Exam 2 Infection Study Guide- Adult Health 3

Healthcare-acquired infection (HAI)

An infection that develops while receiving healthcare and was not present or incubating when the patient entered the healthcare setting.

Community-acquired infection

An infection acquired outside of a healthcare setting.

Most important way to prevent healthcare-acquired infections

Hand hygiene before and after patient contact and after potential exposure to infectious material.

Major risk factors for healthcare-acquired infections

Invasive devices, surgery, open wounds, immunosuppression, neutropenia, diabetes, older age, malnutrition, chronic illness, and prolonged hospitalization.

Why do invasive devices increase infection risk?

They can break the skin or mucous membranes and provide surfaces where bacteria attach and form biofilms.

Preventing central-line infections

Perform hand hygiene, use aseptic technique, keep the site clean and dry, assess for infection, and remove unnecessary lines promptly.

Preventing catheter-associated urinary tract infections

Avoid unnecessary catheterization, use sterile insertion technique, maintain a closed drainage system, keep the bag below bladder level, prevent kinks, and remove the catheter promptly.

Preventing ventilator-associated infection

Elevate the head of the bed 30-45 degrees unless contraindicated, provide oral care as ordered, and follow appropriate ventilator and suctioning care.

Neutropenic patient with fever

Report immediately. Fever in a neutropenic or immunocompromised patient can indicate a life-threatening infection.

Why may an immunocompromised patient have few infection symptoms?

Weakened immune function may prevent a strong WBC or inflammatory response, so a serious infection may occur without classic signs.

Absolute neutrophil count (ANC)

The number of neutrophils available to fight infection; it helps determine the patient's risk for infection.

Normal ANC

Generally greater than 1,500 cells/mm³.

Mild neutropenia

ANC of 1,000-1,500 cells/mm³.

Moderate neutropenia

ANC of 500-1,000 cells/mm³.

Severe neutropenia

ANC below 500 cells/mm³; the patient has a very high risk of serious infection.

ANC below 500 nursing priority

Use prescribed infection-prevention precautions, monitor closely for infection, and report fever immediately.

Standard Precautions

Used for every patient, regardless of whether infection is suspected. Include hand hygiene, appropriate PPE, and safe injection practices.

Airborne Precautions

Use a fit-tested N95 respirator or higher-level respirator and a negative-pressure airborne infection isolation room when indicated.

Droplet Precautions

Use a surgical or procedure mask when entering the room; add eye protection if splashes or sprays are anticipated.

Contact Precautions

Wear a gown and gloves as indicated before contact with the patient or contaminated environment.

Enteric precautions for C. difficile

Use Contact and Standard Precautions, wear a gown and gloves, and wash hands with soap and water.

Tuberculosis (TB) precautions

Airborne and Standard Precautions; use an N95 or higher-level respirator and a negative-pressure room for suspected or confirmed pulmonary or laryngeal TB.

How is tuberculosis transmitted?

Through tiny infectious particles that remain suspended in the air and can be inhaled.

Transporting a patient with suspected TB

Have the patient wear a surgical mask during necessary transport.

Malaria precautions

Standard Precautions; malaria is primarily transmitted by the bite of an infected Anopheles mosquito, not routine airborne or droplet spread.

Rhinovirus precautions

Droplet and Standard Precautions; use a surgical or procedure mask.

How is rhinovirus transmitted?

Through respiratory secretions, coughing, sneezing, close contact, and contaminated hands or surfaces.

Disseminated varicella-zoster precautions

Airborne, Contact, and Standard Precautions; use an N95 respirator plus gown and gloves.

When can varicella-zoster isolation precautions stop?

Continue precautions until lesions are dry and crusted, according to the study guide.

Airborne infection examples

Tuberculosis, measles, varicella, and disseminated herpes zoster.

Droplet infection examples

Influenza, pertussis, rhinovirus, and meningococcal disease.

Contact infection examples

MRSA, VRE, C. difficile, RSV, draining wounds, and some multidrug-resistant organisms.

MRSA precautions

Contact and Standard Precautions; use a gown and gloves as indicated.

Influenza precautions

Droplet and Standard Precautions; use a surgical or procedure mask.

C. difficile transmission

Fecal-oral transmission through contaminated hands, surfaces, equipment, and stool.

Why use soap and water for C. difficile?

Alcohol-based hand sanitizer does not reliably kill C. difficile spores.

Isolation precaution memory trick

Airborne = N95; Droplet = surgical mask; Contact = gown and gloves; C. difficile = Contact plus soap and water.

WBC normal range

Approximately 4,500-11,000 cells/mm³, depending on the laboratory.

Leukocytosis

An increased WBC count; may occur with infection, inflammation, or stress.

Leukopenia

A decreased WBC count; may occur with bone marrow suppression, chemotherapy, some viral infections, or immunosuppression.

Neutropenia

A decreased number of neutrophils, increasing the risk of serious infection.

Why is a normal WBC count not reassuring in a neutropenic patient?

The patient may be unable to produce a strong WBC response despite a serious infection.

Lactate normal range

Approximately 0.5-2.2 mmol/L, depending on the laboratory.

Elevated lactate

May indicate tissue hypoperfusion, severe hypoxia, shock, sepsis, or septic shock.

High lactate plus suspected infection

Think sepsis and impaired tissue perfusion; assess the patient and report findings promptly.

Why does lactate rise when tissues lack oxygen?

Cells may shift toward metabolism that produces more lactate when oxygen delivery is inadequate.

ESR (erythrocyte sedimentation rate)

A nonspecific blood test that measures how quickly red blood cells settle; it is used as a marker of inflammation.

Elevated ESR

Indicates possible increased inflammation but does not identify the exact cause or prove infection.

CRP (C-reactive protein)

A protein produced by the liver that increases with acute inflammation.

CRP normal value from the study guide

Less than 10 mg/L.

Elevated CRP

May indicate active inflammation, infection, tissue injury, or autoimmune disease.

ESR versus CRP

Both are nonspecific inflammatory markers. ESR changes more slowly, while CRP responds more quickly to changes in inflammation.

Does a high ESR prove infection?

No. ESR is a nonspecific marker of inflammation and may be elevated for many reasons.

Does a high CRP prove bacterial infection?

No. CRP indicates inflammation but does not automatically mean the cause is bacterial.

Low WBC and low neutrophils

Think immunosuppression, bone marrow suppression, and increased infection risk.

Priority for a patient receiving chemotherapy

Monitor WBC and ANC, follow infection-prevention precautions, and report fever immediately.

Preventing community-acquired infections

Practice hand hygiene, stay up to date on vaccinations, use respiratory hygiene, prepare food safely, practice safe sex, and use proper wound care.

Community-acquired infection risk factors

Close contact with infected people, crowded living conditions, poor hygiene, lack of vaccination, contaminated food or water, travel, sexual exposure, and animal or insect exposure.

Why are older adults and very young patients at increased infection risk?

Extremes of age can be associated with less effective immune defenses and increased vulnerability to infection.

Biofilm

A community of microorganisms attached to a surface, such as an indwelling catheter, that can make infections difficult to eliminate.

Aseptic technique

Practices used to prevent contamination by microorganisms during procedures and care.

Negative-pressure room

A room designed to keep air from flowing out into surrounding areas, helping contain airborne infectious particles.

Personal protective equipment (PPE)

Protective equipment, such as gloves, gowns, masks, or respirators, selected according to the transmission risk and anticipated exposure.

Standard versus transmission-based precautions

Standard Precautions apply to every patient; transmission-based precautions add measures for infections spread by airborne, droplet, or contact routes.

Neutropenic patient priority

Prevent infection, monitor for subtle changes, and report fever immediately, even if the WBC count is not elevated.

TB NCLEX memory

TB = Airborne = N95 + negative-pressure room.

Rhinovirus NCLEX memory

Rhinovirus = Droplet = surgical mask.

Disseminated varicella-zoster NCLEX memory

Disseminated varicella-zoster = Airborne + Contact = N95 + gown and gloves.

Malaria NCLEX memory

Malaria = mosquito-borne = Standard Precautions in routine healthcare care.

C. difficile NCLEX memory

C. difficile = Contact/Enteric Precautions + gown and gloves + soap-and-water hand hygiene.

High-yield infection lab memory

High WBC may indicate infection or inflammation; low WBC/ANC indicates increased infection risk; high lactate suggests poor perfusion; high ESR or CRP indicates inflammation.