Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (604 page)

BOOK: Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis
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   Uncomplicated bacterial superinfection typically resolves without antibiotic treatment within 4 weeks.
   Serious complications are suspected in patients with high fever (>39°C), severe headache, visual changes, periorbital edema, change in mental status, or other evidence of extension of infection. These infections require urgent referral for imaging, collection of diagnostic specimens, and consideration of invasive intervention.
   Increased risk for severe or invasive ARS include immunodeficiency, impaired sinus drainage (e.g., foreign body, abnormal ciliary function), and mucosal irritation (e.g., allergy, intranasal drug abuse).
   Diagnosis
   During early ARS infection, clinical finding cannot be used to accurately differentiate patients with viral infection from those with bacterial superinfection.
   Because most viral and bacterial ARS infections resolve spontaneously within 10 days, specific diagnostic testing is not recommended. Testing for influenza virus may be considered if circulating in the community and if antiviral therapy would be indicated for the patient.
   Empiric antimicrobial therapy may be considered in patients with symptoms persisting >10 days, patients with severe symptoms (e.g., high fever for at least 3–4 days), patients with evidence of intracranial spread, and patients with worsening symptoms after a period of improvement.
   Identification of the infecting pathogen should be attempted in patients with severe disease. Nasopharyngeal and throat cultures are of no value in diagnosis. In children, sinus aspiration is the preferred method for specimen collection; in adults, endoscopic collection from an infected sinus may be used as a less invasive method for specimen collection. In addition to aerobic cultures, anaerobic cultures should be performed if a dental infection is considered as a potential source of infection.
Suggested Reading
Chow AW, Benninger MS, Brooks I, et al. IDSA clinical practice guideline for acute bacterial rhinosinusitis in children and adults.
Clin Infect Dis.
2012;54:e72–112.
DIPHTHERIA
   Definition

Diphtheria is caused by infection with
Corynebacterium diphtheriae
a pleomorphic gram-positive rod that produces an exotoxin. Most patients present respiratory or cutaneous disease.

Diphtheria has a global distribution, primarily affecting unvaccinated individuals in underdeveloped, economically disadvantaged areas. Humans are the only known reservoir for
C. diphtheriae
, and transmission is mediated by contact with respiratory droplets or secretions from patients with actively infectious mucous membrane or cutaneous lesions. Disease usually occurs within 1 week after infectious contact. The lesions in untreated patients may be infectious for up to 6 weeks; treated patients become noninfectious within days. Diphtheria is a national notifiable disease, reportable to the CDC and local departments of public health.

   Who Should Be Suspected?
   Diphtheria usually presents as respiratory disease. The common presentation of respiratory disease is pseudomembranous pharyngitis, with formation of a gray membrane of necrotic material in the tonsillar area, which may extend to adjacent posterior pharyngeal surfaces. Patients often complain of sore throat and difficulty swallowing. There is a risk of dislodgement, with respiratory obstruction, in patients with extensive pseudomembrane formation. The underlying mucosa is friable and edematous. Local adenopathy and tissue edema (bull neck) may occur. Low-grade fever, malaise, or other nonspecific symptoms are common.

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