I&I

Immunology

Branch of medicine that concerns with the study of human response to foreign substances

Immunity

–the body’s specific protective response to an invading foreign agent or organism.

Immune system

this consist of complex and vital network of organs and cells that is responsible for protecting the body from invading microorganisms.

Antibody

protein substance developed by the body in response to and interactingwith a specific antigen.

Antigen

substance that induces the production of antibodies

B- Cells

cells that are important for producing a humoral immune response

T-Cells

cells that are important for producing a cellular immune response

Humoral immune response

immune system’s 2 nd line of defense; often termed the antibody response.

Cellular immune response

immune system’s 3 rd line of defense, involving the attack of pathogens by T-cells.

Complement

series of enzymatic proteins in the serum that when activated, destroy bacteria and other cells

Interferons

protein formed when cell are exposed to viral or foreign agents; capable of activating other components of the immune system.

Functions of the Immune system

Defense against physical injury and infection Maintenance of homeostasis (state of equilibrium of the internal environment)

LYMPH

Fluid that goes between capillary blood and tissues.1. Carries digested food, O2, and hormones to cells

Carries wastes back to capillaries for excretion

Since lymphatic system has no pump, skeletal muscle action squeezes along in tissues is interstitial fluid

LYMPH VESSELS

Transport excess tissue fluid back into circulatory system.

1. Valves prevent backward flow

• 2. Lymph flows in only one direction – from body organs to heart

• 3. Closely parallel veins

• 4. Tissue lymph enter small lymph vessels which drain into larger lymph vessels

(lymphatics) into two main lymphatics – the thoracic duct and right lymphatic duct

LYMPH NODES

Are rounded structures varying in sizes from that of small seeds that are distributed

along the lymphatic vessels

• Functions:

a. Transporting lymph

b. Filtering & phagocytizing (processing & killing) antigens

c. Generating lymphocytes & monocytes

Produce lymphocytes, filter out harmful bacteria.

SPLEEN

Produces lymphocytes and monocytes, blood reservoir, recycles old red cells.highly vascular bean-shaped, gland like organ beneath the diaphragm and behind to the

left of the stomach

• Functions:

a. Removing worn-out erythrocytes from blood

b. Storing blood & platelets

c. Filtering & purifying blood

THYMUS GLAND

Produces T-LYMPHOCYTES

Single unpaired gland located in the mediastinum

• Primary central gland of the lymphatic system

• Function is to allow T - lymphocytes to develop before migrating to the lymph nodes & spleen

Bone marrow

Specialized soft tissue filling the spaces in cancellous bone of the epiphyses.

• Responsible for:

1. Releasing mature B lymphocytes into blood circulation

2. Moving T lymphocytes from bone marrow to the thymus.

disease causing micro-organisms

bacteria

• virus

• fungi,

• protozoa,

• parasite,

• Prion

• Helminths

Second lines of defense

Involves white blood cells

Non-specific response

invading pathogens are targeted by macrophages

Specific response

lymphocytes produce chemicals called antibodies that target specific pathogens

Stages in phagocytosis

1.Phagocyte detects chemicals released by a foreign intruder (e.g. bacteria)

2. Phagocyte moves up the concentration gradient towards the intruder

3. The phagocyte adheres to the foreign cell and engulfs it in a vacuole by an

infolding of the cell membrane.

4. Lysosomes (organelles which are rich in digestive enzymes & found in the

phagocytes cytoplasm) fuse with the vacuole & release their contents into it.

Phagocytosis

The bacterium is digested by the enzymes, and the breakdown products are absorbed by the phagocyte.

Pus

is dead bacteria and phagocytes!An accumulation of : -

– dead phagocytes

– destroyed bacteria

– dead cells

Provide a specific immune response to infectious diseases.

There are 2 types: -

T-cells - B-cells

Antigen

all cells have surface markers

body can recognise these as self or non-self (foreign)

Specific response

Lymphocytes detect presence of foreign antigens

• Stimulated to produce specific proteins called antibodies.

antibodies.

• antibodies combine with their specific antigen (like a lock and key)

this renders the pathogen harmless.

Immunity

the bodies ability to resist infection

can be natural or acquired

Immunological memory

after an infection is fought off some lymphocytes become memory cells.

secondary response

the infection is fought off before symptoms appear

Natural /Innate immunity (non-specific)

Present at birth

• the body recognizes and destroys foreign substances but the response to them is the

same time the body is exposed to them.

Acquired/Adaptive immunity (specific)

Develops after birth

• the body recognizes and destroys foreign substances but the response improves each

time the foreign substances is encountered.

Nonspecific Defenses

Major Categories:

Mechanical categories

Major Categories:

Physical categories

Mechanical categories

Tears

– Urine flow

– Normal Peristaltic activity

– Vomiting and diarrhea

Leukocytes

a mobile system originate in the bone marrow when large pools

of mature cells are stored until they are needed and released in the

circulation and emigrate to the center of the cellular injury.

2 major classes of Leukocytes

Agranulocytes and Granulocytes

Inflammatory response

Is a localized protective response elicited by injury or destruction of tissues, which

serves to destroy, dilute, wall off both injurious agent and injured tissue.

Functions of Inflammatory Response

The delivery of effector molecules and cells to the sites of infection

• The formation of a physical barrier to the spread of tissue damage or infection.

• Wound healing and tissue repair

Systemic response to inflammation

Fever is the most common sign of systemic response to injury caused by endogenous

pyrogens

b. During this process, leukocytosis occur thus general nonspecific symptoms develop

including malaise, loss of appetite, aching and weakness.

Local manifestations

Erythema

 Warmth

 Pain

 Edema

 Functional impairment

Systemic Manifestations

T > 100.4 F (38C) or 96.8F (36C)

 P> 90/min

 R> 20/min (tachypnea)

 WBC > 12,000mm3 or > 10% bands

Factors affecting the outcome of the Inflammatory Process

Nature of the stressor

Nature of the person stress response

Nature of the person stress response

Age

b. Nutrition

c. Economic standing

d. Social setting

e. Tissue affected

f. Presence of chronic diseases

g. Presence of diabetes

Nature of the stressor

Number or amount

b. Virulence

c. The spreading factor

d. Resistance of phagocytosis

NURSING interventions for inflammation

1. Health History

2. Physical assessment

a. Identifying the cause of inflammation

b. Determining the location of the inflammation

c. Estimating the location of inflammation

Physical Assessment

Assess the general appearance

• Assess skin color, temperature and moisture

• Inspect the mucous membranes of the nose and mouth for color and condition

• Inspect and palpate the cervical lymph nodes for evidence of lymphadenopathy

(swelling) or tenderness

• Assess the musculoskeletal system by inspecting and palpating the joints for redness,

swelling, tenderness or deformity

Diagnostic Assessment

WBC count

Cultures of the wound, blood or other infected body fluids

Serologic testing

ERYTHROCYTE SEDIMENTATION RATE (ESR or sed rate)

Radiologic examination of the chest, abdomen, or urinary system

Lumbar puncture

Ultrasonic examination

Serum protein

Antibody testing

Skin testing

Cultures of the wound, blood or other infected body fluids

Are used to identify probable microorganisms by their charac. Such as shape, growth

patterns and gram-staining qualities

 After the organism is cultured it is subjected to various antibiotics known to be effective

against it…..known as SENSITIVITY TESTING

 24 to 48 hours is required to grow the organism

Serologic testing

 Provides an indirect means of identifying infecting agents by detecting antibodies to the

suspected organism.

 Not as accurate as culture, serology is particularly useful for organisms that cannot

easily be cultured (Hepatitis B or HIV)

Serum protein

Measures the total protein in the blood including albumin and globulins

 Adult: 6 to 8 g/dL, Albumin 3.2 to 4.5 g/dL, Globulins 2.3 to 3.4 g/dL

 If Total protein levels, albumin, globulin are decreased indicative of malnutrition, liver

disease or immunologic deficencies.

Skin testing

Can assess cell mediated immunity

 An antigen such as streptokinase, tuberculin PPD or candida is injected ID. The site is

observe for induration and erythema for 24 to 48 hrs.

 An induration of 10mm in diameter is (+) reaction indicating previous exposure and

sensitization to the antigen.

 No reaction or ANERGY indicates depressed cell mediated immunity.

• Communicable Diseases

Antibody testing

Is ordered to determine if a client has developed antibodies in response to an infection

or immunization. (Hepa, HIV ,rubella, treponema pallidum)

 An elevated level of titer indicates immunity.

Ultrasonic examination

Is a noninvasive diagnostic test to evaluate organ function such as echocardiogram or

renal ultrasonography

Lumbar puncture

Is performed to obtain cerebrospinal fluid (CSF) for examination and culture if a CNS infection

is suspected. (Meningitis or Encephalitis)

Radiologic examination of the chest, abdomen, or urinary system

To detect organ abnormalities indicating an inflammatory response or tissue damage

ERYTHROCYTE SEDIMENTATION RATE (ESR or sed rate)

Is a nonspecific test to detect inflammation.

 An increased ESR indicate acute or chronic inflammation, TB, autoimmune disorders,

malignancies, nephritis.

 Decreased ESR is found in congestive heart failure, sickle cell anemia, & polycythemia

vera

WBC count

Provides clues about the infecting organism and the body’s immune response to it.

Epidemiology

Greek words epi, meaning on or upon, demos, meaning people, and logos, meaning the study of

is the study (scientific, systematic, data-driven) of the distribution

(frequency, pattern) and determinants (causes, risk factors) of health-related

states and events (not just diseases) in specified populations (patient is community, individuals viewed collectively), and the application of

is a discipline within public health) this study to the control of health problems.

CONTAGIOUS DISEASE

Disease that is easily transmitted from one person to another

INFECTIOUS DISEASE

Disease transmitted by direct inoculation through a break in the skin

INFECTION

-Invasion of the body by the pathogenic microorganisms that reproduce and multiply causing

disease by local cellular injury, secretion of toxin, or antibody-antigen reaction of the

host.

INFESTATION

The presence of animal parasites in the environment, on the skin, or in the hair of the a host.

ASEPSIS

The absence of disease -producing microorganisms

SEPSIS

The presence of infection or contamination

MEDICAL ASEPSIS

Clean technique

- Practices designed to reduce the number and transfer of pathogens

SURGICAL ASEPSIS

Sterile technique

- Practices that render and keep objects and areas free from microorganisms

HOST

A person, animal or plant which harbors and provides nourishment for a parasite

RESERVOIR

Natural habitat for the growth, multiplication and reproduction of microorganism

ISOLATION

The separation of persons with communicable diseases from other persons

QUARANTINE

The limitation of the freedom of movement of persons exposed to communicable diseases

CONCURRENT

is a method of disinfection done immediately after the infected individual discharges infectious

material/secretions.

TERMINAL

- applied when the patient is no longer the source of infection

BACTERICIDAL

A chemical that kills microorganisms

BACTERIOSTATIC

An agent that prevents bacterial multiplication but does not kill microorganisms

2 Types Reservoir

HUMAN RESERVOIR

ANIMAL RESERVOIR

HUMAN RESERVOIR

Main reservoirs of infection

• Infected persons from whom the infectious agent is transmitted to other person

Frank or Typical

patient is obviously ill and manifests signs and symptoms

Subclinical

patient has mild or inapparent signs and symptoms

Carriers

does not manifest signs and symptoms

Contact

in close association

Suspect

patient displays signs and symptoms

Portal of Exit from Reservoir

Respiratory tract

• Gastrointestinal tract

• Genitourinary tract

• Blood

MODE OF TRANSMISSION

CONTACT TRANSMISSION

VEHICLE/ROUTE TRANSMISSION

VECTOR-BORNE TRANSMISSION

Direct contact

involves immediate and direct transfer from person-to-person

Droplet Transmission

occurs when the mucous membrane of the nose,

mouth or conjunctiva are exposed to secretions of an infected person within a

distance of three feet

Airborne Transmission

occurs when fine particles are suspended in the air

for a long time or when dust particles contain pathogens

Indirect contact –

occurs when a susceptible host is exposed to a contaminated

object

VEHICLE/ROUTE TRANSMISSION

Transfer of microorganisms by way of vehicles or contaminated items that transmit pathogens

VECTOR-BORNE TRANSMISSION

Transmitted by biologic vectors like rats, snails and mosquitoes, anthropods

(flies, ticks, and others)

The EASIEST way to break the Chain of infection

is through MODE OF TRANSMISSION

Distribution of a Disease

SPORADIC

ENDEMIC

EPIDEMIC

PANDEMIC

HERD IMMUNITY

SPORADIC

Intermittent occurrence of a few isolated and unrelated cases in a given locality

b. Disease is occasionally present here and there.

c. High number of immunes and low number of susceptibles

d. Eg. Rabies

ENDEMIC

Continuous occurrence throughout a period of time of the usual number of cases in a

given locality

b. Low number of immunes and low number of susceptibles

c. Eg. Malaria

EPIDEMIC

Occurrence of an unusually large number of cases in a relatively short period of time

b. Low number of

PANDEMIC

Simultaneous occurrence of epidemics of the same disease in several countries

b. Worldwide epidemic

c. Low number of immunes and high number of susceptibles

d. Eg. SARS, HIV

HERD IMMUNITY

state of immunity of the community

STAGES OF THE INFECTIOUS PROCESS

Incubation Period

Prodromal Period /Catarrhal Period

Period of Illness/Acme

Convalescent Period/

signs and symptoms start to abate and client returns to normal health