Sinusitis...................... ETIOLOGY Sinusitis is a suppurative infection of the paranasal sinuses and often complicates the common cold and allergic rhinitis. The maxillary and ethmoid sinuses are present at birth, but only the ethmoidal sinuses are pneumatized. The maxillary sinuses become pneumatized at 4 years of age. Frontal sinuses begin to develop at 7 years of age and are not completely developed until adolescence. The sphenoid sinuses are present by 5 years of age. The ostia draining the sinuses are narrow (1 to 3 mm) and drain into the middle meatus in the ostiomeatal complex. The mucociliary system maintains the sinuses as normally sterile. Obstruction to mucociliary flow, such as mucosal edema resulting from the common cold, impedes sinus drainage and predisposes to bacterial proliferation. In 90% of children with acute sinusitis, the bacterial causes are Streptococcus pneumoniae, nontypable Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and group A streptococcus. Anaerobes emerge as important pathogens in subacute and chronic sinusitis. Indwelling nasogastric and nasotracheal tubes predispose to nosocomial sinusitis, which may be caused by gram-negative bacteria (Klebsiella and Pseudomonas). Antibiotic therapy predisposes to infection with antibiotic-resistant organisms. Sinusitis in neutropenic and immunocompromised persons may be caused by Aspergillus and the Zygomycetes (e.g., Mucor, Rhizopus). EPIDEMIOLOGY The true incidence of sinusitis is unknown. The common cold is the major predisposing factor for developing sinusitis at all ages. Other risk factors include cystic fibrosis, immunodeficiency, human immunodeficiency virus (HIV) infection, nasogastric or nasotracheal intubation, immotile cilia syndrome, nasal polyps, and nasal foreign body. Sinusitis also is a frequent problem in immunocompromised children after organ transplantation CLINICAL MANIFESTATIONS Clinical manifestations most commonly include persistent, mucopurulent, unilateral or bilateral rhinorrhea, nasal stuffiness, and cough, especially at night. Less common symptoms include a nasal quality to the voice, halitosis, facial swelling, facial tenderness and pain, and headache. Sinusitis may exacerbate asthma. LABORATORY AND IMAGING STUDIES Culture of the nasal mucosa is not useful. Sinus aspirate culture is the most accurate diagnostic method but is not practical or necessary. Transillumination may show evidence of fluid, but this is difficult to perform in children and is not reliable. Plain x-ray and computed tomography may reveal sinus clouding, mucosal thickening, or an air-fluid level. Abnormal radiographic findings do not differentiate infection from allergic disease; computed tomography and magnetic resonance imaging often show abnormalities, including air-fluid levels, in the sinuses of asymptomatic persons. Conversely, normal radiographs have high negative predictive value for bacterial sinusitis. DIFFERENTIAL DIAGNOSIS The diagnosis usually is based on history and physical findings for longer than 10 to 14 days without improvement or increased severity of symptoms compared with the common cold. TREATMENT Amoxicillin administered for 7 days after resolution of symptoms is recommended for treatment of uncomplicated sinusitis. Alternative antibiotics for penicillin-allergic patients include cefuroxime axetil, cefpodoxime, clarithromycin, and azithromycin. For children at increased risk for resistant bacteria (antibiotic treatment in the preceding 1 to 3 months, day care attendance, age
Posted on: Sun, 09 Mar 2014 08:23:20 +0000
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