Edema

Today we saw of case of severe non-pitting edema, and a case of what appeared to be cellulitis, but in fact was radiation-induced skin changes.

An approach to Edema is below.

Here is a link to diseases which may masquerade as cellulitis from the Annals of Internal Medicine.


Edema is a common finding in clinics and on the wards. It is usually found in dependent areas like the ankles and legs, but may be seen in the sacrum of supine individuals.

Pitting vs Non-Pitting: to have 'pitting' edema, a dent is left in the skin after pressure is applied over a bony prominence. How long do you have to press? Some say 5 seconds, however many experienced clinicians agree that 15-20 seconds is more appropriate.

• Non-Pitting: Suggests lymphedema, or rarely hypothyroidism (pretebial myxedema).
  

An Approach to Bilateral Leg Edema:

• Cardiogenic: think about right-sided heart failure or constrictive pericarditis
• Venous Obstruction: should be above the level of iliac veins, or bilateral distal venous thrombus
• Hepatic: when the synthetic function declines, decreased protein production like in late cirrhosis
• Other GI: protein losing enteropathies, malnutrition
• Kidney: nephrotic syndrome
• Endocrine: Cushing's syndrome - high cortisol levels increase renal sodium absorption. Also remember hypothyroidism (pretibial myxedema)
• Drugs: calcium channel blockers, OCP, corticosteroids, minoxidil
• Pregnancy: an planned (or unplanned?) mass pressing on IVC

Unilateral Edema: this may be caused by

• Venous disease: such as DVT, thrombophlebitis, damaged venous valves after infection or clot.
• Lymphatic disease or disruption: often lymph nodes are removed during surgery (eg for breast cancer). Infection is a common cause of LN damage, such as in recurrent cellulitis or lymphatic filariasis. You may see unilateral edema from LN disease with certain malignancies or radiation-induced damage as well.