Common causes of generalized edema:

1). Heart failure.

2) Renal cause :

• Nephrotic syndrome.
• Acute nephritic syndrome.

3) CLD (Chronic liver disease): Cirrhosis of liver.

4) PEM (Protein energy malnutrition): Kwashiorkor.

5) Hypothyroidism.

Common causes of localized/unilateral edema:

1. Venous obstruction: Deep vein thrombosis (DVT).
2. Lymphatic obstruction: Filariasis.
3. Acute inflammatory edema: Cellulitis.
4. Type-I hypersensitivity edema.

Causes (differential diagnoses) of leg swelling/leg edema:

Bilateral leg swelling:

1) Heart failure:  Right or combined left & right heart failure, pericardial constriction, cardiomyopathy.

2) Chronic venous insufficiency.

3) Hypoproteinaemia: (edema is often widespread, can affect arms & face)

• Nephrotic syndrome.
• Chronic liver disease.
• Protein losing enteropathy.

4) Drugs:

a) Na+ retention: NSAIDs, fludrocortisone.

b) Increased capillary permeability: Nifedipine, amlodipine.

5) Idiopathic:  Women > men.

6) Chronic lymphatic obstruction:  Filariasis, pelvic tumour.

Unilateral leg swelling:

1. Deep vein thrombosis (DVT).
2. Lymphatic obstruction (eg. in filariasis).
3. Soft tissue infection (cellulitis).
4. Ruptured Baker’s cyst.
5. Calf muscle haematoma.

Common causes of generalized edema with oliguria:

• Nephrotic syndrome.
• Acute nephritic syndrome.
• Heart failure.

How will you clinically asses and investigate unilateral leg swelling? 

Unilateral leg swelling:

Clinical assessment:

History:

• Prolonged immobility.
• Recent major surgery.
• Oral contraceptive pill (female).
• Pregnancy (female).
• Trauma.
• Filaria endemic zone.
• Varicose vein.

Examination:

Inspection:

• Swelling, extent of swelling.
• Veins: Engorged, varicosities.
• Scratch mark.
• Pigmentation.
• Purpura.
• Hair change.
• Trophic ulcer.
• Associated joint swelling, clubbing,
• Swelling of the back of the leg

Palpation:

• Temperature: Warm or cold.
• Pulse: Popliteal, posterior tibial, arteria dorsalis pedis.
• Edema – pitting or non-pitting.
• Calf tenderness, localized swelling (DVT, ruptured Baker’s cyst).
• Popliteal and inguinal lymph nodes.

Investigations:

1. CBC with ESR: Eosinophilia in filariasis, raised ESR & neutrophilia in cellulitis.
2. For DVT: Doppler USG of lower limb veins for DVT, venography.
3. For filariasis: Blood film, provocation test (by diethylcarbamazine), CFT, lymphoscintigraphy.
4. USG or CT scan of whole abdomen.
5. Factor VIII and IX level in suspected haemophilia.