Lecture 2: The challenge of pathology

Question 1

What is pathology?

Answer 1

the study of the cause and mechanism of disease
cause - etiology
mechanism - cellular and molecular changes that cause disease

Question 2

Why is pathology important in a clinical context?

Answer 2

• it provides a framework to understand disease, link between clinical pathology/laboratory medicine and clinical medicine
• it underpins the practive of clinical medicine
• key to medical science and research

bench to bedside and back to bench

Question 3

What are the two major factors in etiology?

Answer 3

genetic factors and aquired/environmental (infection, trauma, diet)

Question 4

Give an example of a disease that is primarily genetic in etiology

Answer 4

cystic fibrosis - autosomal recessive disorder, mutation in CFTR gene

Question 5

Give an example of a disease that is primarily environmental in etiology

Answer 5

asbestosis - lung and pleural fibrosis, mesothelioma (malignant tumour of the mesothelium)

Question 6

Explain how genetics can influence the susceptibilty to a disease

Answer 6

• genes predispose you towards disease
• modify the course of the disease process.

eg. crohns disease

Question 7

most diseases have an etiology of ?

Answer 7

combined interaction of genetic and environmental factors which can alter predisposition and course of disease

Question 8

What is the pathogenesis of disease

Answer 8

sequence of cellular and molecular events in cells and tissues following the initial insult or injury

Question 9

What are the limited cellular/molecular changes/sequence of events that occur in the cells and tissues after insult/injury

Answer 9

1. degeneration and atrophy
2. apoptosis and necrosis
3. inflammation
4. regeneration, hyperplasia, hypertrophy
5. dysplasia and neoplasia

Question 10

describe the disease process in 4 steps

Answer 10

1. etiology
2. pathogenesis
3. structural changes in cells and tissues
4. clinical manifestations

Question 11

What are some structural changes that occur as a result of pathogenesis

Answer 11

gross changes
microscopic

Question 12

What are clinical manifestations?

Answer 12

the physical result of illness or infection

• symptoms
• clinical signs
• laboratory and readiological changes
• clinical course, therapy and possible complications

Symptoms: subjective, perceived only by person affected
Signs: objective findings. seen or measured.

Question 13

Why is understanding pathology and pathogenesis so critical in medicine?

Answer 13

plays a role in
- diagnosis
- prognosis
- monitoring the response to treatment (is the patient actually getting better)
- screening strategies
- preventative strategies

Question 14

What are the three tools of pathology? I.e. how do we investigate the nature of the process of disease?

Answer 14

• clinical situation
• symptoms
• examination findings

Question 15

give two examples of investigating a mass/abnormal tissue

Answer 15

fine needle aspiraton and biopsy

Question 16

What is the key difference between aspiration and biopsy?

Answer 16

• aspiration: only get a collection of cells, not the bigger picure
• biopsy: see all pieces of tissue, fixed and sectioned, gives you a better understanding of the relationship between the cells
  -* (see types of cells and architecture of tissue)*

Question 17

How can aspirates and biopsies help in the diagnosis/investigation of disease

Answer 17

used for cytology (looks at morphology of cells)
used for microbiolgy (agar plates)
antigen expression
molecular studies (FISH)

Question 18

Explain how biopsies and morphology help identify disease

Answer 18

• shows types of cells present
• shows architecure of the tissue

Question 19

explain how biopsies and antigen expression help identify disease

Answer 19

• stain tissue with labeled antibodies
• flow cytometry (passed through lazer, proteins stained that recognise antibodies will show up)

Question 20

explain how biopsies and molecular studies identify disease

Answer 20

molecular genetic studies like
- karyotype (trisomey or monosomy)
- FISH (locate a specific DNA sequence on a chromosome, more red dots = overexpression of gene)
- DNA analysis
- RNA analysis