Citelli Abscess

Citelli Abscess
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Radiopaedia	https://radiopaedia.org/articles/citelli-abscess

1. Citelli Abscess

Overview

Citelli abscess (also known as Citelli's abscess or retrofacial abscess) is an extracranial complication of acute or chronic suppurative otitis media, characterized by abscess formation in the posterior mastoid region between the sigmoid sinus and the posterior semicircular canal. The abscess occurs within the bony confines of the mastoid, specifically in the area of the retrofacial air cells and Trautmann's triangle.

This condition was first described by Italian otologist Salvatore Citelli in 1931. It represents a relatively rare but important complication of otitis media that requires prompt surgical management to prevent progression to sigmoid sinus thrombosis or posterior fossa intracranial complications.

The condition is most commonly encountered in the pediatric population and in patients with chronic suppurative otitis media with cholesteatoma. Early recognition and surgical drainage are essential for optimal outcomes.

History

Salvatore Citelli (1875-1947), an eminent Italian otologist from Catania, Sicily, first characterized this entity in 1931. Citelli made numerous contributions to otology, including descriptions of the Citelli angle (sinodural angle), the Citelli-Meltzer punch forceps, and the Citelli abscess.

Prior to the antibiotic era, otogenic complications including Citelli abscess were common and frequently fatal. The advent of antibiotics dramatically reduced the incidence of this and other mastoid complications. However, the condition remains clinically relevant, particularly in developing countries and in patients with cholesteatoma or inadequately treated otitis media.

Epidemiology

Acute mastoiditis represents the most common complication of acute otitis media, affecting approximately 1 in 400 cases, with incidence varying in pediatric ages from 1.2 to 6.1 per 100,000 children aged 0-14 years per year. Approximately 75% of cases occur in children under the age of 2 years, with peak incidence at age 6-13 months.

The incidence of mastoiditis complications has consistently increased in the last two decades even in developed countries, attributed to selection of resistant bacterial strains due to inadequate antibiotic treatments.

Risk factors for complicated mastoiditis:

• Young age (often under 2 years)
• High fever
• Elevated inflammatory markers (very high WBC count, absolute neutrophil count, and C-reactive protein)
• Cholesteatoma
• Inadequately treated or recurrent otitis media
• Immunocompromise

Pathophysiology

Relevant Anatomy

• 

  Anatomy of the mastoid bone

• 

  Digastric muscle

The Citelli abscess forms in a specific anatomical region of the mastoid bone:

Trautmann's triangle:

• Bounded by the sigmoid sinus posteriorly, the superior semicircular canal superiorly, and the posterior semicircular canal anteroinferiorly
• Contains the sinodural angle (Citelli angle) superiorly
• This area provides potential pathway for spread from middle ear/mastoid to posterior fossa

Retrofacial air cells:

• Air cells located posterior to the vertical (mastoid) segment of the facial nerve
• Communicate with the mastoid antrum and other mastoid air cell tracts
• May extend to contact sigmoid sinus plate or posterior fossa dura

Related structures:

• Sigmoid sinus: Major venous sinus forming posterior boundary, vulnerable to thrombophlebitis
• Posterior fossa dura: May be eroded, leading to epidural or subdural abscess
• Posterior semicircular canal: Located anteriorly
• Facial nerve: Vertical segment passes anterior to abscess location
• Jugular bulb: Located inferiorly

Disease Etiology

The pathogenesis involves several steps:

Progression from otitis media: 1. Acute or chronic suppurative otitis media with mastoiditis 2. Spread of infection to retrofacial air cells 3. Bony erosion by granulation tissue, cholesteatoma, or osteitis 4. Pus accumulation in confined space between sigmoid sinus and labyrinth 5. Potential erosion into sigmoid sinus (thrombophlebitis) or posterior fossa

Predisposing factors:

• Inadequately treated acute otitis media
• Chronic suppurative otitis media
• Cholesteatoma
• Well-pneumatized retrofacial air cells
• Immunocompromise

Microbiology:

The bacteriology differs between acute and chronic otitis media complications:

Acute mastoiditis pathogens:

• Streptococcus pneumoniae (most common)
• Streptococcus pyogenes
• Haemophilus influenzae
• Staphylococcus aureus

Chronic suppurative otitis media pathogens:

• Pseudomonas aeruginosa
• Staphylococcus aureus (including MRSA)
• Anaerobes (Bacteroides, Peptostreptococcus)
• Polymicrobial infections common

Diagnosis

Patient History

Clinical presentation may be subtle early in the disease course:

• Ear symptoms: Otalgia, otorrhea (often purulent and foul-smelling)
• Hearing loss: Usually conductive, may be longstanding in chronic cases
• Fever: May be low-grade initially, becoming high-grade with progression
• Headache: Particularly postauricular or occipital
• Neck pain/stiffness: With posterior fossa extension
• History of chronic ear disease: Particularly with cholesteatoma

Warning signs of complications:

• High spiking fevers (suggests sigmoid sinus thrombosis)
• Neck swelling (extension to neck - consider Bezold abscess)
• Visual changes, papilledema
• Cranial nerve deficits

Physical Examination

Otoscopy:

• Tympanic membrane perforation with otorrhea (in chronic OM)
• Cholesteatoma debris
• Granulation tissue in middle ear
• Sagging of posterosuperior ear canal wall

Postauricular examination:

• Tenderness over mastoid, particularly posteriorly
• Swelling may be minimal if abscess is contained within bone
• May have mastoid fluctuance if cortical erosion present

Neurological examination:

• Facial nerve function (monitor for involvement)
• Signs of meningitis (neck stiffness, photophobia)
• Papilledema (if increased intracranial pressure)
• Lateral rectus palsy (abducens nerve involvement suggests petrous apicitis - Gradenigo syndrome)

Laboratory Tests

• Complete blood count: Leukocytosis with left shift
• Inflammatory markers: Elevated CRP, ESR
• Blood culture: Especially if febrile or septic
• Culture of ear discharge: Guides antibiotic therapy

Imaging

High-resolution CT of temporal bone (imaging modality of choice):

• Findings:
  • Opacification of mastoid air cells
  • Coalescence of air cells with bone erosion
  • Soft tissue density in retrofacial region (Trautmann's triangle)
  • Erosion of sigmoid sinus plate
  • Cholesteatoma if present (bony erosion pattern)

MRI with contrast:

• Superior for soft tissue evaluation
• Evaluates sigmoid sinus patency
• Detects intracranial complications (meningitis, abscess)
• MR venography for sigmoid sinus thrombosis

Delta sign (empty delta sign on CT/MRI): An empty triangle surrounded by contrast-enhancing dura in the sigmoid sinus area is pathognomonic for sigmoid sinus thrombosis.

Differential Diagnosis

Condition	Location	Key Features
Bezold abscess	Digastric groove/neck	Neck mass, extension below mastoid tip
Subperiosteal abscess	Over mastoid cortex	Postauricular swelling with fluctuance
Luc's abscess	Zygomatic root	Swelling anterior to ear
Zygomatic abscess	Zygomatic process	Periorbital/temporal swelling
Sigmoid sinus thrombosis	Sigmoid sinus	High spiking fevers, delta sign on imaging
Petrous apicitis (Gradenigo)	Petrous apex	CN VI palsy, retro-orbital pain, otorrhea
Posterior fossa epidural abscess	Posterior fossa	Intracranial symptoms, meningismus

Management

Medical Management

Antibiotic therapy:

• Broad-spectrum coverage for gram-positive, gram-negative, and anaerobic organisms
• Empiric regimen:
  • Ceftazidime or cefepime (Pseudomonas coverage) PLUS
  • Vancomycin (MRSA coverage) PLUS
  • Metronidazole (anaerobic coverage)
• Duration: 4-6 weeks (6 weeks for otogenic meningitis or brain abscesses)
• IV initially then oral step-down based on cultures
• Adjust based on culture and sensitivity results

Supportive care:

• Adequate hydration
• Analgesia
• Management of complications (anticoagulation if sigmoid sinus thrombosis - controversial)

Surgical Management

Surgical drainage is the definitive treatment:

Canal wall-up mastoidectomy:

• Preferred if middle ear can be preserved
• Complete exenteration of mastoid air cells including retrofacial cells
• Identification and drainage of abscess in Trautmann's triangle
• Preservation of ear canal and ossicular chain if possible

Canal wall-down mastoidectomy:

• May be necessary for extensive cholesteatoma
• Provides wider access to retrofacial area
• Creates open mastoid cavity requiring lifelong water precautions
• Lower recurrence rate for cholesteatoma but higher risk of chronic otorrhea

Key surgical principles:

• Complete removal of cholesteatoma matrix if present
• Wide saucerization of abscess cavity
• Inspection of sigmoid sinus plate for granulations or frank thrombophlebitis
• Inspection of tegmen for dural involvement
• Preservation of facial nerve
• Culture of purulent material intraoperatively

Management of complications:

• Sigmoid sinus thrombosis: May require needle aspiration, sinus exposure, or clot evacuation
• Frank intracranial extension requires neurosurgical consultation
• Anticoagulation for sigmoid sinus thrombosis remains controversial

Outcomes

Complications

Local complications:

• Sigmoid sinus thrombophlebitis/thrombosis
• Facial nerve injury (surgical complication)
• Labyrinthitis
• Petrous apicitis

Intracranial complications:

• Posterior fossa epidural abscess
• Subdural empyema
• Brain abscess (cerebellar most common with Citelli abscess)
• Meningitis
• Otitic hydrocephalus

Intracranial manifestations of acute mastoiditis occur in 6 to 23% of cases, with meningitis being the most common reported intracranial complication (46.4%), followed by brain abscess and sinus thrombosis.

Systemic complications:

• Sepsis
• Metastatic infection (Lemierre syndrome pattern)

Complications of related Bezold abscess:

• Mediastinal extension with risk of acute mediastinitis (mortality rate 70%)
• Intracranial involvement including abscess, empyema, meningitis, and venous sinus thrombosis

Prognosis

With appropriate surgical and medical management, prognosis is generally good:

• Resolution of infection expected with adequate drainage and antibiotics
• Mortality is low with modern management but increases significantly with intracranial complications
• Hearing outcomes depend on extent of disease and whether ossicular chain preserved

Despite advanced imaging techniques, antibiotics, and microsurgical procedures, the mortality of mastoiditis sequelae in children remains approximately 10%.

Long-term considerations:

• May require second-look surgery for cholesteatoma (typically 9-12 months)
• Patients with canal wall-down mastoidectomy require lifetime surveillance and water precautions
• Hearing rehabilitation options include conventional hearing aids, BAHA, or ossicular chain reconstruction

See Also

• Acute Mastoiditis
• Bezold Abscess
• Chronic Suppurative Otitis Media
• Cholesteatoma
• Sigmoid Sinus Thrombosis