Sinusitis

Sinusitis (from Latin “sinus”) is an inflammation of the mucous membrane lining one or more paranasal sinuses. Since the inflammatory process almost always affects the mucous membrane of the nasal cavity (rhinitis), modern medical practice uses a more accurate term — rhinosinusitis.

The disease is categorized by the duration of the course into acute (up to 4 weeks), subacute (4 to 12 weeks), and chronic (more than 12 weeks). Depending on the sinus affected, there are maxillary sinusitis, frontal sinusitis, ethmoiditis, and sphenoiditis.

Aetiology and Pathophysiology

The paranasal sinuses are air-bearing cavities in the bones of the skull that communicate with the nasal cavity through narrow openings, junctions. A key link in the development of sinusitis is the blockage of these junctions.

The pathologic process develops as follows:

1. Inflammation of the nasal mucosa (for example, in acute respiratory infections or allergies) causes it to swell.
2. The swollen mucosa blocks the narrow junction, impairing drainage and ventilation of the sinus.
3. Secretion accumulates in the closed sinus and the remaining air is sucked in, creating negative pressure.
4. Congestive secretion is an ideal medium for bacterial growth, leading to the development of secondary bacterial infection and pus accumulation.

Major causes include:

• Viral infections: most cases of acute rhinosinusitis begin as a “cold.”
• Bacterial infections: most common causative agents are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis.
• Allergic rhinitis: chronic mucosal edema.
• Anatomical abnormalities: nasal septal deviation, nasal polyps, nasal shell hypertrophy.
• Odontogenic causes: infection from the roots of the upper teeth spreading to the floor of the maxillary sinus.

Clinical Significance

The clinical representation depends on the form of the disease and the sinus involved, but has a number of common features.

Symptoms of acute rhinosinusitis:

• Difficulty in nasal breathing (nasal congestion).
• Nasal discharge: may be serous at first, then become mucopurulent or purulent.
• Pain or a feeling of pressure/irritation in the facial region: the localization of the pain corresponds to the affected sinus (cheeks for maxillary sinusitis, forehead for frontal sinusitis). The pain increases when the head is tilted forward.
• Decreased or absent sense of smell.
• Common symptoms: fever, malaise, headache.

The diagnosis of acute rhinosinusitis is made primarily on the basis of clinical findings. Treatment of viral sinusitis is symptomatic. For bacterial sinusitis, antibiotics may be prescribed.

Chronic rhinosinusitis is characterized by similar but less severe and persistent symptoms lasting more than 12 weeks. Its diagnosis and treatment requires the mandatory involvement of an ENT specialist and often includes endoscopic examination and CT scan of the sinuses.

Differential Diagnosis

The main task in the acute process is to distinguish viral rhinosinusitis from bacterial one to decide whether antibiotics should be prescribed. A bacterial infection is indicated by symptoms lasting more than 10 days, worsening after a temporary improvement (“second wave” of illness), or a severe onset of illness. Facial pain in sinusitis should be differentiated from trigeminal neuralgia and migraine, but without nasal discharge and nasal congestion. In persistent unilateral maxillary sinusitis, an odontogenic (dental) cause should always be excluded.