Acute Rhinosinusitis (sinusitis) – An overview for GP’s and patients
Acute rhinosinusitis remains a common cause for GP and otolaryngology specialist consultations. Adults experience on average one to three episodes of viral acute rhinosinusitis per year but children may experience many more depending on their exposure to viral pathogens. The condition is similar in children and adults but the adenoid pad can play a large role in the pathophysiology of children’s infections. There are a plethora of medical treatments available but evidence suggests not all are helpful.
- Rhinosinusitis lasting more than 10 days or in which symptoms worsen after a few days, a unilateral predominance or severe pain all suggest a bacterial rather than viral infection
- In children, inflammation of the adenoid pad can mimic or cause rhinosinusitis and is an important consideration
- Important differential diagnoses include allergic rhinitis, dental disease and headache syndromes
- Complications can be orbital, intracranial or osseous. If identified, they require a hospital admission and specialist consultation. Allow children to be assessed by an otolaryngologist before CT scans are ordered. They are not always needed.
- Antibiotics are not always needed.
- Topical corticosteroids are helpful. Oral corticosteroids are generally not recommended.
- Patients experiencing more than four episodes of acute rhinosinusitis per year may benefit from a specialist review as there may be treatments to reduce the frequency of these infections.
Acute rhinosinusitis (ARS) is defined as sinonasal inflammation lasting less than four weeks. In adults the symptoms must include nasal obstruction or nasal discharge (anterior/posterior) and facial pain or reduction/loss of smell. Acute rhinosinusitis in children is defined as the sudden onset of two or more of nasal obstruction, discoloured nasal drainage or a cough.
Rhinosinusitis that persists beyond 12 weeks is termed chronic rhinosinusitis. Chronic rhinosinusitis is really an umbrella term describing several persistent inflammatory disease states in the sinonasal cavities. It remains a condition we are really only starting to understand. It can be broadly divided into two syndromes: Chronic rhino sinusitis with polyps and Chronic rhinosinusitis without polyps.
Sinusitis or Rhinosinusitis?
The term “sinusitis” was replaced with the term “rhinosinusitis” in 1996 by the American Academy of Otolaryngology Head and Neck Surgery. They hoped to emphasise the close relationship between the mucosal lining of the nasal cavity and the paranasal sinuses. Typically the two conditions exist simultaneously in the same patient. The term has been widely accepted in the literature and community since that time.
Recurrent acute rhinosinusitis
Recurrent acute rhinosinusitis is a clinical syndrome defined by four or more episodes of rhinosinusitis per year with distinct symptom-free episodes in between. Patients suffering from this many infections per year fall outside the population average and may possess contributing factors that can be treated. The factors may include frequent exposure to viral infections, allergic rhinitis, environmental factors and immunodeficiency. They may also include anatomical factors such as a deviated nasal septum, concha bullosae, accessory drainage pathways or additional or misplaced paranasal sinus air cells.
Patients with recurrent acute rhinosinusitis may benefit from an otolaryngology specialist review and consideration of endoscopic sinus surgery. Properly selected patients may benefit symptomatically year round and achieve a reduction in the number of infections per year and antibiotic usage.
Pathophysiology of acute rhinosinusitis
The body’s defense of the sinonasal tract is multifaceted, complex and interrelated. Important factors include sneezing to remove large particles, mucus to trap smaller particles, ciliary transport to propel mucus and the innate and adaptive immune systems. Mucosal swelling from the body’s own response can obstruct sinuses. Nose blowing can seed pathogens into the sinuses. Smoking, air pollution and allergic rhinitis all cause mucosal swelling and other changes at the cellular level which have been shown to be linked to acute rhinosinusitis episodes.
Anatomical abnormalities may also predispose to rhinosinusitis. These include recirculation phenomena (from additional sinus openings), conchae bullosae (air filled middle turbinates), Haller cells (additional ethmoid air cells underneath the orbits) and nasal septal deviations. Periapical infections of the maxillary molar teeth can also infect the overlying sinus cavities.
Acute rhinosinusitis typically begins with a viral infection that causes epithelial damage and cytokine upregulation as well as activating the parasympathetic nervous system. Activated inflammatory pathways in the nasal mucosa cause oedema, fluid extravasation, mucus production and obstruction of the sinus ostia. Mucociliary transport is disrupted through either paralysis of the cilia or from obstruction of sinus ostia. Impaired ventilation and drainage of the sinuses creates a favourable environment for bacterial secondary infection.
The most frequently isolated organisms from maxillary sinus cultures are S. pneumonia (30%), H. influenza (20%) and M. Catarrhalis (20%). The routine use of the pneumococcal conjugate vaccine is reducing the frequency of S. pneumoniae infections.
Contributing factors in children
There are a range of factors that can predispose children to acute rhinosinusitis episodes. These include any type of rhinitis (allergic or non-allergic), certain medical conditions (cystic fibrosis, immune deficiency, ciliary dyskinesia) and environmental factors (parental smoking, daycare attendance). Daycare attendance is probably the most common association where children are frequently exposed to a large number of viral pathogens.
Adenoiditis in younger patients (up to 5 years) may also contribute significantly. This can have a very similar presentation to acute rhinosinusitis with anterior and posterior nasal drainage. Often it co-exists with acute rhinosinusitis and serve as a source of pathogens for recurrent infections. The diagnosis can usually only be made by direct visualisation of the adenoids by nasendoscopy.
Making the diagnosis
Take a history which covers the four key symptoms of nasal blockage, anterior/posterior discharge, facial pain/pressure and loss of smell. Additional symptoms may include cough, sore throat, hoarseness, malaise and fever. Anterior rhinoscopy may reveal mucosal oedema and discharge. Other parts of the upper aerodigestive tract may show signs of the infective process (middle ear, tonsils, cervical lymph nodes).
It is important to keep in mind the complications of rhinosinusitis and organise urgent specialist referral if these are suspected. Patients who are immunocompromised (including patients with diabetes mellitus) are at risk of fungal sinus infections. These can occasionally progress very rapidly with severe tissue damage and death.
Is it a viral or bacterial infection?
This can be challenging to differentiate as the symptoms of both viral and bacterial causes are often similar. Most cases of rhinosinusitis begin with a viral upper respiratory tract infection but can eventually involve bacterial or fungal pathogens.
Duration of symptoms is a key factor. A viral rhinosinusitis episode is generally present for fewer than 10 days. Bacteria are generally thought to be the chief pathogen when symptoms persist beyond 10 days or if symptoms worsen after 5 days. Bacterial infections are more likely to have discoloured discharge, a unilateral predominance and moderate to severe localised pain. They are also more likely to have a raised ESR and CRP.
Nasopharyngeal cultures are not helpful in differentiating viral from bacterial rhinosinusitis but can assist with antibiotic choice when these are necessary.
Differential diagnosis: allergic rhinitis
A very important differential diagnosis in both adults and children with these symptoms is allergic rhinitis. Allergic rhinitis can cause many of the symptoms of acute rhinosinusitis and the clinical picture can be confusing. There is often a prior history of atopy or allergy or an exacerbation of symptoms with exposure to certain allergens, a particular time of year or in a certain environment. Inquiry should be made during the history for the symptoms of sneezing, watery rhinorrhoea, nasal and ocular itchiness and watery eyes. These symptoms would suggest allergic rhinitis may be part of the patient’s syndrome. The acute rhinosinusitis symptoms of mucopurulent discharge, pain and anosmia are uncommon in allergic rhinitis.
Differential diagnosis: dental disease
Dental disease can present with sinus pain sometimes in the absence of a toothache. The other diagnostic criteria (nasal obstruction, discharge, change in smell) are typically not met.
Differential diagnosis: headaches and facial pain syndromes
A number of headache syndromes can mimic rhinosinusitis. These include tension-type headache, atypical facial pain, migraine, paroxysmal hemicrania, cluster headache and midfacial segment pain. Ocular pain syndromes such as glaucoma can also mimic acute rhinosinusitis. Temporomandibular joint disorders can also cause facial pain. With the exception of cluster headaches other nasal symptoms are typically absent in all of these conditions.
It can become confusing when patients with headache syndromes have sinus disease illustrated on their CT scan. It is worth remembering that if you took 100 normal individuals with no sinus disease around 35% would have some sinus inflammation demonstrable on a CT scan of their sinuses.
Complications from acute rhinosinusitis are uncommon but can be serious. They can be divided into orbital (70%), intracranial (20%) and osseous (10%). Orbital complications tend to occur primarily in young children but intracranial and osseous complications can occur at any age.
Chandler’s classification of orbital complications of acute rhinosinusitis divides them into preseptal cellulitis, orbital cellulitis, subperiosteal abscess, orbital abscess and cavernous sinus thrombosis. Preseptal cellulitis is essentially eyelid cellulitis as tissues in front of the orbital septum are outside the orbit. Signs of orbital cellulitis include chemosis (conjunctival oedema), proptosis, eye pain and tenderness and diplopia. If a subperiosteal abscess develops visual acuity may become impaired. Management is with intravenous antibiotics and surgical drainage of any abscess.
Children with preseptal cellulitis do not routinely require a CT scan. This is frequently over-ordered and exposes them unnecessarily to radiation. Most cases of preseptal cellulitis respond quickly to intravenous antibiotics. It is best to allow children with suspected preseptal or orbital cellulitis to be seen by an otolaryngolist before any scans are ordered. If a scan is needed (because an orbital complication is suspected), it is important to request a CT scan of the sinuses and orbits, not just the orbits, otherwise occasionally this then needs to be repeated.
Intracranial complications include an epidural, subdural or brain abscess, meningitis, cerebritis or sagittal or cavernous sinus thrombosis. Look for severe lethargy, headaches, photophobia, cranial neuropathies, seizures or focal neurologic deficits.
Osseous complications include osteomyelitis of the frontal and maxillary bones. Look for localised tenderness, erythema or fluctuance of the overlying skin.
Complications require a specialist consultation, IV antibiotics and usually (apart from preseptal cellulitis) a CT scan of the paranasal sinuses to confirm the diagnosis. Surgical treatment may sometimes be needed in addition to IV antibiotics.
Antibiotics – should they be prescribed?
Once the clinical suspicion that bacterial acute rhinosinusitis rather than viral exists the decision as to whether to prescribe antibiotics is still controversial. Traditionally antibiotics have been given but this has recently been questioned due to the high spontaneous recovery rate without them. Four recent systemic review of RCT’s compared the use of antibiotics versus placebo for bacterial acute rhinosinusitis. The reviews found there was a benefit from antibiotics but it was small. The rate of cure from 7 to 15 days improved from 86% with placebo to 91% with antibiotics. The number needed to treat to show an improvement in one patient was between 11 to 15. Adverse events were higher in the antibiotic groups.
The decision as to whether to prescribe antibiotics for acute rhinosinusitis needs to take into account the patient’s expectations. Educating patients on the small benefit of antibiotics relative to the risk of adverse events takes time but is worth it if we are to practice evidence based medicine. One option is to give patients a prescription for antibiotics but to advise them not to fill the prescription unless there has been no improvement at 7 days or if their symptoms significantly worsen at any stage.
Antibiotics – which antibiotic?
Multiple systematic reviews have compared antimicrobial agents for acute rhinosinusitis. The consensus is that amoxicillin with or without clavulanate is the first line antibiotic of choice. Second-line antibiotics or for those who are allergic to amoxicillin may include cefuroxime, trimethoprim-sulfamethoxzole, doxycycline or a fluoroquinolone. Duration of therapy is recommended as 5 to 10 days.
Resistance of common bacteria in acute rhinosinusitis to penicillin is rising. Different practice guidelines advise the use of clavulanate whereas others suggest using amoxicillin alone. The Australian Therapeutic Guidelines publication recommends initial treatment with amoxicillin alone and to withhold the addition of clavulanate to those who have an inadequate response to therapy in 48 to 72 hours. A Cochrane review showed that dropout rates due to adverse events were higher in patients treated with amoxicillin-clavulanate versus amoxicillin alone. If resistant organisms are suspected, consider first line amoxicillin-clavulanate.
Intranasal corticosteroid sprays act through anti-inflammatory and possibly some decongestant actions. They offer a modest improvement in symptoms and rate of resolution of acute rhinosinusitis symptoms. They have infrequent adverse events and limited systemic uptake. The use of a product such as a mometasone 200mcg daily is recommended. They could be trialed as monotherapy or as an adjuvant to antibiotic therapy.
Systemic corticosteroids in cases of uncomplicated acute rhinosinusitis are not recommended. When headache or facial pain are the predominant symptoms they may offer some palliation.
Decongestants, antihistamine, mucolytics and ipratropium bromide are generally not recommended as no clinical studies have been able to demonstrate any improvement over placebo. Nasal saline irrigation in acute rhinosinusitis has been shown in a number of systematic reviews to offer a possible improvement in symptoms and is unlikely to lead to significant harm.
Surgery plays a role in the management of complications of acute rhinosinusitis and if chronic rhinosinusitis develops. It generally has no role in uncomplicated acute rhinosinusitis.
Acute rhinosinusitis is generally very well managed by general practitioners. Occasionally differential diagnoses like allergic rhinitis or facial pain syndromes are missed. A careful history and examination will generally be all that is necessary to make the diagnosis and select the appropriate management plan. Convincing patients antibiotics are not always needed remains a challenge. Consider a specialist referral for patients in whom you suspect a complication has occurred, who have symptoms persisting beyond four weeks or who develop more than four infections in twelve month period.
Orlandi RR, Kingdom TT, Hwang PH. International Consensus Statement on Allergy and Rhinology: Rhinosinusitis Executive Summary. Int Forum Allergy Rhinol. 2016;6:S3–S21.