Edema resident survival guide
Synonyms and keywords: Generalized edema, localized edema, unilateral edema, bilateral edema

# Overview
Edema is an abnormal collection of fluid in interstitial space because of increased hydrostatic pressure, decreased oncotic pressure, increased capillary permeability, and obstruction in lymphatic drainage. Edema may be  due to underlying systemic diseases such as nephrotic syndrome, right sided heart failure, hypothyroidism, hyperthyroidism, side effect of some drugs, complications of recent surgery and malignancy. Edema may be generalized due to cardiac, thyroid, kidney diseases or localized due to cellulitis, deep vein thrombosis (DVT), chronic venous insufficiency and lymphedema. Diagnosis is based on taking history of recent surgery, trauma, systemic illness, malignancy and  doing physical examination about the distribution of edema and determination of pitting or non pitting edema, inducing  pain on palpation. Duplex sonography is helpful for finding the evidence of DVT. For more investigation about localized edema with unknown etiology, abdominal computer tomography, magnetic resonance venography maybe required.

# Causes

## Life Threatening Causes of peripheral edema
Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated.
- Generalized edema caused by decompensated heart failure
- Localized leg edema caused by proximal deep vein thrombosis leading to acute pulmonary embolism

## Common Causes of peripheral edema
- Advanced kidney disease
- Nephrotic syndrome
- Systolic or diastolic heart failure 
- Constrictive pericarditis
- Pulmonary hypertension
- Anemia
- Nutritional deficiency
- Malabsorption
- Refeeding edema
- Deep vein thrombosis
- Cellulitis
- Superficial thrombophlebitis
- Baker cyst
- Chronic venous insufficiency
- Lymphedema  
- Pregnancy
- Menstrual cycle
- Hyperthyroidism
- hypothyroidism
- Medications
- Obstructive sleep apnea

# Diagnosis
Shown below is an algorithm summarizing the diagnosis of edema.

# Treatment
Shown below is an algorithm summarizing the treatment of edema.

# Do's
- Before initiation of medical compression therapy, checking the arterial circulation is recommended. If foot pulses or ankle pulses are weak or not palpable, the ankle-brachial index(ABI) should be measured.
- In proximal deep vein thrombosis (DVT), using compression bandage or medical compression stockings and walking accompanied with anticoagulant therapy will lessen the pain and swelling.
- In DVT, using medical compression  will not increase the risk of pulmonary thromboembolism and post thrombotic syndrome.  
- Early mobilization in acute deep vein thrombosis will not increase the risk of pulmonary thromboembolism.
- In the acute phase of DVT, calf compression reduces irreversible skin alteration, edema, and pain.
- In compensated heart failure NYHA  and , mild compression of both legs may increase cardiac preload.
- Correction the sizing of compression therapy is recommended in diabetic neuropathy for prevention of peripheral nerve damage, especially peroneal nerve palsy and foot drop.
- Obstructive sleep apnea in obese patients may cause bilateral leg edema due to pulmonary hypertension induced by hypoxia.
- After harvesting of leg vein for bypass graft surgery, mild compression stocking about 15-20 mmHg, reduced leg edema significantly. 
- Daflon or micronized purified flavonoid fraction (MPFF) is recommended in chronic venous insufficiency because of anti-inflammatory effect and enhancement of  venous contractility.
- Topical steroid maybe useful in stasis dermatitis (scaling, erythematous skin changes) due to chronic venous insufficiency and lymphedema.

# Dont's
- Do not use medical compression device in the conditions include:
Severe peripheral arterial occlusive disease  when the ankle-brachial index (ABI)< 0.6, ankle pressure<60 mmHg, transcutaneous oxygen pressure<20 mmHg;
Suspected compression of bypassed arteries in coronary artery bypass graft;
Severe decompensated heart failure (NYHA 4) due to  increased preload leading to deterioration right and left ventricular function;
History of allergic reaction to compression material;
Severe diabetic neuropathy with sensory loss, microangiopathy, and risk of skin necrosis.
- Severe peripheral arterial occlusive disease  when the ankle-brachial index (ABI)< 0.6, ankle pressure<60 mmHg, transcutaneous oxygen pressure<20 mmHg;
- Suspected compression of bypassed arteries in coronary artery bypass graft;
- Severe decompensated heart failure (NYHA 4) due to  increased preload leading to deterioration right and left ventricular function;
- History of allergic reaction to compression material;
- Severe diabetic neuropathy with sensory loss, microangiopathy, and risk of skin necrosis.