Pathology

Third Year, Pharmacy Dept.

College of Pharmacy 2nd Lecture

Dr. Ahmad H. Ibrahim

PhD. University of Science Malaysia USM Malaysia MSc . University of Science Malaysia USM Malaysia

Pathology

• Explain the disease by studying the 4 aspects

of the disease (characteristics of disease) : • Incidence and prevalence (epidemiology) • Aetiology • Pathogenesis • Morphological changes (clinical features).

Objectives

Characteristics of disease:

• There are characteristics of infectious disease

agents which determine whether or not an infectious disease will be transmitted to and

infect a host. • These characteristics also influence the

severity of the disease and even the outcome

of the resulting infection.

Incidence

• The “incidence” or incidence rate of a condition is the number of new cases per

population at risk in a period of time - usually

one year ( see Table 1 ).

Table 1: Incidence (millions) of selected conditions by WHO region, 2004.

a. New cases.

b. Episodes of illness.

c. Incidence of congestive heart failure

due to rheumatic heart disease,

hypertensive heart disease, ischaemic

heart disease or inflammatory heart

diseases.

d. Incidence of injuries severe enough

to require medical attention.

e. An entry of 0.0 in the table refers to

an incidence of less than 0.05 million

(less than 50 000).

Incidence • is the rate of new cases (or newly diagnosed) of the

disease. It is generally reported as the number of new cases occurring within a period of time (e.g., per month, per year). • It is more meaningful when the incidence rate is reported as a fraction of the population at risk of developing the disease (e.g., per 100,000 or per million population).

Incidence • The accuracy of incidence data depends upon the

accuracy of diagnosis and reporting of the disease. • Incidence rates can be further categorized according to

different subsets of the population - e.g., by gender, by racial origin, by age group or by diagnostic category.

Prevalence • is the actual number of cases alive, with the disease

either during a period of time (period prevalence) or at a particular date in time (point prevalence). • Period prevalence provides the better measure of the

disease load since it includes all new cases and all deaths between two dates, whereas point prevalence only counts those alive on a particular date.

Prevalence • The prevalence of an illness or condition is the number

of individuals who have the condition at any moment. Such as epilepsy, individuals will not have symptoms most of the time, but still have the condition.

Prevalence • The effects of the illness and the loss of health

will vary from one individual to another. • The result may be serious impairments and disability or only mild impairments or disability.

Prevalence • "Incidence" means the number of people who

are newly diagnosed with a condition, while

"prevalence" includes newly diagnosed people, plus people who were diagnosed in the past with the condition

Epidemiology

• Incidence and Prevalence are words used in the

field of epidemiology.

• is the study of factors affecting the health and

illness of populations. • means the ways of transmission of a disease inside

community and the leading caused of spread.

Etiology • Why a specific disease occurs?

• Factors that produce predispose toward a

certain disease or disorder. • Cause of disease - primary etiology known, idiopathic unknown. • Help in diagnosis understanding and , treatment of disease.

Etiology • is the study of causes.

• In medical research, etiology can be used to

provide clues into methods of treatment. • In medicine, etiology refers to the many factors coming together to cause an illness. • It is normally the focus of epidemiological studies.

Major etiological factors: • Genetic: age, genes.

• Acquired: infectious, environmental, nutritional etc. • Etiology is followed by pathogenesis

Pathogenesis

-means step by step development of a disease and the chain of events leading to that disease due to a series of changes in the structure and function of a

cell, tissue, and organ being caused by a microbial (inflammation). -Most disease caused by multiple pathogenetical process

together. -The pathogenesis of a disease is the mechanism by

which an etiological factor causes the disease

Infection: This is when an organism enters the body, increases in number and causes damage to the host in the

process.

pathogen: This is an organism that is able to avoid the

various normal defences of the human host to cause

infection.

Stages of Infection

1) The time between the exposure to an agent and the first appearance of clinical symptoms is called the incubation period 2) There may follow a period known as the

prodrome, where non-specific signs and symptoms

such as headache, fever are noted,

It was nothing that you would think was anything’: Qualitative analysis of appraisal and help seeking preceding brain cancer diagnosis

3) Period of signs and symptoms known as acute

stage.

4) Once the acute stage has passed, a period of resolution occurs, where the severity of the

symptoms gradually decreases

5) finally convalescence where the symptoms have

largely gone, but the body is still recovering.

Types of Infection

1/ Acute infection: an acute disease is a disease with either or both of: A/ a rapid onset; B/ a short course (as opposed to a chronic course).

Types of Infection 2/ a chronic disease is a disease that is long-lasting.

The term chronic describes the course of the

disease, or its rate of onset and development.

Hypothetical mechanism of chronic diseases in correlation with COVID-19 infection

Thank you