What are the causes of pitting edema?

From the Guidelines

Pitting edema is primarily caused by fluid retention in the body's tissues, particularly in the lower extremities, with heart failure, kidney disease, liver cirrhosis, and certain medications being major contributors. The main causes of pitting edema include:

• Heart failure, where the heart cannot pump blood effectively, leading to fluid backup in the legs
• Kidney disease, which impairs the kidneys' ability to remove excess fluid and sodium
• Liver cirrhosis, causing decreased albumin production and fluid leakage into tissues
• Venous insufficiency, where damaged valves in leg veins allow blood to pool
• Certain medications like calcium channel blockers, NSAIDs, and steroids, such as thiazolidinediones (TZDs) which can cause edema as a side effect, as noted in a consensus statement from the American Heart Association and American Diabetes Association 1 Other causes include prolonged sitting or standing, pregnancy, hormonal changes, and low protein levels in the blood. Severe pitting edema requires medical attention, as it may indicate serious underlying conditions. Treatment typically addresses the root cause, often including diuretics like furosemide (20-80mg daily) or spironolactone (25-100mg daily) to reduce fluid retention, along with lifestyle modifications such as leg elevation, compression stockings, and reduced salt intake. The severity of pitting edema is assessed by pressing a finger into the swollen area and observing how long the indentation remains, with deeper and longer-lasting indentations indicating more severe edema. It is essential to note that the use of certain medications, such as TZDs, can increase the risk of edema, particularly in patients with preexisting heart disease, as highlighted in the consensus statement from the American Heart Association and American Diabetes Association 1.

From the Research

Causes of Pitting Edema

The causes of pitting edema can be attributed to various factors, including:

• Excess accumulation of interstitial fluid due to increased transfer of fluid across the capillary membranes or excess retention of salt and water 2
• Fluid retention, which can be a result of heart failure, leading to peripheral edema (anasarca) 3
• Venous insufficiency, especially in the presence of dependent edema and hemosiderin deposition 4
• Systemic disease, which can cause rapid development of generalized pitting edema 4
• Congestive heart failure, which activates humoral and neurohumoral mechanisms that promote sodium and water reabsorption by the kidneys and expansion of the extracellular fluid 5
• Hypervolemia due to water retention, which can predispose patients to hypertension and manifest as peripheral edema 6

Associated Conditions

Pitting edema can be associated with various conditions, including:

• Heart failure, which can cause peripheral edema (anasarca) 3
• Venous insufficiency, which can lead to dependent edema and hemosiderin deposition 4
• Systemic disease, which can cause rapid development of generalized pitting edema 4
• Congestive heart failure, which can activate humoral and neurohumoral mechanisms that promote sodium and water reabsorption by the kidneys and expansion of the extracellular fluid 5
• Hypertension, which can be exacerbated by hypervolemia due to water retention 6

Diagnostic Considerations

Diagnosing pitting edema can involve various methods, including:

• Clinical examination, which can include the presence of pitting located in the lower extremities and/or over the sacrum 6
• Bioimpedance, inferior vena cava diameter, and biomarkers, which can be used to detect edema, although these methods may not always be available 6