What Treatments Should Be Used for Influenza?
A 13-month-old previously healthy female comes to clinic with a 1 day history of non-productive cough, runny nose, fever to 102 degree F and being fussy. She has been drinking well but not eating.
Her social history reveals that she attends day care where influenza A has been documented. His father has had similar symptoms for 3 days.
The review of systems reveals no rashes, nausea, emesis, change in urination or defecation. She has not received an influenza vaccine.
The pertinent physical exam shows her to have a respiratory rate of 18 and is well hydrated. HEENT reveals copious clear rhinorrhea, teary eyes but conjunctiva are clear, ears, throat and neck are normal. Her lung examination has transmitted course upper airway sounds but no rubs, rales or rhonchi. The remainder of her examination is normal.
A clinical diagnosis of influenza was made based upon consistent symptoms and known contacts.
Laboratory testing was not done because of known contacts.
She was treated with Oseltamivir for 5 days and supportive care. She began improving after day 3. Her father was not treated because he has had symptoms for more than 2 days, but the other household contacts were given prophylaxis with Amantadine.
Influenza is an orthomyxovirus first isolated in 1933. There are 3 types:
- A – moderate to severe disease in every age group
- B – milder epidemic, primarily affects children
- C – rarely reported in humans
New variants results from antigenic change called antigenic drift. Rates of infection are highest in children (10-40%) but most serious illness and death occurs in people >65 years or persons of any age with medical conditions that put them at risk for infection.
Deaths do occur in children but are not common.
Incubation period is 1-3 days with an average of 2 days. Children can be infectious for >10 days.
High risk children include those with:
- Asthma or other chronic pulmonary disease
- Hemodynamically significant cardiac disease
- Immunosuppressive disorders or therapy
- Sickle cell anemia and other hemoglobinopathies
- Diseases requiring long term salicylate therapy such as rheumatoid arthritis or Kawasaki disease
- Chronic renal problems
- Chronic metabolic diseases
- Children under 24 months of age
Influenza is characterized by the abrupt onset of respiratory signs and symptoms (i.e. nonproductive cough, sore throat, rhinitis) accompanied by constitutional symptoms (i.e. fever, malaise, headache, myalgia). In children, otitis media, nausea and vomiting are common.
Symptoms usually resolve over a few days for most people, but cough and malaise can last >2 weeks.
Rapid diagnostic testing is approximately 70% sensitive for detecting influenza and approximately 90% specific compared with the gold standard of viral culture. Therefore if the test is positive, the result is most likely correct. If the test is negative, as many as 30% of the negative results are falsely negative. Tests are most reliable when there is known influenza in the community. Once influenza is documented in the community or geographical area, a clinical diagnosis can be made for patients with consistent signs and symptoms, especially during peak activity.
Prevention includes vaccination for high risk groups, meticulous hand-washing, use of tissue to cover noses and mouths during coughing or sneezing, and self-imposed quarantine to keep infected individuals away from other persons.
There are currently four medications available to treat influenza (i.e. Amantadine, Rimantadine, Oseltamivir, Zanamivir ). All are similarly effective in reducing symptom duration by 1-2 days, if given within the first 2 days of the onset of symptoms.
Three medications can be given for influenza prophylaxis (i.e. Amantadine, Rimantadine, Oseltamivir). The dosing recommendations depend on the child’s age and the indication for use (i.e. treatment or prophylaxis). Which medication to use may also be dictated by local medication supplies and cost.
The Centers for Disease Control currently recommends that:
Patients with high risk medical conditions should be given priority for antiviral therapy
Use Oseltamirvir or Zanamivir (if available)
Patients with potentially life-threatening influenza-related illness should be treated
Patients with high risk medical conditions in the first two days of symptoms should be treated
Use Amantadine or Rimantadine (if available)
Persons who live or work in institutions should be given prophylaxis if an institutional outbreak occurs
Patients with high risk medical conditions should be given prophylaxis if they are likely to be exposed to others infected with influenza (e.g. household contacts)
Figure 5 – 12-20-04 – Table of Recommended daily dosage of influenza antiviral medications for treatment and prophylaxis from the CDC Morbidity and Mortality Weekly Report 28 May 2004 at http://www.cdc.gov/mmwr/PDF/rr/rr5306.pdf
Questions for Further Discussion
1. What are the current guidelines for giving influenza vaccine?
2. How effective are alcohol-based handwashes for decreasing infection?
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Information prescriptions for patients can be found at Pediatric Common Questions, Quick Answers for this topic: Influenza (Flu)
American Academy of Pediatrics. Influenza, In Pickering LD, ed. Red Book: 2003 Report of the Committee on Infectious Diseases. 26th edit. Elk Grove Village, IL: American Academy of Pediatrics; 2003;382-391.
Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP) (MMWR 28 May 2004;53[RR06]:1-40)
Centers for Disease Control. Influenza. Available from the Internet at http://www.cdc.gov/flu/ (cited 11/29/04).
Donna M. D’Alessandro, MD
Associate Professor of Pediatrics, Children’s Hospital of Iowa
December 20, 2004