Infections of the Upper Respiratory Tract
Upper respiratory tract infections are the most common infections and the most frequent reasons for office visits in the United States. Most upper respiratory infections are minor and self-limiting and do require specific antimicrobial therapy, but some (e.g., peritonsillar abscess [PTA], epiglottitis, invasive fungal sinusitis) may be life-threatening.1
The common cold is a mild, self-limiting infection and is the most frequent acute illness in the United States.2 Approximately 500 million noninfluenza viral respiratory infections occur yearly, resulting in estimated direct costs of $17 billion and indirect costs of $22.5 billion annually.3 Six major viral families are responsible: rhinovirus (30%–40% of cases); influenza virus (25%–30%); coronavirus (10%–15%); adenovirus (5%–10%); parainfluenza virus (5%); and respiratory syncytial virus (RSV) (5%). Each virus has several serotypes; rhinovirus has 100. More recently recognized viruses, such as human metapneumovirus and bocavirus can also cause the common cold.4 Adults have an average of two to four colds and children six to eight colds per year.
In the United States, the incidence of colds is seasonal, with most occurring fall through spring. Young children are the main reservoir of respiratory viruses, and adults with children have more colds than those without. Transmission probably occurs either by inhalation of infectious droplets or by hand-to-nose “self-inoculation” after touching infectious secretions. The pathogenesis of rhinovirus infections is thought to include viral entry into the nose followed by infection of the epithelial cells of the upper airway. Frequent use of alcohol-based hand sanitizers or virucidal impregnated nasal tissues may reduce transmission.5 Symptoms (sneezing, nasal discharge and congestion, and a “scratchy” throat) develop 16 to 72 hours after inoculation, and last for 1 to 2 weeks. Fever is uncommon in adults but may occur in children. Acute viral bronchitis is commonly associated with the common cold in adults. The peak of rhinoviral excretion in nasal secretions coincides with the peak of clinical illness. Complications of the common cold include bacterial superinfections of the upper respiratory tract, such as acute otitis media (AOM) and acute sinusitis, and exacerbations of asthma.6
Treatment of the common cold is symptomatic. Symptoms of rhinorrhea and sneezing may be improved by the use of intranasal ipratropium.7 Antihistamine use alone in patients with the common cold is of minimal benefit and frequently results in troublesome side effects.8 Guidelines from the American College of Chest Physicians do not recommend use of cough suppressants (codeine or dextromethorphan) for cough associated with upper respiratory infections.9 Treatment with antibiotics for uncomplicated upper respiratory tract infections causes more harm than benefit and should not be used.10,11 The value of zinc, vitamin C, Echinacea, and other herbal products has not been definitely proven.12–14 Careful hand washing and use of hand disinfectants may be the most ...