Lecture 1

Question 1

Define and explain what pathophysiology is? (3 mark)

Answer 1

pathophysiology → alterations to normal physiology (body function) resulting in or due to disease/ injury

(pathology → study of disease, thus pathophysiology → study of disease with relation to physiology)

Question 2

Explain the relevance of pathophys?

Answer 2

consequence of pathophys → diagnosis and treatment of disease + form guidelines for biomedical research aimed to improve health

Question 3

aetiology

Answer 3

cause

Question 4

pathogenesis

Answer 4

mechanism by which aetiology operates to cause pathological and clinical manifestations

Question 5

complications and sequelae

Answer 5

secondary effects

Question 6

prognosis

Answer 6

likely outcome

Question 7

epidemiology

Answer 7

incidence (new cases), prevalence (total cases), distribution in population

Question 8

cause vs agent of disease?

Answer 8

• cause → root reason why host was exposed to certain environment
  
  • ie. cause of tubercolosis ⇒ poverty, social depravation, malnutrition
• agent → direct factor responsible for disease
  
  • ie. agent of tubercolosis ⇒ Mycobacterium tubercolosis

Question 9

categories of causal agents:

Answer 9

• genetic abnormalities
• chemicals
• infective agents
• radiation
• mechanical trauma
• socio-economic

Question 10

when cause unknown, disease classified as?

Answer 10

essential/ idiopathic/ spontaneous/ cryptogenic/ primary

(a primary disease = due to root cause of illness, secondary disease = due to complications of the root cause not the root cause itself)

Question 11

cause of disease may be…

Answer 11

1. entirely genetic → inherited or prenatally acquired defects of genes (mutations after conception but before birth)
2. entirely environmental → no genetic component
3. multifactorial (most common) -> interactions between genetics and environment

Question 12

genetic abnormalities may be due to:

Answer 12

• abnormal chromosome numbers (autosomal or sex)
• single gene defects (autosomal dominant or recessive)
• fragile sites & chromosomal translocations
  
  • inherited predispositions to translocations at specific sites
• X-linked disorders (DMD, hemophilia)

Question 13

environmental factors which may cause disease include?

Answer 13

• general agents
  
  • infective agents, bacteria, viruses, yeasts, fungi, parasites, prions, proteinaceous infectious particles
• chemical agents
  
  • pollutants → dusts (coal, asbestos)
  • industrial and domestic materials → acids, alkalis
  • drugs → cigarette smoke (cancer), alcohol (hepatic cirrhosis), prescription or recreational
• physical agents
  
  • mechanical injury → trauma
  • thermal injury → burns, hypothermia, frostbite
  • radiation injury →
    
    • ionizing radiation → medicine, nuclear accident
    • non-ionizing radiation → UV exposure causing melanoma, dermal elastosis

Question 14

Main types of pathogenesis?

Answer 14

1. inflammation → in response to microbes/ harmful agents
2. degeneration (metabolic) → deterioration of cells in response to or due to failure to adapt to agents
3. carcinogenesis → growth disorders like tumors
4. immune reactions → overreaction of immune system
5. haemodynamic → shock, ischemia

Question 15

sign Vs symptom?

Answer 15

• symptom → felt & described by patient ; subjective abnormality
  
  • fatigue, nausea, pain, fever, malaise, altered bowel habits, shortness of breath
• sign → objective findings detectable by senses, instruments, tests etc.
  
  • sight (rash, pupil dilation), taste (sweet urine), hearing (heart beat), smell (ketoacidosis), touch (pulse, swollen lymph nodes), blood pressure

Question 16

lesions may be?

Answer 16

• Structural abnormalities
  
  • space occupying (tumors)
  • deposition of excessive substance (amyloid)
  • abnormally sited tissue (tumors) due to metastasis/ invasion/ abnormal development
  • loss of healthy tissue (ulceration, infarction)
  • obstruction to normal flow (asthma, vascular occlusion)
  • rupture of hollow viscus (aneurism, intestinal perforation)
• Functional abnormalities
  
  • excessive secretion cell product (nasal mucus, hormones)
  • insufficient secretion cell product (insulin in diabetes)
  • impaired nerve conduction
  • impaired muscle contractility

Question 17

effects of disease may be (3)

Answer 17

• prolonged → host has impaired capacity for defense or repair
• secondary → tumors
• distant → spread of infectious agent

Question 18

morbidity

Answer 18

sum of disease effects on patient

Question 19

importance of epidemiology?

Answer 19

1. aetiological clues
2. allows planning of preventative measures
   
   • vaccination programs, quarantine measures
   • sanitation, antibiotics
   • screening population for disease early
   • planning & provision adequate medical facilities

Question 20

primary Vs secondary disease?

Answer 20

• primary → without evident cause
  
  • may be essential, idiopathic and/ or cryptogenic
  • ie. primary hypertension has no direct cause
• secondary → complication or manifestation of underlying lesion
  
  • ie. secondary hypertension may be consequence of renal artery stenosis

Question 21

primary Vs secondary stages of disease?

Answer 21

primary tumor is initial site from which cancer cells travel to cause secondary tumors in other tissues/ organs

Question 22

benign Vs malignant?

Answer 22

• benign → remain localized within tissue of origin, rarely lethal
• malignant → spread or metastasize, usually lethal
  
  • metastasis → spread of pathogenic agent

Question 23

syndrome

Answer 23

• aggregation of signs & symptoms which occur together

- Down syndrome, cushing’s etc.

Question 24

congenital

Answer 24

present from birth, may be genetic or non-genetic

Question 25

latrogenic

Answer 25

attributable to practitioners actions

Question 26

nosocomial

Answer 26

acquired as consequence of hospital stay

Question 27

numerical codes of disease used for?

Answer 27

1. disease registration | 2. epidemiological studies

Question 28

Numerical coding systems of disease include?

Answer 28

1. International Classification of Disease (ICD), by WHO 2. Systematized Nomenclature of Medicine (SNOMED), by American college of Pathologists 3. American Psychiatric Association (DSM)

Question 29

Purpose of International statistical classification of diseases & health related problems?

Answer 29

- classify diseases and other health problems - many types of health & vital records - includes death certificates & health records - enables storage and retrieval of diagnostic information → clinical, epidemiological & quality purposes - provides basis for compilation of mortality and morbidity statistics by WHO member states - influences reimbursement, resource allocation, decision making of countries

Question 30

diagnosis

Answer 30

the act of naming the disease

Question 31

why diagnosis is needed?

Answer 31

relevant as allows allocation of appropriate treatment → effectivity

Question 32

general process of diagnosis?

Answer 32

- observe clinical history → document patient symptoms - examine patient → clinical signs - perform investigations guided by provisional diagnosis, which was based on signs and symptoms (allows ordering of relevant tests)

Question 33

strategy for diagnosis?

Answer 33

1. decide which organ/ system affected 2. signs & symptoms → general category of disease (inflammation, neoplasia) 3. use other factors (age, gender, previous health issues) → infer diagnosis or narrow possibilities 4. only perform investigations if outcome of each one can be expected to either: - resolve diagnosis, or - influence management (if diagnosis already known)