Edema

1 What Is Edema?

Edema is a medical term for swelling caused by the build-up of fluid in body tissue. It can occur anywhere in the body, especially in the hands, arms, legs, ankles, and feet.

Edema is usually caused by health conditions such as pregnancy or medication side effects, or it may be a symptom of heart conditions or liver or kidney disease.

To treat edema, the doctor may prescribe medications to remove excess fluid from the body and encourage you to reduce your salt intake. If edema occurs as a sign of disease, the underlying cause must be addressed as well.

The formation of edema is usually controlled by creating a balance between a number of forces, two of the most important being oncotic pressure and hydrostatic pressure. Oncotic pressure is generated by the proteins present in blood plasma. It is also known as osmotic pressure. Hydrostatic pressure is generated by fluids.

Types of Edema

There are various types of edema, some of which are specific to certain parts of the body, while others are more general.

  • General edema: In general edema, an individual starts noticing swelling or water retention in various parts of the body, such as the face, arms, legs, abdomen, or feet. This accompanies other symptoms, such as puffiness, bloating, pitted skin or skin that holds an imprint, and tightening of the skin. Pitted skin indicates a severe case of edema, wherein the skin retains an indentation after pressing it for ten to thirty seconds. General edema is usually caused by some form of trauma, pregnancy, past or current illnesses, or any imbalance of the chemicals present in the body.
  • Corneal edema: Corneal edema refers to water retention in the cornea. This then leads to swelling of the cornea and other eye problems. The main causes of corneal edema are ocular surgery, an increase in ocular pressure, dehydration, endothelial disorder, viral infections affecting the body, or a traumatic injury.
  • Skin edema: Skin edema is known to be harmless and mostly occurs in skin cells and tissues. It is also called cutaneous edema. Although it is harmless, there are instances where it can be painful. One suffering from skin edema, may encounter issues such as parts of the skin being tight, water retention, and puffiness. The cause of skin edema is usually some kind of surface allergic reaction caused by mosquito bites, chemical reactions, or other skin irritants.
  • Cerebral edema: In cerebral edema, fluid accumulates in the extracellular and intracellular space located in the brain. The causes for the condition can be metabolic abnormalities due to an underlying medical condition or a bodily response to oxygen deprivation at high altitudes. Cerebral edema, which is also known as brain edema, is a very severe form, since it can lead to loss of consciousness and permanent brain damage. This edema is mostly caused by a blockage in fluid drainage, head trauma, brain tumors, high altitudes, and low blood sodium. The symptoms seen in brain edema include feelings of confusion, unconsciousness, severe headaches, and in serious cases, coma. Cerebral edema is further sub-categorized into four parts: vasogenic, osmotic, cytotoxic, and interstitial cerebral edemas.
    • Vasogenic cerebral edema occurs when there is a breakdown in the blood brain barrier. Due to this breakage, plasma leaks into the brain, which first reaches the white matter before entering the gray matter. The causes of vasogenic cerebral edema are any kind of cardiovascular event, brain trauma, or a brain tumor. If cancer is involved, vasogenic is caused by the release of destructive compounds from those tumors, which compromise the integrity of the blood brain barrier.
    • Osmotic cerebral edema is known to occur when there is an increase in the brain osmolality compared to the plasma osmolality. The pressure generated drives the fluids into the brain, which leads to edema.
    • Cytotoxic cerebral edema is due to the sodium and potassium pump malfunctioning. This then leads to the accumulation of water and sodium, which swells the white and gray matter. Cytotoxic edema does not affect the blood brain barrier.
    • Interstitial cerebral edema occurs when the barrier between the brain and the cerebrospinal fluid ruptures. This causes the cerebrospinal fluid to flow into the brain and accumulate in the white matter and extracellular spaces.
    • Myxedema: This kind of edema is quite rare. Myxedema is known to occur when the connective tissues are filled with water-loving, carbohydrate-like compounds known as hyaluronan. These water-loving compounds are known to attract water into the tissue matrix, due to which it quickly swells. Myxedema may worsen if the transfer of fluids in the tissues to the lymphatic system is hampered. This kind of edema is seen mostly among the elderly, as they are more prone to this edema because they sit for longer durations.
    • Pulmonary edema: This type of edema happens because of an accumulation of fluids in the lungs due to a blockage in the pulmonary veins. As blood pressure rises in the blood vessels located in the lungs, a rush of fluids fills the lungs. The cause of pulmonary edema is improper functioning of the left ventricle of the heart. It is also triggered by inhaling harmful air-borne chemicals or toxins, or through exposure to high altitudes.
    • Peripheral edema: Peripheral edema is known to mostly occur in the ankles, feet, and legs. This is one of the most common types of edema. Peripheral edema leads to swelling in the lower extremities. The causes of peripheral edema are hypertension, pregnancy, age, kidney disease, heart failure, and other medical conditions. If one has been sitting or standing for longer durations, they may also experience peripheral edema. There are certain kinds of medicines which can cause peripheral edema, including NSAIDs, corticosteroids, calcium channel blockers, and pioglitazone.
    • Lymphedema: This type of edema is usually due to failure of the lymphatic system to remove fluids from the interstitial spaces. There are various causes for lymphedema, but it is usually a result of the reticence of the lymphatic system’s pumping actions due to certain medicines.

2 Symptoms

Signs and symptoms of edema include:

  • Swelling or puffiness
  • Shiny appearance of stretched skin
  • When the skin is pressed for several seconds, it leaves a dimple (“Pitting” edema)
  • Noticeably increased size of the abdomen

If you have these symptoms, you need to see a doctor soon. The following symptoms require emergency treatment:

  • Chest pain
  • Shortness of breath
  • Breathing difficulties
  • Any swelling or pain in the leg that does not go away after prolonged sitting, like during long flights

Persistent swelling and pain in the leg can be a sign of deep vein thrombosis (DVT), caused by the formation of a blood clot in the veins of the leg. DVT is a serious condition that requires treatment to prevent the blood clot from traveling to the lungs, which can be fatal.

3 Causes

Fluid build-up, or edema, is caused when fluid leaks from the bloodstream, or if too little is absorbed back into the blood vessels.

Your tissues contain tiny blood vessels called capillaries, which provide a connection between the arteries and veins. Capillaries are microscopic and have very thin walls to allow the passage of nutrients, water, and waste products. However, capillaries also pass fluid that stays in spaces between cells, known as interstitial fluid. The combination of proteins in the blood plasma and pressure from the heart’s pumping action causes the interstitial fluid to be absorbed back into the bloodstream, which prevents fluid build-up in the tissues.

You can develop mild edema even if you do not have any health problems. Sometimes, you can get edema from:

  • Sitting or staying in a single position for too long, like during long flights or a long drive, watching TV, or being at your desk for hours
  • Eating lots of salty foods
  • Premenstrual syndrome and being days away from your period
  • Pregnancy

Edema can also be a side effect of the following medications:

  • Antihypertensives
  • NSAIDS (non-steroidal anti-inflammatory drugs)
  • Steroids
  • Estrogen, like contraceptive pills
  • Thiazolidinediones, prescribed for treating type-2 diabetes

Edema can also be a symptom of serious health problems. Here are the diseases that often cause severe edema:

  • Congestive heart failure often causes edema in the legs, ankles, feet, and abdomen. This condition is caused by failure of the heart to pump blood effectively, so blood backs up in the legs and causes edema. Congestive heart failure also causes edema in the lungs (pulmonary edema). When the heart becomes weak, the blood pumping becomes less effective, due to which there is a build-up of fluid, which leads to leg edema. If there is heart failure on the right side of the heart, edema can develop in the abdomen.
  • Cirrhosis, a condition caused by liver damage. The liver produces the protein albumin, which helps the blood retain fluid so it will not end up in the interstitial tissues. Cirrhosis notably causes edema in the legs and abdomen (called ascites).
  • Kidney diseases can prevent extra fluid and salt from being filtered out of the blood, causing excess fluid to leak into tissues.
  • Chronic venous insufficiency, a condition caused by damage to the valves inside large veins of the legs. These valves help blood flow against gravity in the veins and, if damaged, cause blood to pool in the legs, resulting in edema.
  • Problems in the lymphatic system, which can be due to cancer or surgery. The lymphatic system captures fluid that inevitably leaks into blood vessels. Edema develops in an area if the lymphatic vessels there are damaged and fail to drain excess fluid.

4 Making a Diagnosis

An edema diagnosis must be made by a physician, so medications can be prescribed to alleviate swelling.

If you experience edema, go to your family doctor or general practitioner for evaluation. If you have existing health conditions and experience edema, give your doctor or specialist a call and describe your symptoms.

Before the appointment, it can make things easier if you do the following:

  • Ask if there are any restrictions that may be required for diagnostic tests.
  • List down your symptoms and when they appeared. Also, list any medications, supplements, or vitamins you are currently taking.

You can ask your doctor questions about your condition, such as:

  • What are the causes of edema and the other symptoms?
  • What are the tests I need?
  • Is this edema temporary?
  • Do I need treatment?
  • What are the treatment options?
  • Will the treatment interfere with my other health problems?
  • Can I have printed materials or visit websites to help me understand my condition?

Your doctor will likely ask you questions about the following:

  • A description of your symptoms and how long you’ve been experiencing them
  • If you’ve had edema before
  • Anything that seems to worsen or lessen the swelling
  • If your edema is reduced after a night’s rest
  • Foods that you regularly eat, especially salty items
  • Alcohol intake
  • Urinating habits

5 Treatment

Mild edema does not require any treatment, since it usually goes away on its own. Elevating the affected limb higher than the heart for some time is often enough to relieve mild edema.

Severe edema is usually addressed with medications as well as treating the underlying cause.

Medications like furosemide (Lasix) help the body expel excess fluid.

If edema is caused by medication side effects, the doctor will adjust the dosage or look for alternatives that do not cause edema.

6 Lifestyle and Coping

There are different ways to adapt your lifestyle to cope with edema.

You can try these remedies to deal with edema caused by pregnancy or prescribed medications, or long-term edema:

  • Try to move more. Moving promotes fluid drainage and blood flow to relieve edema. You can ask your doctor about exercises to help reduce swelling.
  • For edema in a specific limb, elevate the affected part above heart level. The extra help from gravity promotes fluid drainage.
  • You can massage the affected part, focusing on long, flowing strokes toward the heart, to improve fluid drainage.
  • For edema in the legs or arms, you can ask your doctor for compression stockings, gloves, or sleeves. These compression garments put pressure on the affected part to prevent fluid build-up.
  • Reduce the amount of salt in the diet. Salt promotes fluid build-up in the tissues, and high consumption worsens edema.
  • Protect edema-affected skin. Skin with edema becomes thin and more prone to cuts, scrapes, and infections. Keep your skin clean and moisturized, and protect it from cuts. If your feet swell, protect them by wearing socks.

7 Risks and Complications

Your risk of having edema is increased if you:

  • Use medications such as antihypertensives, NSAIDS, steroids, estrogen birth control pills, or thiazolidinediones
  • Have conditions like heart disease or kidney, liver, or lymphatic problems
  • Underwent surgery, which can cause edema due to damage in the blood or lymphatic vessels.
  • Sitting or staying in one place for a long time.

Conditions like pregnancy cause edema because the body stores more sodium and water.

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