NCLEX-RN: Infection Control

Infection Control: Emerging Viruses

Focus topic: Infection Control

Infection Control: Biology of Infectious Disease

Focus topic: Infection Control


A. Various forms of flora help protect the human from invasion of pathogens, usually microorganisms that can cause disease.
B. Host defenses determine whether infection will occur.

  • Natural barriers: skin and mucous membranes.
  • Nonspecific immune responses: white cells.
  • Specific immune responses: antibodies.

C. Pathogenesis of infection.

  • Toxins: protein molecules that cause development of disease (diphtheria, cholera, tetanus, etc.).
  • Virulence factors: assist pathogens in invasion and resistance of host defense mechanisms (different forms of Haemophilus influenzae).
  • Microbial adherence: ability to adhere to surfaces to invade tissue (Escherichia coli attaching to human cells in GI tract).
  • Antimicrobial resistance: agents that can exert selective pressures on microbial populations allowing bacteria to develop resistance to an antimicrobial agent (MRSA).

Infection Control: Marburg and Ebola Viruses

Focus topic: Infection Control

Definition: Acute infection (perhaps related to exposure to monkeys in Africa or the Philippines) that produces severe illness.

A. Vector is unknown, human to human.
B. Transmission occurs via skin and mucous membrane contact with an infected person.
C. Incubation period is 5–10 days.
D. Mortality rate is 25–90%.

A. Fever with myalgia and headache with upper respiratory symptoms.
B. Hemorrhagic symptoms begin within a few days.

A. Mask-gown-glove precautions.
B. There is no vaccine or effective antiviral therapy.

Infection Control

Infection Control: Hanta Virus

Focus topic: Infection Control

Definition: Acute infection caused by the hanta virus transmitted to humans from rodents.

A. Transmission is through inhalation of infectious aerosols from rodent excreta.
B. Characterized by acute renal failure or acute pulmonary edema.
C. Incubation period 7–36 days.

A. Sudden onset with high fever, headache, backache, and abdominal pain.
B. Hemorrhages appear; severe neurological symptoms occur in 1%; severe cases are 10–15%.

A. Treatment is ribavirin IV and supportive care.
B. Overall mortality rate is 6–15%.

Infection Control: Lassa Fever

Focus topic: Infection Control

Definition: Systemic arena virus infection that involves visceral organs; spares the central nervous system (CNS).

A. Most human cases result from contamination of food with rodent urine; human-to-human transmission can occur.
B. Mortality rate 16–45%.
C. Incubation period 1–24 days.

A. Initial symptoms are sore throat, fever, headache, myalgia, and malaise.
B. Onset of severe symptoms take several days; severity correlates with amount of virus absorbed and degree of fever.

A. Standard precautions, airborne isolation including high-efficiency mask and negative-pressure room.
B. Ribavirin used to reduce mortality rate, given within 6 days of onset.
C. Supportive care including fluid and electrolyte balance critical.

Infection Control: Dengue Fever

Focus topic: Infection Control

Definition: Acute febrile disease caused by flavivirus transmitted by bite of Aedes mosquito.

A. Occurs mostly in children living where dengue is endemic (Southeast Asia, China, and Cuba).
B. Incubation period is 3–15 days.

A. Abrupt onset with chills, headache, and aching joints, with rapid rise in temperature (104°F, 40°C) followed by afebrile period for 24 hours.
B. Second rise in temperature follows with rash covering entire body.

A. Dengue prophylaxis requires eradication of mosquito vector.
B. Treatment is symptomatic—complete bed rest and acetaminophen (avoid aspirin).

Infection Control: Severe Acute Respiratory Syndrome

Focus topic: Infection Control

Definition: A respiratory illness of unknown etiology; the first severe and readily transmittable viral disease of the 21st century.

A. First detected in November 2002 in China; in March 2003, the World Health Organization (WHO) announced a global alert. Severe acute respiratory syndrome (SARS) proceeded to be reported in 30 countries.
B. SARS is believed to be caused by a new variety of the coronavirus (the common cold).
C. Transmission of SARS.

  • Spread by person-to-person contact.
  • Possibly spread by contact with objects that have been contaminated with infectious droplets.
  • Disease may have airborne transmission, but this is still undetermined.

D. Incubation period is 2–7 days (or possibly as long as 10 days).

A. SARS begins with elevated temperature (> 100.4°F or > 38°C).

  • Fever may be associated with chills, headache, or malaise.
  • During this prodromal period, client may develop mild respiratory symptoms.

B. After 3 to 7 days, lower respiratory symptoms develop.

  • Dry, nonproductive cough and dyspnea.
  • Hypoxemia may develop, as well as respiratory distress syndrome.

C. The last stage of SARS is classified as atypical pneumonia.
D. No definitive diagnostic test for SARS; CDC has serum tests to detect antibodies to the virus but specificity is still being evaluated.
E. Epidemiological criteria: travel (through an airport) within 10 days of onset of symptoms; close contact with a person known or suspected to have SARS.

A. Implement immediate infection control measures with a suspected case of SARS.

  • Use standard hand hygiene (soap and water or alcohol-based gel).
  • Use contact protection (gloves, gown, and eye shield).
  • Use airborne protection: N95 disposable respirators; place client in a negative-pressure isolation room.

B. No accepted medical treatment.

  • A viral drug, ribavirin (a drug used to treat AIDS clients), may be useful for those younger than age 40.
  • Elderly clients do not react well to this drug.

C. Give supportive care; in some cases mechanical ventilation is started when normal functioning of the lungs is compromised.
D. Complementary physicians are recommending the herb Echinacea because it boosts immune responses and aids clients in fighting the virus.
E. As of 2006, the SARS virus had mutated to a weaker virus that is no longer a threat. It could, however, reverse course in the future.

Infection Control: West Nile Virus

Focus topic: Infection Control

Definition: A mosquito-borne viral disease that has been detected in 43 states. It is a single-stranded RNA virus of the family of encephalitis-causing viruses.

A. First cases were identified in New York City in 1999; introduced by an infected host (bird or human) or vector (mosquito).
B. Transmission occurs in summer and early fall when mosquitoes are active.

A. Infection occurs 3 to 14 days after infected mosquito bites.

  • 80% of infections are mild, without symptoms.
  • 20% develop flu symptoms, lasting less than 1 week.
  • Less than 1% develop a severe illness—encephalitis or meningitis.

B. Assess for symptoms of severe neurologic disease.

  • Fever, headache, stiff neck, and mental confusion.
  • Tremors, muscle weakness, and convulsions in about 15% (of the 1%).

C. Symptoms may be confused with (or misdiagnosed) Guillain-Barré syndrome.

D. The Food and Drug Administration (FDA) has approved a rapid West Nile Virus test, called West Nile IgM STATus test.

  • This test can confirm the diagnosis in 15 minutes.
  • Early diagnosis and treatment may prevent serious complications.

E. MAC-ELISA (membrane attack complex–enzyme-linked immunosorbent assay) is another diagnostic test to detect antibody in serum or cerebrospinal fluid (collected within 8 days of illness onset).

A. No treatment is needed for asymptomatic West Nile virus.
B. Clients with symptoms of encephalitis or meningitis require hospitalization.

  • No specific therapy is available; give supportive therapy.
  • Airway management, respiratory support (mechanical ventilation) may be ordered to control cerebral edema.
  • Fluid management.

C. Use standard precautions to protect healthcare workers.
D. Teach clients preventive methods.

  • Avoid mosquito bites.
  • Use the chemical insect repellent DEET, which will offer protection. (Studies show DEET lasts 5 hours after application.)

Infection Control: Avian (Bird) Influenza (H5N1)

Focus topic: Infection Control

Definition: A viral infection caused by the avian influenza virus found in wild birds.

A. Infected birds carry the virus in their intestines (which does not cause illness). Virus that causes illness is transferred to domesticated birds.
B. Virus is then transmitted to people who work closely with these birds or eat meat that has been under cooked.
C. Outbreaks of H5N1 occurred in poultry in eight countries during 2003–2004.
D. This virus can result in a pandemic threat—there is a 50-50 chance it could mutate and easily spread from one person to another.

A. Symptoms range from fever, cough, and sore throat to eye infections, pneumonia, and severe respiratory distress.

B. Humans have little or no immune protection because these viruses do not commonly infect humans.

A. The CDC recommends total infection control precautions with airborne precautions to prevent transmission.
B. Isolation precautions for clients who have traveled within 10 days to a country where avian flu has been detected and who are hospitalized with a severe respiratory illness.

  • Use of a HEPA-filtered negative-pressure isolation room.
  • Healthcare workers should wear a respirator mask (N95 face piece).

C. The FDA has approved a vaccination against H5N1 avian flu.

  • Vaccine will be stockpiled and sold publicly if the virus acquires the ability to pass from person to person.
  • Vaccine would be used in the early phase for protection until a specific vaccine that is tailored to the actual strain is developed.

Infection Control: Immunosuppression

Focus topic: Infection Control

Infection Control: The Immunosuppressed Client

Focus topic: Infection Control

Definition: An acquired immune deficiency characterized by a defect in natural immunity against disease. With loss of the immune system, the individual is susceptible to a variety of “opportunistic infections.”

A. The immune system—how it functions.

  • A complex system of organs and cells that work to distinguish foreign invaders from natural components in the body.
    a. The body’s skin and mucous membranes provide the first line of defense against invading organisms.
    b. When a foreign organism enters the body, it may be destroyed by circulating white blood cells, macrophages, and neutrophils—the second line of defense.
  • The immune system is triggered when an antigen has not been stopped or destroyed by the body’s first and second defense system.
    a. Lymphocytes then mobilize to defend the body against invaders or antigens.
    b. Lymphocytes fall into two classes.
    (1) B cells (30% of blood lymphocytes) develop in the bone marrow.
    (2) T cells (70% of blood lymphocytes) originate in the bone marrow but complete development in the thymus gland.

B. Etiology of immunosuppression.

  • Drug treatment protocols.
    a. Cancer chemotherapeutic agents.
    b. Antibiotics such as tetracycline, chloramphenicol, streptomycin, and gentamicin inhibit cellular immunity.
    c. Mafenide and silver sulfadiazine inhibit neutrophil movement to the area of inflammation.
    d. Steroids cause temporary lymphocytopenia, increase in neutrophils, decrease in monocytes and eosinophils.
    (1) Chronic use leads to nonresponsive immune system.
    (2) Anergy may lead to susceptibility to opportunistic infections.
  • Age—the older a client’s chronologic age, the more susceptible to infections.
  • Acute and chronic diseases.
    a. Acquired immune deficiency syndrome (AIDS).
    b. Cancer.
    c. Inflammatory bowel disease.
    d. Diabetes.
    e. Chemical sensitivity.
    f. Chronic fatigue syndrome.
  • Poor nutritional status.
    a. Protein and calorie depletion lead to lymphocyte suppression.
    b. Iron deficiency causes atrophy of the liver, spleen and bone marrow, and lymphoid tissue.
    c. Zinc deficiency affects thymus gland.
  • Surgery and anesthesia.
  • Stress, both specific and generalized.
    a. Environmental stress such as pollution, high-intensity sound, or noise, may create stress that results in immunosuppression.
    b. Stressful life events, such as loss of job, marriage, or death, decrease immune function.
  • Psychiatric illness, especially major illness such as schizophrenia, depression, or manic episode.
  • Lesions of the central nervous system, especially the hypothalamus, produce changes in the immune response.

A. Observe for possible sites of infection.

  • IV sites and invasive devices (prosthetic devices).
  • Catheter sites.
  • Surgical wounds.
  • All body crevices.
  • Respiratory tract (lungs) and genitourinary tract.

B. Observe for signs of inflammation or systemic infection.

  • Changes in temperature—fever may be only sign since signs of inflammation may not appear due to diminished neutrophils.
  • Changes in white blood cell count and differential count.
  • Signs of inflammation: pain, redness, swelling, and heat.

C. Assess the lungs for adventitious sounds.
D. Assess nutritional status.

  • Calorie and protein intake to build immune system.
  • Adequate vitamins (including vitamins A and C) and minerals (iron and zinc).

A. Prevention and early detection of infection.

  • Hand hygiene and gloving are essential for prevention.
    a. Wash hands frequently during the care, and wash thoroughly before and after any contact with an immunosuppressed client. Use antiseptic, not bar soap, or waterless antiseptic.
    b. Wear gloves for any client contact where there is possibility of contact with blood, body secretions, or contaminated surface.
  • Use of aseptic technique when caring for all possible entrance sites for infection: catheters, central lines, endotracheal tubes, pressuremonitoring lines, and peripheral IV lines.
  • Be aware of possibility of crosscontamination—deliver care first to the immunosuppressed client.
  • Assign client to private room, if possible.
    a. Keep door closed to prevent transmission of airborne organisms.
    b. Keep room well ventilated.
  • Use masks for all persons with the slightest evidence of upper respiratory or other type of infection.
  • Damp dust with a disinfectant solution when cleaning client’s room or objects used in care.
  • Use a humidifier to reduce microorganisms that may thrive in an arid environment.
  • Do not allow water to collect and stagnate; change every 24 hours to prevent breeding of organisms.
  • Prevent contamination of suctioning equipment.
    a. Use two-glove technique to prevent spread of organisms.
    b. Complete thorough hand hygiene before and after suctioning.
    c. Clean connecting tubes with germicide solution.
    d. Change tubes every 8 hours.
  • Use strict aseptic technique for every dressing change.

B. Complete, impeccable skin care for the immunosuppressed client.

  • Observe all pressure areas for signs of breakdown.
  • Turn frequently, every hour if client is immobile.
  • Complete passive or active range-of-motion exercises when indicated.
  • Change any wet clothing or dressing immediately; wetness will break down skin.
  • Lubricate and massage skin to prevent cracks and stimulate blood circulation to potential areas of breakdown.

✦✦ C. Perform pulmonary toilet.

  • Assess pulmonary function frequently for lung sounds, coughing, drainage, and ability to breathe.
  • Perform toilet every 2–4 hours.

D. Monitor nutritional status.

  • Provide high-calorie, high-protein diet; without adequate nutrients, client cannot produce enough lymphocytes to fight infection.
  • Malnutrition impairs the humoral system of the immune response.
  • Administer enteral feedings for clients with normal GI functions.
  • Administer total parenteral nutrition (TPN/TNA) if GI tract is not functioning. This achieves high-density caloric support.

E. Assist client to handle stressful conditions.

  • Support accommodation to hospital regimen. Normalize hospital environment as much as possible.
  • Allow client to be as independent as possible.
    a. Support concerns about forced dependency.
    b. Support client taking an active role in care activities.
  • Provide method of dealing with psychological impact of illness—special consultation, extra time to communicate, etc.
  • Provide care that will enhance body image.
    a. Frequent assistance for bathing, hair washing, etc.
    b. Use touch to communicate; do not act as if client is “untouchable.”
  • Allow client to make choices and discuss options for care.
  • Allow private time for client and make allowances for family and friends to spend time with client.

F. Present realistic optimism when caring for client—a no-hope attitude on the part of the nurse will be conveyed.








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