Dependent Edema: This is the most common cause of bilateral foot edema, often seen in individuals who stand or sit for long periods, leading to fluid accumulation in the feet due to gravity.

Heart Failure: Edema in the feet can be a sign of right-sided heart failure, where the heart is unable to pump blood effectively, leading to fluid buildup.
Renal Failure: Decreased kidney function can lead to fluid retention, causing edema.
Liver Cirrhosis: Cirrhosis can cause hypoalbuminemia, leading to decreased oncotic pressure and fluid leakage into tissues.
Chronic Venous Insufficiency: Poor circulation can cause fluid to accumulate in the feet and ankles.
Medication Side Effects: Certain medications, such as calcium channel blockers and steroids, can cause edema as a side effect.

Deep Vein Thrombosis (DVT): Although less common, DVT can cause unilateral or bilateral edema and is a medical emergency due to the risk of pulmonary embolism.
Lymphoma or Other Malignancies: Certain cancers can cause edema due to obstruction of lymphatic or venous vessels.
Nephrotic Syndrome: A condition characterized by severe proteinuria, leading to hypoalbuminemia and edema.

Lymphedema: A chronic condition characterized by the abnormal collection of protein-rich fluid in the interstitial tissue, leading to swelling of one or more extremities.
Pulmonary Arterial Hypertension: A rare condition that can cause right-sided heart failure, leading to edema.
Sarcoidosis: A systemic granulomatous disease that can affect multiple organs, including the lungs, heart, and kidneys, potentially leading to edema.
Thyroid Disorders: Both hypothyroidism and hyperthyroidism can cause edema, although this is less common.