Lecture 1 Flashcards
Define and explain what pathophysiology is? (3 mark)
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)
Explain the relevance of pathophys?
consequence of pathophys → diagnosis and treatment of disease + form guidelines for biomedical research aimed to improve health
aetiology
cause
pathogenesis
mechanism by which aetiology operates to cause pathological and clinical manifestations
complications and sequelae
secondary effects
prognosis
likely outcome
epidemiology
incidence (new cases), prevalence (total cases), distribution in population
cause vs agent of disease?
- 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
categories of causal agents:
- genetic abnormalities
- chemicals
- infective agents
- radiation
- mechanical trauma
- socio-economic
when cause unknown, disease classified as?
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)
cause of disease may be…
- entirely genetic → inherited or prenatally acquired defects of genes (mutations after conception but before birth)
- entirely environmental → no genetic component
- multifactorial (most common) -> interactions between genetics and environment
genetic abnormalities may be due to:
- 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)
environmental factors which may cause disease include?
- 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
Main types of pathogenesis?
- inflammation → in response to microbes/ harmful agents
- degeneration (metabolic) → deterioration of cells in response to or due to failure to adapt to agents
- carcinogenesis → growth disorders like tumors
- immune reactions → overreaction of immune system
- haemodynamic → shock, ischemia
sign Vs symptom?
- 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
lesions may be?
- 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
effects of disease may be (3)
- prolonged → host has impaired capacity for defense or repair
- secondary → tumors
- distant → spread of infectious agent
morbidity
sum of disease effects on patient
importance of epidemiology?
- aetiological clues
- allows planning of preventative measures
- vaccination programs, quarantine measures
- sanitation, antibiotics
- screening population for disease early
- planning & provision adequate medical facilities
primary Vs secondary disease?
- 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
primary Vs secondary stages of disease?
primary tumor is initial site from which cancer cells travel to cause secondary tumors in other tissues/ organs
benign Vs malignant?
- benign → remain localized within tissue of origin, rarely lethal
- malignant → spread or metastasize, usually lethal
- metastasis → spread of pathogenic agent
syndrome
- aggregation of signs & symptoms which occur together
- Down syndrome, cushing’s etc.
congenital
present from birth, may be genetic or non-genetic
latrogenic
attributable to practitioners actions
nosocomial
acquired as consequence of hospital stay
numerical codes of disease used for?
- disease registration
2. epidemiological studies
Numerical coding systems of disease include?
- International Classification of Disease (ICD), by WHO
- Systematized Nomenclature of Medicine (SNOMED), by American college of Pathologists
- American Psychiatric Association (DSM)
Purpose of International statistical classification of diseases & health related problems?
- 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
diagnosis
the act of naming the disease
why diagnosis is needed?
relevant as allows allocation of appropriate treatment → effectivity
general process of diagnosis?
- 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)
strategy for diagnosis?
- decide which organ/ system affected
- signs & symptoms → general category of disease (inflammation, neoplasia)
- use other factors (age, gender, previous health issues) → infer diagnosis or narrow possibilities
- only perform investigations if outcome of each one can be expected to either:
- resolve diagnosis, or
- influence management (if diagnosis already known)
