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Colds and the flu - Complications

Description

An in-depth report on the diagnosis, treatment, and prevention of colds and flu.

Alternative Names

Influenza; Strep throat; Bird flu; Avian influenza

Complications:

Colds rarely cause serious complications. In about 1% of cases, a cold can lead to other complications, such as sinus or ear infections. It can also aggravate asthma and, in uncommon situations, increase the risk for lower respiratory tract infections.

Ear Infections. The rhinovirus infection, a major cause of colds, also commonly predisposes children to ear infections, possibly by obstructing the Eustachian tube, which leads to the middle ear. Viruses may even attack the ear directly.

Sinusitis. Between 0.5 - 3% of people with colds develop sinusitis, an infection in the sinus cavities (air-filled spaces in the skull). Sinusitis is usually mild, but if it becomes severe, antibiotics generally eliminate further problems. In rare cases, however, sinusitis can be serious.

Lower Respiratory Tract Infections. The common cold poses a risk for bronchitis and pneumonia in nursing home patients, and in other people who may be vulnerable to infection. Some experts believe that the rhinovirus may play a more significant role than the flu in causing lower respiratory infections in the vulnerable population.

Aggravation of Asthma. Rhinovirus infections can aggravate asthma in both children and adults. In fact, rhinovirus has been reported to be the most common infectious organism associated with asthma attacks. Colds may promote allergic inflammation of the airways, and increase the intensity of their responsiveness for weeks.

Complications of Influenza

The flu is usually self-limited. However, each year in the United States, more than 200,000 people are hospitalized due to complications of the flu. An estimated 36,000 people die each year of influenza-related complications. People at highest risk for serious complications are those over 65 years old and those with chronic medical conditions. Influenza A is the most severe strain. Influenza B tends to be milder.

Pneumonia. Pneumonia is the major serious complication of influenza and can be very serious. It can develop about 5 days after viral influenza. More than 90% of the deaths caused by influenza and pneumonia occur among older adults. Flu-related pneumonia nearly always occurs in high-risk individuals, such as the following:

People with weakened immune systems, such as AIDS patients
Elderly patients, particularly patients in nursing home
Very young children (it may be difficult to tell whether pneumonia is related to influenza or caused by respiratory syncytial virus [RSV])
Hospitalized patients and anyone with serious medical conditions, such as diabetes, heart, circulation, or lung disorders, particularly chronic lung disease
Drug abusers who use needles

Combinations of these factors further increase the risk. It should be noted that pneumonia is an uncommon outcome of influenza in healthy adults.

Complications in the Central Nervous System in Children. Influenza increases the risk for complications in the central nervous system of small children. Febrile seizures are the most common neurologic complication in children The risks decline after a child turns 1 year old, but are still high in children aged 3 - 5 years old.

Resources

www.cdc.gov/flu -- U.S. Centers for Disease Control and Prevention
www.niaid.nih.gov -- National Institute for Allergy and Infectious Diseases
www.who.int/csr/disease/influenza/en -- World Health Organization
www.cdc.gov/vaccines -- National Immunization Program
www.immunize.org -- Immunization Action Coalition
www.entnet.org -- American Academy of Otolaryngology -- Head and Neck Surgery
www.cdc.gov/flu/avian -- Avian Influenza Information

References

American Academy of Pediatrics Committee on Infectious Diseases. Recommended childhood and adolescent immunization schedule: United States, 2005. Pediatrics. 2005 Jan;115(1):182.

Caruso TJ, Prober CG, Gwaltney JM Jr. Treatment of naturally acquired common colds with zinc: a structured review. Clin Infect Dis. 2007;45(5):569-74.

Centers for Disease Control and Prevention. Key Facts About Seasonal Influenza (Flu). Available online.

Centers for Disease Control and Prevention. 2007-08 Influenza Prevention & Control Recommendations: Vaccination of Specific Populations. Available online.

Centers for Disease Control and Prevention. Acute Respiratory Disease Associated with Adenovirus Serotype 14 -- Four States, 2006-2007. MMWR. 2007;56(45):1181-84.

Centers for Disease Control and Prevention. FDA Approves New Laboratory Test To Detect Human Infections With Avian Influenza A/H5 Viruses. February 3, 2006.

Harper SA, Fukuda K, Uyeki TM, Cox NJ, Bridges CB. Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2005 Jul 29;54(RR-8):1-40.

Hayden GF, Turner RB. Acute Pharyngitis. In: Behrman RE, Kliegman RM, Jenson HB, eds. Behrman: Nelson Textbook of Pediatrics, 17th ed. Philadelphia, Pa: Saunders; 2004.

Interagency Task Force on Antimicrobial Resistance. Executive Summary: 2006 Annual Report on Progress on "A Public Health Action Plan to Combat Antimicrobial Resistance." Draft release, June 2007. Available online.

Jefferson T, Demichelli V, Rivetti D, Jones M, Di Pietrantonj C, Rivetti A. Antivirals for influenza in healthy adults: systematic review. Lancet 2006 Jan 28;367(9507):303-13.

Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2008. MMWR. July 17, 2008/57(Early Release);1-60.

Reveiz L, Cardona AF, Ospina EG. Antibiotics for acute laryngitis in adults. Cochrane Database Syst Rev. 2007 Apr 18;(2):CD004783.

Sasazuki S, Sasaki S, Tsubono Y, Okubo S, Hayashi M, Tsugane S. Effect of vitamin C on common cold: randomized controlled trial. Eur J Clin Nutr. 2006;60(1):9 - 17.

Shah SA, Sander S, White CM, Rinaldi M, Coleman CI. Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis. Lancet Infect Dis. 2007;7(7):473-80.

Simasek M, Blandino DA. Treatment of the common cold. Am Fam Physician. 2007;75(4):515-20.

Taverner D, Latte J. Nasal decongestants for the common cold. Cochrane Database Syst Rev. 2007 Jan 24;(1):CD001953.

U.S. Food and Drug Administration: Nonprescription Drugs and Pediatric Advisory Committee Meeting. Joint Meeting of the Nonprescription Drugs Advisory Committee and the Pediatric Advisory Committee October 18-19, 2007. Available online.

World Health Organization: Neuraminidase Inhibitor Susceptibility Network. Monitoring of neuraminidase inhibitor resistance among clinical influenza virus isolates in Japan during the 2003-2006 influenza seasons. Weekly epidemiological record. 2007;82(17):149-50.

World Health Organization. Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO. December 16, 2008. Available online.

Reviewed last on: 6/17/2009
A.D.A.M. Editorial Team: David Zieve, MD, MHA, Greg Juhn, MTPW, David R. Eltz. Previously reviewed by Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital (2/10/2009).

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