Session 1 - Pictures and Drug Overdose Flashcards
What can be seen on this image?
Coagulative necrosis
Name three features of coagulative necrosis
Dead tissue has solid consitency
Ghost outline of cells
Appearance lasts a few days before phagocytes invade and ingest dead material
What can be seen?
Liquefactive necrosis
Why does this type of necrosis occur?
Release of active enzymes such as proteases by neutrophils in response to bacterial infection.
What is the type of necrosis demonstrated in the picture?
Caseuous necrosis
How can caseuous necrosis occur?
* Tissue appears amorphous
* Associated with infections such as tuberculosis
What is the type of necrosis shown here?
Fat necrosis
How can fat necrosis occur?
* Occurs in pancreatitis > release of lipases > damage adipocytes
What is the cause of this necrosis?
Infarction causing white necrosis
What causes this type of necrosis?
- Occurs with the occlusion of an “end” artery (sole source of arterial blood to a segment of an organ). If occluded, the tissue will die and appear white due to lack of blood
What is this type of necrosis caused by?
Red infarction
Why does this type of infarction occur?
Tissue filled with blood due to extensive haemorrhage. Limited blood supply, not enough for tissue to survive so lots of blood. Can be caused by occlusion of one of a pair of arteries.
What is the pathway for alchol metabolism?
Ethanol –> (alcohol dehydrogenase, CYPZE1, catalase) –> Acetaldehyde –> (aldehyde dehydrogenase) –> Acetate
How can excess alcohol abuse be detected in blood?
- Elevated mean cell volume (large red blood cells) due to direct toxic effects of alcohol on bone marrow, or folate defiency.
- Raised AST and ALT, due to damage to hepatocytes
- Gamma-GT (aminotransferase) - Raised in regular moder and heavy drinkers
- Alcoholic hepatitis, eleveated serum bilirubin, aminotransferases, alkaline phosphatases
What affect does alcohol have on liver presentation?
How are these changes caused?
Fatty change
Acute hepatitis
Alcoholic cirrosis
- Caused by toxicity
What change to liver cells can been seen here, and what is the clinical name for it?
Fatty change
Steatosis
What affect can alcohol have on nervous system?
- Wernicke syndrome, due to thiamine defiency
- Results in ataxia (loss of voluntary muscle control), disturbed cognition, nystagmus (involuntary eye movement)
- Korkasoff syndrome
- Thiamine defiency + toxicity
- Sever memory loss
- Peripheral neuropathy
- Epilepsy
What affect can alcohol have on cardiovascular system?
Cardiomyopathy
Hypertension
Beri Beri heart disease
What affect does alcohol have on GI tract?
Pancreatitis, leads to vitamin defiency (unable to breakdown fat, fat soluble vitamins cannot be absorbed)
What is foetal alcohol syndrome?
Acetaldehyde crosses over placental barrier and damages foetal brain. Causes mental retardation.
What happens after an OD of paracetamol?
Glutathione depleted and NAPQI binds with suplhdryl groups on liver membrane, causing necrosis and liver failure
Give three examples of patients will suffer from paracetamol OD at lower doses and why
Lower glutathione in first place
- Alcohol with the OD
- Malnourished
- HIV positive
What are the physiological effects of paracetamol overdose?
What is the antidote?
Liver failure at 36-96 hours and death
N-acetylcysteine, which increases availability of hepatic glutathione
What is a method of determining severity of liver damage?
Prothrombin time (PT), clotting in blood
Measure Creatinine and blood pH
What are the consequences of an aspirin overdose?
Acidosis (acetysalicylic acid)
Increase in lactose, ketones and pyruvate also contributes to acidosis
