Differential diagnosis of Pedal Edema / Lower Extremity Edema
Systemic causes (usually bilateral/symmetric edema):
Heart failure (CHF/RHF)
Heart valve disease (pulmonic, tricuspid)
Constrictive pericarditis
Liver disease; Cirrhosis
Renal disease,
Nephrotic syndrome
Obstructive sleep apnea (leading to pulmonary hypertension)
Malnutrition; Malabsorption/protein-calorie malnutrition
Hypoalbuminemia
Allergic reaction, angioedema, urticaria
Thyroid disorder (Hypothyroidism)
Pregnancy
Premenstrual edema
Lipedema (accumulation of fluid in adipose tissue)
Lymphatic disease
IVC filter thrombosis
Idiopathic
Medications: NSAIDs, CCB (amlodipine), steroids, antidepressants, beta blockers, clonidine, estrogen/progesterone, hydralazine, pramipexole
Local causes (often unilateral/asymmetric edema):
Deep vein thrombosis
Venous insufficiency, dependency, garments
Iliac vein obstruction
Cellulitis
Stasis dermatitis
Popliteal (Baker) cyst rupture
Ruptured muscle/tendon (e.g. gastrocnemius)
Complex regional pain syndrome
Pelvic Tumor
Idiopathic
Lymphedema
Mechanical edema (post injury or surgery)
Myxedema
Retroperitoneal fibrosis
Compartment syndrome
Compression of left iliac vein by right iliac artery
Thinking through the differential diagnosis
Systemic vs. Localized causes of Edema.
Divide the differential diagnosis into 1) systemic illnesses such as heart failure, liver disease, malnutrition, and thyroid disorder; 2) local conditions such as pelvic tumors, infection, trauma, and venous thrombosis; and 3) medications known to increase the risk of edema of the lower extremities.
Edema can be categorized according to duration (acute or chronic), distribution (unilateral or bilateral), and accompanying symptoms (such as dyspnea, pain, thickening of skin, and pigmentation).
Most systemic causes above are
Further Reading
Geriatrics. 1993 May;48(5):34-40, 45. https://www.ncbi.nlm.nih.gov/pubmed/7695655
Am Fam Physician. 2013 Jul 15;88(2):102-110. https://www.aafp.org/afp/2013/0715/p102.html