EDEMA, EFFUSIONS, HYPEREMIA, CONGESTION Flashcards
What is an effusion?
Accumulation of fluid inside the body cavities
What is hemostasis?
This is a blood clotting process that prevents excessive bleeding after damage
What happens if hemostasis is not sufficient?
If it is inadequate, then it can lead to hemorrhage, hypotension and shock
However if its excessive it can lead to a Thromboembolism
What is shock?
This is a state of circulatory failure which prevents tissue perfusion and leads to cellular hypoxia
Explain the differences between inflammatory and non inflammatory Edema
Inflammatory edema fluid is rich in proteins(exudate) and their basic mechanism is increased vascular permeability. They are also usually localized, except in sepsis where they are generalized
In non inflammatory edema fluid, it is usually protein poor and occur in heart failure, liver failure, nutritional disorders and Renal disease
List the causes of Edema
Increased hydrostatic pressure Decreased plasma oncotic/osmotic pressure Increased salt and water retention Lymphatic obstruction inflammation
How is increased hydrostatic pressure caused?
It is caused mainly by diseases that affect venous return
Impaired venous return can be systemic or localized
Explain the difference between localized and systemic impaired venous return.
Localized IVR can be caused by a venous obstruction such as thrombosis or a mass exerting an external pressure. It can also be caused by lack of activity in the lower limbs
Systemic causes are Chronic heart failure, constrictive pericarditis and liver cirrhosis
What causes decreased oncotic pressure?
This is caused by conditions which lead to a decrease in the synthesis of Albumin. This leads to a fall in in Intra Vascular volume causing Renal hyper fusion. This leads to stimulation of the Renin angiotensin system. This then leads to release of aldosterone hormone that causes water and salt retention exacerbating the edema.
Conditions that may cause this include
Liver cirrhosis
Malnutrition
Protein losing gastro enteropathy
Explain causes of inflammation and lymphatic obstruction.
Causes include, Trauma, fibrosis, invasive tumors, infections and post surgical or post irradiation.
These causes can lead to the disruption of lymphatic channels and impair the clearance of interstitial fluid resulting in lymhedema
On example is fliarsis which leads to fibrosis of lymphatics ultimately causing edema of the external genitalia. This condition is known as elephantiasis.
Describe the mechanism of edema in heart failure
Whenever there is heart failure, capillary hydrostatic pressure increases due to and increase in venous blood pressure and this leads to Edema. There is also a decrease in renal blood flow, which will stimulate the renin angiotensin system causing retention of salt and water, increasing the blood volume leading to edema.
Explain how edema is caused in Malnutrition.
In malnutrition, there is insufficient intake of protein which causes a decrease in plasma protein. This leads to reduced plasma oncotic pressure, causing edema
How is edema recognized microscopically?
It is seen as a clearing and separation of extracellular matrix as well as subtle cell swelling
Explain the differences between hyperaemia and congestion
Hyperaemia is an active process and is caused by arteriolar dilatation at the sites of inflammation and skeletal muscle during exercise. The affected tissue turns red because of an increased amount of oxygenated blood. (Erythema)
Congestion is a passive process and is caused by venous dilatation due to reduced blood flow out of the tissue caused by systemic defects like congenital heart failure or localized issue like a venous obstruction. Affected tissue can be dusky red or blue because of increased amount of deoxygenated blood. (cyanosis)
