

What is pitting edema and how does it differ from non-pitting edema?

Pitting edema can be demonstrated by applying pressure to the swollen area by depressing the skin with a finger. If the pressing causes an indentation that persists for some time after the release of the pressure, the edema is referred to as pitting edema. Any form of pressure, such as from the elastic in socks, can induce pitting with this type of edema.

In non-pitting edema, which usually affects the legs or arms, pressure that is applied to the skin does not result in a persistent indentation. Non-pitting edema can occur in certain disorders of the lymphatic system such as lymphedema, which is a disturbance of the lymphatic circulation that may occur after a mastectomy, lymph node surgery, or congenitally. Another cause of non-pitting edema of the legs is called pretibial myxedema, which is a swelling over the shin that occurs in some patients with hyperthyroidism. Non-pitting edema of the legs is difficult to treat. Diuretic medications are generally not effective, although elevation of the legs periodically during the day and compressive devices may reduce the swelling.

The focus of the rest of this article is on pitting edema, as it is by far the most common form of edema.

What causes pitting edema?

Edema is caused by either systemic diseases, that is, diseases that affect the various organ systems of the body, or by local conditions involving just the affected extremities. The most common systemic diseases associated with edema involve the heart, liver, and kidneys. In these diseases, edema occurs primarily because of the body's retention of too much salt (sodium chloride). The excess salt causes the body to retain water. This water then leaks into the interstitial tissue spaces, where it appears as edema.

The most common local conditions that cause edema are varicose veins and thrombophlebitis (inflammation of the veins) of the deep veins of the legs. These conditions can cause inadequate pumping of the blood by the veins (venous insufficiency). The resulting increased back-pressure in the veins forces fluid stay in the extremities (especially the ankles and feet). The excess fluid then leaks into the interstitial tissue spaces, causing edema.

How does salt intake affect edema?

The body's balance of salt is usually well-regulated. A normal person can consume small or large quantities of salt in the diet without concern for developing salt depletion or retention. The intake of salt is determined by dietary patterns and the removal of salt from the body is accomplished by the kidneys. The kidneys have a great capacity to control the amount of salt in the body by changing the amount of salt eliminated (excreted) in the urine. The amount of salt excreted by the kidneys is regulated by hormonal and physical factors that signal whether retention or removal of salt by the kidneys is necessary.

If the blood flow to the kidneys is decreased by an underlying condition such as heart failure, the kidneys react by retaining salt. This salt retention occurs because the kidneys perceive that the body needs more fluid to compensate for the decreased blood flow. If the patient has a kidney disease that impairs the function of the kidneys, the ability to excrete salt in the urine is limited. In both conditions, the amount of salt in the body increases, which causes the patient to retain water and develop edema.

Patients experiencing a disturbance in their ability to normally excrete salt may need to either be placed on a diet limited in salt and/or given diuretic medications (water pills). In the past, patients with diseases associated with edema were placed on diets very restricted in salt intake. With the development of new and very potent diuretic agents, this marked restriction in dietary salt intake is generally no longer necessary. These diuretics work by

blocking the reabsorption and retention of salt by the kidneys, thereby increasing the amount of salt and water that is eliminated in the urine.

Why does a patient with heart disease retain fluid?

Heart failure is the result of poor cardiac function and is reflected by a decreased volume of blood pumped out by the heart, called cardiac output. Heart failure can be caused by weakness of the heart muscle, which pumps blood out through the arteries to the entire body, or by dysfunction of the heart valves, which regulate the flow of blood between the chambers of the heart. The diminished volume of blood pumped out by the heart (decreased cardiac output) is responsible for a decreased flow of blood to the kidneys. As a result, the kidneys sense that there is a reduction of the blood volume in the body. To counter the seeming loss of fluid, the kidneys retain salt and water. In this instance, the kidneys are fooled into thinking that the body needs to retain more fluid volume when, in fact, the body already is holding too much fluid.

This fluid increase ultimately results in the buildup of fluid within the lungs, which causes shortness of breath. Because of the decreased volume of blood pumped out by the heart (decreased cardiac output), the volume of blood in the arteries is also decreased, despite the actual increase in the body's total fluid volume. An associated increase in the amount of fluid in the blood vessels of the lungs causes shortness of breath because the excess fluid from the lungs' blood vessels leaks into the airspaces (alveoli) and interstitium in the lungs. This accumulation of fluid in the lung is called pulmonary edema. At the same time, accumulation of fluid in the legs causes pitting edema. This edema occurs because the build-up of blood in the veins of the legs causes leakage of fluid from the legs' capillaries (tiny blood vessels) into the interstitial spaces.

An understanding of how the heart and lungs interact will help you to better comprehend how fluid retention works in heart failure. The heart has four chambers; an auricle and a ventricle on the left side of the heart and an auricle and ventricle on the right. The left auricle receives oxygenated blood from the lungs and transfers it to the left ventricle, which then pumps it through the arteries to the entire body. The blood then is transported back to the heart by veins into the right auricle and transferred to the right ventricle, which then pumps it to the lungs for re-oxygenation.

Left-sided heart failure, which is due primarily to a weak left ventricle, usually is caused by coronary artery disease, hypertension, or disease of the heart valves. Typically, when these patients initially come to the doctor they are troubled by shortness of breath with exertion and when lying down at night (orthopnea). These symptoms are due to pulmonary edema that is caused by pooling of the blood in the vessels of the lungs.

In contrast, right-sided heart failure, which often is due to chronic lung diseases such as emphysema, initially causes salt retention and edema. Persistent salt retention in these patients, however, may lead to an expanded blood volume in the blood vessels, thereby causing fluid accumulation in the lungs (pulmonary congestion) and shortness of breath.

In patients with heart failure due to weak heart muscle (cardiomyopathy), both the right and left ventricles of the heart are usually affected. These patients, therefore, can initially suffer from swelling both in the lungs (pulmonary edema) and in the legs and feet (peripheral edema). The physician examining a patient who has congestive heart failure with fluid retention looks for certain signs. These include:

pitting edema of the legs and feet,

rales in the lungs (moist crackle sounds from the excess fluid that can be heard with a stethoscope),

a gallop rhythm (three heart sounds instead of the normal two due to muscle weakness), and

distended neck veins. The distended neck veins reflect the accumulation of blood in the veins that are returning blood to the heart.

Why do patients with liver disease develop ascites and edema?

In patients with chronic diseases of the liver, fibrosis (scarring) of the liver often occurs. When the scarring becomes advanced, the condition is called cirrhosis of the liver. Ascites is excessive fluid that accumulates in the abdominal (peritoneal) cavity. It is a complication of cirrhosis and appears as an abdominal bulge. The peritoneum is the inner lining of the abdominal cavity, which also folds over to cover the organs inside the abdomen such as the liver, gallbladder, spleen, pancreas, and intestines. Ascites develops because of a combination of two factors:

1. increased pressure in the vein system that carries blood from the stomach, intestines, and spleen to the liver (portal hypertension); and

2. a low level of the protein albumin in the blood (hypoalbuminemia). Albumin, which is the predominant protein in the blood and which helps maintain blood volume, is reduced in cirrhosis primarily because the damaged liver is not able to produce enough of it.

Other consequences of portal hypertension include dilated veins in the esophagus (varices), prominent veins on the abdomen, and an enlarged spleen. Each of these conditions is due primarily to the increased pressure and accumulation of blood and excess fluid in the abdominal blood vessels. The fluid of ascites can be removed from the abdominal cavity by using a syringe and a long needle, a procedure called paracentesis. Analysis of the fluid can help differentiate ascites that is caused by cirrhosis from other causes of ascites, such as cancer, tuberculosis, congestive heart failure, and nephrosis. Sometimes, when ascites does not respond to treatment with diuretics, paracentesis can be used to remove large amounts of the ascitic fluid.

Peripheral edema, which is usually seen as pitting edema of the legs and feet, also occurs in cirrhosis. The edema is a consequence of the hypoalbuminemia and the kidneys retaining salt and water.

The presence or absence of edema in patients with cirrhosis and ascites is an important consideration in the treatment of the ascites. In patients with ascites without edema, diuretics must be given with extra caution. Diuresis (induced increased volume of urine by use of diuretics) that is too aggressive or rapid in these patients can lead to a low blood volume (hypovolemia), which can cause kidney and liver failure. In contrast, when patients who have both edema and ascites undergo diuresis, the edema fluid in the interstitial space serves as somewhat of a buffer against the development of low blood volume. The excess interstitial fluid moves into the blood vessel spaces to rapidly replenish the depleted blood volume.

What is idiopathic edema?

Idiopathic edema is a pitting edema of unknown cause that occurs primarily in pre-menopausal women who do not have evidence of heart, liver, or kidney disease. In this condition, the fluid retention at first may be seen primarily pre-menstrually (just prior to menstruation), which is why it sometimes is called "cyclical" edema. However, it can become a more constant and severe problem.

Patients with idiopathic edema often take diuretics to decrease the edema in order to lessen the discomfort of bloating and swelling. Paradoxically, however, the edema in this condition can become more of a problem after the use of diuretics. The patients can develop fluid retention as a rebound phenomenon each time they discontinue diuretics. It is important to talk to your doctor before using any diuretics.

Patients with idiopathic edema appear to have a leak in the capillaries (tiny peripheral blood vessels that connect the arteries with the veins) so that fluid passes from the blood vessels into the surrounding interstitial space. Thus,

a patient with idiopathic edema has a decreased blood volume, which leads to the typical reaction of salt retention by the kidneys.

The leg edema in these patients is exaggerated in the standing position, since edema tends to accumulate in those parts of the body that are close to the ground at the time.

These patients often have edema around the eyes (periorbital edema) in the morning because the edema fluid accumulates during the night around their eyes as they lay sleeping flat.

In contrast, edema around the eyes does not tend to develop in cardiac patients who keep their heads elevated at night because of shortness of breath when they lie flat. These patients characteristically experience varying amounts of edema in different parts of the body at different times of the day.

Patients with idiopathic edema often become dependant on diuretics, and this dependance is often difficult to interrupt. A period as long as three weeks off diuretics may be required to break the dependency cycle. The withdrawal from diuretics may lead to fluid retention that produces major discomfort and swelling. Furthermore, there are definite risks associated with the prolonged use of diuretics in these individuals, which are compounded by the tendency to increase the doses of the diuretics.

As a result of chronic diuretic use and abuse, patients may develop:

a deficiency of potassium,

depletion of blood volume in the blood vessels, and

kidney insufficiency or failure.

Other side effects of diuretics include:

high blood sugar (diabetes),

high uric acid (gout),

muscle cramps, tender and enlarged breasts (gynecomastia), and

pancreatitis (inflammation of the pancreas).

Although withdrawal from diuretics is the most important factor in treating these patients, other medications have been used to try to minimize the fluid retention. These medications include ACE inhibitors, low-dose amphetamines, ephedrine, bromocriptine (Parlodel), or levodopa-carbidopa (Sinemet) in combination. However, their effectiveness is uncertain and side effects of these drugs may occur. For example, hypotension (low blood pressure) may be seen with the use of ACE inhibitors, especially if the patient is also taking diuretics.

How does venous insufficiency cause edema?

The veins in the legs are responsible for transporting blood up to the veins of the torso, where it is then returned to the heart. The veins of the legs have valves that prevent the backward flow of blood within them. Venous insufficiency is incompetence of the veins that occurs because of dilation, or enlargement, of the veins and dysfunction of their valves. This happens, for example, in patients with varicose veins. Venous insufficiency leads to a backup of blood and increased pressure in the veins, thereby resulting in edema of the legs and feet. Edema of the legs also can occur with an episode of deep vein thrombophlebitis, which is a blood clot within an inflamed

vein. In this situation, the clot in the deep vein blocks the return of blood, and consequently causes increased back-pressure in the leg veins.

Venous insufficiency is a problem that is localized to the legs, ankles, and feet. One leg may be more affected than the other (asymmetrical edema). In contrast, systemic diseases that are associated with fluid retention generally cause the same amount of edema in both legs, and can also cause edema and swelling elsewhere in the body. The response to therapy with diuretic drugs in patients with venous insufficiency tends to be unsatisfactory. This is because the continued pooling of fluid in the lower extremities makes it difficult for the diuretics to mobilize the edema fluid. Elevation of the legs periodically during the day and the use of compression stockings may alleviate the edema. Some patients require surgical treatment to relieve chronic edema that is caused by venous insufficiency.

Which diuretics are used to treat edema?

Edema can become a problem in systemic diseases of the heart, liver or kidneys. Diuretic therapy can be initiated, often alleviating the edema. The most potent diuretics are loop diuretics, so-called because they work in the portion of the kidney tubules referred to as the loop of Henle. The kidney tubules are small ducts that regulate salt and water balance, while transporting the forming urine. Clinical loop diuretics available are:

furosemide (Lasix),

torsemide (Demadex), and

butethamine (Bumex).

The doses of these diuretics vary depending upon the clinical circumstances. These drugs can be given orally, although seriously ill patients in the hospital may receive them intravenously for more prompt or effective response. If one of the loop diuretics is not effective alone, it may be combined with an agent that works further down (more distally) in the tubule. These agents include the thiazide type diuretics, such as hydrochlorothiazide (HydroDIURIL), or a similar but more potent type of diuretic called metolazone (Zaroxolyn). When diuretics that work at different sites in the kidney are used together, the response often is greater than the combined responses to the individual diuretics (synergistic response).

Some diuretics frequently cause an excessive loss of potassium in the urine, leading to the depletion of body potassium. These drugs include the loop diuretics, the thiazide diuretics, and metolazone. Patients on these diuretics are commonly advised to take potassium supplements and/or to eat foods high in potassium. High potassium foods include certain fruits such as:

bananas,

orange juice,

tomatoes, and

potatoes.

Patients with impaired kidney function often do not require potassium supplements with diuretics because their damaged kidneys tend to retain potassium. In certain instances, the volume of urine induced by the diuretic can be improved by adding a potassium-sparing diuretic, one that does not cause depletion of potassium. These diuretics include spironolactone (Aldactone), triamterene (Dyrenium, a component of Dyazide), and amiloride (Midamor). Adding one of these diuretics to the patient's diuretic regimen may preclude the need for potassium supplements. Another diuretic that can be used is acetazolamide (Diamox), which counteracts the development of an increased

concentration of bicarbonate (too much alkali) in the blood. Increased bicarbonate sometimes occurs in patients receiving other diuretics.

Are diuretics used for other purposes?

Diuretics have several other uses in addition treating edema.

A diuretic may be used as part of the treatment program for patients with hypertension. (High blood pressure may be caused by salt retention, or caused by some antihypertensive medications). In fact, most medications that dilate the blood vessels and reduce blood pressure, except for ACE inhibitors and angiotensin receptor blockers, lead to secondary salt retention by the kidneys.

Thiazide diuretics also have been used to prevent the formation of kidney stones. These drugs reduce the urinary excretion of calcium, which is a component of the kidney stone.

Acetazolamide (Diamox) taken a few days before going to high altitudes, appears to reduce the tendency for people to develop altitude sickness.

Edema At A Glance

Edema is a swelling, usually of the legs, due to the accumulation of excessive fluid in the tissues.

The edema that occurs in diseases of the heart, liver, and kidneys is mainly caused by salt retention, which holds the excess fluid in the body.

In certain liver and kidney diseases, low levels of albumin in the blood can contribute to fluid retention.

Heart failure, cirrhosis of the liver, and a kidney disease called nephrotic syndrome are the most common systemic diseases that cause edema.

Excess fluid that accumulates in the lungs is called pulmonary edema.

Excess fluid that accumulates in the abdominal cavity is called ascites.

Edema of unknown cause occurs primarily in women.

Varicose veins or thrombophlebitis (a blood clot in an inflamed vein) of the deep veins in the legs causes edema that is localized to the legs.

Therapy for edema consists of treating the underlying conditions, restricting salt intake, and often using diuretics (medicines to induce urination).

Reference: Harrison's Principles of Internal Medicine, McGraw-Hill, edited by Eugene Braunwald, et. al., 2001

Previous contributing authors and editors:

Medical Author: Mark Scott Noah, MDMedical Editor: Leslie J. Schoenfield, MD, PhD