Sinusitis: Causes, Bacteria & Clinical Features

Sinusitis

• Sinusitis involves inflammation of the sinus mucoperiosteum
• Usually related to blockage of the ostium due to thickened mucosa, which prevents drainage into the middle meatus
• Decreased ciliary action of respiratory epithelial cells and mucous secretions are vital

Causes of Sinusitis

• Acute sinusitis is commonly preceded by rhinovirus infections (common cold)
• Bacteria from the upper respiratory tract (URT) can induce sinusitis

Bacteria Causing Sinusitis

• S. pneumoniae is the most common bacterial cause
• H. influenzae causes sinusitis
• Moraxella catarrhalis causes sinusitis

Acute Sinusitis: Clinical Features

• Includes pain and stuffiness
• Sinus walls are tender to pressure
• Pain may be referred to maxillary molars or premolars and may worsen with percussion and may indicate dental disease
• Adults may experience thick nasal discharge containing blood and pus
• Fever, chills, malaise, and elevated WBC count may occur

Acute Sinusitis: Radiographic Features

• Air-fluid level shows a horizontal, faintly radiopaque line in the sinus
• The line represents the junction of air above and fluid consisting of mucus, blood, or pus along the sinus's inferior aspect
• The bony wall of the sinus usually shows no alteration

Chronic Sinusitis

• Encompasses recurring acute sinusitis incidents, or symptomatic sinus disease for >3 months
• Often a sequella of acute sinusitis, but may arise without an acute phase
• Bacteria are usually anaerobes, like Streptococci, Bacteroides, or Veillonella species

Chronic Sinusitis: Radiographic Features

• The mucosa shows localized thickening along a sinus wall portion
• Or the mucosa shows generalized thickening along walls
• The sinus shows diffuse radiopacity throughout
• Sinus walls usually remain intact

Odontogenic Sinusitis

• Mucositis resulting from periapical inflammation or periodontitis
• Characterized by thickening and mucoperiosteal inflammation in the sinus
• Some patients may experience only vague sinus stuffiness or may be asymptomatic
• Pus can form in the lesion
• Accounts for 25% to 40% of all chronic sinusitis cases

Odontogenic Sinusitis: Radiographic Features

• Location-wise, odontogenic sinusitis appears on the floor or inferior aspects of the sinus wall, centered over areas of periapical or periodontal inflammation
• Periapical mucositis presents as thickening and increased radiodensity of mucosa along walls
• Periapical osteoperiostitis can occur around the tooth apex presenting as a "halo" of bone due to periosteal proliferation

Periapical Mucositis

• Indicated by localized mucosal tissue edema
• Symptomatic or asymptomatic apical periodontitis in direct contact with the antral mucosa produces edema

Signs of Periapical Mucositis

• Mucosal thickening or dome-shaped soft tissue expansion in the floor of the sinus directly adjacent to the infected root apex

Periapical Osteoperiostitis

• Apical periodontitis near maxillary sinus can expand the sinus periosteum, displacing it upward
• Periodontitis induces periosteal reaction, depositing a thin layer of new bone on the periosteum's inner periphery as it expands

Features of Periapical Osteoperiostitis

• Also known as PAO
• It forms a thin, hard-tissue dome on the sinus floor and appears as a radiopaque "halo" in radiographs and CT images

Diagnosing and Treating Odontogenic Sinusitis

• Differentiate from chronic sinusitis by identifying a dental or periodontal source
• Treatment involves addressing dental or periodontal disease to resolve the sinus lesion successfully
• ENT treatment may be necessary for painful lesions not improved by dental care

Fungal Sinusitis

• Caused by infection via invasive fungi
• Typically found in debilitated patients

Conditions Predisposing Fungal Sinusitis

• Found in patients with diabetes mellitus
• Immunosuppression (HIV/AIDS) contributes to fungal sinusitis
• Leukemia causes fungal sinusitis
• Chronic corticosteroid therapy may cause it

Mucormycosis (Phycomycosis)

• A form of fungal sinusitis
• Presents as a rhinocerebral form in the nose and sinuses
• Causes bloody discharge from the nose
• Patients report sinus pain
• Proptosis (eye bulging) and palate expansion
• Extensive necrosis is expected

Mucormycosis Radiographic & Diagnostic Features

• Radiographically, you can see sinus opacification with wall destruction
• Similar to malignant tumors or granulomatous inflammation
• Necrotic tissue interspersed with large non-septate hyphae (6-30 microns) is present upon histology

Aspergillosis

• A form of fungal sinusitis
• Noninvasive forms can affect healthy people
• Invasive forms typically affect people with poor immune function such as those with diabetes or HIV)
• Patients may experience symptoms resembling asthma
• Patients may find it more painful, especially after tooth extraction or RCT
• More severe forms present with pain, swelling, tenderness to pressure, and nasal discharge

Radiographic & Diagnostic Features of Aspergillosis

• Radiographic signs shows thickened mucoperiosteum with focal soft tissue masses (aspergillomas)
• Masses of fungi appear as antroliths due to the presence of calcifications
• The differential diagnosis includes malignant lesions and granulomatous inflammations
• Septate hyphae (3-4 microns) can be detected upon histologic examination
• Often detected near or in blood vessels

Treatment

• Acute sinusitis is treated with antibiotics and by removing the cause of infection if possible
• Chronic sinusitis is treated surgically to open the ostium if symptomatic; if not, no treatment is needed

Treatment of Fungal Sinusitis Types

• Involves surgical debridement
• Can use corticosteroids
• Use antibiotics

Antral Pseudocyst & Mucous Retention Cyst

• Serous inflammatory exudate accumulates under the periosteum, causing sessile elevation of the lining
• Antral pseudocysts that lack an epithelial lining, or Mucous Retention Cysts that contain one

Causes of Antral Pseudocyst & Mucous Retention Cyst

• Antral pseudocyst is caused by inflammatory exudate
• Mucous retention cyst is caused by the blockage of seromucinous glands

Number of Antral Pseudocyst & Mucous Retention Cysts

• Antral pseudocysts are usually solitary
• Mucous retention cysts can be multiple

Antral Pseudocyst & Mucous Retention Cyst; Clinical Features

• Usually asymptomatic, though some patients may experience vague stuffiness
• Large lesions can prolapse through the ostium into the nose, and cause nasal discharge

Antral Pseudocyst & Mucous Retention Cyst; Radiographic Features

• Solitary (AP) or multiple (MRC) on the inferior aspect of the sinus wall
• Faintly radiopaque, homogeneous dome-shaped mass
• Usually sessile and less than 2cm in diameter
• Difficult to distinguish AP from MRC
• Sinus wall is typically not disrupted

Differences in Treatment of Antral Pseudocyst or Mucous Retention Cyst

• Antral pseudocysts typically don't need treatment and lesions may resolve spontaneously
• Mucous retention cysts may need surgical removal if symptomatic

Antral Polyp Presentation

• Thickened mass of chronically inflamed mucous membrane
• Irregular folds or nodular masses arising out of a generalized thickened mucosa
• Can be solitary or multiple

Clinical and Radiographic Features of Antral Polyps

• May cause displacement or destruction of sinus walls
• Radiographically, polyps occur in chronically inflamed sinus lining
• They differ from antral pseudocysts in that the adjacent mucosa is usually normal

Management of Antral Polyps

• If polyps occur with bone destruction, refer to to a physician
• Sinus wall destruction can indicate serious inflammatory or neoplastic disease

Antrolith Formation

• Centers on a calcified nidus inside the sinus
• The nidus can be intrinsic, like stagnant mucus or a fungus ball, or extrinsic, like a foreign object
• Small antroliths display asymtomatic presentation

Symptoms of Larger Lesions

• Larger antrolith lesions produce the signs and symptoms of sinusitis (discharge, pain)

Antrolith; Radiographic Features

• Solitary or multiple in the mucoperiosteum
• Appearance varies from faintly to extremely radiopaque
• Can be homogeneous or varied in density, well-defined and either round or oval
• Size can vary from a few millimeters to centimeters
• Usually doesn't affect sinus walls

Antrolith; Diagnosis & Treatment

• Differentiated from root fragments by the presence of a pulp space
• Small and asymptomatic antroliths require no treatment
• ENT removal for larger or symptomatic lesions

Mucocele Formation

• Occurs due to the blockage of the ostium, either by inflammatory or neoplastic reasons
• Mucous secretions then fill the sinus
• Results in the thinning and expansion of sinus walls and the possibility of perforation

Mucocele; Clinical Features

• Swelling and sensation of fullness where the sinus wall is compromised
• Expansion through walls can cause issues

Issues of Mucocele Expansion

• Inferior expansion will loosen posterior teeth
• Superior expansion can cause diplopia and/or proptosis
• Medial expansion can cause nasal cavity obstruction
• Lateral expansion will result in fullness in the mucobuccal fold

Mucocele; Radiographic Features

• Mucoceles commonly occur in the ethmoid and frontal sinuses, but are less common in the maxillary sinus
• Show well-defined, round or irregular and faintly radiopaque masses made of soft tissue
• Sinus walls gets resorbed and expanded, and may be perforated

Mucocele's Differential Diagnosis

• Odontogenic cyst, which originates in the alveolar process and does not involve ostium blockage
• Antral carcinoma, which can look really similar

Mucocele Treatment

• Surgical removal through the Caldwell-Luc procedure
• Prognosis with the procedure is generally excellent

Antral Carcinoma Details

• A malignancy of the sinus mucosa
• Cause remain unknown, but are not related to tobacco use, sinonasal inflammation, or polyps
• Risk factors include wood dust, nickel, and chromium

Antral Carcinoma Progression

• Lesions can grow inside the sinus without any symptoms
• Often are detected very late in the disease stage
• A "silent killer" malignancy

Clinical Features of Antral Carcinoma

• Almost always occurs in adults, average patient age is 60
• Larger number of cases occur in males
• Patients experience unilateral nasal stuffiness or unilateral nasal obstruction
• Patients experience palatal enlargement
• Patients experience tooth displacement or eye alteration, depending on which wall of the sinus is affected
• Can simulate toothache pain; but occurs late in the disease progression

Antral Carcinoma Radiographic Signs

• Solitary lesion arising in the mucoperiosteum along walls is expected
• Expect irregular soft tissue radiopacity in sinus

Antral Carcinoma Effects/Findings

• Expect destruction of the involved sinus wall
• Expect poorly defined radiolucency in the involved alveolar process and palate
• Loose teeth that appear to be "floating in space" if the lesion has become extensive
• Eye rotation caused by diplopia
• Disruption of fascial planes on CT scans with sinus wall destruction

Antral Carcinoma Diagnoses

• To rule out differential diagnoses, run tests to make sure it's not one of the other similar presentations

Differential Diagnoses to Rule Out

• Antral mucocele, but antral mucoceles also cause destruction of sinus walls
• Odontogenic cyst and tumors, which can extend into the sinus, destroying the wall, but originates the alveolar process
• Salivary gland malignancies, but these can perforate the palate and invade the sinus

Signs of Squamous Cell Carcinoma

• Consists of 90% cancer
• Some lessions become adenocarcinoma

Poor Prognosis

• 10-30% of patients survive 5 years after diagnosis and maxillectomy
• If metastases in lymph nodes or pterygopalatine fossa are detected fewer than 10% will survive 5 years

Sinusitis involves inflammation, often due to ostium blockage from thickened mucosa. Acute sinusitis is commonly preceded by rhinovirus infections. Key bacterial causes include S. pneumoniae, H. influenzae, and Moraxella catarrhalis.