Sinusitis, also referred to as rhinosinusitis, is defined as the symptomatic inflammation of paranasal sinuses and nasal cavity mucosa. This inflammation can be as a result of viruses, bacteria, and allergens for discussion of acute and recurrent sinusitis. Acute recurrent sinusitis is diagnosed when patients have 4 or more episodes of rhinosinusitis per year without persistent symptoms in between. When symptoms continue to last for more than 12 weeks, with or without acute exacerbation, it is termed chronic sinusitis. For the purpose of this article, we will be referring onlu to uncomplicated rhinosinusitis and not to sinus infection with orbital, central nervous system, or suppurative complications.
Most common etiology for acute and recurrent sinusitis is viral infection. They are associated with acute viral upper respiratory infection. Similar to viral upper respiratory infections, they are self-limiting. When the mucous membrane of the nasal cavity and paranasal sinus is inflamed due to viruses, there is a predisposition to bacterial infection of the sinus cavity. Most common bacterial pathogens are Streptococcus pneumoniae, Hemophilus influenza, other Streptococcus species, Moraxella catarrhalis, or Staphylococcus aureus. Infrequently, methicillin-resistant Staphylococcus aureus (MRSA) or fungal pathogen can be the cause of chronic sinusitis.
Sinusitis is one of the most common causes for seeking medical attention. There are more than 30 million annual diagnoses in the United States. Among all antibiotics prescribed, one-fifth of them are directed for treatment of sinusitis. The direct cost of treatment of sinusitis is more than $11 billion in the United States. If other unaccounted losses of productivity are included, there is a significant impact on the healthcare cost and economy.
Pathogenesis of rhinosinusitis is as a result of dysfunction of sinus ostia (narrowing), the ciliary apparatus, and viscous sinus secretions. Viral upper respiratory infection or allergens result in mucosal edema to lead to narrowing of the sinus ostia causing direct mechanical obstruction. When there is an obstruction of the sinus ostium, there is a transient increase in pressure within the sinus cavity. As air is depleted in this close space, the pressure in the sinus becomes negative relative to atmospheric air pressure. This negative pressure possibly allows nasal bacteria into sinuses during sniffing or nose blowing. When the sinus ostium is obstructed, secretion of mucous by mucosa continues, resulting in fluid accumulation in the sinus. During viral colds other inflammation of nasal ostia and mucosal membranes, both the structure and the function of the mucociliary apparatus are impaired. The quality and characteristics of sinus secretions also determine the pathogenesis of sinusitis. Cilia can beat only in a fluid. The mucous blanket in the respiratory tract is made up of two layers. The sol phase is a thin, low-viscosity layer that surrounds the shaft of the cilia and allows the cilia to beat freely. The gel phase is a more viscous layer and rides on the sol phase. Alterations in the mucous layer, which occur in the presence of inflammatory debris, as in infected sinus, may further impair ciliary movement. Similarly, mucociliary dysfunction may occur due to frequent irrigation of the nasal cavity.
Up to 4 weeks of purulent nasal drainage (anterior, posterior, or both) accompanied by nasal obstruction, facial pain, pressure, and/or fullness. Nasal obstruction may be reported by patients as obstruction, congestion, blockage, or stuffiness or may be identified during the physical examination. Facial pain, pressure, or fullness may involve pain and tenderness over the maxillary, frontal bone or around the eyes. Acute, viral sinusitis should be presumed if the patient reports nasal cleat discharge with persistent symptoms without deterioration present for less than 10 days. Acute bacterial rhinosinusitis is presumed when the symptoms last more than 10 days or worsen within 2 days after initial improvement. Despite nature of viral or bacterial pathogens, most of the acute sinusitis resolve within 10 to 14 days. Sinusitis that persists beyond 12 weeks is termed chronic sinusitis and will require radiographic imaging and endoscopic evaluation.
History and physical examination are key to making a diagnosis of acute and recurrent sinusitis. Radiological imaging, either x-rays, CT, or MRI are not recommended to make the diagnosis of acute recurrent sinusitis. CT of sinuses is recommended if symptoms persist for more than 12 weeks. Nasal endoscopy is recommended if there is suspicion of resistant bacterial infection, allergic fungal sinusitis, or nasal polyps and mass. In case of persistent or chronic sinusitis, cultures obtained from sinus aspirates or endoscopy may be needed to identify any resistant bacterial or fungal pathogen. Most frequent pathogens are Streptococcus pneumoniae, Hemophilus influenza, other Streptococcus species, Moraxella catarrhalis, or Staphylococcus aureus.
An oral decongestant will help reduce inflammation and secretion from the nasal, sinus, and respiratory tract mucosa thus assisting symptomatic relief. This may also assist in keeping the nasal ostia open and resulting in a reduction of sinus pressure. An oral antihistamine may be helpful if suspected sinusitis is as a result of allergic rhinitis. Oral steroids are not recommended for symptomatic relief.
Topical Intranasal Therapy
Nasal irrigation with saline is an effective symptomatic relief as a result of viral or allergic rhinosinusitis. It should be stressed that prolonged and frequent nasal irrigation of nasal cavity may alter the mucociliary apparatus to result into increase in symptoms of sinus congestion. A topical spray of fluticasone may help reduce inflammation and reduce the flaring up. Another topic spray such as oxymetazoline or phenylephrine nasal may help reducing congestion. Patients should be cautioned of rebound congestion following these decongestant sprays and limit the spray to 3 days.
Only 0.5% to 2% of viral sinusitis results into bacterial sinusitis. Therefore, antibiotics therapy should be started only if the symptoms persist for more than 7 to 10 days without improvement and there are symptoms and signs of possible bacterial infection. The first-line of antibiotics is amoxicillin with or without clavulanate for 5 to 10 days. In patients who are allergic to penicillin, or in cases that second-line antibiotics are needed, the alternatives are doxycycline or respiratory fluoroquinolone (levofloxacin, moxifloxacin). Other alternative antibiotics include clindamycin with cefixime or cefpodoxime for 10 days.
Medical management of recurrent acute sinusitis is the mainstay of treatment. However, when the diagnosis of recurrent acute sinusitis has been made, furtherevaluation is indicated.
Interventions such as balloon sinuplasty are not recommended for recurrent sinusitis and should be reserved for patients with chronic sinusitis refractory to medical management.
Points to remember:
|||Current Concepts in Adult Acute Rhinosinusitis., Aring AM,Chan MM,, American family physician, 2016 Jul 15 [PubMed PMID: 27419326]|
|||Physiology and pathophysiology of respiratory mucosa of the nose and the paranasal sinuses., Beule AG,, GMS current topics in otorhinolaryngology, head and neck surgery, 2010 [PubMed PMID: 22073111]|
|||Clinical practice guideline (update): adult sinusitis., Rosenfeld RM,Piccirillo JF,Chandrasekhar SS,Brook I,Ashok Kumar K,Kramper M,Orlandi RR,Palmer JN,Patel ZM,Peters A,Walsh SA,Corrigan MD,, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2015 Apr [PubMed PMID: 25832968]|