Swelling in the lower legs – known as “lower extremity edema” in medical terms – is a problem that often affects older adults.
The good news is that most of the time, it’s annoying, but not terribly dangerous. However, in other cases, swelling in the feet, ankles, or lower legs can be the sign of a new health problem, or a worsening
chronic condition.
And, even if it’s “benign” and not related to a dangerous health condition, edema can be a major risk factor for skin breakdown and reduced mobility in aging adults.
Since leg swelling becomes so common as people get older, in this article we’ll demystify leg edema and cover the most important things that older adults and families should know about this condition. In particular, we’ll cover:
How does edema happen?
Common causes of swollen ankles or legs in aging adults
Medications that can cause leg swelling as a side-effect
How leg swelling should be medically evaluated
How to prevent and treat leg swelling
What to know BEFORE going on a “water pill”
How does edema happen?
We notice edema when our shoes are too tight, or we get marks on our ankles from our socks. But what’s really going on inside the body?
Edema happens when fluid moves outside of blood vessels and into what’s called the interstitial spaces of the body. These spaces are also sometimes called the extra-vascular space (which literally just means “outside of blood vessels”), and is basically the moist space between cells, organs, and body parts.
Although you make think of blood vessels as being “waterproof”, physically they are more like a semi-permeable membrane, made of blood vessel cells that usually stay close together, and it’s normal for small quantities of fluid to pass back and forth.
If more fluid than usual passes out of the blood vessels, and this happens in the legs or near the surface of the body, it looks like a swollen or puffy area under the skin.
Fluid can move into the interstitial spaces and cause edema for a few different reasons. The most common causes are
“Leaky” blood vessels: Sometimes the blood vessel cells don’t stick together as tightly as they should. This can allow fluid molecules to slip through the connections between the blood vessel cells (like gaps between the bricks in a wall).
This can happen due to severe infection or inflammation, among other things.
Low levels of protein in the blood: Proteins, such as albumin, help keep fluid inside blood vessels. This is because protein molecules in the blood exert an “osmotic” pressure (also called “oncotic pressure”) that helps retain fluid inside a blood vessel. If protein levels fall in the blood vessel, even if the membrane of the blood vessel is intact, fluid moves outside of the vein or artery to equalize the osmotic pressure across the membrane, and this
creates edema.
Some causes of low albumin levels in the blood include certain types of kidney disease, liver disease, and malnutrition.
Fluid overload: If there’s more fluid than usual in the blood vessel, it becomes “overloaded.” The extra fluid will be then end up pushed across the blood vessel wall because of high hydrostatic pressures.
Normally, our kidneys regulate body fluid levels by adjusting the amount of water and salt that is excreted or retained. But if those mechanisms fail or are overwhelmed, edema is often the result.
When we look at common causes of edema, keep these different mechanisms in mind. The cause of the edema will play a major role in deciding on the best course of treatment.
What are the most common causes of leg edema
By far, the most common cause of leg edema is chronic venous insufficiency, but there are some other causes that are critical to rule out.
Chronic venous insufficiency
This is the cause in about 70% of older adults with leg edema. To understand chronic venous insufficiency (CVI), we first need to cover how veins work.
Veins are the blood vessels that return blood to the heart so that it can be pumped to the lungs and get oxygenated. Veins don’t have muscles in their linings like arteries do; instead, they rely on a system of valves to keep blood from flowing backwards. Over time, these valves become less effective, and blood can hang around in the veins longer than it needs to – a phenomenon called venous insufficiency.
When venous insufficiency becomes chronic, this can cause varicose veins and/or edema, due to there being extra fluid in the veins. Venous insufficiency can also end up causing phlebitis (inflammation of the veins), ulceration of the skin (sores and wounds) and even sometimes cellulitis (skin infections).
CVI is common, affecting an estimated 7 million people worldwide and causing 3 million to develop venous ulcers, the most common type of leg ulcers. The cost of venous ulcers to the US healthcare system is estimated at 2 to 3 billion dollars a year.
Risk factors for CVI include:
In the section on treatment, I’ll explain how to manage edema due to CVI and share tips on reducing the risk of complications. Keep in mind that leg swelling is something that people live with on a chronic basis and is rarely completely cured. The goals of a treatment plan are to reduce the edema, prevent the discoloration and thinning of the skin, and prevent or heal
skin sores.
Congestive Heart Failure (CHF)
Congestive heart failure (CHF) is the most common cause of generalized edema (affecting the legs, abdomen, and sometimes the lower back and even higher on the body), and a major cause of edema of the legs.
Heart failure is a term that we use when the heart muscle is weakened and not pumping blood as effectively as it should. Heart failure is often described as being “right-sided” or “left-sided” depending on which chamber of the heart is most affected. The “congestive” part refers to the backflow of blood into the veins in the lungs (if it’s “left-sided”) or the legs or lower part of the body (if right-sided”). Some people have right-and left-sided heart failure.
In CHF, there’s fluid congestion in the veins, but that’s not the whole story. When CHF is chronic, lasting more than a few weeks, it reduces blood flow to the kidneys, and they respond by causing the retention of salt and fluid in the body. This is an especially important factor when treating the edema associated
with CHF.
In CHF, the edema in the lungs, or pulmonary edema, can be much more difficult to live with; it usually causes shortness of breath, coughing, and breathlessness when lying flat to sleep.
CHF treatment frequently involves diuretic medications (also known as “water pills” to relieve symptoms. Some commonly used diuretics used for CHF include furosemide, spironolactone and metalazone. The dosing of diuretics often must be managed carefully to minimize the potential side effects of low blood pressure, potassium depletion, dehydration, and kidney injury.
People living with CHF are usually advised to restrict their daily fluid and salt intake, weigh themselves frequently, and adjust the daily water pill dose depending on their weight, along with regular bloodwork.
In this article, we won’t go into more detail about CHF, as it’s a complicated topic of its own. The main thing you should know is that if you’ve been concerned about leg swelling in an older person, it’s important to find out if they have a history of heart failure or heart problems, especially if they are also reporting symptoms of shortness of breath.
Medication-related leg edema
Some medications can cause or worsen swollen legs. or make them worse. In most cases, the drugs increase fluid and salt retention, causing edema, but for some drugs, such as dihydropyridine calcium channel blockers (like amlodipine) the capillaries become leakier, and in other cases, the exact mechanism for edema isn’t known. Below is a list of medications that may cause edema.
Antihypertensive drugs
Calcium channel blockers
Beta blockers
Clonidine
Hydralazine
Minoxidil
Methyldopa
Hormones
Corticosteroids
Estrogen
Progesterone
Testosterone
Other
New or worsened leg swelling should always prompt a medical evaluation, to make sure the swelling isn’t due to a medication side-effect. (To learn more about medications to avoid in aging adults, read this article: Medications Older Adults Should Avoid or Use with Caution).
Liver disease
In cirrhosis of the liver, edema may occur in the lower limbs or, more commonly, localized to the belly (called ascites). The liver is where the body makes albumin, a major component of protein in the blood, but in cirrhosis, the damaged liver can no longer maintain adequate production of albumin and other key proteins. The resulting lower blood protein levels mean that fluid will leak out into the interstitial spaces, which can cause edema and also noticeable swelling of the belly.
Diuretics can be used to help people with cirrhosis, and sometimes drainage of the abdominal ascites is performed, with careful management of blood pressure and electrolyte balance.
Kidney disease
A kidney condition called nephrotic syndrome is associated with protein leaking out into the urine. This can cause edema in the legs and elsewhere in the body.
A urine dipstick normally checks for protein in the urine, and a more precise check can be done through
a urinalysis.
Lymphedema
Although most fluid in the body moves through blood vessels, the body also has a network of lymphatic vessels, which connect to lymph nodes and move fluid and immune system cells through the body.
Lymphedema means edema caused by fluid overload in the lymphatic vessels, not the veins. When there’s too much fluid for the lymph system to drain, or not enough capacity in the lymphatic channels, swelling is the result.
Lymphedema is most often associated with a history of cancer and/or lymph node surgery, and usually affects one limb, rather than both. Seventy percent of prostate and breast cancer survivors experience lymphedema as do 80% of those with severe obesity.
This type of edema is treated by elevating the limb as much as possible, the use of compression garments, a special kind of decongestive massage, or microsurgery to enhance the lymphatic system. Of note, treatment with diuretics (“water pills”) is not usually effective.
