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Health & Medicine

2010-04-01 12:04:00

Edema and diabetes - series

Answer: Edema is the medical term for swelling. It is a general response of the body to injury or inflammation. Edema can be isolated to a small area or affect the entire body. Medications, infections, pregnancy, and many medical problems can cause edema. Edema results whenever small blood vessels become "leaky" and release fluid into nearby tissues. The extra fluid accumulates, causing the tissue to swell. Causes of Edema Edema is a normal response of the body to inflammation or injury. For example, a twisted ankle, a bee sting, or a skin infection will all result in edema in the involved area. In some cases, such as in an infection, this may be beneficial. Increased fluid from the blood vessels allows more infection-fighting white blood cells to enter the affected area. Edema can also result from medical conditions or problems in the balance of substances normally present in blood. Some of the causes of edema include: • Low albumin (hypoalbuminemia): Albumin and other proteins in the blood act like sponges to keep fluid in the blood vessels. Low albumin may contribute to edema, but isn't usually the sole cause. • Allergic reactions: Edema is a usual component of most allergic reactions. In response to the allergic exposure, the body allows nearby blood vessels to leak fluid into the affected area. • Obstruction of flow: If the drainage of fluid from a body part is blocked, fluid can back up. A blood clot in the deep veins of the leg can result in leg edema. A tumor blocking lymph or blood flow will cause edema in the affected area. • Critical illness: Burns, life-threatening infections, or other critical illnesses can cause a whole-body reaction that allows fluid to leak into tissues almost everywhere. Widespread edema throughout the body can result. • Edema and heart disease (congestive heart failure): When the heart weakens and pumps blood less effectively, fluid can slowly build up, creating leg edema. If fluid buildup occurs rapidly, fluid in the lungs (pulmonary edema) can develop. • Edema and liver disease: Severe liver disease (cirrhosis) results in an increase in fluid retention. Cirrhosis also leads to low levels of albumin and other proteins in the blood. Fluid leaks into the abdomen (called ascites), and can also produce leg edema. • Edema and kidney disease: A kidney condition called nephrotic syndrome can result in severe leg edema, and sometimes whole-body edema (anasarca). • Edema and pregnancy: Due to an increase in blood volume during pregnancy and pressure from the growing womb, mild leg edema is common during pregnancy. However, serious complications of pregnancy such as deep vein thrombosis and preeclampsia can also cause edema. • Cerebral edema (brain edema): Swelling in the brain can be caused by head trauma, low blood sodium (hyponatremia), high altitude, brain tumors, or an obstruction to fluid drainage (hydrocephalus). Headaches, confusion, and unconsciousness or coma can be symptoms of cerebral edema. • Medications and edema: Numerous medications can cause edema, including: - NSAIDs (ibuprofen, naproxen) - Calcium channel blockers - Corticosteroids (prednisone, methylprednisolone) - PPioglitazone and rosiglitazone - Pramiprexole Most commonly, these medications produce no edema, or mild leg edema. Symptoms of Edema Edema symptoms depend on the amount of edema and the body part affected. Edema in a small area from an infection or inflammation (such as a mosquito bite) may cause no symptoms at all. On the other hand, a large local allergic reaction (such as from a bee sting) may cause edema affecting the entire arm. Here, tense skin, pain, and limited movement can be symptoms of edema. Food allergies may cause tongue or throat edema, which can be life-threatening if it interferes with breathing. Leg edema of any cause can cause the legs to feel heavy and interfere with walking. In edema and heart disease, for example, the legs may easily weigh an extra 5 or 10 pounds each. Severe leg edema can interfere with blood flow, leading to ulcers on the skin. Pulmonary edema causes shortness of breath, which can be accompanied by low oxygen levels in the blood. Some people with pulmonary edema may experience a cough with frothy sputum. Treatment of Edema Treatment of edema often means treating the underlying cause of edema. For example, allergic reactions causing edema may be treated with antihistamines and corticosteroids. Edema resulting from a blockage in fluid drainage can sometimes be treated by eliminating the obstruction: • A blood clot in the leg is treated with blood thinners, and the clot slowly breaks down. Leg edema then resolves as fluid drainage improves. • A tumor obstructing a blood vessel or lymph flow can sometimes be reduced in size or removed with surgery, chemotherapy, or radiation. • Leg edema related to congestive heart failure or liver disease can be treated with a diuretic like furosemide (Lasix). When urine output increases, more fluid drains from the legs back into the blood. Maintaining a sodium-restricteddiet will also help limit fluid retention associated with heart failure or liver disease. We will talk more next month on edema and diabetes.