Nasopharyngeal infections

• ANATOMY OR SYSTEM AFFECTED: Nose, pharynx, upper respiratory tract, throat
• ALSO KNOWN AS: Upper respiratory tract infections

Definition

Nasopharyngeal infections are upper respiratory infections (URIs) caused by bacteria or viruses growing in the nasopharynx, the back of the throat, the top of the soft palate, and the nasal passages.

Causes

Nasopharyngeal infections result from direct contact with discharge or droplets from the mouth or nose of infected persons through coughing or sneezing. The most frequent illnesses from organisms in the nasopharynx include the common cold and influenza. Some two hundred viruses cause the common cold, including retrovirus, coronaviruses, adenovirus, enterovirus, respiratory syncytial virus (RSV), and influenza A and B viruses.

About 5 to 15 percent of URIs are caused by group A streptococcal bacteria, including Streptococcus pyogenes. Bordetella pertussis and Corynebacterium diphtheriae, sometimes found in the nasopharynx, cause severe upper respiratory infections but are infrequent in the United States because of immunizations.

Asymptomatic carriers of nasopharyngeal organisms such as Staphylococcus aureus, Streptococcus pneumonia, and Neisseria meningitidis spread these organisms through nasal secretions. S. aureus and S. pneumonia can cause pneumonia and N. meningitidis can result in meningitis.

The incubation period for URIs varies with causative organisms. Cold viruses can show symptoms within sixteen hours of contact with infected persons; an average incubation period is twenty-four to forty-eight hours, with a duration of seven to ten days.

Risk Factors

Nasopharyngeal infections are the most common infectious diseases in the United States. More than one billion people contract colds each year. Incidence varies by age, with the greatest risk for children younger than five years. The prevalence of the cold for children attending school or daycare is between six and ten per year. Older youth and adults contract colds two to four times a year, while those older than age sixty experience fewer than one cold each year.

Persons with influenza usually experience URI symptoms in the early stages of the disease. Some 5 to 20 percent of Americans experience flu annually, according to WebMD. Influenza outbreaks are risky to public health.

URIs occur anytime of the year, but mostly in the fall to early spring. In cold weather, people tend to gather indoors at work or school in close, less ventilated environments, increasing exposure to infected persons. Humidity levels are often lower in winter too; URI viruses thrive in low humidity with cold temperatures. Persons with suppressed immune systems or who are under acute or chronic stress are at risk for URIs. When normal defenses of the nasopharynx are compromised, URIs may occur.

Symptoms

Nasopharyngeal infections produce typical URI symptoms. Cold symptoms include nasal congestion, runny nose, and sneezing. Additional symptoms include sore throat, post-nasal drip, cough, mild headache, muscle aches, malaise, watery eyes, hoarseness, mild fever (less than 101° Fahrenheit), and decreased appetite. Mucus secretions may change from thin to thick and from clear to yellow or green. However, symptoms of flu include high fever (102° to 104° F) in a three-to-four-day period, prominent headaches, severe aches, chest congestion, and fatigue or exhaustion.

Screening and Diagnosis

Healthcare providers take medical histories and perform physical examinations to diagnose URIs. They review self-reported complaints. Diagnosis is made on assessment of physical symptoms of the suspected URI, ranging from scratchy, nasal stuffiness with reddened pharynx to marked redness of the pharynx and fever. If clinical symptoms indicate a common cold, no further tests are done.

Viral cultures may be needed to diagnose serious URIs, such as influenza with potential complications like pneumonia. A throat or nasal culture guides treatment. A nasopharyngeal culture may be appropriate for infants, the elderly, or debilitated persons. The culture results will determine the course of therapy.

Treatment and Therapy

Treatment of nasopharyngeal infections depends on the causative agent and course of the illness. The common cold has no prescribed therapy and can be treated in diverse ways. Some $17 billion is spent annually treating colds, including with many over-the-counter medications. Treatment of URIs includes antiviral medications, interferon nasal spray, zinc gluconate lozenges, and high doses of vitamin C. Most people manage their common cold symptomatically, with acetaminophen or ibuprofen used for relief of pain, fever, and muscle aches. Antihistamines, decongestants, and cough syrups or mucolytics address symptoms. One should maintain adequate fluid intake and get plenty of rest.

Antibiotics are not prescribed for the common cold or flu because they are ineffective against viruses. They may treat bacterial complications such as bronchitis, acute otitis media, or pneumonia. Patient comorbidities, including asthma, kidney disease, diabetes, and cardiac concerns, are considered when diagnosing and treating persons with URIs.

Prevention and Outcomes

The common cold causes the greatest loss of work and school days in the United States. Some 22 million school days and 20 million work days are missed annually with colds. The common cold translates into $25 billion in lost productivity. About 34 million people contracted influenza during the 2023-2024 respiratory season, according to the National Foundation for Infectious Diseases. This cost employers and businesses an estimated $11.2 billion in direct and indirect costs.

Primary prevention of URIs depends on a healthy nasopharynx to trap foreign organisms. Precautions include covering the mouth when sneezing or coughing, frequent handwashing, and minimizing touching of the face with hands. Lifestyle changes include exercise, a nutritious diet, and sufficient rest, all of which promote a healthy immune system. Adequate hydration keeps mucus membranes moist so the natural defenses in the nasal passages can function best. Complementary therapies may help boost the immune system to decrease URIs.

Influenza vaccinations are encouraged each fall for healthy people but especially for the most vulnerable, including the young, old, debilitated, or immunosuppressed. Healthcare workers are at risk of exposure and may benefit from vaccinations.

Bibliography

Brammer, Lynette, et al. "Influenza." Manual for the Surveillance of Vaccine Preventable-Disease. 4th ed. Atlanta: Centers for Disease Control and Prevention, 2008.

"Common Cold." WebMD, 15 Mar. 2024, www.webmd.com/cold-and-flu/common‗cold‗overview. Accessed 4 Feb. 2025.

"Flu (Influenza)." National Foundation for Infectious Diseases, Sept. 2024, www.nfid.org/infectious-disease/flu/. Accessed 4 Feb. 2025.

Griffin, R. Morgan. "What Are Your Odds of Getting the Flu?" WebMD, 7 Nov. 2024, www.webmd.com/cold-and-flu/flu-statistics. Accessed 4 Feb. 2025.

Helms, Richard A., et al., eds. Textbook of Therapeutics: Drug and Disease Management. 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.

Pappas, Diane E. "Patient Education: The Common Cold in Children (Beyond the Basics)." UpToDate, 22 Apr. 2024, www.uptodate.com/contents/the-common-cold-in-children-beyond-the-basics/print. Accessed 4 Feb. 2025.

Pettigrew, Melinda M., et al. “Microbial Interactions During Upper Respiratory Tract Infections.” Emerging Infectious Disease 10 (2008): 1584-1591.

Sexton, Daniel J. and Micah T. McClain. "The Common Cold in Adults: Diagnosis and Clinical Features." UpToDate, 31 Oct. 2023, www.uptodate.com/contents/the-common-cold-in-adults-diagnosis-and-clinical-features/print. Accessed 4 Feb. 2025.