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Questions and Answers

Which type of gangrene is characterized by the presence of foul odor due to the breakdown of necrotic tissue by bacteria?

Dry gangrene

Moist gangrene

Infective gangrene

Gas gangrene (correct)

Arterial occlusion is the primary cause of moist gangrene.

False

Which type of gangrene is characterized by gas production in deep wounds?

Moist gangrene

Infective gangrene

Gas gangrene (correct)

Dry gangrene

Name one predisposing factor for developing dry gangrene.

Atherosclerosis Signup and view all the answers

Moist gangrene is primarily caused by poor blood supply.

False Signup and view all the answers

What is the primary cause of infective gangrene?

Pathogenic bacteria Signup and view all the answers

In gangrene, ______ is caused by bacteria breaking down necrotic tissue.

putrefaction Signup and view all the answers

Moist gangrene is characterized by _____ putrefaction due to the presence of tissue fluids.

rapid Signup and view all the answers

Match the type of gangrene with its description:

Dry gangrene = Caused by arterial occlusion and poor collateral circulation Moist gangrene = Involves wet, necrotic tissue due to venous obstruction Infective gangrene = Caused by bacterial infection of wounds Gas gangrene = Characterized by the presence of gas bubbles in tissues Signup and view all the answers

What is the most common site affected by gangrene?

Toes Signup and view all the answers

What occurs when gangrene reaches a level with good blood supply?

It stops. Signup and view all the answers

Infective gangrene is solely caused by gas-producing bacteria.

False Signup and view all the answers

Match the type of gangrene with its primary characteristic:

Dry gangrene = Tissue dryness and shrunken appearance Moist gangrene = Rapid putrefaction and internal occurrence Infective gangrene = Caused by pathogenic bacteria Gas gangrene = Gas production in tissues Signup and view all the answers

Which type of gangrene lacks a clear line of demarcation?

Moist gangrene Signup and view all the answers

List one characteristic of gas gangrene.

Presence of gas bubbles in tissues Signup and view all the answers

What is the effect of putrefaction products on the surrounding healthy tissue in gangrene?

It acts as an irritant causing inflammation. Signup and view all the answers

Which of the following is NOT a common cause of acute ischemia?

Vascular inflammation Signup and view all the answers

Chronic ischemia can lead to patchy cell injury.

True Signup and view all the answers

What is the primary aetiology of an infarct?

Arterial occlusion by thrombus or embolus Signup and view all the answers

An area of ischemic necrosis due to sudden ischemia is called an __________.

infarct Signup and view all the answers

Match the types of gangrene with their characteristics:

Dry Gangrene = Develops from chronic ischemia, often due to atherosclerosis Moist Gangrene = Occurs in tissues that become infected and swell due to loss of blood supply Gas Gangrene = Caused by infection with clostridial bacteria producing gas Infective Gangrene = Characterized by rapid tissue death with systemic toxicity Signup and view all the answers

What type of infarction occurs due to venous obstruction?

Red (hemorrhagic) infarction Signup and view all the answers

Buerger's disease is associated with elderly males and is a result of atherosclerosis.

False Signup and view all the answers

What is the mechanism behind infective gangrene?

Rapid infection leading to tissue necrosis and systemic toxicity Signup and view all the answers

Study Notes

Ischemia

Reduction of blood supply to a tissue
Can be acute (sudden and complete) or chronic (gradual and incomplete)

Acute Ischemia

Caused by thrombosis (blood clot), embolism (traveling clot), surgical ligature, strangulation, twisting, severe arterial spasm, Buerger's disease, frostbite, severe compression.
Thrombosis and embolism are the most common causes.
Effects depend on collateral circulation: occlusion of end artery or artery with poor collaterals results in ischemic necrosis (infarction or gangrene).
Occlusion of an artery with good collaterals may cause no significant effects.

Chronic Ischemia

Caused by atherosclerosis, endarteritis, arterial compression.
With efficient collaterals, there are no effects.
With poor collaterals, the effects include pain on exercise (angina pectoris or intermittent claudication), and patchy cell injury that leads to fibrosis.

Infarction

Area of ischemic necrosis due to sudden ischemia.
Most often caused by arterial occlusion.
Can be pale (anemic) or red (hemorrhagic).

Infarction Due to Arterial Occlusion

The occluded artery has poor collaterals, therefore the area appears pale immediately after occlusion.
After 24 hours blood collects in the area due to dilatation of poor arterial collaterals.