Sinusitis is caused by the obstruction of the paranasal sinuses. Swelling of the mucosa obstructs the ostium of the ostiomeatal complex, which is continuous with the nasal mucosa and the mucosa of the sinuses. This impedes the drainage and ventilation of the sinuses, causing pressure and pain and creates a breeding ground for micro-organisms. Generally, sinusitis starts with a viral infection of the nasal mucosa. Rhinosinusitis refers to inflammation in the nasal cavity and paranasal sinuses. Bacterial superinfection in the sinuses is possible and more common in patients consulting the GP for their symptoms.
Usually, several sinuses are inflamed at the same time, with the maxillary sinus almost always being affected. Isolated inflammations of sinus frontalis, ethmoidalis and sphenoidalis are rare. Facilitating factors are anatomic variations (e.g. palatoschisis, previous surgery of the nose or sinuses), allergies and smoking.
Symptoms can be (unilateral) facial pain or pressure, pain or pressure in the sinuses (which increases when bending over), tooth or molar pain, affected smell and headache. The diagnosis can be made based on history taking and the presence of at least one of these symptoms, in addition to nasal congestion or purulent rhinorrhoea. Temperature might be subfebrile. It is not necessary for diagnosis to obtain pus from a sinus, or to prove sinusitis radiologically. Acute rhinosinusitis lasts less than four weeks.
Chronic rhinosinusitis is an inflammation of the paranasal sinuses and the linings of the nasal passages that lasts 12 weeks or longer. This may present abruptly, starting as acute sinusitis or nonspecific upper respiratory infection that fails to resolve, or it may develop slowly, over months or years. In adults, it is often accompanied by nasal drainage, nasal congestion, facial pain or pressure, and a reduction or loss of the sense of smell. Children with chronic rhinosinusitis may cough instead of having a diminished sense of smell. Three subtypes of chronic rhinosinusitis can be distinguished: a subtype with nasal polyposis, a subtype without nasal polyposis and allergic fungal rhinosinusitis.
The treatment of acute rhinosinusitis is focused on symptom relief. Analgesics play an important role, since pain seems to be the major nuisance and often negatively impacts daily functioning. Decongestants can provide relief for the nasal obstruction complaints. Antibiotics are commonly prescribed but often unnecessary, since they only have a small effect on recovery, while side effects and resistance may occur. In the context of the Dutch healthcare system, where continuous GP care is readily accessible and patients can return to the same GP (practice) in case of persistent or worsening symptoms, GPs can apply ‘watchful waiting’ and prescribe antibiotics at a later time if necessary. The Dutch Royal College of General Practitioners advises to prescribe antibiotics in exceptional cases only. Their guideline focuses on acute rhinosinusitis and provides no specific treatment advice for the chronic variant. International treatment recommendations for chronic rhinosinusitis include the use of intranasal corticosteroids and other options that can be performed after referral, e.g. endoscopic surgery.