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Influenza (flu)

Last updated: March 2025

Understanding Influenza (Flu): Causes, Symptoms, and Treatment Options

Article Highlights

Influenza, commonly known as the flu, is a contagious respiratory usually self-limiting illness caused by influenza viruses (myxovirus influenza). It can lead to severe health complications, especially in vulnerable populations. This comprehensive guide provides an overview of the causes, symptoms, effective treatment options, nursing care, prevention as well as possible complications for influenza.

Contents of this article


  1. Topic Overview
  2. What is Influenza
  3. Causes of Influenza
  4. Pathophysiology of Influenza
  5. Symptoms of Influenza
  6. Diagnostic Investigations
  7. Treatment of Influenza
  8. Nursing care of Influenza
  9. Complications of Influenza
  10. Preventions of Influenza


What is Influenza?

Influenza (flu) is an acute, usually self-limiting febrile contagious infection of the respiratory tract caused by myxovirus influenzae.Influenza is usually a self-limiting disease that lasts from 2 to 7 days.
Three groups of influenza virus have been identified. They are types A, B, and C. However, of these three viruses, influenza C has little pathogenic potential. It can also be defined as an acute, highly contagious viral respiratory infection that is caused by myxovirus influenzaeor by one of the three types of myxovirus influenzae.

Causes - Mode of Transmission

Influenza can be transmitted through droplet infection or inhalation of infected droplets during coughing, sneezing and talking, contact with contaminated objects such as drinking cups. Flu viruses enter the body through the mucous membranes of the eyes, nose or mouth.

Incidence of Chronic Kidney Disease

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. The disease also spreads rapidly through populations, creating epidemics and pandemics.



Pathophysiology of Influenza

On entering the respiratory tract, the influenza virus irritates the epithelial cells of the respiratory tract causing inflammation and desquamation. This results in sudden onset of chills, malaise and other symptoms.



Signs & Symptoms of Influenza

  • Fever
  • Chills
  • Headache
  • Malaise
  • Myalgia (muscle pain), particularly in the back and limbs
  • Dry, non productive cough
  • Anorexia
  • Nausea and vomiting
  • There may be laryngitis, hoarseness, conjunctivitis, rhinitisand rhinorrhoea

Diagnostic Test & Investigations

  • History taking and Physical examination / Observation of signs and symptoms
  • Full blood count
  • Throat and nose swab for culture and sensitivity

You may also like: Everything you need to know about Viral Rhinitis

Treatment of Influenza (Flu)

  • No specific management is required.
  • Symptomatic treatment is what is rendered or given.
  • This is because medical treatment does not cure influenza but it is aimed at controlling the symptoms and preventing complications.
  • Annual influenza vaccine
  • Phenylephrine to relieve nasal congestion / Nasal expectorants
  • Antipyretics such as Paracetamol to relief fever and myalgia / Analgesics
  • Antitussives for cough
  • Amantadine (100 to 200mg PO bd).
    • Amantadine provides antiviral action against influenza (prophylaxis and symptomatic).
    • Thus, for persons who are not immunized but are exposed to the virus, amantadine may prevent active infection.
    • Amantadine can also be given to reduce duration of symptoms

Nursing Management of Influenza

The subsequent measures are essential for effectively caring for patients with Tuberculosis (TB)

  • Ensure patient has adequate bed rest
  • Administer copious fluids (about 2 to 3 L daily) to liquefy bronchial secretions
  • Administer oxygen when needed
  • Ensure oral hygiene to improve patient appetite
  • Warm bath and warm compresses should be given to patient to relief muscle pain
  • Monitor vital signs for fever and for increased respiratory rate
  • Monitor fluid intake and output
  • Teach patient proper hand washing, proper disposal of secretions and used or infected articles to prevent the virus from spreading.
  • Limit visitors or restrict visitation when necessary.
  • Educate patient to cover his or her nose and mouth when coughing or sneezing.
  • Administer prescribed medications and observe for the desired and side effects.
  • Educate patient on immunization against influenza
  • Teach patient about the potential side effects of vaccination such as fever, malaise, and discomfort at the injection site.
    • Note that influenza vaccine is not recommended for pregnant women unless they are highly susceptible to influenza.
  • Educate relatives to wash their hands after contact with patient.
  • Observe the amount and characteristics of sputum if any
  • Teach patient deep breathing and coughing exercises to localize and bring out secretions
  • Teach patient and relatives to report signs and symptoms of complications such as chest pain, ear pain, or change in respiration.

Complications of Influenza


Preventions of Influenza

  • Proper hand washing
  • Proper disposal of soiled clothing and secretions
  • Vaccination against influenza (flu)
  • Education on good personal hygiene
  • Reduce dosage further for persons with impaired renal function and children under 9 years of age
  • Disease surveillance