Many people who develop ankle edema are inappropriately diagnosed as having heart failure. In particular, the diagnosis of right heart failure should not be made in the absence of jugular venous distention. Venous varicosities, cyclic edema, thrombophlebitis, and hypoalbuminemia all cause ankle edema and should be considered in the differential diagnosis. Usual causes of unilateral edema include trauma, cellulitus, osteomyelitis, ruptured Baker's Cyst, deep vein thrombosis (DVT) and occasionally lymphatic obstruction (due to neoplasm and filariasis). The following algorithm will help keep your thoughts organized as to the proper work up for pedal edema. Always keep in mind that you should always think about DVT in patients with new or worsening leg swelling. Be aware that clinical signs serve only alert clinicians to the possiblity of a DVT but are unreliable. Thus you should get objective studies (venogram, compression ultrasonography, or IPG) whenever you suspect the possibility of a DVT.
A good history might be able to help you sort out the need to rule out DVT. For instance, this patient had a prior history of DVT and came in for new-onset swelling of the left leg. The suspcion for a second DVT was confirmed with a compression ultrasonogram:
In contrast this patient began to develop swelling the left leg over a period of several years:
Another type of chronic edema might be secondary to obesity:
Finally, do NOT forget common endocrine disorders, i.e. hypothyroidism. By the time you see this profound of peripheral edema you should be able to elicit a good history (cold intolerance, constipation, slow thick voice, ) and physical exam findings (thinning of the lateral third of eyebrows; coarse, thick, dry skin; thin brittle hair; dull expressin with thick tongue and lips; slowed mentation; delayed relaxation phase of deep tendon reflexes; muscle weakness) to have a high degree of suspicion:
Don't also forget about medications, the most common being the dihydropyridine calcium anatagonist, can also induce peripheral edema.