Edema
Paul Evans and Michael P. Rowane
Edema is defined as a clinically apparent increase in interstitial fluid volume (1–3). A number of possible factors cause edema.
Approach
The diagnostic process begins by determining if edema is localized or generalized.
A. Localized edema. This can present as hydrothorax (excess fluid in the thoracic cavity) or ascites (excess fluid in the peritoneal cavity).
B. Generalized edema. The patient may or may not have hypoalbuminemia:
1. Normal serum albumin level. Consider congestive heart failure (CHF) and renal causes (oliguria or anuria).
2. Hypoalbuminemia (<2.5 g/dl). Initial considerations should include cirrhosis, severe malnutrition, protein-losing gastroenteropathy, and nephrotic syndrome.
History
A. Onset. When the onset of edema is sudden, consider the following possible causes: cellulitis, deep venous thrombosis (DVT), compartment syndrome, trauma, and exacerbation of chronic problems (systemic disease, medications, venous insufficiency, lymphedema).
When the onset is gradual, consider the causes listed below.
B. Clinical course. Is the edema intermittent or recurrent, or is it chronic?
C. Painful edema most likely results from (3):
1. Cellulitis
2. Trauma
3. Ruptured Baker’s cyst
4. Compartment syndrome
5. DVT
D. Painless edema or bilateral edema usually results from a systemic cause.
E. Associated systemic symptoms
1. Fever and chills can be caused by cellulitis, lymphangitis, or venous thrombosis.
2. Dyspnea and orthopnea suggest that the edema is of cardiac origin.
3. Either a history of streptococcal throat infection or recurrent urinary tract infection (UTI) points to renal causes.
F. Medications that can be associated with edema include the following: diazoxide, minoxidil, hydralazine, calcium channel blockers, alpha- and beta-blockers, reserpine, guanethidine, nonsteroidal antiinflammatory drugs (NSAIDs), carbenicillin, amantadine, lithium, phenothiazines, thioridazine, monoamine oxidase (MAO) inhibitors, corticosteroids, testosterone, estrogen, progesterone, or interleukin-2 (2, 3).
G. Endocrine diseases
1. Hypothyroidism can present with pretibial myxedema (Chapter 14.4).
2. Cushing’s syndrome can cause edema.
H. Miscellaneous causes of edema. These include:
1. Pregnancy
2. Sodium overload
3. Malnutrition
4. Stopping laxatives
5. Prolonged dependent position
6. Cyclic edema in women
7. Lymphatic obstruction (neoplastic, parasitic, iatrogenic)
8. Idiopathic
Physical examination
A. Generalized edema manifests in the most dependent area (e.g., pedal edema in ambulatory patients, presacral edema in bedbound patients).
B. Peripheral edema (3)
1. Sparing of the feet suggests lipedema.
2. Pitting edema present for more than 3 months usually indicates a low serum protein level. Chronic edema can have fibrosis as well.
3. Assessment of color
a. Redness suggests infection or phlebitis.
b. A red-blue color suggests DVT.
c. A slightly cyanotic color bilaterally suggests CHF (Chapter 7.5).
d. The presence of ecchymosis suggests trauma.
Testing
Routine studies can include complete blood count (CBC), urinalysis, chest films, electrocardiogram (ECG), and biochemical screening to include albumin, total protein, total cholesterol, liver function tests, and thyroid function tests (4). Specific tests or imaging studies are indicated in clinical situations listed below.
Diagnostic assessment
A. Edema affecting the arms only
1. Edema exclusively of the upper extremities, caused by increased venous pressure, points to superior vena cava syndrome. A venogram will be useful.
2. If venous obstruction is suspected, obtain a venogram and Doppler or ultrasound studies.
3. If a thoracic outlet syndrome is suggested, computed tomography (CT), magnetic resonance imaging (MRI), or plain films may be helpful.
B. Edema of the arms and legs
1. Cardiac causes include CHF and constrictive pericarditis (Chapter 7.5). Diagnostic studies include a chest x-ray (CXR) study and ECG.
2. A leading hepatic cause is cirrhosis. Liver function tests are indicated.
3. Renal causes
a. Nephrotic syndrome: order 24-hour urine protein and lipids.
b. Glomerulonephritis or acute tubular necrosis: obtain urinalysis with sediment evaluation.
c. Preeclampsia: laboratory tests include urine protein, urate, blood urea nitrogen (BUN), creatinine, and serum bilirubin (5).
4. Other causes of generalized edema and tests that may be useful include hypothyroidism [thyroid-stimulating hormone, (TSH)], aldosteronism (serum potassium), Cushing’s disease (cortisol or dexamethasone test), malnutrition (prealbumin), beriberi (thiamine), malabsorption (total protein), angioedema, inflammatory bowel disease (sigmoidoscopy), serum sickness, malignancies (CT or MRI), and idiopathic edema (6).
C. Unilateral edema of the legs only points to a local peripheral cause such as trauma, venous obstruction, mass, or inflammation.
D. Bilateral chronic edema of the legs only
1. If tenderness is present, consider lipedema if no foot involvement, or varicose veins if the foot is involved.
2. Consider the possibility of a medication-related cause: see above.
3. An elevated TSH may point to a diagnosis of hypothyroidism or Grave’s disease.
4. Unilateral left-sided edema could be caused by iliac compression or pelvic mass obstructing venous outflow. A venogram, CT, or MRI may be helpful.
References
1. Braunwald E. Edema. In: Fauci AS, ed. Harrison’s principles of internal medicine, 14th ed. New York: McGraw Hill, 1998:210–214.
2. Powel AA, Armstrong MA. Peripheral edema. Am Fam Physician 1997;55:1721–1726.
3. Weber R. Leg edema. In: Rakel RE, ed. Saunders manual of medical practice. Philadelphia: WB Saunders, 1996:207–209.
4. Friedman HH. Edema. In: Friedman HH, ed. Problem oriented medical diagnosis, 6th ed. Boston: Little, Brown and Company, 1996:1–4.
5. Taylor RB. Manual of family practice. Boston: Little, Brown and Company, 1997:
497–499.
6. MacGregor GA, deWardner HE. Idiopathic edema. In: Schrier RW, Gottschalk CW, eds. Diseases of the kidney, 5th ed. Boston: Little, Brown and Company, 1993:
2493–2501.>
Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
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Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2008 Williams & Wilkins.
More About Causes of Ankle swelling
» Next page: Edema (Field Guide to Bedside Diagnosis)
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