Pedal oedema, swelling in the feet & ankles due to fluid accumulation, requires a thorough assessment for accurate diagnosis & tailored treatment. A comprehensive approach involves detailed history-taking, physical examination, & diagnostic tests to ensure precise management.

Introduction

Pedal oedema is a common presentation of various systemic and non-systemic diseases. Understanding the underlying physiological mechanisms of pedal oedema and employing a systematic approach to patient assessment can assist physicians in identifying the specific cause more accurately.

Aetiology

Based on the mechanism of origin, it can be divided into:

1. Increased capillary permeability
   1. Local causes: Cellulitis
   2. Systemic causes: Allergic reactions
2. Increased hydrostatic pressure
   1. Local causes: Compartment syndrome, chronic venous insufficiency
   2. Systemic causes:

• Anemia
• Congestive cardiac failure
• Chronic kidney disease
• Pulmonary hypertension (OSA)

3. Decreased oncotic pressure
   1. Liver cirrhosis
   2. Nephrotic syndrome
   3. Protein-losing enteropathy
4. Lymphatic obstruction
   1. Filariasis
   2. Lymphedema praecox
5. Drug-induced
   1. Anti-hypertensives: Calcium channel blockers, beta-blockers
   2. Hormones: Corticosteroids, estrogen
   3. NSAIDS: Diclofenac, ibuprofen
   4. Anti-diabetics: Pioglitazone

Approach to the patient

History taking

1. Onset, duration and progression:
   1. Pedal oedema has usually a gradual onset and progression of a few days to a few weeks' duration. If it’s associated with a chronic systemic condition, a long-standing oedema history of many weeks to months might also be there. Acute onset is more common in deep vein thrombosis, cellulitis, and allergic reactions.
2. Unilateral or bilateral:
   1. Unilateral oedema primarily occurs due to localised factors, such as deep vein thrombosis (DVT), cellulitis, compartment syndrome, and filarial lymphatic obstruction.
   2. Bilateral pedal oedema primarily arises from systemic factors such as congestive cardiac failure, anaemia, chronic kidney disease, and chronic liver disease.
3. Associated with other symptoms like pain and redness:
   1. Cellulitis will have a history of severe pain not relieved by rest. DVT will also be associated with pain, which increases with walking.
   2. Oedema, because of chronic systemic conditions, is not associated with pain unless complicated by a secondary skin infection or DVT.
4. Diurnal variation:
   1. Venous oedema because of congestive cardiac failure and venous insufficiency is aggravated by standing and improves with overnight limb elevation during sleep.
5. Associated systemic illnesses:
   1. Symptoms of systemic diseases like exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea and chest pain point to cardiac failure.
   2. Oliguria's history and facial puffiness indicate a renal aetiology.
   3. Long-term alcohol consumption, yellowish discolouration of eyes and urine and abdominal distension points to cirrhosis of the liver.
   4. Symptoms of endocrine disorders like hypothyroidism are often missed.
   5. A similar history of all other systemic causes of pedal oedema should be elicited in detail.
6. Drug history

Physical examination

1. Distribution- Unilateral or bilateral
2. Site- Careful examination of bony prominences such as the medial malleolus, medial surface of the tibia, and dorsum of the foot is essential. Notably, lipedema typically affects the medial malleolus area but not the dorsum of the foot.
3. Tenderness- Deep vein thrombosis, cellulitis, lipedema, and compartment syndrome typically present with tenderness. Conversely, lymphedema and oedema, because of systemic diseases, are usually painless.
4. Pitting oedema- Except in cases of oedema because of lymphatic obstruction and myxedema, most of the other diseases cause pitting pedal oedema. However, in the early stages of lymphedema, it is usually pitting.
5. Skin changes
   1. Myxedema- Dry, coarse and thick skin is noted.
   2. Chronic venous insufficiency- Hemosiderin deposition causes brawny skin commonly over the medial malleolus. Often, varicose veins are seen on the medial side of the leg.
   3. Chronic lymphedema- hyperkeratotic and papillomatous skin with induration.
6. Systemic examination

• Congestive cardiac failure- Elevated jugular venous pressure, third heart sound and crepitations over the lung bases.
• Decompensated liver disease- Jaundice, ascites, splenomegaly gynaecomastia and spider naevi.
• Chronic kidney disease- Anemia, dry skin, uremic breath.
• Hypothyroidism- Bradycardia, skin changes like dry skin and sparse hair, hoarseness of voice.

Diagnostic tests

1. Laboratory investigations

• Complete blood count- Helps to diagnose anaemia.
• Urine analysis, renal function test & USG KUB- Help to diagnose chronic kidney disease & nephrotic syndrome.
• Liver function tests including serum protein (Cirrhosis, nephrotic syndrome, protein-losing enteropathy and malnutrition).
• Serum lipid profile- Nephrotic syndrome is associated with hyperlipidemia. Dyslipidemia is also a risk factor for coronary heart disease.
• NT-proBNP- For identifying heart failure.
• D-dimer estimation- D-dimer estimation can be employed to diagnose acute cases of pedal oedema and identify deep vein thrombosis.

2. Radiological Investigations

• Echocardiogram- For the assessment of left ventricular function in patients with congestive heart failure. It can also measure pulmonary artery pressure and help in diagnosing pulmonary hypertension in conditions like cor pulmonale.
• Ultrasound abdomen- For assessment of liver parenchyma and renal size and cortex along with evidence of ascites.
• Doppler in both lower limbs- For diagnosis of DVT.
• Lympho-scintigraphy- For diagnosis of lymphedema.

Treatment

1. Venous insufficiency: Initial stages limb elevation is helpful. In chronic states, it needs high knee compression stockings. Prior to utilising stockings, it is essential to exclude peripheral vascular disease through the ankle-brachial index or arterial Doppler evaluations, as they have the potential to exacerbate the underlying condition.
2. Congestive heart failure and chronic liver disease: Fluid restriction, salt restriction and limb elevation in the early stages and diuretics like furosemide and spironolactone can be used for patients who do not respond to the above measures. Albumin infusion can also be used to correct hypoalbuminemia in liver failure, which provides temporary relief.
3. Chronic renal failure: The primary management of renal failure involves initial fluid and salt restriction. Additionally, diuretics such as furosemide or torsemide may be prescribed. It's important to note that aldosterone antagonists are contraindicated due to the risk of potentially life-threatening hyperkalemia.
4. Obstructive sleep apnea: Weight reduction and continuous positive pressure ventilation help in reducing pulmonary hypertension and improving oedema.
5. Lymphedema: Initially treated with manual massaging. Compressive bandages and stockings can also be used. Later, intermittent pneumatic compression devices are used. In refractory cases of lymphedema, surgical procedures like bypass surgery and debulking can be done. Diuretics are of no use in these patients.
6. Deep vein thrombosis: In chronic bedridden patients, compression devices like bandages and stockings can prevent DVT. DVT is treated with early initiation anticoagulant therapy using low molecular weight heparin, which is followed by oral anticoagulants.
7. Idiopathic oedema: Responds to treatment with aldosterone antagonists like spironolactone.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Bhavin Mandowara is a practising nephrologist at Zydus Hospital, Ahmedabad.