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     If you have noted the presence of swelling in your legs, just like any other new symptom, the causes are many.  Please understand that you probably do not have the most serious issue we discuss, but you could.  Our job here is to structure a conversation about the potential causes of lower extremity swelling, also known as edema. 

     If you experience sudden onset of swelling from the foot up to the thigh, or anywhere in between, in a single leg and/or you are a smoker and/or you have had recent air travel or a long car ride, then there is a possibility that you might have formed a clot somewhere in the venous system in that leg.  That clot would be called a deep vein thrombosis, or DVT for short.  A blood clot in the leg often but not always causes swelling in the affected leg or legs.  The swelling can be in the foot, the ankle, the calf, and in bad cases, all the way up to the thigh.  The DVT in and of itself is not particularly dangerous, as long as it stays put, however, clots in the legs tend to dislodge and fly to the lungs.  When they travel to the lungs, these are called a pulmonary embolus.  A pulmonary embolus causes sudden onset of chest pain and shortness of breath, or unexplained passing out.  The medical term for passing out is syncope.  If you have that, get help NOW! 

     There can be single pulmonary embolus, or multiple pulmonary emboli.  Sometimes they are mild, and sometimes they are severe.  If you have sudden onset of swelling in your leg after being sedentary for quite a while, it would be a good idea to see your physician and perhaps have that physician order an ultrasound of the leg to visualize the presence or absence of a blood clot.  

     Blood clots tend to form in females who are on birth control pills, or hormone replacement therapy.  They are more common in smokers, and they are more common in people who are somewhat older, being greater than 50; however, they can certainly occur in people in their 20s and 30s.  They also may occur in siblings or parents.  Clots in the legs can run in families and are due to a deficit in the normal coagulation cascade that stops you from bleeding when you cut yourself. 

     If the swelling affects both legs then it is unlikely that you would have clots in both legs, but it is not impossible, so the above still applies. 

     If you have been diagnosed with a blood clot, you will need to go on a blood thinner.  Your doctor will have this conversation with you.  

     Unilateral leg swelling (occurring in only one leg) also commonly occurs in patients who have undergone bypass surgery.  The reason for this is because many patients have superficial veins harvested to use as bypass conduits during bypass surgery.  As there are less veins in the leg where the veins were taken, the blood doesn’t drain the lower leg as well as the unaffected leg.  This usually is more prominent after being in an upright position for quite some time.  This is usually of no consequence other than that it is uncomfortable.  

     Bilateral leg swelling (swelling occurring in both legs) is a frequent problem.  There are many, many causes of this, and we will try to go through most of them.  The most important questions to answer are how long has the swelling been going on, how severe is it, does it occur at the end of the day or is it still present in the morning, do you have underlying lung disease, and what medications you are taking?  We will now address these individually.

      One of the more common causes of chronic lower extremity swelling, that is swelling that has lasted for weeks or longer, could be an early sign of a weakened heart muscle, also known as congestive heart failure.  If you have a history of known heart disease, whether it is blocked arteries or valvular heart disease, then it would be a good idea to get an ultrasound of the heart, or echocardiogram.  The ultrasound of the heart will reveal to the physician how well the heart squeezes and the competency of its valves.  Rarely, pericarditis can result in fluid in the bag around the heart.  This is called a pericardial effusion.  The pericardial effusion, which is fluid around the heart, is not a normal circumstance.  When present to an excessive degree, it restricts the heart from filling adequately with blood and results in lower extremity swelling and a multitude of other symptoms.  This is usually brought on by the presence of pericarditis.  Pericarditis is usually caused by a viral infection, though there are other causes.  It usually results in the presence of chest pain, particularly when lying flat on the back and relieved upon sitting up.  

      Congestive heart failure-caused lower extremity swelling is usually heralded in advance by the onset of exertional shortness of breath, and it can be preceded by the presence of exertional discomfort.  Underlying atrial fibrillation, where the heart is beating out of control and fast, can cause lower extremity swelling.   

     High blood pressure, poorly or inadequately treated, can result in the heart becoming thick.  As the heart becomes thick, it becomes stiff and difficult to fill.  This can result in lower extremity swelling.  An echocardiogram can measure the thickness of your heart and measure how easily it relaxes. 

     Valvular heart disease is very common, particularly in those who have a history of rheumatic fever.  You do not have to have had rheumatic fever to have valvular heart disease, however.  Some patients are born with a congenital bicuspid aortic valve.  That simply means that the aortic valve has two cusps instead of three.  Over time, usually in the 4th to 6th decades, the aortic valve becomes narrowed and in some cases leaky.  This over-works and over-stresses the heart, resulting in lower extremity swelling and is also usually associated with shortness of breath with exertion.  A leaky aortic valve can do the same thing as well as a leaky mitral valve.  This is the one-way check valve between the left atrium and the left ventricle.  The left ventricle is the main pumping chamber of the heart, responsible for pumping blood to all of your body except for your lungs.  

     In some patients with mitral valve prolapse, in which the prolapse has gotten severe, the regurgitation of blood back into the left atrium causes swelling.  This can occur gradually or suddenly, and this would require an echocardiogram to make the diagnosis.  In patients with mitral valve prolapse, the physician will typically hear a click and a murmur.  If the patient has mitral valve prolapse with coincident mitral regurgitation or leakage of the mitral valve and has associated palpitations, this has a name, Barlow’s syndrome.  This is the combination of mitral valve prolapse, mitral regurgitation or leakage, and the presence of palpitations coincident with rapid heartbeats, whether continuous or intermittent. 

     The right-sided heart valves, particularly the tricuspid valve, which is the valve interspersed between the right atrium and the right ventricle, if leaking severely can result in lower extremity edema.  This is particularly true in patients with chronic underlying lung disease.  We will address lung disease in the paragraphs below.  

     Patients with chronic obstructive pulmonary disease (COPD) or emphysema are prone to have lower extremity swelling.  The reason for this is rather simple.  People with emphysema and chronic obstructive pulmonary disease tend to run low oxygen levels.  This causes the arteries in the lungs to constrict.  The constriction of these arteries increases the resistance of blood flow through the lungs.  The right side of the heart is responsible for pumping the blood through the lungs.  In the circumstance of severe emphysema or chronic obstructive pulmonary disease, blood has difficulty traversing the lungs, and this difficulty is reflected back into the legs and results in swelling.  Most people with emphysema or chronic obstructive pulmonary disease are well-aware of this condition long before the swelling occurs.  So, if you have chronic obstructive pulmonary disease or emphysema to any significant degree, lower extremity swelling should not be terribly alarming, but may require further attention. 

      Diabetics can develop swelling.  The swelling can come from some of the medications used to treat diabetes, particularly Actos.  More commonly, swelling in diabetics is due to chronic kidney disease associated with the diabetes, or can, in rare instances, be a product of a result of leakage of protein in the urine.  Diabetes, over a long period of time, can damage the kidneys’ ability to retain albumin, which is a major protein in blood plasma.  This albumin assists the blood with retaining the fluid, called plasma.  This is due to osmotic forces and concentration gradients that you do not have to know.  Longstanding diabetics tend to leak an abnormal amount of protein in the urine which results in the appearance foamy urine seen in the toilet bowl.  If the doctor suspects the presence of an excessive amount of protein in the urine and confirms it by a 24-hour urinalysis, which shows an excess of 3 grams of protein excreted in a 24-hour period, this is called nephrotic syndrome.  This will require medications and probably a referral to a nephrologist.  

     Anemia is a not infrequent cause of lower extremity swelling.  Anemia is a condition in which the hemoglobin level or hematocrit level is too low.  Essentially, there are not enough red blood cells to deliver oxygen to the tissues.  Because the tissues demand more oxygen, this requires the heart to work harder and faster.  Anemia that is untreated over time can wear the heart out and cause what we call high output congestive heart failure.  High output congestive heart failure can, over time, lead to lower extremity swelling.  The anemia can be diagnosed very simply by a blood test.  

     Excessive, or too little, thyroid hormone production can result in lower extremity swelling.  This swelling differs from other causes of swelling in that it is somewhat woody in nature and non-pitting.  Hyperthyroidism or hypothyroidism can be diagnosed by a simple blood test.  

     Chronic kidney disease, that is kidneys that fail to filter the blood properly and remove excess fluid, can result in lower extremity swelling.  This is diagnosed through a blood test and can be treated with diuretics, mitigation of fluid and salt intake, and other medications.  If you have chronic kidney disease that is fairly significant, it would be a good idea to avoid excessive salt and fluid consumption.  In that circumstance, the usually recommended 8 glasses of water a day would not be a good idea.  

     Liver disease, in the form of cirrhosis of the liver usually seen in alcoholics, but in some patients it can be the result of previous hepatitis, can cause scarring of the liver which impedes blood flow out of the lower extremities back to the heart.  The scarring of the liver is called cirrhosis.  It is also termed portal hypertension.  Portal hypertension simply means that the blood draining from the lower extremities up to the inferior vena cava and back to the heart has difficulty making its way through the liver.  This reflects back pressure on the veins in the legs, thus producing lower extremity swelling.  

     There is also primary pulmonary hypertension, which is a genetic abnormality for the most part, and there are secondary causes and other toxic agents and can be a side effect of certain, but rare, medications as well as the hepatitis mentioned earlier.  If you have significant liver disease, it is entirely possible that your bilirubin level could be elevated, which would be noted by yellow eyes and a yellow tinge to the skin.  Liver disease can easily be diagnosed by an ultrasound or a CT scan of the liver and simple blood tests that can be performed at your physician’s office.  If you have a long history of alcohol use and have yellow eyes and lower extremity edema, we suggest you see your physician and have your liver checked.  

     One supplement has recently been implicated in lower extremity swelling through the causation of portal hypertension.  That supplement is vitamin A, used in excess.  There was a recent publication that demonstrated that in certain individuals excessive vitamin A can trigger portal hypertension and resultant lower extremity swelling.  So, if you are on multivitamins and note that your legs have been gradually swelling, we suggest that you stop the multivitamins, unless advised by your physician not to.  Most multivitamins contain vitamin A.  The report stated that this can occur in rare cases in individuals that take just one multivitamin a day.  Bear in mind that carrots contain ample amounts of vitamin A. 

     Venous stasis:  The way we are made, the veins drain the blood in the legs back to the heart.  Veins have small check-valves within them.  Over time these check-valves can become worn or damaged.  The check-valves function to allow the blood to pass from the feet up the leg back towards the heart without interruption.  Gravity, however, would tend to pull the blood back down to the feet.  Sometimes the gravity overwhelms the vascular system’s ability to retain blood plasma or fluid.  As we age, in certain populations of patients, the check-valves wear out and do not function properly.  This can contribute to lower extremity swelling. 

      Obesity is a rampant epidemic in the United States and elsewhere.  Obesity can cause lower extremity swelling just by the sheer pressure of the fat pad on the front surface of the abdomen. 

 Untreated sleep apnea, usually associated with obesity, can cause lower extremity swelling.  Sleep apnea can easily be diagnosed by an overnight sleep study.  Sleep apnea is often associated with early morning headaches and daytime somnolence or fatigue and having difficulty staying awake during the normal day.  Patients with sleep apnea typically snore quite a bit, and their partners might note that snoring and a lack of breathing during the sleeping hours.  Untreated sleep apnea is dangerous and could cause sudden death.

     Any damage to the lymphatic drainage of the lower extremities can cause swelling, whether unilateral or bilateral.  Unilateral means one leg and bilateral means both legs.  If you have had blocked arteries in your leg and had an open revascularization procedure, the lymphatic system could have been inadvertently damaged during the surgery.  Lymphatic swelling is usually discriminated versus vascular swelling, because lymphatic swelling causes massive lower extremity swelling that is very difficult to relieve. 

      Lymphedema Praecox is a rare genetic disorder that affects lymphatic drainage from the legs. 

     Though very rare, cancer in the pelvic or abdominal region can gradually cause lower extremity swelling, either unilateral or bilateral.  One of the more common malignancies that cause leg swelling in somewhat older females is ovarian cancer that has spread to the peritoneum, which is the lining of the inside of your abdominal and pelvic cavity.  Sometimes tumors, whether in the ovary or elsewhere, can impinge on the main vein that drains the lower body called the inferior vena cava.  If there is a mechanical obstruction of this inferior vena cava, lower extremity swelling can often occur. 

      Excessive salt consumption, certain nonsteroidal anti-inflammatory drugs, and other medications can cause lower extremity swelling, but not usually to a severe degree.  

     Swelling after a long day of standing on your feet with few breaks with no significant pathology is called dependent edema.  This is a normal consequence of standing up for too long.  This is generally nothing to worry about.  The treatment is to get off of your feet and raise your feet occasionally throughout the day, and usually the swelling resolves overnight. 

     Speaking of medications earlier, we would like to draw your attention to a couple of specific medications that cause lower extremity swelling.  Some of the more common drugs that causes lower extremity edema are blood pressure medications.  In this circumstance, we are speaking specifically of calcium channel blockers, though others can be implicated, as well.  Calcium channel blockers are commonly used to treat hypertension.  The type of calcium channel blocker that is more prone to cause swelling comes under the general heading of dihydropyridine calcium channel blockers.  These go by the generic names of nifedipine, amlodipine, and felodipine.  The swelling associated with these occurs in approximately, anecdotally, 1 out of 10 patients who take them.  The swelling can come on nearly immediately after initiating drug therapy for hypertension, but, more importantly, can occur months and even years after starting the medication.  When this is the cause, a lot of times the feet appear rather bright red.  The only way to make the diagnosis of a medication-derived cause of swelling is to stop the medication transiently and see if the swelling resolves.  Certainly, you would want to consult with your physician prior to doing this. 

      There are more causes of lower extremity swelling that are somewhat esoteric and will not be addressed.  This is an attempt to keep this document readable and to focus on the more important and more common causes. 

     In summary, if you have lower extremity swelling, it is important to know how long, what are your coexisting conditions, do you have lung, kidney, or liver disease, and anemia, and what medications you are taking.  You will need a basic metabolic profile to include an evaluation of your kidney function, your liver function, and the level of the normal protein albumin in your blood.  You might require a urine dip to see if there is the presence of protein, and if present in high quantity, a 24-hour urinalysis to see if you have nephrotic syndrome, particularly if you are a diabetic.  If the swelling is unilateral, that means one leg, and came on suddenly, then it would be a very good idea to get immediate medical attention to make sure you do not have a DVT that could result in a pulmonary embolus that could have a bad consequence.