Recurrent Acute Rhinosinusitis

Etiology

The most common etiologies for RARS mirror those of other sinusitis types. Viral upper respiratory tract infection is the most common cause of sinusitis and is typically self-limiting.[3] In these cases, viral inoculation triggers inflammation and irritation of the nasal cavity mucosa and paranasal sinuses (see Image. Anatomical Position of Sinuses). This inflammation reduces the size of the sinus ostia (outflow openings), obstructing the clearance of nasal flora, mucus, and inhaled particles from the sinuses. Inflammation also impairs ciliary movement and causes mucus stasis, predisposing the sinuses to bacterial infection. Similarly, untreated allergic rhinitis can cause chronic inflammation in the nose and paranasal sinuses, resulting in outflow tract obstruction, secretion buildup, and potential bacterial infection.

The most common bacterial pathogens causing RARS are Streptococcus pneumoniae, Haemophilus influenzae, other Streptococcus species, Moraxella catarrhalis, and Staphylococcus aureus.[4] Methicillin-resistant S aureus (MRSA) often colonizes the nares and leads to recurrent sinusitis, especially in patients who have undergone multiple courses of antibiotics.

There is some etiologic overlap between RARS and chronic rhinosinusitis. Noninvasive fungal pathogens such as Aspergillus fumigatus may be isolated in these patients (see Image. Fungal Sinusitis and Image. Axial View Fungal Sinusitis). Anatomic obstructive abnormalities, including turbinate hypertrophy, conchae bullosae, stenosed sinus ostia, Haller cells (ethmoid cells within the medial orbital floor impinging the maxillary sinus drainage pathway), nasal polyposis, nasal masses, and septal spurs and deviation, can predispose the nasal cavity and sinuses to infection.[5][6] These structural abnormalities are often correctable through endoscopic surgical techniques.

Genetic factors affecting nasociliary motion or mucus production, like Kartagener syndrome, have also been suggested to play a role in sinus disease pathophysiology. Environmental factors, such as tobacco smoke and chronic exposure to inhaled irritants, have been implicated in the development or exacerbation of RARS. These factors impair ciliary motility and disrupt cell signaling in the innate immune system, exacerbating the condition.[7][8]

Epidemiology

Sinusitis ranks among the most common conditions prompting medical attention, with 1 in 8 adults receiving a sinusitis diagnosis at least once in their lifetime.[9] Sinusitis accounts for 20% of all antibiotic prescriptions.[10] In the United States alone, in 2015, there were 30 million diagnosed sinusitis cases, incurring a substantial treatment cost exceeding $11 billion: $3 billion allocated to acute sinusitis and $8.3 billion to chronic sinusitis.[4] A comprehensive review of a medical claims database encompassing 13.1 million people from 2003 to 2008 revealed a RARS prevalence of 1 in 3,000. Within this population, females constituted the majority (72.1%) of affected individuals, with a mean age of 43.5 years. On average, patients had 5.6 annual healthcare visits and filled 9.4 prescriptions per year, resulting in an annual direct cost burden of $1,091 per patient.[11]

Pathophysiology

The pathogenesis of rhinosinusitis likely involves a combination of viscous sinus secretions and dysfunction of the sinus ostia and ciliary apparatus. Viral upper respiratory infections and allergens cause mucosal edema, narrowing the sinus ostia and causing direct mechanical obstruction. Obstruction of the sinus may lead to the accumulation of secretions, providing an environment conducive to bacterial and fungal growth (see Image. Sinus Anatomy). Outflow blockage may also cause pressure changes within the sinus as oxygen is resorbed by the mucosa, resulting in a partial vacuum. This negative pressure can be painful and result in the transudation of more fluid into the sinus. The excess fluid, combined with inflammation and the influx of neutrophils and lymphocytes, can ultimately create excessive positive pressure, causing discomfort for patients.

In certain cases, typically chronic sinusitis, negative pressure can persist to the extent that it causes contraction of the maxillary sinus, a condition termed "silent sinus syndrome." This process may lead to the descent of the orbital floor and enophthalmos.[12]

In rhinosinusitis, altered sinus secretions exacerbate the susceptibility to persistent infection and subsequent inflammation. Normally, the mucous blanket in the respiratory tract consists of 2 distinct layers: the periciliary liquid phase, a thin, low-viscosity layer surrounding the cilia shaft allowing free ciliary movement, and the gel phase, a more viscous layer atop the periciliary liquid. In the presence of inflammation, derangements in the mucous layer separation can impair ciliary movement by disrupting the usual low-viscosity environment.[13] 

Additionally, bacterial biofilms contribute to sinusitis pathogenesis, although they are more prevalent in chronic cases rather than in RARS.[14] Biofilms hinder antibiotic penetration because bacteria within this layer are not only attached firmly to one another as well as their substrate but they are also surrounded by a protective proteinaceous or polysaccharide matrix.[15] S aureus, notably, is adept at producing biofilms, which often require chemical and possibly mechanical disruption for definitive infection clearance.

History and Physical

Individuals experiencing acute sinusitis typically present with symptoms persisting for less than 4 weeks. Specific symptoms may include nasal or postnasal (nasopharyngeal) purulence, nasal obstruction, hyposmia, anosmia, fever, facial pain or pressure, maxillary dental pain, fatigue, halitosis, and headache, among other complaints[10]. Patients with RARS, by definition, will have encountered at least 4 of these episodes within the preceding year, often necessitating multiple treatment regimens involving nasal sprays, steroids, and antibiotics.

During a physical examination, observable signs may include purulent rhinorrhea or pharyngeal drainage, turbinate hypertrophy, mucosal edema, or erythema observed on anterior rhinoscopy. External tenderness upon palpation of the frontal, ethmoid, or maxillary sinuses might be present. Patients could display fever or tachycardia due to generalized facial pain. Although rare, acute sinusitis can lead to complications such as orbital cellulitis, preseptal cellulitis, or cavernous sinus thrombosis.[16] Cranial nerve evaluation and close orbit inspection should be performed to rule out these complications.

Patients with RARS often experience symptoms similar to those of acute sinusitis. A viral origin is presumed if the patient reports symptoms lasting fewer than 10 days during an acute sinusitis episode.[1] The diagnosis of acute bacterial rhinosinusitis should be considered if symptoms last more than 7 days or worsen within 2 days after initial improvement, also known as "double worsening" or "second sickening."[10][17] Most episodes of acute sinusitis, whether viral or bacterial in etiology, resolve within 10 to 14 days.

Evaluation

History and physical examination are crucial to diagnosing RARS. In most cases, healthcare providers can accurately diagnose RARS by evaluating the duration and progression of symptoms, along with applying the major and minor diagnostic criteria set outlined by the American Academy of Otolaryngology-Head and Neck Surgery.[18] Patients exhibiting unilateral disease without septal deviation, experiencing severe and debilitating symptoms, or those whose symptoms persist despite appropriate empirical treatment should undergo nasal endoscopy for further evaluation.[1]

Radiological imaging is not routinely recommended to evaluate patients with presumed uncomplicated RARS. However, a noncontrast computed tomography scan of the sinuses is indicated for patients with chronic rhinosinusitis, suspected anatomical abnormalities, or possible orbital complications (see Image. Axial CT of Sphenoid Sinus). Additionally, CT scans are integral to presurgical planning for procedures like balloon sinuplasty and functional endoscopic sinus surgery (FESS).[19] Research suggests that imaging is overutilized for patients with sinusitis. According to a 2012 study published by Bhattacharyya et al, 11.4% of patients with uncomplicated RARS received a CT scan within 1 year of diagnosis; the number increased to 39.9% at 4 years.[11]

In cases of persistent or chronic sinusitis, cultures obtained from sinus aspirates or endoscopy might be necessary to identify resistant bacterial or fungal pathogens. The most common pathogens involved in RARS overlap those causing acute sinusitis, including S pneumoniae, H influenzae, other Streptococcus species, M catarrhalis, and S aureus.[4]

Treatment / Management

Medical management stands as the primary approach for treating RARS. Many patients require a combination of therapies addressing different components of the complex pathophysiology underlying RARS. These treatments are outlined below.

• Topical intranasal therapy
• Nasal saline irrigation effectively removes or reduces debris and pathogens from the nares, offering potential symptomatic relief. The efficacy of hypertonic versus isotonic saline solutions is debated, with hypertonic saline causing more adverse effects like increased nasal discharge and local discomfort. Excessive irrigation may disrupt natural protective mechanisms within the nose and paranasal sinuses by disrupting the mucus layer, reducing effectiveness.[20][21]
(A1)

• Topical corticosteroid nasal sprays reduce mucosal inflammation, decreasing stenosis of sinus drainage pathways. These sprays are beneficial as preventive measures and also during acute infections.

• Topical antihistamines, such as azelastine, can help alleviate mucosal inflammation and irritation, reduce nasal passage edema, and open the sinus ostia. 

• Topical decongestant sprays such as oxymetazoline and phenylephrine can reduce congestion via local vasoconstriction. Patients should be cautioned about rebound congestion, a potential side effect of prolonged use. The use of these medications should be limited to 3 to 5 consecutive days.[22]
(B3)

• Antibiotics
• Bacterial sinusitis complicates only 0.5% to 2% of cases of viral sinusitis.[21] Therefore, antibiotic therapy should be started only if the symptoms persist for more than 7 days without improvement or if symptoms worsen after an initial improvement period. 
(A1)

• For RARS, the recommended initial antibiotic therapy is amoxicillin with or without clavulanate for 5 to 10 days. A 2021 study published by Rovelsky et al indicates that amoxicillin is as effective as amoxicillin-clavulanate in treating acute sinusitis but causes fewer adverse gastrointestinal symptoms.[23] Alternatives for penicillin-allergic patients or resistant infections include doxycycline and respiratory fluoroquinolones (levofloxacin, moxifloxacin). Other options include third-generation cephalosporins with or without clindamycin, depending on the clinical situation.[4] 
(A1)

• Intravenous antibiotics are the mainstay of treatment for patients with orbital cellulitis or moderate-to-severe preseptal cellulitis. Recommended antibiotics include vancomycin and ampicillin-sulbactam, clindamycin, third-generation cephalosporins, or piperacillin-tazobactam.[24]  

• Decongestants
• Oral decongestants provide symptomatic relief by reducing inflammation and secretions in the nasal, sinus, and respiratory tract mucosa. They may also help maintain patency of the nasal ostia, leading to a reduction of sinus pressure. 

• Oral antihistamines
• Oral antihistamines disrupt the biological histamine pathway, preventing mucosal edema and inflammation triggered by inhaled allergens in sensitized patients. They can benefit patients whose sinusitis is suspected to be precipitated or exacerbated by allergic rhinitis.[25]
(A1)

• Oral steroids
• Oral steroids are not recommended as a monotherapy for acute rhinosinusitis. Limited evidence supports the use of oral steroids as an adjunct treatment alongside antimicrobial therapy for acute sinusitis.[26]
(A1)

• Oral leukotriene modifiers
• Leukotriene modifiers, such as montelukast, are effective treatments for allergic rhinitis and nasal polyposis. They can be particularly beneficial for patients with rhinosinusitis who have asthma, allergic rhinitis, or nasal polyposis.[27]
(B3)

Surgical intervention for recurrent acute rhinosinusitis can be considered for patients who do not respond to medical management, particularly if they have documented anatomic abnormalities that correlate with their symptoms. Surgery has been shown to decrease symptoms and improve the quality of life for appropriately selected patients.[9][28][29] Surgical intervention is also often required for patients with sinusitis-related complications such as subperiosteal abscess, orbital abscess, or cavernous sinus thrombosis. Specific surgical approaches are detailed below.(A1)

Functional endoscopic sinus surgery can correct anatomic abnormalities that prevent optimal sinus drainage. Various procedures, including maxillary antrostomy, uncinate process resection, ethmoidectomy, and Draf I-III frontal sinusotomies can be performed depending on the location and severity of the individual patient’s pathology. Before surgical intervention, a noncontrast CT of the sinuses should be performed to confirm the diagnosis and localize the pathology for surgical planning.[19] Preoperative CT imaging can also aid intraoperative navigation, improving outcomes and reducing complication rates, particularly in revision cases.[30][31](B2)

Balloon sinuplasty is a tissue-sparing procedure designed to permanently dilate the sinus ostia and drainage pathways through localized microfracturing via balloon insufflation. This procedure enhances mucus drainage and reduces negative pressure within the sinus cavities. Balloon sinuplasty treats patients with RARS and chronic rhinosinusitis without nasal polyposis (CRSsNP).[28] This minimally invasive procedure may be performed in an operating room or office setting. (A1)

Septoplasty is a surgical option for patients with obstructive nasal septal deviations. The procedure reduces impingement of the sinus ostia, improves airflow, and facilitates proper mucociliary clearance.

Turbinate reduction may alleviate nasal obstruction and allow further anterior drainage of nasal and sinus contents in patients with hypertrophy of the inferior turbinates. 

Differential Diagnosis

Several disease processes share overlapping symptoms with RARS, necessitating careful consideration of differential diagnoses. Before confirming the diagnosis, other diseases and conditions that should be ruled out include:

• Allergic rhinosinusitis
• Acute rhinosinusitis
• Chronic rhinosinusitis with nasal polyposis (CRSwNP)
• Chronic rhinosinusitis without nasal polyposis (CRSsNP)
• Subacute rhinosinusitis
• Viral rhinosinusitis (upper respiratory tract infection)
• Noninvasive fungal rhinosinusitis
• Invasive fungal rhinosinusitis
• Adenoiditis
• Cerebrospinal fluid (CSF) rhinorrhea
• Vasomotor rhinitis
• Laryngopharyngeal/gastroesophageal reflux disease

Prognosis

The prognosis for recurrent acute rhinosinusitis is generally good. Most patients respond well to medical management, including topical nasal sprays and oral antibiotics. Patients rarely develop complications requiring hospitalization for immediate surgical intervention or intravenous antibiotics. Appropriately selected patients who undergo surgery typically experience symptomatic relief and appreciable improvement in quality of life.[28][29][32] 

Complications

Although rare, complications of recurrent acute rhinosinusitis include but are not limited to the following:

• Persistent hyposmia/anosmia
• Preseptal cellulitis
• Orbital cellulitis
• Subperiosteal abscess
• Orbital abscess
• Cavernous sinus thrombosis