Pathophysiology of Oedema

Questions and Answers

What is a common feature in children and young adults in liver disease?

Pleural effusion

Anasarca

Facial oedema and periorbital puffiness

Ascites (correct)

What is a characteristic of low oncotic pressure?

Decrease in capillary permeability

Increase in intravascular volume

Increase in capillary permeability (correct)

Features of hypervolemia

Which of the following is not a feature of oedema caused by low intravascular volume?

Facial oedema and periorbital puffiness

Pleural effusion (correct)

Periorbital oedema

Ascites

What is the primary goal of treatment in oedema caused by venous or lymphatic obstruction?

Correction of the underlying cause Signup and view all the answers

What is the purpose of measuring serum albumin in the investigation of oedema?

To assess the oncotic pressure Signup and view all the answers

In which cases of oedema may a large dose of diuretics be required?

Severe cases with venous thrombosis Signup and view all the answers

What is the primary mechanism of dependent oedema in the lower limbs?

Effect of gravity on the venous hydrostatic pressure Signup and view all the answers

Which of the following is a characteristic of pitting oedema?

It leaves an indentation after pressure on the affected area Signup and view all the answers

What is the primary cause of oedema in patients with nephrotic syndrome?

Decreased plasma oncotic pressure due to renal loss of protein Signup and view all the answers

Which of the following is a cause of non-pitting oedema?

Protein deposition in chronic lymphoedema Signup and view all the answers

What is the primary cause of oedema in patients with deep venous thrombosis?

High local venous pressure due to deep venous thrombosis Signup and view all the answers

Which of the following is a characteristic of anasarca?

Generalized oedema that affects the entire body Signup and view all the answers

What is the primary cause of oedema in patients with liver failure?

Decreased plasma oncotic pressure due to decreased protein synthesis Signup and view all the answers

Which of the following is a common site of oedema formation in bed-ridden patients?

Sacrum Signup and view all the answers

Study Notes

Oedema

Oedema is the accumulation of interstitial fluid, causing "pitting oedema" which leaves an indentation after pressure on the affected area.
It results from a disruption of the pressures across the capillaries, leading to fluid movement across the capillary basement membrane.

Types of Oedema

Pedal oedema: oedema of the lower limbs, resulting from the effect of gravity on venous hydrostatic pressure.
Anasarca: a type of oedema characterized by facial oedema and periorbital puffiness.
Cerebral oedema: oedema affecting the brain.
Macular oedema: oedema affecting the macula of the eye.
Pulmonary oedema: oedema affecting the lungs.

Causes of Oedema

High hydrostatic pressure:
- Congestive heart failure.
- Renal failure.
- Hypervolemic status (e.g. iatrogenic, Conn's syndrome).
- Deep venous thrombosis (DVT) or venous insufficiency.
- Pregnancy.
- Pelvic tumor.
Low plasma oncotic pressure/low serum albumin:
- Nephrotic syndrome.
- Liver failure.
- Malnutrition/malabsorption.
Increased capillary permeability:
- Infection.
- Burn.
- Allergic reaction.
- Trauma.
- Anoxia.
- Acidosis.
Lymphatic obstruction:
- Infection (e.g. filariasis).
- Malignancy.
- Radiation injury.
- Congenital abnormality.

Clinical Features

Dependent regions are usually the first site of oedema formation.
Ankle oedema is characteristic, but oedema can also develop over the sacrum in bed-ridden patients.
With increasing severity, oedema will rise higher in the lower limbs and affect the genitalia and abdomen.
Ascites is also common.
Pleural effusion.
Facial oedema and periorbital puffiness are seen in young patients and in cases of low oncotic pressure.

Investigations

The cause of oedema can be easily detected from the history and physical examination of the CVS and abdomen.
Serum albumin measurement and urine examination for protein are also necessary.

Treatment

Treatment for specific causes, such as venous thrombosis.
Diuretics with restriction of sodium (sometimes fluids) is rational.
In mild cases, thiazides or small dose loop diuretics (e.g. furosemide) can be used.
In severe cases, large doses of diuretics, sometimes in combination, are required.
In cases of oedema caused by venous or lymphatic obstruction and oedema caused by increased capillary permeability, correction of the underlying cause and local compression (e.g. compressing stockings) are necessary.