i bc27f85be50b71b1 (188 page)

INFEcnous DISEASES 607

Table LO·I. Terminology Associated with Infectious Disease Processes

Antibody

A highly specific prorein that is manufactured in

response ro antigens and defends against subsequent infection

Antigen (immunogen)

An agent that is capable of producing antibodies

when introduced inro the body of a susceptible person

Carrier

A person who harbors an infectious agenr that

can cause a specific disease but who demon·

strates no evidence of the disease

olonization

The process of a group of organisms living

togetherj the host can carry the microorganism without being sympromatic

Communicable

The ability of an infective organism to be transmitted from person to person, either direcdy

or indirecrly

Dissem i na ted

Distribured over a considerable area

Host

The person whom the infectious agent invades

and fr0111 whom it gathers its nourishment

Immunocompromised

An immune system that is incapable of responding to pathogenic organisms and tissue dam·

age

Immunosuppression

The prevention of formation of an immune

response

Nosocomial infection

Infection that is acquired in the hospital setting

Opportunistic

An infectious process that develops in immunosuppressed individuals (Opportunistic infec·

rions normally do nor develop in individuals

with intact immune systems.)

Parhogen

An organism capable of producing a disease

Subclinical infection

A disease or condition that does not produce

clinical symproms, or the rime period before

the appearance of disease·specific symptoms

Physical Examillatioll

Observation

Clinical presentation of infectious diseases is highly variable according to the specific system that is involved. However, common physical findings that occur with infection include sweating and inflammation,

both of which are related to the metabolic response of the body to the

antigen. The classic signs of inflammation (redness and edema) in cer-

608

ACUfE CARE HANDBOOK FOR PHYSICAL THERAPISTS

Table 10-2. Components of the Immune System

Lines of Defense

Components

Descri ption

First (ine of

Skin, conjunctivae,

Physical barriers to pathogens.

defense

mucous membranes

Second line of

Inflammamry response

If physical barriers are crossed,

defense

inflammatory response

to (I) contain pathogen and

(2) bring immune cells to

�lntigen.

Third line of

lmmune response

Specific immune response ro

defense

pathogens.

Humoral immunity

B cells produce antibodies.

(B cells)'

Cellular immunity

T cells:

(T cells)'

(1) Augment production of

antibodies.

(2) Dirccdy kill antigens.

(3) Turn off immune system.

-B cells and T cells can also be referred ro as B Iympbocytes or T iyml)hocyces,

respectively.

Sources: Data from NS Rote. Immunity. In SE Heucher, KL McCance (cds), Understanding Pathophysiology (2nd cd). St. Louis: Mosby, 2000;125-150; EN Marich (ed).

Human Anatomy and Physiology (2nd cd). Redwood City, CA: Benjamin Cummins.

1992;690-723; and AC Guyton, JE Hall. Textbook of Medical Physiology (9th ed).

Philadelphia: Saunders, 1996;445-455.

tain areas of the body can help delineate the source, location(s), or

both of infection. Delineating the source of infection is crucial to the

diagnostic process.

Palpation

The presence of warmth and possible pain or renderoess is another

typical sign of inflammation that may be consistent with active infection. Lymphoid organs (lymph nodes and spleen) can also be swollen and tender with infection, as lymphocytes (processed in these organs)

are multiplying in response to rhe antigen. lnAammarion and tenderness .in these or other areas of the body can further help to delineate the infectious process.

INFECllOUS DISEASES 609

Table 10-3. Facrors Affecting the Immune System

Congenital (rare)

Disruption in the development of lymphocytes

Acquired

Pregnancy

Pre-existing infections

Malignancies (Hodgkin's disease, acute or chronic leukemia, nonlymphoid

malignancy or myeloma)

Stress (emotional or surgical-anesthesia)

Malnutrition (insufficiency of calories, protein, iron, and zinc)

Age

Chronic diseases (diabetes, alcoholic cirrhosis, sickle cell anemia)

Immunosuppressive treatment (corticosteroids, chemotherapy, or radiation

therapy)

Indwelling lines and tubes

Source: Data from NS Rote, SE Hcuther, KL McCance. Hypersensitivities, Infection,

and Immunodeficiencies. In SE Heuther, KL McCance (eds), Understanding Pathophysiology (2nd cd). St. Louis: Mosby, 2000;204-208.

Vital Signs

Heart Rate, Blood Pressure, and Respiratory Rate

Measurement of heart rate and blood pressure helps in determining

whether an infectious process is occurring. (Infections result in an

increased metabolic rate, which presents as an increased heart rate

and respiratory rate.) Blood pressure may also be elevated when

metabolism is increased, or blood pressure can be decreased secondary to vasodilation from inflammatory responses in the body.

Temperature

Monitoring the patient's temperature over time (both throughout the

day and daily) provides information regarding the progression (a rise

in temperature) or a regression (a fall in temperature) of the infectious

process. A fall in body temperature from a relatively elevated temperature may also signify a response to a medication.

Auscultation

Heart and lung sounds are examined to determine whether any infectious processes could be occurring from these areas directly or affecting these areas indirectly.