Causes and Classification of Disease Flashcards
(43 cards)
What is pathophysiology?
The study of the functional changes in cells, tissues and organs that are altered by disease or injury.
What is the concept of disease?
the presence of an abnormality over the loss of normal health. Is the clinical manifestation of underlying structural and/or functional abnormality.
What is Aetiology?
The study of what causes a disease. Specifically the interaction between the host (genetic) and environmental factors.
What are the categories of causal agents?
- genetic abnormalities
- infectious agents
- chemicals
- radiation
- mechanical trauma
- socio-economic
If the cause of the disease is unknown, how do we classify the disease?
The disease is classified as primary, idiopathic, essential, spontaneous or cryptogenic.
If the cause is unknown but the disease is associated with risk factors, list some general risk factors.
constitutional traits, malnutition, ocupation, habits
What is the difference between cause and agent? give an example.
The cause is why the disease took place and the agent is the disease itself.
e.g. Tuberculosis is caused by poverty, social deprivation, and malnutrition.
The agent is the tubercle bacillus Mycobacterium tuberculosis.
What is Pathogensis?
Is the mechanism by which the aetiology operates to produce the pathological and clinical manifestations.
List disease mechanisms and give an example for each. (hint = there are 5 mechanisms)
- Inflammation = response to many microbes and other harmful agents e.g. tissue damage
- Degeneration = deterioration of cells or tissue in response to, failure to adapt to a variety of agents
- Carcinogenesis = mechanism by which carcinogenic agents grow e.g. growth disorders or tumours
- Immune Reactions = undesirable effects of the body’s immune system
If a disease does not occur immediately after exposure then there are periods of; (a) & (b)
a = latency (carcinogenesis)
b = incubation (infectious disease)
What is meant by the “manifestation” of a disease?
It is the signs and symptoms of the morphological, function and clinical changes to the patient.
What is a Sign? give some examples.
Signs are the objective findings detectable via senses, instruments, and tests.
e.g.
- Sight = rash, pupil dilation
- Taste = sweet urine
- Hearing = heartbeat
- Smell = ketoacidosis
- Touch = pulse, swollen lymph nodes
- Blood pressure
- Liver function tests
What is meant by Symptom? give some examples.
Symptoms are felt and describe by the patient and are the subjective abnormalities.
- Fatigue
- nausea
- pain
- malaise
- fever
- altered bowel habits
- shortness of breath
What are the two ways lesions described?
Lesions are either;
a. structural abnormalities
b. functional abnormalities
Describe what is meant when a lesion is “structural abnormalities”? give examples of each. (hint = 6)
Structural abnormalities are;
- space-occupying lesions e.g. tumours
- deposition of excessive or abnormal material in organ (e.g. amyloid)
- Abnormally sited tissue (e.g. tumours) due to metastasis, invasion or abnormal development
- loss of healthy tissue (ulceration or infraction)
- obstruction to normal flow (asthma)
- rupture of a hollow viscus (aneurism, intestinal perforation)
Describe what it means when a lesion is termed “functional abnormalities”? Give examples. (hint = 4)
Functional abnormalities are;
- excessive secretion of a cell product e.g. nasal mucus or hormones
- Insufficient secretion of a cell product e.g. insulin in diabetes mellitus (DM) type 1
- impaired nerve conduction
- impaired contractility of muscle
What is meant by complications and sequelae?
complications are the effects of the disease which may be;
- prolonged (if host has impaired capacity for defence and repair)
- secondary (tumours)
- distant (spread of infective agent)
Sequelae are the secondary effects of the disease or the effects of the previous disease. e.g. reoccurring pneumonia and respiratory problems as a result of COVID19
What is epidemiology?
Is the study of the incidence, prevalence, and population distribution of the disease.
allows for the identification of causes, modes of acquisition of disease.
What is the difference between primary and secondary disease? Give an example
- Primary = (essential, idiopathic, cryptogenic) means without evident cause e.g. primary hypertension has no apparent cause
- Secondary means = complication or manifestations of underlying lesions e.g. secondary hypertension may be a consequence of rental artery stenosis
What is the difference between primary and secondary stages?
- Primary stage = primary tumour is in the initial site from which the cancer cells travel which cause …
- Secondary tumour is in other tissues or organs
What is the difference between Acute and Chronic?
Both Acute and Chronic describe the temporal dynamics of any disease.
Acute = rapid onset and often has a rapid resolution
Chronic = prolonged course of months or years, is often insidious onset and may follow an initial acute episode
Both can also describe the inflammatory process
What is the difference between Benign and Malignant? Give examples for both.
Both are used to classify the likely outcome of a disease.
- Benign = means the disease is in the original tissue site, is rarely lethal and proceeds in a gradual subtle manner til its lethal
- Malignant = the disease has spread diffusely or metastasis and is usually lethal or causing severe damage to the body
Examples
- Benign vs Malignant Tumour = B - remains localised and is rarely lethal vs. M - spread or metastasised are is lethal.
- Hypertension = B (mild) - insidious tissue injury if left can progress to harmful condition vs. M (severe) - headaches, blindness, renal failure cerebral haemorrhage
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What do these prefixes mean?
- -ana
- Dys-
- Hyper -
- Hypo-
- Meta-
- Neo-
- Absence
- Disordered
- raised
- Lowered
- Change
- New
What do these suffixes mean
- -itis
- -oma
- -osis
- -oid
- -penia
- -cytosis
- -ectasis
- -plasia
- -opathy
- inflammation
- tumour
- state or condition
- resemblance to
- to lack or have a deficiency in
- referring to cells
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