Chronic Suppurative Otitis Media (CSOM)

Definition

Classification

• The tubotympanic type shows retraction of the TM confined to the pars tensa
• The atticoantral type involves pars flaccida retraction and cholesteatoma is commonly present

Epidemiology & Risk Factors

• Most common in low socioeconomic settings with limited healthcare access
• Peak age: children under 2 years old
• Risk factors include:
  • Multiple prior episodes of acute otitis media (AOM)
  • AOM in the first months of life
  • Chronic secretory otitis media
  • Eustachian tube (ET) dysfunction
  • Genetic predisposition (higher incidence in Inuit, Native Americans, Aboriginal Australians/New Zealanders)
  • Nasopharyngeal reflux

Pathophysiology

1. ET dysfunction → decreased middle ear aeration → nitrogen absorption by mastoid cells → negative middle ear pressure
2. Negative pressure → TM retraction (pars flaccida most susceptible) → effusion (serous or purulent) → mucosal oedema
3. Bacterial infection → purulent effusion → inflammatory mediators → chronic mucosal changes, submucosal gland metaplasia (secretory mucosa perpetuates effusion)
4. Granulation tissue forms as bacterial toxins disrupt the basement membrane; inflammatory cells extrude, fibroblasts and angiogenic factors are recruited → polyp formation
5. TM weakening - enzymes in granulation tissue and effusion break down the collagen skeleton of the TM; combined with negative pressure → retraction pockets deepen → contact with underlying mucosa → perforation
6. Cholesteatoma genesis - deep retraction pockets and perforations allow keratinizing squamous epithelium to invade the middle ear, leading to cholesteatoma

Microbiology

Clinical Features

• Intermittent or continuous otorrhoea (sometimes foul-smelling with anaerobes)
• Conductive hearing loss (the most common functional deficit)
• Otalgia and headache are uncommon - their presence should raise suspicion for intracranial involvement or malignancy
• Vertigo should raise suspicion for labyrinthitis or labyrinthine fistula

• Otoscopy/otomicroscopy: TM perforation, retraction pockets, atelectasis; otorrhoea may obscure the TM
• Inspect for: scutal erosion, ossicular erosion, granulation tissue, aural polyps
• An aural polyp should be considered cholesteatoma until proven otherwise
• White keratin debris in the attic region = cholesteatoma (primary acquired type - see below)

Otoscopic Images

Cholesteatoma

• Congenital (rare, present behind intact TM in young children)
• Primary acquired - keratinizing epithelium migrates through a pars flaccida retraction pocket
• Secondary acquired - epithelium migrates through a pre-existing TM perforation

Diagnosis

• Otomicroscopy with pneumatic insufflation - identifies retraction pockets, mobility, cholesteatoma
• Audiometry - conductive hearing loss is typical (low frequency); mixed hearing loss if sensorineural damage has occurred. A conductive loss >30 dB suggests ossicular erosion
• High-resolution CT temporal bones - indicated for surgical planning, complicated CSOM, and identified or suspected cholesteatoma
• MRI with contrast - for suspected intracranial complications
• Biopsy of granulation tissue unresponsive to topical therapy - to exclude malignancy (squamous carcinoma of temporal bone is associated with long-standing CSOM)
• Ear swab for culture - guides antibiotic selection

Management

Primary Goal

Medical Treatment

• Ciprofloxacin ear drops - the most evidence-supported agent; fluoroquinolones are preferred because they are non-ototoxic and active against Pseudomonas
• A 4-6 week course following debridement
• 2025 Cochrane evidence: Three Cochrane meta-analyses published June 2025 confirm topical antibiotics are more effective than systemic antibiotics or topical antiseptics for CSOM. Topical antiseptics (acetic acid, Burow's solution) remain an alternative.
• Biofilms are frequently resistant; high concentrations from topical delivery partially overcome this

Indications for Surgery

• Cholesteatoma combined with medically refractory CSOM = near-absolute indication
• Failure of multiple courses of medical treatment
• Symptoms suspicious of complications: vertigo, facial weakness, headache
• Deep retraction pockets threatening ossicular chain
• Persistent conductive hearing loss

Surgical Options

• CWD provides better surgical access and potentially lower recurrence, but results in an open cavity requiring lifelong routine follow-up and debridement
• CWU preserves normal anatomy and dramatically reduces post-op convalescence, but higher disease recurrence risk for cholesteatoma
• Anatomical position of cholesteatoma is a stronger predictor of recurrence than choice of technique

Complications

Intracranial Complications

• Meningitis
• Brain abscess (temporal lobe, cerebellar)
• Epidural/subdural abscess
• Sigmoid sinus thrombophlebitis
• Otitic hydrocephalus

Extracranial Complications

• Labyrinthine fistula (most commonly horizontal semicircular canal) - presents with vertigo and SNHL
• Facial nerve paralysis - acute (infection) or insidious (cholesteatoma expansion through fallopian canal)
• Coalescent mastoiditis / subperiosteal abscess
• Petrositis (Gradenigo syndrome: otorrhoea, ipsilateral abducens palsy, deep facial pain)
• Ossicular erosion (most commonly the long process of the incus) → conductive hearing loss
• Tegmen tympani/mastoideum erosion → CSF leak, brain herniation

Key Points Summary

1. CSOM = TM perforation + chronic otorrhoea >6 weeks; tubotympanic (safe) vs atticoantral (unsafe/cholesteatoma)
2. Core pathophysiology: ET dysfunction → negative middle ear pressure → TM retraction → perforation/cholesteatoma
3. Most common pathogen: Pseudomonas aeruginosa; mixed aerobic/anaerobic flora
4. Foul-smelling discharge = anaerobes/cholesteatoma; malodour is a red flag for the atticoantral type
5. An aural polyp = cholesteatoma until proven otherwise
6. Otalgia/headache/vertigo/facial weakness = possible complications; urgent evaluation needed
7. Topical ciprofloxacin + aural toilet is first-line medical treatment (2025 Cochrane evidence confirms superiority over systemic antibiotics)
8. Surgery (tympanoplasty ± mastoidectomy) is indicated for cholesteatoma, treatment failure, or complications
9. Cholesteatoma is aggressive: erodes ossicles, otic capsule, fallopian canal, tegmen - treat surgically without delay
10. Long-term surveillance is mandatory after CWD mastoidectomy

Available ENT Books in This Library

About Salah Mansour's Book

• Authors: Salah Mansour, Jacques Magnan, Karen Nicolas, Hassan Haidar
• Publisher: Springer (2018)
• eBook ISBN: 978-3-319-72962-6
• Hardcover ISBN: 978-3-319-72961-9

1. Otosclerosis
2. Acute Otitis Media and Acute Coalescent Mastoiditis
3. Otitis Media with Effusion
4. Chronic Suppurative Otitis Media (CSOM)
5. Cholesteatoma
6. And further chapters on tympanoplasty, ossiculoplasty, and related topics

What I Can Do Instead

Branchial Cyst

Definition

• Cyst = no communication with body surface (skin or pharynx)
• Sinus = tract communicates with only one surface (skin or pharynx, not both)
• Fistula = complete tract communicating with both the skin and pharynx

Embryology

• The 1st cleft gives rise to the external auditory canal
• The 2nd arch overgrows the 2nd, 3rd, and 4th clefts, burying them in a transient structure called the cervical sinus
• The cervical sinus then obliterates; failure of this obliteration traps ectoderm → branchial remnant

Classification

First BCA - Work's Classification

Pathology (Histology)

• Well-circumscribed cystic lesion, 2-5 cm in diameter
• Lined by stratified squamous or pseudostratified columnar (respiratory-type) ciliated epithelium
• Fibrous cyst wall contains dense lymphoid tissue with prominent germinal centres - this is pathognomonic
• Cyst contents: clear watery or mucinous fluid, desquamated cells, and granular/keratinous debris
• Secondary inflammatory infiltrates and wall thickening if previously infected

Clinical Features

• Second BCCs (the vast majority) typically present between ages 10-40 years
• Often diagnosed in early adulthood after an incidental finding or acute infection
• Usually unilateral; bilateral cases are rare and often familial

• Smooth, fluctuant, non-tender lateral neck mass
• May transilluminate (early/thin-walled cysts)
• Can be very soft and difficult to palpate when small
• Often swells and becomes tender during upper respiratory infections (antigen stimulation of wall lymphoid tissue)
• Intermittent drainage if a sinus is present

• At the anterior border of the sternocleidomastoid (SCM) muscle, at the junction of the upper and middle thirds - just inferior to the angle of the mandible
• Superficial to the carotid sheath, posterior to the submandibular gland

Surgical Anatomy of the 2nd BCA Tract

1. From the external opening at the anterior border of the SCM in the lower/middle neck
2. Through the platysma
3. Between the internal and external carotid arteries at the carotid bifurcation (level of thyroid cartilage = C3/C4)
4. Superficial to CN IX (glossopharyngeal) and CN XII (hypoglossal)
5. Deep to the posterior belly of digastric, stylohyoid ligament
6. The vagus (CN X) and spinal accessory (CN XI) lie posterior to the tract
7. Terminates at the internal opening in the tonsillar fossa (anterior wall of the posterior faucial pillar)

Investigations

Ultrasound (first-line)

• Classic appearance: anechoic simple cyst with posterior acoustic enhancement, avascular on Doppler
• If previously infected: heterogeneous, thick-walled, with internal debris and septae (pseudosolid appearance)
• If a medially-directed "beak" is seen → suggests sinus/fistula → proceed to CT/MRI

Ultrasound with colour Doppler: avascular pseudosolid right level II mass consistent with 2nd branchial cleft cyst (Scott-Brown's, Fig. 37.33)

CT (contrast-enhanced)

• Classic: homogeneous low-attenuation (fluid density, 0-20 HU), thin smooth wall, displaces submandibular gland anteriorly and lies deep to SCM
• Infected: thick-walled, septated, heterogeneous, ill-defined

Axial CECT: septated, thick-walled right level II mass (arrow) deep to SCM, displacing the submandibular gland anteriorly - infected 2nd branchial cleft cyst (Scott-Brown's, Fig. 37.34)

MRI

• High T2 signal, low T1 signal (simple fluid)
• Infected: mixed T1/T2 signal, thick irregular wall

FNAC (Fine-Needle Aspiration Cytology)

• Yields thick, turbid, "motor oil"-like fluid
• Cytology: squamous cells, lymphocytes, cholesterol crystals
• Used diagnostically and therapeutically (aspiration)
• Mandatory in patients >35 to exclude cystic SCC metastasis

Differential Diagnosis

Critical rule: In any patient over 35 years with a lateral cystic neck mass, malignancy must be excluded before assuming benign BCC. If FNAC is not diagnostic and no primary tumour is found on CT/MRI, PET-CT should be considered (especially if smoker/alcohol history). This is a CUP (carcinoma of unknown primary) investigation protocol.

Management

Conservative

• Asymptomatic small cysts in young patients may be observed
• Aspiration for symptomatic relief (high recurrence rate without excision)

Medical

• Acute infection: antibiotics (oral or IV depending on severity) to render the lesion quiescent before definitive surgery
• Surgery is best performed when the lesion is quiescent - operating on an infected cyst is associated with higher rates of incomplete excision, recurrence, and nerve injury

Surgical Excision (Definitive Treatment)

• Complete surgical excision is the standard of care
• Approach: transverse cervical skin crease incision ± "step-ladder" incisions for fistulas
• For a fistula, the entire tract must be excised to prevent recurrence - often requires two transverse incisions (upper and lower) to avoid longitudinal scars
• Key structures to identify and protect:
  • CN VII (especially for 1st BCA)
  • CN IX (glossopharyngeal)
  • CN XII (hypoglossal)
  • CN XI (spinal accessory)
  • Internal and external carotid arteries
  • Internal jugular vein

Recurrence

• Incomplete excision (especially if operating on an infected cyst or failing to trace the entire fistula tract) → recurrence
• Multiple previous incisions/infections create fibrosis and distort anatomy → higher surgical difficulty

Branchial Cyst Carcinoma (Branchiogenic Carcinoma)

1. No primary elsewhere in the aerodigestive tract
2. Histological appearance consistent with origin from branchial remnant
3. Long clinical history of a benign cyst before malignant change

All patients >35 years with lateral cystic neck masses should enter a CUP investigation protocol even if FNAC is not suggestive of metastatic SCC.

Key Points

1. Second BCC = 95% of cases; presents at anterior border of SCM, ages 10-40
2. Classic triad: lateral neck swelling + fluctuant + enlarges with URTIs
3. Histology: squamous/respiratory epithelium + lymphoid tissue with germinal centres (pathognomonic)
4. US first-line: anechoic, avascular; CT if sinus/fistula or surgical planning needed
5. FNAC: turbid fluid + squamous cells + lymphocytes
6. >35 years = exclude malignancy first (cystic SCC metastasis from HPV oropharyngeal cancer)
7. Treatment = complete surgical excision when quiescent
8. Fistula tract must be completely excised - two-incision technique
9. Protect CN VII (1st BCA), CN IX, CN XII during surgery
10. Third/fourth BCAs → arise from piriform sinus; may present as suppurative thyroiditis