Chapter 036. Edema (Part 7) Additional Factors in Diagnosis The color, thickness, and sensitivity of the skin are significant. Local tenderness and warmth suggest inflammation. Local cyanosis may signify venous obstruction. In individuals who have had repeated episodes of prolonged edema, the skin over the involved areas may be thickened, indurated, and often red. Estimation of the venous pressure is of importance in evaluating edema. Ordinarily, a significant generalized increase in venous pressure can be recognized by the level at which cervical veins collapse (Chap. 220). In patients with obstruction of the superior vena cava, edema is confined to the face, neck, and upper extremities, in which the venous pressure is elevated compared with that in the lower extremities. Severe heart failure may cause ascites that may be distinguished from the ascites caused by hepatic cirrhosis by the jugular venous pressure, which is usually elevated in heart failure and normal in cirrhosis. Determination of the concentration of serum albumin aids importantly in identifying those patients in whom edema is due, at least in part, to diminished intravascular colloid oncotic pressure. The presence of proteinuria also affords useful clues. The absence of proteinuria excludes nephrotic syndrome but cannot exclude nonproteinuric causes of renal failure. Slight to moderate proteinuria is the rule in patients with heart failure. Approach to the Patient: Edema An important first question is whether the edema is localized or generalized. If it is localized, those local phenomena that may be responsible should be considered. If the edema is generalized, it should be determined, first, if there is serious hypoalbuminemia, e.g., serum albumin <25 g/L. If so, the history, physical examination, urinalysis, and other laboratory data will help evaluate the question of cirrhosis, severe malnutrition, or the nephrotic syndrome as the underlying disorder. If hypoalbuminemia is not present, it should be determined if there is evidence of congestive heart failure of a severity to promote generalized edema. Finally, it should be determined whether the patient has an adequate urine output, or if there is significant oliguria or anuria. These abnormalities are discussed in Chaps. 45, 273, and 274. Further Readings Abassi ZA et al: Control of extracellular fluid volume and the pathophysiology of edema formation, in The Kidney , 7th ed, BM Brenner (ed). Philadelphia, Saunders, 2004, pp 777–856 Chertow GM: Approach to the patient with edema, in Car diology for the Primary Care Physician , 2d ed, E Braunwald, L Goldman (eds). Philadelphia, Saunders, 2003, pp 117–128 Diskin CJ et al: Edema, oncotic pressure, and free entropy: Novel considerations for treatment of edema through attention to thermodyna mics. Nephron 78:131, 1998 [PMID: 9496727] McCullough JC: Renal disorders and heart disease, in Braunwald's Heart Disease, 7th ed, D Zipes et al (eds). Philadelphia, Saunders, 2005 O'Brien JG et al: Treatment of edema. Am Fam Physician 71:2111, 2005 [PMID: 15952439] Streeten DH: Idiopathic edema. Pathogenesis, clinical features, and treatment. Endocrinol Metab Clin North Am 24:531, 1995 [PMID: 8575408] . Chapter 036. Edema (Part 7) Additional Factors in Diagnosis The color, thickness, and sensitivity of the. Patient: Edema An important first question is whether the edema is localized or generalized. If it is localized, those local phenomena that may be responsible should be considered. If the edema. episodes of prolonged edema, the skin over the involved areas may be thickened, indurated, and often red. Estimation of the venous pressure is of importance in evaluating edema. Ordinarily,