Upper Respiratory Tract Infections
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INFECTIONS OF THE UPPER RESPIRATORY TRACT

General Goal: To know the major cause(s) of these diseases, how they are transmitted, and the major manifestations of each disease.

Specific Educational Objectives: The student should be able to:

1. recite the common cause(s) of these disease.

2. describe the common means of transmission.

3. describe the major manifestations of this infection.

4. describe how you diagnose, treat and prevent this infection.

Reading: MEDICAL MICROBIOLOGY by P.R. Murray, K.S. Rosenthal, G.S. Kobayashi and M.A. Pfaller, 3rd Edition. page number depends on microorganism.

Mosby's Color Atlas and Text of Infectious Diseases by Christopher P. Conlon and David R. Snydman. pp.53-66.

Lecture: Dr. Neal R. Chamberlain

References:

Acute Rhinosinusitis

Acute rhinosinusitis is defined as inflammation or infection of the mucosa of the nasal passages and at least one of the paranasal sinuses that lasts no longer than 4 weeks. Rhinosinusitis occurs in about 32 million people each year in the United States. Rhinitis and sinusitis usually coexist and, therefore, the medical terminology has changed from sinusitis to rhinosinusitis.

Etiology

Most cases of acute rhinosinusitis are due to respiratory viruses, which include rhinovirus, parainfluenza virus, respiratory syncytial virus, and adenovirus. However, acute rhinosinusitis can occasionally be complicated by a bacterial infection and is diagnosed as acute bacterial rhinosinusitis. The two most common causes of community-acquired acute bacterial rhinosinusitis are Streptococcus pneumoniae and nontypeable Haemophilus influenzae. The bacteria listed in Table URI-2 cause over 70% of the infections of the paranasal sinuses. Immunocompromised patients are also prone to acquire fungal infections of the sinuses due to Aspergillus and Mucor species.

Table URI-2. Causes and Percentage of Cases of Community-Acquired Acute Bacterial Rhinosinusitis
Microorganism	Percentage of Cases	Comments
Haemophilus influenzae, nontypeable	35%
Streptococcus pneumoniae	34%
Anaerobic bacteria	6%	Anaerobic and polymicrobial infections are much more common in chronic rhinosinusitis
Gram-negative bacteria	4%	More common in hospital- acquired rhinosinusitis
Staphylococcus aureus	4%
Moraxella catarrhalis	2%	More common in children
Streptococcus pyogenes	2%

Manifestations

Acute rhinosinusitis is characterized by mucosal inflammation of both the nose and the paranasal sinuses. Symptoms include sneezing, rhinorrhea, nasal congestion and postnasal drip, aural fullness, facial pressure and headache, sore throat, cough and fever, and myalgias. A viral upper respiratory tract infection usually precedes acute bacterial rhinosinusitis, and differentiating between a bacterial and a viral infection is difficult.

Epidemiology

Respiratory viruses cause most cases of acute rhinosinusitis. Symptoms usually resolve within 5–7 days, and most people recover without medical treatment.
Infection of the sinuses may follow the common cold, dental extractions, rhinitis due to allergies, and forcing water into the sinuses by jumping into water.
Infections of the sinuses develop most often during winter months when the common cold occurs more frequently.
In approximately 2% of adults and 10% of children, acute bacterial rhinosinusitis can follow acute viral rhinosinusitis, allergic rhinitis, or other upper respiratory tract infections.
Table URI-3 contains many of the predisposing factors that cause individuals to be more likely to develop acute bacterial rhinosinusitis.
Patients with hospital-acquired infections are more likely to be infected with gram-negative organisms when they develop acute bacterial rhinosinusitis.
Anaerobic acute bacterial rhinosinusitis infections are usually associated with dental infections or procedures.

Table URI-3. Acute Bacterial Rhinosinusitis: Predisposing Conditions

Viral infection

Allergic and nonallergic rhinitis

Anatomic variations

Abnormality of the ostiomeatal complex
Septal deviation
Concha bullosa
Hypertrophic middle turbinates
Haller cells*

Topical nasal medications

Cigarette smoking

Diabetes mellitus

Swimming, diving, high-altitude climbing

Dental infections and procedures

Cocaine abuse

Rhinosinusitis is more common in patients with

Cystic fibrosis
Mechanical ventilation
Head injuries
Use of nasal tubes
Samter triad†
Sarcoidosis
Wegener granulomatosis
Immotile cilia syndrome
Immune deficiency

Common variable
IgA
IgG subclass
Iatrogenic
AIDS (acquired immunodeficiency syndrome)

Note: Conditions are listed in order of relative frequency.

*Infraorbital ethmoid cells.

†Aspirin allergy, nasal polyps, and asthma.

Pathogenesis

The most common precursor to acute bacterial rhinosinusitis is a viral upper respiratory tract infection followed by sinus obstruction from the mucosal edema of inhalant allergies and by anatomic factors (e.g., nasal polyps). Obstruction of the paranasal sinusal ostia impedes drainage of mucus secretions. Bacteria then grow in these secretions, irritating the underlying mucosa and producing more secretions. Death and sloughing of the mucosal cells does occur. The cells will regenerate after the infection has cleared.

Diagnosis

Diagnosis of acute rhinosinusitis is based on the patient’s clinical signs and symptoms. Acute bacterial rhinosinusitis is correctly diagnosed about half the time based on clinical impressions. Acute bacterial rhinosinusitis and viral rhinosinusitis are difficult to differentiate because no single clinical finding can accurately distinguish between acute viral rhinosinusitis and acute bacterial rhinosinusitis. Acute bacterial rhinosinusitis, however, is more likely to become a chronic disease.

A diagnosis of acute bacterial rhinosinusitis is likely when a patient has symptoms of rhinosinusitis that include purulent nasal drainage that worsens after 5 days and persists beyond 10 days, or is out of proportion to symptoms typically seen in viral upper respiratory disease. Signs and symptoms considered more likely to be due to a bacterial pathogen include high (> 39°C) or persistent fever, periorbital swelling, severe facial or dental pain, altered mental status, diplopia, and infraorbital hypesthesia.

Four signs and symptoms that appear to be most helpful in diagnosing a patient with acute bacterial rhinosinusitis are (1) purulent nasal discharge; (2) maxillary tooth or facial pain (especially unilateral); (3) unilateral maxillary sinus tenderness; and (4) worsening symptoms after initial improvement. Table URI-4 includes a criterion-based means of diagnosing acute bacterial rhinosinusitis.

Table URI-4. Signs and Symptoms Associated with the Diagnosis of Acute Bacterial Rhinosinusitis*

Major

Facial pain, pressure, fullness†
Nasal obstruction and blockage
Nasal or postnasal discharge or purulence (by history or physical examination)
Hyposmia, anosmia
Fever (in acute rhinosinusitis only††)

Minor

Headaches
Fever (other than acute rhinosinusitis)
Halitosis
Fatigue
Dental pain
Cough
Ear pain, pressure, fullness

* The presence of two or more major signs and symptoms; OR one major and two or more minor signs or symptoms; OR nasal purulence on examination.

Acute bacterial rhinosinusitis is by definition an illness that lasts < 4 weeks.

†Facial pain and pressure alone does not constitute a suggestive history in the absence of another finding listed in the major category.

††Fever alone in acute rhinosinusitis does not constitute a suggestive history in the absence of another finding listed in the major category.

Therapy and Prevention

Several different treatments can be employed to aid the patient in recovery. Symptomatic treatment is recommended for patients with acute viral rhinosinusitis; however, if a patient has acute bacterial rhinosinusitis, symptomatic and antibiotic treatment is recommended.

Symptomatic treatment

Increase oral hydration with liberal use of nasal saline and steam to promote drainage.
Antipyretics, analgesics (e.g., acetaminophen), and decongestants (e.g., oxymetazoline, phenylephrine, and naphazoline) may be needed for fever, headache, and facial pain.
Mucolytics (e.g., guaifenesin) are helpful for thinning thick nasal secretions and especially for postnasal drip.

Antibiotic treatment

Recommendations for initial antibiotic therapy for patients with acute bacterial rhinosinusitis include amoxicillin or cefdinir. If the patient is allergic to β-lactam antibiotics, trimethoprim-sulfamethoxazole or azithromycin can be prescribed.

Prevention

No vaccines are available that prevent acute viral or bacterial rhinosinusitis; however, some patients can avoid future problems by

Avoiding jumping in water without plugging the nose.
Have septal deviations and polyps or foreign bodies surgically removed.
Practice proper dental management.