• Nasal blockage, rhinitis and pressure symptoms over the cheeks are often present during a viral upper respiratory tract infection (URTI). These symptoms are associated with the viral infection and no antimicrobial therapy or further investigations are usually indicated [Evidence Level: C].
• Diagnosis of acute sinusitis requires clinical examination of the nose and pharynx, in particular. Purulent secretions in the middle nasal meatus, nasopharynx or on the posterior wall of the pharynx suggests bacterial sinusitis.
• Ultrasonography of the maxillary sinus is the first-line imaging study due to its good availability and lack of adverse effects but it cannot be used to differentiate between viral and bacterial sinusitis.
• Imaging of the paranasal sinuses may be useful in the case of acute or chronic sinusitis to confirm the diagnosis.
• Antimicrobial treatment should only be considered for patients with severe symptoms suggesting bacterial infection.
• In recurring sinusitis, any predisposing factors should be identified and an ENT specialist consulted, as necessary.
• For maxillary sinusitis in children, see (Rhinosinusitis in children).

• There are maxillary, frontal, sphenoidal and ethmoidal sinuses.
• Sinusitis means inflammation of one or more of these. The most common form of sinusitis is maxillary sinusitis.
• In rhinosinusitis, symptoms and findings often occur simultaneously in the area of both the nasal cavity and sinuses.
• Acute maxillary sinusitis is defined as an inflammation that has lasted no more than 12 weeks. Maxillary sinusitis is defined as chronic if it has lasted more than 12 weeks (see also (Chronic sinusitis)).
• If acute purulent sinusitis recurs at least 3–4 times a year, it is called frequently recurring sinusitis.

• Sinusitis is usually preceded by viral URTI.
• Predisposing factors include allergic or other chronic rhinitis, nasal polyps or other tumours in the nasal cavity, structural abnormalities of the middle nasal meatus or septum, dental root infection and, rarely, a foreign body.
• Air impurities, such as tobacco smoke, may also be predisposing factors.
• Obstruction of the natural opening (ostium) to the maxillary sinus and impaired ciliary function play a major role in the development of maxillary sinusitis.

• The main symptoms are usually nasal congestion and purulent nasal discharge or postnasal drip.
• In addition, there may be:
  • facial pain, especially around the eyes and over the cheeks
  • toothache in the upper canine teeth or molars
  • prolonged cough (particularly in the mornings), rhinitis or nasal congestion
  • hyposmia.

• The symptoms of a viral common cold and a sinusitis are quite similar. Bacterial aetiology is suggested by:
  • purulent secretions in the middle nasal meatus, nasopharynx or on the posterior wall of the pharynx
  • impaired general condition or fever (> 38 °C)
  • pain radiating to teeth
  • severe local facial pain that may be worse on one side.
• Clinical examination
  • There is purulent discharge, mucosal swelling or erythema in the nose, particularly the middle nasal meatus.
  • It is easier to examine the nose after applying a decongestant (e.g. wiping the nasal mucosa with a cotton-tipped swab soaked in adrenaline solution or with xylometazoline sprays).
  • There may be purulent postnasal drip.
• Ultrasonography is a relatively reliable diagnostic method in adults and teenagers but requires training and practice [Evidence Level: A].
  • If ultrasonography of the maxillary sinus repeatedly shows a back-wall -echo at a distance of 4–6 cm, the diagnostic accuracy for acute stasis of secretions may be as good as 80–95%.
  • The state of the mucous membranes (e.g. mucosal oedema) cannot be reliably evaluated with ultrasonography.
  • Ultrasonography cannot be used to differentiate between viral and bacterial sinusitis.
• X-ray examination (occipitomental view of the paranasal sinuses) is not necessary for diagnosing acute sinusitis but it may be useful in confirming the diagnosis of recurrent acute or chronic sinusitis.
• Laboratory investigations are usually not needed for the diagnosis of acute sinusitis. However, in patients with severe symptoms, laboratory investigations (basic blood count with platelet count, CRP) may be necessary to confirm bacterial infection (also other than sinusitis).

Symptomatic treatment and glucocorticoid sprays

• The aim of the treatment is to alleviate the symptoms and to reduce tissue oedema.
• Symptomatic treatment is sufficient for patients whose symptoms and findings are consistent with common cold.
• Decongestants, antihistamines and analgesics, as well as combinations of these, alleviate the symptoms of upper respiratory tract infections but also have adverse effects in many patients.
• Saline irrigation may alleviate the symptoms in patients with flu as well as in those with chronic sinusitis [Evidence Level: D].
• Antihistamines alleviate mucosal symptoms in patients with allergic rhinitis.
• Combinations of antihistamines and sympathomimetics may be useful in short-term (for a maximum of 10 days) use.
• Glucocorticoid sprays can be used as adjunct therapy for acute maxillary sinusitis [Evidence Level: A] or to prevent frequently recurring acute maxillary sinusitis.

Antimicrobial treatment

• Antimicrobial treatment should be considered in patients with symptoms suggestive of bacterial sinusitis (see Diagnosis).
• If the decision is made to start antimicrobial treatment, amoxicillin, amoxicillin-clavulanic acid and doxycycline are suitable. For recommended antimicrobial therapy, see table T1.
• The recommended length of a course of antimicrobial therapy is 7 days.
• For patients allergic to penicillin or doxycycline, sulphadiazine/trimethoprim or macrolides may be considered.
• If the primary drug has not been effective, it is recommended to take a bacterial culture from the middle meatus or to consider a maxillary sinus puncture for a culture sample from the secretion, and to target the antimicrobial according to sensitivity assays.

Maxillary sinus irrigation

• There is little research-based evidence on the efficacy of maxillary sinus puncture but in patients with severe symptoms, it may have the following benefits:
  • removal of purulent discharge
  • alleviation of pressure pain
  • provision of a sample of discharge for bacterial culture
  • a negative finding will exclude purulent maxillary sinusitis.
• Local anaesthesia is provided with a cotton-tipped swab that has been soaked in a solution of 4% lidocaine, to which 2–3 drops of adrenaline (1:1,000) have been added for each 5 ml. The swab is placed below the inferior nasal concha at the point of puncture where there is bone contact. The anaesthesia will take about 20 minutes to become effective.
• Local anaesthesia may also be provided with EMLA^® cream [Evidence Level: B].
• The site of puncture is laterally at the inferior nasal meatus 2–3 cm from the nasal orifice.
• Physiological saline at 37 °C is injected into the maxillary sinus, after which it flows out through the natural opening (ostium) into the nasal meatus.
• Increased resistance felt during the injection may be due to viscous mucus or an obstructed ostium. However, pressure must not be forcibly increased as this will cause pain and may result in complications.
  • Resistance may be lowered by anaesthetising the middle nasal meatus, which will reduce the mucosal oedema around the ostium.
  • It is also possible to insert another puncture needle into the sinus, through which the irrigation fluid may be evacuated in cases where the ostium does not become patent even after the local anaesthesia.
• No air must be present in the irrigation syringe as any air injected with pressure into the sinus could predispose the patient to an air embolus.
• Complications
  • Bleeding usually stops spontaneously. Should bleeding persist the inferior nasal meatus can be re-anaesthetised and a piece of absorbable packing placed in the inferior meatus.
  • If the patient’s cheek swells up during the procedure, the tip of the irrigation needle is outside the maxillary sinus. Should this happen, the irrigation must be stopped and the patient prescribed a course of antibiotics.
  • Any irrigation fluid in the tissue will be absorbed within a few days.
  • If the patient’s eye or eyelids swell during the procedure, the needle has entered the orbit. As above, the irrigation must be stopped immediately and the patient sent to an ENT emergency department.

• If the symptoms of sinusitis resolve completely, no follow-up is indicated.
• If symptoms persist despite treatment:
  • Topical nasal treatment (nasal glucocorticoid, moistening of the nasal mucosa) should be intensified, as necessary.
  • Maxillary sinus puncture should be considered to obtain material for bacterial culture, to confirm the diagnosis and to remove retained secretions.
  • If indicated, antimicrobial therapy in accordance with sensitivity testing should be prescribed.
  • Any predisposing factors should be identified (see above).
    • Allergic or other chronic rhinitis (history, allergy tests)
    • Mucosal oedema, polyps, septal deviation (anterior rhinoscopy)
    • Dental health (odontogenic maxillary sinusitis)

• Symptomatic maxillary sinusitis persisting after 12 weeks despite appropriate treatment
• At least 3–4 recurring episodes of maxillary sinusitis a year
• Suspicion of a complication of maxillary sinusitis, in which case the patient should be referred to emergency services.

• In specialized care, surgical treatment may be considered for the management of chronic or frequently recurring maxillary sinusitis (Chronic sinusitis).
• The most common type of surgery is endoscopic paranasal surgery carried out through the nostrils (FESS, functional endoscopic sinus surgery), see(Chronic sinusitis).

• See (Chronic sinusitis).