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: DL Kasper and AS Fauci, 2013. Harrison's Infectious Diseases, Chapter 17. 2nd Edition. Pg. 192-206 McGraw Hill Education, New York

Lecture: Dr. Neal R. Chamberlain


Acute Rhinosinusitis and Rhinocerebral Mucormycosis

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 US. 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 (98-99.8%), 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.

 

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%

 

 

Rhinocerebral mucormycosis- Immunocompromised patients (e.g., diabetic patients with ketoacidosis, transplant recipients) can acquire an invasive, life-threatening fungal infection called rhinocerebral mucormycosis. It is caused by fungal genera Rhizopus, Rhizomucor, Mucor, Mycocladus (formerly Absidia), and Cunninghamella. The most common causes of this disease are Rhizopus and Rhizomucor. Occasionally Aspergillus and Fusarium fungi can cause this disease.

 

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.

In rare cases, patients with advanced frontal rhinosinusitis may present with Pott’s puffy tumor. A soft tissue swelling and pitting edema over the frontal bone from a subperiostal abscess.

 

Rhinocerebral mucormycosis- Patients initially present with signs and symptoms of rhinosinusitis. However, in a few days the disease progression indicates a more serious infection. In addition to the manifestations of rhinosinusitis the patient may present with bloody nasal discharge, dusky or necrotic turbinates, and changes in mental state. The black eschar of the palate (necrotic hard-palate lesions that respect the midline) is a hallmark of this disease unfortunately; if no treatment begins before this the patient’s prognosis is poor. Earlier changes in the palate should be looked for: discolored or hyperemic areas of the palata. If the orbit is infected patient may have diplopia, decreased ocular motion, chemosis, and late in the disease proptosis and ptosis. The organism may also get into the brain producing abscess. The signs and symptoms vary depending on the part of the brain that is infected.

 

Epidemiology

Rhinosinusitis

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.

 

Rhinocerebral mucormycosis

 

Pathogenesis

 

Rhinosinusitis- 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 occurs. The cells will regenerate after the infection has cleared.

 

Rhinocerebral mucormycosis- The spores from these fungi are in the soil and air and enter through the mouth and the nose. The spores attach to the nasal or oral mucosa where massive spore germination occurs. Individuals who are immunocompetent produce phagocytes that will phagocytize these spores and they do not develop the disease. In immunocompromised patients their phagocytes aren’t able to phagocytize the spores quick enough. This allows the spores the time they need to germinate and form hyphae. The hyphae then get into the blood vessels. The hyphae invade the nasal cavity and maxillary sinuses. If the organisms get into the ethmoid sinuses the orbital regions can be affected. Intracranial spread can occur through the ophthalmic artery, superior fissure, or cribriform plate. The fungi invade the blood vessel lumina and cause thrombosis through inflammatory occlusion. Areas of ischemic infarction and necrosis will then appear in the infected tissue. Death may occur within 2 weeks if untreated or unsuccessfully treated.

 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 an adult patient has moderate symptoms of rhinosinusitis that persists beyond 7 days or severe symptoms of any duration including unilateral/focal facial swelling or tooth pain. A diagnosis of acute bacterial rhinosinusitis is likely when a child has moderate symptoms of rhinosinusitis for longer than 10-14 days or severe symptoms of any duration that include fever (> 39°C or >102oF), unilateral/focal facial swelling or pain. Other signs and symptoms considered to be severe and more likely to be due to a bacterial pathogen include;

 

Rhinocerebral mucormycosis- Clinical signs and symptoms are important in making the diagnosis. Culture and microscopic examination of biopsy samples are critical in making an accurate diagnosis. Significant amounts of tissue is needed therefore swabs are insufficient. Growth of the organisms is seen in 2 days and identified using microscopic techniques.

 

Therapy

 

Rhinosinusitis

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

 

 

Antibiotic treatment

 

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

 

Cerebral Mucormycosis

 

Three factors are key to successful treatment:

Prevention

 

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

Rhinocerebral mucormycosis can be prevented by encouraging diabetic patients to maintain good control over their serum glucose levels.


Send comments and mail to Dr. Neal R. Chamberlain, nchamberlain@atsu.edu
Revised 8/21/14
©2014 Neal R. Chamberlain, Ph.D., All rights reserved.