Differential Diagnosis for Lower Extremity Swelling in a 78-year-old Female

Single Most Likely Diagnosis

• Chronic Venous Insufficiency: This condition is common in the elderly and can cause swelling, especially in the lower extremities due to the inability of veins to return blood to the heart efficiently. The patient's age and the chronic nature of the swelling support this diagnosis.

Other Likely Diagnoses

• Nephrotic Syndrome: Characterized by significant proteinuria, hypoalbuminemia, and edema. The lack of heart failure history and the possibility of renal issues in an elderly patient make this a plausible diagnosis.
• Liver Cirrhosis: Can lead to fluid retention and peripheral edema. Although less common, cirrhosis should be considered, especially if there's a history of alcohol abuse or other liver disease risk factors.
• Medication Side Effects: Certain medications, such as calcium channel blockers, can cause peripheral edema. Given the patient's age, she may be on multiple medications, increasing the likelihood of drug-induced edema.

Do Not Miss Diagnoses

• Deep Vein Thrombosis (DVT): Although less likely given the chronic nature of the swelling, DVT is a critical diagnosis to consider due to its potential for severe complications, including pulmonary embolism.
• Lymphoma or Other Malignancies: Can cause lymphedema or venous obstruction leading to swelling. Given the patient's age, malignancy is always a concern.
• Infection (Cellulitis): Can present with swelling, redness, and warmth of the affected limb. It's crucial to consider infection, especially if there are signs of acute inflammation.

Rare Diagnoses

• Sarcoidosis: A systemic disease that can cause lymphadenopathy, skin lesions, and potentially swelling due to granulomatous inflammation affecting various organs.
• Thyroid Disorders: Both hypothyroidism and hyperthyroidism can lead to edema, though this is less common and usually accompanied by other systemic symptoms.

Initial Labs to Consider in the Emergency Department:

• Complete Blood Count (CBC)
• Basic Metabolic Panel (BMP) to assess renal function and electrolytes
• Liver Function Tests (LFTs) to evaluate for liver disease
• Urinalysis to check for proteinuria
• D-dimer (if DVT is suspected, though its utility in diagnosing DVT is limited by low specificity)
• Consider thyroid function tests (TFTs) if there are other suggestive symptoms
• Imaging studies (e.g., ultrasound of the lower extremities) may be necessary based on the initial evaluation and suspected diagnoses.