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Upper Respiratory Tract Infections

Contributed by Peter Chin-Hong, MD

CHAPTER CONTENTS

INTRODUCTION

Infections of the upper respiratory tract are a common ambulatory care complaint, resulting in a large proportion of office visits. Although the vast majority of infections are viral and are self-limited, some may require hospitalization, particularly in the pediatric population. Bacterial etiologies of some of the common upper respiratory tract infections may be primary or superinfections of the original viral processes and are amenable to treatment (Table 75–1).

TABLE 75–1 Common Infections of the Upper Respiratory Tract

OTITIS MEDIA

Definition

Otitis media is an infection of the middle ear caused by either viruses or bacteria. Otitis media can be either acute or chronic. The information in this chapter refers to acute otitis media.

Pathophysiology

Any process that leads to eustachian tube obstruction can result in fluid retention and concomitant infection of the middle ear. The most common predisposing factors are upper respiratory tract infections and seasonal allergic rhinitis. Otitis media is very common in children under the age of 3 years because they have a small opening of the eustachian tube that is easily blocked by the inflammation caused by a viral infection or an allergic response.

Clinical Manifestations

Patients present with ear pain and pressure, often accompanied by an upper respiratory tract infection. In infants, the ear pain may manifest as ear pulling. Patients may also complain of decreased hearing and fever. On examination, the tympanic membrane is erythematous (Figure 75–1A and B) with a loss of the light reflex and decreased mobility. In some cases, the tympanic membrane may bulge and then rupture.

FIGURE 75–1 A: Normal tympanic membrane in 6-year-old child. B: Otitis media in 3-year-old child. Note bulging tympanic membrane and loss of light reflex. (From Tintinalli JE et al: Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed. New York: McGraw-Hill, 2009. Copyright © 2009 by The McGraw-Hill Companies, Inc. Courtesy of Dr. Shelagh Cofer, Department of Otolaryngology, Mayo Clinic.)

Pathogens

Both bacteria and viruses cause otitis media. Among bacteria, Streptococcus pneumoniae is the most common cause. Nontypeable strains of Haemophilus influenzae and Moraxella catarrhalis are also common causes. Among viruses, respiratory syncytial virus, coronaviruses, and rhinoviruses are commonly involved.

Diagnosis

Otitis media is usually diagnosed clinically. If the membrane ruptures, a sample of the exudate can be analyzed by Gram stain and culture. If indicated, tympanocentesis can be done to relieve pressure before the drum ruptures and to obtain a specimen for culture.

Treatment

Amoxicillin orally is usually the drug of choice together with nasal decongestants to open the eustachian tube. In cases of bacterial resistance, amoxicillin-clavulanate (Augmentin) may be used.

Prevention

Recurrent episodes of otitis media can be suppressed by prophylactic antibiotics such as amoxicillin or sulfisoxazole. Ventilating tubes may be inserted as a strategy to prevent recurrent infections. The conjugate pneumococcal vaccine is effective in preventing invasive pneumococcal disease but is less effective in preventing otitis media.

SINUSITIS

Definition

Sinusitis is inflammation of the paranasal sinuses. It can be either acute or chronic. Acute infections are considered those with symptoms lasting less than 4 weeks. The information in this chapter refers to acute sinusitis.

Pathophysiology

Impaired mucociliary clearance caused by viral infection or allergic rhinitis can obstruct the orifice of the sinus. Mucus then accumulates in the sinus cavity. Stasis can lead to bacterial overgrowth and superinfection. Sinusitis frequently involves the maxillary sinus because the ostium of that sinus is located superior to most of the sinus and drainage of mucus has to occur against gravity. Drainage of the other sinuses is aided by gravity.

Clinical Manifestations

Clinical manifestations include purulent nasal discharge, nasal congestion, facial or sinus pain, decreased sense of smell, and fever. Headache and malodorous breath may be present.

Pathogens

Many cases begin with a viral upper respiratory tract infection. Bacterial superinfection can then occur. In the case of acute bacterial sinusitis, common organisms are S. pneumoniae, H. influenzae, and M. catarrhalis, as in the case of acute otitis media. Staphylococcus aureus also causes sinusitis but less commonly. In immunocompromised patients and diabetics, sinusitis caused by fungi such as Aspergillus or Mucor may occur.

Diagnosis

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