2d:I[856015,["/_next/static/immutable/chunks/1xzisbplk9czp.js","/_next/static/immutable/chunks/3j2i1faptc_-9.js","/_next/static/immutable/chunks/0fma7nlq6immz.js","/_next/static/immutable/chunks/08tq8rmv423j5.js","/_next/static/immutable/chunks/1chr5wkk3j58k.js","/_next/static/immutable/chunks/37kmmh_zm4dov.js","/_next/static/immutable/chunks/311zvdjfxff-f.js","/_next/static/immutable/chunks/1a_hqhrsle_n_.js"],"default"] 2e:T4d18,

Summary Table

Feature	Detail
Risk Factors	Recurrent acute otitis media (AOM), tympanic membrane (TM) perforation, poor eustachian tube function, cleft palate, immunocompromised states, low socioeconomic status, overcrowding, malnutrition, lack of breastfeeding
Etiology	Polymicrobial: Pseudomonas aeruginosa (most common), Staphylococcus aureus, Proteus species, anaerobes; often follows inadequately treated AOM or persistent TM perforation
Patient Presentation	Persistent otorrhea > 6 weeks through a perforated TM, with or without hearing loss
Classic Physical Exam	Perforated tympanic membrane with active mucopurulent discharge; conductive hearing loss on tuning fork tests (Weber lateralizes to affected ear, Rinne negative on affected side); granulation tissue or polyp may be visible in the ear canal
Key Diagnostic Results	Otoscopy showing TM perforation with discharge; culture of ear discharge (Pseudomonas predominates); audiometry showing conductive hearing loss; CT temporal bone if complication suspected (cholesteatoma, intracranial extension)
Management	Aural toilet + topical antibiotic drops (ciprofloxacin or ofloxacin) as first-line; systemic antibiotics for complications; tympanoplasty for persistent perforation after infection control; mastoidectomy if cholesteatoma or mastoiditis develops
Keywords	"Foul-smelling ear discharge for weeks," "perforated eardrum," "painless otorrhea," "conductive hearing loss," "Pseudomonas"

1. Pathophysiology

CSOM represents a chronic inflammatory process of the middle ear and mastoid cavity characterized by persistent discharge through a non-intact tympanic membrane lasting more than 6 weeks (some sources use 2 to 12 weeks as a threshold, but 6 weeks is the most commonly tested cutoff).

The pathogenesis begins with eustachian tube dysfunction. When the eustachian tube fails to equalize pressure or drain secretions from the middle ear, a negative pressure environment develops. This predisposes to recurrent infections. Over time, repeated bouts of acute otitis media cause progressive damage to the TM, eventually leading to a persistent perforation. Once the TM is no longer intact, the middle ear mucosa is chronically exposed to external pathogens and moisture, which sustains the inflammatory cycle.

The shift in microbiology is a key teaching point. While AOM is dominated by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, CSOM is dominated by Pseudomonas aeruginosa and Staphylococcus aureus. This shift occurs because the perforated TM allows colonization by organisms from the external ear canal. This directly explains why treatment changes from oral amoxicillin (for AOM) to topical fluoroquinolone drops (for CSOM).

Conductive hearing loss results from two mechanisms: the perforation itself reduces the vibrating surface of the TM, and inflammatory debris or fluid in the middle ear impedes ossicular chain movement. If the disease erodes the ossicles, the hearing loss becomes fixed and more severe.

The most feared consequence of CSOM is cholesteatoma formation, particularly in the unsafe (atticoantral) type. Cholesteatoma is not a tumor but an expanding mass of keratinized squamous epithelium that erodes bone through enzymatic activity (collagenase release) and pressure necrosis. This erosion can extend into the mastoid, facial nerve canal, labyrinth, or intracranial cavity.

2. Classification and Clinical Manifestation

CSOM is classically divided into two types based on the location of TM perforation and the risk of complications:

Feature	Tubotympanic (Safe / Mucosal)	Atticoantral (Unsafe / Squamosal)
Perforation Location	Central (pars tensa)	Marginal or attic (pars flaccida or posterosuperior pars tensa)
Discharge Character	Mucoid or mucopurulent, non-foul-smelling	Purulent, scanty, foul-smelling
Cholesteatoma	Absent	Present (or high risk)
Complication Risk	Low	High (bone erosion, intracranial complications)
Granulation Tissue / Polyp	Uncommon	Common (aural polyp)
Management Approach	Conservative first (topical antibiotics, aural toilet); elective tympanoplasty	Surgical (mastoidectomy with tympanoplasty) is primary treatment
Hearing Loss	Mild to moderate conductive	Conductive or mixed (if labyrinth eroded)

The distinction between safe and unsafe types is one of the highest-yield points in this topic. The presence of a marginal or attic perforation should immediately raise concern for cholesteatoma. In a vignette, foul-smelling discharge plus hearing loss plus a posterosuperior or attic perforation points directly to the unsafe type requiring surgical intervention.

Complications of CSOM

Category	Complications
Intratemporal	Mastoiditis, facial nerve palsy, labyrinthitis (sensorineural hearing loss, vertigo), petrositis (Gradenigo syndrome: otorrhea + retro-orbital pain + CN VI palsy)
Intracranial	Brain abscess (temporal lobe or cerebellum), meningitis, lateral sinus thrombosis, extradural abscess, otitic hydrocephalus

3. Diagnostic Workup

Test	Role	Key Findings
Otoscopic examination	Best initial test	Perforated TM (central vs marginal), discharge character, granulation tissue or cholesteatoma
Culture and sensitivity of ear discharge	Guides antibiotic therapy	Pseudomonas aeruginosa most common; also S. aureus, Proteus, anaerobes
Audiometry (pure tone)	Assess hearing loss type and severity	Conductive hearing loss (air-bone gap); mixed loss suggests labyrinthine involvement
Tuning fork tests (Weber and Rinne)	Bedside hearing assessment	Weber lateralizes to affected ear; Rinne is negative (bone conduction > air conduction) on affected side
CT temporal bone (high-resolution)	Best test when complications suspected	Evaluate for cholesteatoma (soft tissue mass in middle ear/epitympanum with bony erosion), mastoid involvement, tegmen dehiscence, or intracranial extension
MRI with diffusion-weighted imaging	Differentiate cholesteatoma from other soft tissue	Cholesteatoma shows restricted diffusion on DWI; useful for detecting residual or recurrent cholesteatoma postoperatively

Otoscopy is the cornerstone of diagnosis. The exam will typically present a patient with weeks of ear discharge, and the expected next step is to look in the ear. The character and location of the perforation guide all subsequent decisions.

Culture of the discharge is not always done in uncomplicated cases but becomes important when the infection fails to respond to empiric topical therapy, or when systemic infection develops.

CT temporal bone is not routinely needed for straightforward tubotympanic CSOM. It becomes necessary when you suspect cholesteatoma (foul discharge, marginal perforation, aural polyp), when there are signs of complication (fever, severe headache, facial weakness, vertigo, signs of meningismus), or for preoperative surgical planning.

Audiometry establishes a baseline and helps quantify the conductive component. An air-bone gap of $\geq$ 25 dB generally indicates a functionally relevant conductive hearing loss. If sensorineural loss is also present (mixed pattern), consider labyrinthine erosion by cholesteatoma.

4. Management and Treatment

Clinical Scenario	Treatment
Uncomplicated CSOM (tubotympanic, no cholesteatoma)	Aural toilet (dry mopping or suction clearance) + topical ciprofloxacin 0.3% or ofloxacin 0.3% drops, 3 drops twice daily for 2 weeks; avoid aminoglycoside ear drops (ototoxicity risk through perforated TM)
CSOM failing topical therapy	Culture-guided systemic oral antibiotics (e.g., ciprofloxacin 500 mg twice daily for 7 to 14 days in adults); reassess for cholesteatoma
Persistent dry perforation after infection control	Tympanoplasty (surgical repair of TM) to restore hearing and prevent recurrence
Atticoantral / unsafe type with cholesteatoma	Mastoidectomy with tympanoplasty; surgery is the primary treatment, not conservative management
Intracranial complications	IV antibiotics (ceftriaxone + metronidazole to cover Pseudomonas and anaerobes; add anti-pseudomonal agent such as IV ciprofloxacin or ceftazidime if Pseudomonas confirmed) + urgent surgical drainage/mastoidectomy + neurosurgical consultation

Step 1: Aural toilet. This is the single most important initial intervention. Clearing the ear canal of discharge and debris allows topical medications to reach the middle ear mucosa. Without adequate aural toilet, topical drops are ineffective. This is a commonly tested principle.

Step 2: Topical fluoroquinolone drops. Ciprofloxacin and ofloxacin are preferred because they cover Pseudomonas, are non-ototoxic, and achieve high local concentrations. Aminoglycoside-containing drops (gentamicin, neomycin) should be avoided when the TM is perforated because they can penetrate into the inner ear and cause sensorineural hearing loss. This is a frequently tested contraindication.

Step 3: Systemic antibiotics are reserved for complications or failure to improve with topical therapy. Oral ciprofloxacin covers Pseudomonas and is the typical choice in adults. In children, fluoroquinolones are used more cautiously.

Step 4: Surgery. Once the infection is controlled and the ear is dry for at least 3 months, tympanoplasty can be performed to close the perforation and improve hearing. For unsafe-type CSOM with cholesteatoma, mastoidectomy is not optional. Cholesteatoma does not resolve with antibiotics; it requires surgical excision to prevent progressive bone destruction.

Key contraindication: Do not instill any ear drops containing alcohol or ototoxic agents (aminoglycosides, polymyxin B) through a perforated TM.

5. Differential Diagnosis and Distractors

Differential Diagnosis	Why It Is Similar	Key Discriminator
Acute Otitis Media (AOM)	Ear pain, discharge, hearing loss	AOM presents acutely (< 3 weeks) with otalgia and fever; TM is bulging and intact (or recently ruptured); CSOM has chronic painless discharge > 6 weeks with an established perforation
Otitis Externa (OE)	Ear discharge, may have hearing loss	OE causes pain on pinna traction or tragal pressure; ear canal is edematous and inflamed but TM is intact; CSOM has a perforated TM and painless discharge
Cholesteatoma (isolated)	Foul discharge, hearing loss, can coexist with CSOM	Cholesteatoma shows a white pearly mass or skin debris in the attic/posterosuperior region; it is a complication/subtype of unsafe CSOM, not a separate entity from it
Malignant (Necrotizing) Otitis Externa	Ear discharge, Pseudomonas, can erode bone	Occurs in elderly diabetics or immunocompromised; presents with severe deep ear pain, granulation tissue at the bony-cartilaginous junction of the ear canal; TM is usually intact; can cause cranial nerve palsies (VII first); ESR and CRP markedly elevated
CSF Otorrhea	Clear fluid from the ear	History of head trauma or skull base fracture; discharge is clear and watery, not purulent; tests positive for beta-2 transferrin; TM may have a traumatic perforation
Tuberculous Otitis Media	Chronic ear discharge unresponsive to standard antibiotics	Multiple small perforations (though this is uncommon), painless otorrhea, pale granulation tissue, disproportionate hearing loss, associated pulmonary TB; biopsy shows caseating granulomas

6. Traps and High-Yield Pearls

The most common way students lose points on CSOM questions is by confusing AOM management with CSOM management. A vignette describing a child with recurrent ear infections who now has weeks of painless discharge and a known TM perforation is not another episode of AOM. The answer is not amoxicillin. The answer is aural toilet plus topical fluoroquinolone drops.

The second major trap involves aminoglycoside ear drops. Many students select gentamicin or neomycin-polymyxin drops reflexively because they associate ear infections with these preparations. Through a perforated TM, aminoglycosides are ototoxic. The correct choice is a fluoroquinolone.

Another commonly tested distinction: if a question describes foul-smelling discharge from a marginal or attic perforation, the test-writer is asking you to recognize the unsafe type with cholesteatoma. The next best step is imaging (CT temporal bone) and referral for surgery, not a prolonged trial of ear drops.

Finally, questions testing complications will describe a CSOM patient who suddenly develops facial nerve palsy, vertigo, severe headache, or high fever. These are red flags for intratemporal or intracranial extension. The core competency being tested is recognizing when CSOM has moved beyond a routine outpatient problem and requires urgent intervention, imaging, and surgical consultation.

1e:["$","$L2d",null,{"article":{"id":"0d000449-8bb8-4e5a-8505-c544ba78334d","title":"Otitis Media Supuratif Kronis (OMSK)","content":"$2e","category":"THT-KL","created_at":"2026-05-15T08:28:10.111347+00:00","status":"published","subcategory":null},"questionCount":6,"sections":[{"id":"section-pathophysiology","num":"01","title":"Pathophysiology"},{"id":"section-classification-and-clinical-manifestation","num":"02","title":"Classification and Clinical Manifestation"},{"id":"section-diagnostic-workup","num":"03","title":"Diagnostic Workup"},{"id":"section-management-and-treatment","num":"04","title":"Management and Treatment"},{"id":"section-differential-diagnosis-and-distractors","num":"05","title":"Differential Diagnosis and Distractors"},{"id":"section-traps-and-high-yield-pearls","num":"06","title":"Traps and High-Yield Pearls"}],"hasSummaryTable":true}]