Acute sinusitis

Acute sinusitis is an acute inflammation of the paranasal sinus mucosa that lasts less than four weeks and can occur in any of the paranasal sinuses. If the nasal cavity mucosa is also involved then the term rhinosinusitis may be used.

Fever, headache, postnasal discharge of thick sputum, nasal congestion and an abnormal sense of smell.

Usually following a viral upper respiratory tract infection. Dental caries, periapical abscess and oroantral fistulation lead to a spread of infection to the maxillary sinus. Cystic fibrosis and allergy are risk factors.

Other anatomical variants that may predispose to the inflammation include nasal septal deviation, a spur of the nasal septum and/or frontoethmoidal recess variants.

An air-fluid level is the most typical imaging finding. However, it is only present in 25-50% of patients with acute sinusitis 4.

Opacification of the sinuses and air-fluid level best seen in the maxillary sinus. It does not allow assessment of the extent of inflammation and its complications.

Better anatomical delineation and assessment of inflammation extension, causes and complications. Peripheral mucosal thickening, air-fluid level, gas bubbles within the fluid and obstruction of the ostiomeatal complexes are recognised findings.

Rhinitis, often associated with sinusitis, is often characterised by thickening of the turbinates with obliteration of the surrounding air channels. This should not be confused with the normal nasal cycle.

Signal characteristics of the affected regions include

  • T1: mucosal thickening is isointense to soft tissue and fluid is hypointense
  • T2: both mucosal thickening and fluid are, to a variable degree, hyperintense
  • T1 C+ (Gd): inflamed mucosa enhances whilst fluid does not

Conservative medical treatment until the inflammation subsides and treatment of the cause, e.g. dental caries. If it becomes chronic sinusitis, functional endoscopic sinus surgery may be considered.

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Article information

rID: 4896
System: Head & Neck
Tag: refs
Synonyms or Alternate Spellings:
  • Sinusitis - acute
  • Acute rhinosinusitis

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Cases and figures

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    Case 1: maxillary sinusitis
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    Case 2: acute maxillary sinusitis
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    Case 3: with Pott's puffy tumour
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    Case 4: acute maxillary sinusitis - MRI
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    Case 5: with subperiosteal orbital abscess
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    Coronal
    Case 6: with subperiosteal orbital abscess
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    Case 7: acute maxillary sinusitis
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    Case 8: with periapical abscess
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    Case 9
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    Case 10: odontogenic sinusitis
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