Not an uncommon complaint, often benign, sometimes ominous. We’re talking about pitting edema; non-pitting lymphedema is rare, associated with lymphatic disorders [which can also pit] & hypothyroidism.
The best way to quantitate the edema, which is essential during follow-up, is by body weight.
Determine if the edema is unilateral or bilateral. Unilateral pedal edema is due to venous obstruction. Venous obstruction is due to:
- Proximal thrombosis. Order a duplex venous ultrasound ASAP on anyone with new onset unilateral edema, before they wind up with a pulmonary embolism.
- Chronic venous insufficiency, common in women who’ve had many pregnancies, but possible in men or anybody whose venous valves give out with age.
- Focal lymph node enlargement, neoplastic or infectious [uncommon].
Systemic causes of pedal edema can also begin unilaterally, since slight venous incompetence is easily asymmetric, showing up first on just one side. But then they turn bilateral.
From now on, we’ll be discussing bilateral pedal edema. Note that all systemic etiologies in the Table below cause sacral instead of pedal edema in patients who are bedridden.
CAUSES OF BILATERAL PEDAL EDEMA
The work-up is straight forward. Start off looking for serious etiologies, quickly summarized by remembering target organs:
During the initial visit, address Heart Failure and Cirrhosis by History & Physical Exam:
Other Findings in Heart Failure
See our posting on CHF (Acute Dyspnea-3).
Auscultate carefully at the lower left sternal border for Tricuspid Regurgitation, which immediately points to pulmonary hypertension & likely cor pulmonale. Click for a description of Tricuspid Regurg, and comments about listening for murmurs in general.
Especially consider Pulmonary Embolism, a common cause of Cor Pulmonale. Seek clinical clues:
- New onset DOE
- Sudden onset SOB (within 1 minute)
- Risk Factors: Prior Hx PE or DVT, Immobility, active Cancer
- See our posting on PE (Acute Dyspnea-2).
In terms of Liver Disease / Portal Hypertension:
Stigmata of Cirrhosis
The H&P may clue you in to a likely cause, but still…
ORDER BASIC TESTS:
CBC, Chemistry Panel, BNP, TSH, U/A, EKG
- CBC — for Anemia; (also ↓ Platelets in Cirrhosis)
- B-Type Natriuretic Peptide (BNP) — for CHF
- Creatinine & BUN — for Nephrotic Syndrome / Renal Failure
- LFTs — for Cirrhosis / Liver Failure (may be deceptively normal)
- Serum Albumin — for Cirrhosis and Nephrotic Syndrome
- TSH — for Hypothyroidism
- Urinalysis — for Nephrotic Proteinuria (causing hypoalbuminemia)
- EKG — for recent MI, a possible cause of new CHF
- Echocardiogram — if reasonable suspicion of CHF (right- or left-sided)
A Few Comments:
Anemia is a common cause of edema, mediated essentially through mechanisms equivalent to CHF. It has to be significant, e.g. Hgb / Hct around 8 gm / 25% (rapid blood loss can cause edema at higher counts). Once you diagnose Anemia as the cause of edema, you need to identify its cause as well (iron deficiency, B12 deficiency, etc). And if it’s Iron Deficiency, you’d better find out why (e.g. colon cancer? ulcer?). See our recent postings [Anemia-1 (Intro), Anemia-2 (Microcytic), Anemia-3 (Macro- & Normocytic)].
CHF likewise; diagnose this, then ask, “Why?” Longstanding HT? Recent MI? Arrythmia? Valvular Disease? See our posting Acute Dyspnea-3. I read of one case of a man with edema and ascites for 3 years before being diagnosed with constrictive pericarditis with right-sided failure, masquerading as cirrhosis.
Cor Pulmonale (Right Heart Failure) of new onset equals Pulmonary Embolism until proved otherwise. Order a helical chest CT or V/Q Scan ASAP. The CT is usually quickest to obtain, but the V-Q scan is more sensitive for chronic PEs.
Portal Hypertension causes ascites & edema due to venous congestion & stasis.
Cirrhosis causes ascites & edema due to both Portal HT & also low colloid osmotic pressure from hypoalbumenia (due to decreased synthesis).
Nephrotic Syndrome causes hypoalbumenia via proteinuria. A urinalysis would have to be maximum “4+” because a 24-hour collection is >4 grams.
So what happens when there’s no clinical suggestion of CHF or Liver disease, and all labs return normal? Consider an echocardiogram if the edema is significant, though the BNP is an excellent surrogate. You reassure the patient of all the terrible conditions they don’t have, and make a diagnosis of Venous Stasis.
Venous Stasis?? Recommend elastic stockings???? Makes me a little nervous, but indeed, we sought what we could, & came up with all negatives. Of course, consider new Medications that commonly cause edema:
- Calcium Channel Blockers (dihydropyridines): nifedipine, amlodipine, felodipine
- Thioglitazones: pioglitazone, rosiglitazone
- NSAIDs (though suspect occult CHF if NSAIDs cause edema)
Discontinue any of these and see what happens.
By all means, also discontinue any diuretics the patient may have been taking. Perhaps not HCTZ taken long-term for HT. But certainly furosemide or other loop diuretics [which don’t even work well for B/P control]. These may have been taken surreptitiously for weight loss, or prescribed for minor degrees of venous stasis edema. Will need to discontinue and be patient for up to 3-4 weeks, employing elastic hose as you go. Not easy.
As for the few other entities in the differential, well, hopefully there won’t be a problem in recognizing 3rd Trimester Pregnancy. Or Severe Malnutrition.
Persistent Upright Posture is a common cause of pedal edema, especially if the patient reports that the swelling fluctuates, or comes & goes. Some examples I’ve seen:
- Homeless person sleeps sitting up
- Elderly person with severe back pain spends entire day in chair
A syndrome of “idiopathic edema” of hands & face as well as feet has been described in premenopausal women, different from premenstrual fluid accumulation. It’s a diagnosis of exclusion, associated perhaps with obsessive weight loss or purging, and diuretic abuse. I’m not convinced.
SUMMARY — Approach to Pedal Edema
1. Target the Main Etiologies:
- Consider risks for possible Pulmonary Embolism
- Discontinue possible culprit meds
3. Basic Work-Up: CBC, Chemistry Panel, BNP, TSH, U/A, EKG4. If work-up Negative:
- Obtain Echo if edema progressive
- Treat for Venous Insufficiency
That’s all for edema; hope it was useful. If you liked it, comment “Swell.”