Influenza (Flu)

Description
  • Influenza (flu) is an acute, highly contagious viral respiratory infection that is caused by one of three types of myxovirus influenzae. Influenza occurs all over the world and is more common during winter months.
  • The incubation period is 24 to 48 hours. Symptoms appear approximately 72 hours after contact with the virus, and the infected person remains contagious for 3 days. Influenza is usually a self-limited disease that lasts from 2 to 7 days.
  • The disease also spreads rapidly through populations, creating epidemics and pandemics. Annual estimates are that approximately 20,000 deaths occur as a result of influenza virus and 250,000 to 500,000 new cases occur each year in the United States.
  • Complications of influenza include pneumonia, myositis, exacerbation of chronic obstructive pulmonary disease (COPD), and Reye’s syndrome.
  • In rare cases, influenza can lead to encephalitis, transverse myelitis, myocarditis, or pericarditis.
Signs and symptoms

People who have the flu often feel some or all of these signs and symptoms:Symptoms_of_influenza.svg

  • Fever* or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (very tired)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults.

*It’s important to note that not everyone with flu will have a fever.

Diagnostic Examination
  • Rapid diagnostic tests for influenza can help in the diagnosis and management  f patients who present with signs and symptoms compatible with influenza. They also are useful for helping to determine whether outbreaks of respiratory disease, such as in nursing homes and other settings, might be due to influenza.
  • No specific diagnostic tests are used because diagnosis is made  by the history of symptoms and onset. If the patient has symptoms of a bacterial infection that complicates influenza, cultures and sensitivities may be required.
Primary Nursing Diagnosis

Infection related to the presence of virus in mucus secretions

OUTCOMES. Immune status; Knowledge: Infection control; Risk control; Risk detection; Nutrition status; Treatment behavior: Illness or injury; Hydration; Knowledge: Infection control
INTERVENTIONS. Infection control; Infection protection; Surveillance; Fluid/electrolyte management; Medication management; Temperature regulation

Complications of flu

Complications of flu can include bacterial pneumonia, ear infections, sinus infections, dehydration, and worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes.

Mode of Transmission

Influenza virus shedding (the time during which a person might be infectious to another person) begins the day before symptoms appear and virus is then released for between 5 to 7 days, although some people may shed virus for longer periods. People who contract influenza are most infective between the second and third days after infection.The amount of virus shed appears to correlate with fever, with higher amounts of virus shed when temperatures are highest.Children are much more infectious than adults and shed virus from just before they develop symptoms until two weeks after infection.

Influenza virus may be transmitted among humans in three ways:

  1. by direct contact with infected individuals;
  2. by contact with contaminated objects (called fomites, such as toys, doorknobs); and
  3. by inhalation of virus-laden aerosols.

The contribution of each mode to overall transmission of influenza is not known. However, CDC recommendations to control influenza virus transmission in health care settings include measures that minimize spread by aerosol and fomite mechanisms.

Medical Management
  • People with the flu are advised to get plenty of rest, drink plenty of liquids, avoid using alcohol and tobacco and, if necessary, take medications such as acetaminophen (paracetamol) to relieve the fever and muscle aches associated with the flu.
  • Children and teenagers with flu symptoms (particularly fever) should avoid taking aspirin during an influenza infection (especially influenza type B), because doing so can lead to Reye’s syndrome, a rare but potentially fatal disease of the liver.
  • Since influenza is caused by a virus, antibiotics have no effect on the infection; unless prescribed for secondary infections such as bacterial pneumonia.
  • Antiviral medication may be effective, but some strains of influenza can show resistance to the standard antiviral drugs and there is concern about the quality of the research.
  • Phenylephrine and antitussive agents such as terpin hydrate with codeine are often prescribed to relieve nasal congestion and coughing. In patients with influenza that is complicated by pneumonia, antibiotics may be administered to treat a bacterial superinfection.
Medication or Drug Class  Dosage  Description     Rationale 
 Antipyretics  Varies with drug  Aspirin, acetaminophen  Control fever and discomfort; generally aspirin is avoided to reduce the risk of Reye’s syndrome
 Amantadine  100–200 mg PO qd, bid for several days  Antiviral infective  Provides antiviral action against influenza (prophylaxis and symptomatic); usually prescribed for outbreaks of influenza A within a closed population, such as a nursing home

  • Other Drugs: Neuraminidase inhibitors (oseltamivir and zanamivir) for use in treatment and prophylaxis of influenza A and B; rimantadine for treatment and prophylaxis of influenza A only; antiviral treatment should be initiatied within 48 hours of the onset of symptoms to be effective.
Nursing Interventions
  1. Administer analgesics, antipyretics, and decongestants, as ordered.
  2. Follow droplet and standard precautions.
  3. Provide cool, humidified air but change the water daily to prevent pseudomonas superinfection.
  4. Encourage the patient to rest in bed and drink plenty of fluids.
  5. Administer I.V. fluids as ordered.
  6. Administer oxygen therapy if warranted.
  7. Regularly monitor the patient’s vital signs, including his temperature.
  8. Monitor the patient’s fluid intake and output for signs of dehydration.
  9. Watch for signs and symptoms of developing pneumonia.
  10. Advise the patient to use mouthwash or warm saline gargles to ease sore throat.
  11. Teach the patient the importance of increasing fluid intake to prevent dehydration.
  12. Suggest a warm bath or heating pad to relieve myalgia.
  13. Review prevention of future influenza episodes with patient and the community.
Prevention
Vaccination

The influenza vaccine is recommended by the World Health Organization and United States Center for Disease Control and Prevention for high-risk groups, such as children, the elderly, health care workers, and people who have chronic illnesses such as asthma, diabetes, heart disease, or are immuno-compromised among others.

There are two types of vaccines:

  • The “flu shot” is an inactivated vaccine (containing killed virus) that is given with a needle. It can be given in the muscle or just under the skin. The flu shot that is given in the muscle is approved for use in people older than 6 months, including healthy people and people with chronic medical conditions. The flu shot that is given below the skin is for those 18-64 years of age.
  • The nasal-spray flu vaccine is a vaccine (sometimes called LAIV for “Live Attenuated Influenza Vaccine”) made with live, weakened flu viruses that do not cause the flu. LAIV is approved for use in healthy people 2 years to 49 years of age who are not pregnant.
Infection control
  • Reasonably effective ways to reduce the transmission of influenza include good personal health and hygiene habits such as: not touching your eyes, nose or mouth;frequent hand washing (with soap and water, or with alcohol-based hand rubs);covering coughs and sneezes; avoiding close contact with sick people; and staying home yourself if you are sick.
  • Although face masks might help prevent transmission when caring for the sick, there is mixed evidence on beneficial effects in the community.
  • Smoking raises the risk of contracting influenza, as well as producing more severe disease symptoms.
  • Since influenza spreads through both aerosols and contact with contaminated surfaces, surface sanitizing may help prevent some infections.
  • Alcohol is an effective sanitizer against influenza viruses, while quaternary ammonium compounds can be used with alcohol so that the sanitizing effect lasts for longer.
  • In hospitals, quaternary ammonium compounds and bleach are used to sanitize rooms or equipment that have been occupied by patients with influenza symptoms.At home, this can be done effectively with a diluted chlorine bleach.

References:
  • http://www.virology.ws/2009/04/29/influenza-virus-transmission/
  • http://www.phac-aspc.gc.ca/influenza/index-eng.php
  • http://en.wikipedia.org/wiki/Influenza#Transmission
  • http://www.health.ny.gov/diseases/communicable/influenza/fact_sheet.htm
  • http://www.cdc.gov/flu/keyfacts.htm
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