Allergy Cases: Adult Sinusitis: A Short Review - Case-based Curriculum of Allergy and Immunology

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

Sinusitis

Paranasal sinuses have an embryogenic origin from the nasal passage and are an integral component of the airway. Drainage pathways of the sinuses are complex and can be blocked during inflammation.

Approximately 31-35 million Americans are affected by sinusitis every year (15% of the population).

Sinusitis of less than 4 weeks’ duration is considered acute. Chronic sinusitis persists for more than 4 weeks.

Recurrent sinusitis is defined as 4 or more episodes of sinusitis per year. Each episode lasting 7-10 days and no symptoms during intervening periods.

Acute Exacerbation of Chronic Sinusitis is the sudden worsening of chronic sinusitis that returns to baseline with treatment.

The term sinusitis is often interpreted as reflecting simply a bacterial sinus infection but the disease can have a significant allergic component.

Sinusitis is mostly preceded by rhinitis and is rarely found without rhinitis.

The 1997 Rhinosinusitis Task Force thus proposed the term Rhinosinusitis instead of Sinusitis (reiterated in 2007 guidelines).

Acute Sinusitis

Symptoms for up to 4 weeks. Viral most of the time. Bacterial in less than 5%. Patients with allergic rhinitis (AR) are more susceptible to acute sinusitis.

Complications of acute sinusitis

Orbital cellulitis
Subperiostal, intraorbital or eyelid abscess
Cavernous sinus thrombosis
Meningitis
Subdural, epidural or brain abscesses
Osteomyelitis of frontal bone (Potts puffy tumor)

Chronic Sinusitis

Symptoms for more than 12 weeks. Not an "infection."

Eosinophilic Sinusitis

Allergic Fungal Sinusitis

Allergic fungal sinusitis is a chronic hyperplastic sinusitis with eosinophilic inflammation. It is associated with fungal allergens. The pathologic features are similar to allergic bronchopulmonary aspergillosis (ABPA).

The typical typical patient is a young adult with a history of allergic rhinitis/chronic sinusitis which is refractory to therapy. Nasal blockage becomes worse as nasal polyps enlarge. CT of sinuses shows extensive mucosal disease with complete sinus opacification. There may be blood eosinophilia and elevated serum IgE.

Diagnostic criteria:
1. chronic sinusitis of at least 6 months with CT or MRI findings
2. nasal polyps
3. typical allergic mucin found at sinus surgery, with absence of tissue invasion
4. fungus in allergic mucin - histopathology/culture

Treatment consists of of surgical debridement followed by a tapering course of oral steroids.

Noneosinophilic Sinusitis

Noneosinophilic sinusitis is considered to have an infectious basis and is treated with antibiotics. Organisms found are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. If a patient has Pseudomonas aeruginosa or Staphylococcus aureus, cystic fibrosis should be considered in differential diagnosis.

Diagnosis

A limited CT of sinuses costs about the same as a standard plain film sinus series but is much more useful.

CT scan findings do not correlate well with symptoms.

Upper airway endoscopy can identify anatomic or mechanical disorders of the upper airway. Anterior rhinoscopy is an examination of the nasal cavity performed with a nasal speculum under good illumination. Usually done with a rigid rhinoscope.

The gold standard for diagnosis of bacterial sinusitis is sinus puncture and culture.

Treatment

Treatment of Acute Sinusitis

Over 70% of patients with acute rhinosinusitis improve after 7 days, with or without antimicrobial therapy.
NNT = 7: 7 patients must be treated to achieve one additional positive outcome at 7 to 12 days.
More adverse effects in treated group, number needed to harm (NNH) = 9.

Start antibiotics if no improvement by day 7 or patient has worsening at any time.

Amoxicillin should be first choice based on safety, efficacy, cost, and narrow spectrum. A 10-14 day course is commonly used (7 days beyond clinical improvement).

Treatment of Chronic Sinusitis

Saline lavage (Ann Fam Medicine, July 2006).

Intranasal steroids (INS)

Antihistamines – not useful, may worsen by drying mucosa. Only consider if significant allergic component.

Itraconazole (Sporanox) for fungal sinusitis (most commonly seen in the Southern states). Itraconazole use requires a close follow-up due to the risk of CHF, cardiac arrhythmias, liver dysfunction and peripheral neuropathy (foot drop). It has a "black box" warning for CHF patients.

Refer to ENT for chronic sinusitis. Balloon sinuplasty is a procedure gaining wider acceptance.

Nasal Polyps

Nasal polyps can be considered a form of chronic hyperplastic sinusitis and usually originate in the ethmoid sinuses. Malignant transformation is uncommon. Polyps can occupy the entire nasal cavity, thus producing a total blockage.

Nasal polyposis can be associated with allergic fungal sinusitis, cystic fibrosis (CF) and the triad of asthma, aspirin intolerance, and nasal polyps (Samter's triad in AERD). In cystic fibrosis, polyps show neutrophilic inflammation.

CF should always be considered in children with nasal polyps.

What is the triad of aspirin-exacerbated respiratory disease (AERD)?

Samter's triad include asthma, aspirin sensitivity, and nasal/ethmoidal polyposis:

ASPirin
Asthma
Sensitivity to aspirin
Polyps

Pediatric sinusitis (click the link to continue).

References

Allergy and Immunology MKSAP, 3rd edition.

Pediatric sinusitis. Ellen R. Wald, MD. Audio-Digest Pediatrics, Volume 55, Issue 14, July 21, 2009.

Acute Bacterial Rhinosinusitis in Adults: Part I. Evaluation. AFP, 2004.