Oedema Flashcards
Definition (& 2 types)
Excess fluid in interstitial space
Pitting oedema is a type of swelling in which pressure applied on the affected area leaves an indentation (or pit) that persists for a few seconds after the pressure is released.
Non-pitting oedema is a type of swelling in which pressure applied on the affected area does not leave an indentation.
Aetiology/ causes
(Pitting & non-pitting)
Pitting oedema can be caused by several underlying conditions, such as heart failure, liver disease, kidney disease, venous insufficiency, lymphatic obstruction, and certain medications.
Non-pitting oedema can be caused by several underlying conditions, such as lymphatic obstruction, hypothyroidism, systemic lupus erythematosus (SLE), and some medications.
Additional info
(Explain lymphatic obstruction and hydrostatic tension)
(Explain osmotic pressure)
Fluid compartments in the human body are divided between the intracellular and extracellular spaces. Fluid balance between the intravascular plasma volume (25%) and the extravascular interstitial space (75%) (the further divisions of the extracellular space) is maintained by hydrostatic tension and osmotic pressure
Lymphatic obstruction - In the context of oedema, hydrostatic pressure refers to the pressure exerted by blood in the capillaries. This pressure pushes fluid out of the capillaries and into the interstitial spaces of tissues. Normally, the lymphatic system removes this excess fluid, but in certain conditions, such as heart failure or liver disease, the lymphatic system may not function properly, leading to the accumulation of fluid in the tissues.
Normally, proteins in the blood help to maintain the balance of fluid in the body by creating an osmotic pressure that draws fluid back into the capillaries from the interstitial spaces. However, if there is a decrease in the concentration of blood proteins (such as in malnutrition or liver disease), the osmotic pressure is reduced, leading to an imbalance in fluid distribution and the development of oedema.
In summary, an increase in hydrostatic tension (such as in heart failure or venous obstruction) or a decrease in osmotic pressure (such as in malnutrition or liver disease) can lead to an accumulation of fluid in the interstitial spaces, resulting in oedema.
Risk factors
Risk factors include obesity, pregnancy, prolonged sitting or standing, and a sedentary lifestyle.
Certain medications that promote fluid retention
Epidemiology/ Population affected
Most common in patients over 50 (due to venous insufficiency)
Can affect any age group as a result of underlying conditions such as heart failure, renal failure, liver failure, and trauma
Non-pitting oedema is less common than pitting oedema.
Clinical presentation
The clinical presentation of oedema includes swelling that can occur in any part of the body, particularly in the lower extremities. The severity of the oedema can vary from mild to severe, depending on the underlying condition.
Prognosis
The prognosis for oedema depends on the underlying cause. With appropriate management of the underlying condition, the oedema can resolve or improve.
DDX
Lymphoedema
Lipodermatosclerosis
Cellulitis and other skin infections
DVT
Additional aspects (Treatment and Pathophysiology)
The lymphatic system collects fluid and filtered proteins from the interstitial space and returns that back to the vasculature
Any disturbance in this delicate homeostasis that results in net filtration out of the vascular space or impaired fluid return by lymphatics leads to fluid accumulation in the interstitial space, called oedema
