Viva questions asked for csom

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CSOM - Viva Questions & Answers

Based on Shambaugh Surgery of the Ear, KJ Lee's Essential Otolaryngology, Cummings Otolaryngology, and Scott-Brown's Otorhinolaryngology

1. What is CSOM? Define it.

Chronic Suppurative Otitis Media (CSOM) is defined as chronic inflammation of the middle ear and mastoid, manifesting most commonly as hearing loss and intermittent otorrhea. It is insidious in onset and usually painless. CSOM can occur with or without cholesteatoma.

Shambaugh Surgery of the Ear, p. 527

2. What are the types of CSOM?

Type	Also Called	Features
Tubotympanic (safe/mucosal)	Inactive mucosal	Central TM perforation, mucopurulent discharge, no cholesteatoma, not dangerous
Atticoantral (unsafe/squamous)	Active squamous	Marginal/attic perforation, cholesteatoma present, dangerous - risk of complications

Pars flaccida retraction leads to atticoantral type
Pars tensa retraction leads to tubotympanic type
KJ Lee's Essential Otolaryngology, p. 445

3. What is cholesteatoma?

A cholesteatoma is an abnormal collection of keratinizing squamous epithelium in the middle ear or mastoid. It is a destructive, expanding lesion that erodes bone through osteoclastic activity.

Types:

Congenital - behind intact TM, no history of ear disease; white pearly mass
Primary acquired - from retraction pocket without prior perforation
Secondary acquired - ingrowth of squamous epithelium through a perforation

4. What are the theories of pathogenesis of cholesteatoma?

Four classical theories (Cummings Otolaryngology, p. block 31):

Invagination/Retraction theory (most accepted) - ET dysfunction causes negative middle ear pressure → pars flaccida (being less fibrous) retracts → keratin accumulates in deepening pocket → cholesteatoma. The pars flaccida is most susceptible.
Epithelial invasion/Migration theory - Squamous epithelium migrates through the margins of a TM perforation into the middle ear (secondary acquired cholesteatoma).
Basal cell hyperplasia/Papillary ingrowth theory - Basal layer of the tympanic membrane proliferates and invades the middle ear; supported by hyperproliferation of keratinocytes.
Squamous metaplasia theory - Middle ear respiratory epithelium undergoes metaplastic change to squamous epithelium under repeated inflammation.

Mucosal traction theory (Jackler): traction from fibrotic middle ear mucosa pulls TM inward.

5. What is the most common organism in CSOM?

Pseudomonas aeruginosa - most common pathogen in OM biofilms
Staphylococcus aureus
Non-typeable H. influenzae, Moraxella catarrhalis
Often polymicrobial; organisms exist in biofilms which are highly resistant to antibiotics

Biofilms: organized networks of sessile bacteria encased in oligopolysaccharide matrix, with:

Escape from phagocytosis and humoral immunity
Decreased metabolic rate
Different gene expression
Efflux pumps for antibiotics
KJ Lee's Essential Otolaryngology, p. 445-446

6. What is the role of Eustachian tube in CSOM?

ET dysfunction is the central pathophysiological mechanism:

Decreased aeration of middle ear space
Nitrogen-absorbing mastoid cells reduce middle ear volume
Negative pressure develops in ME space
TM retraction follows, especially at pars flaccida
Sets the stage for cholesteatoma formation

7. What are the clinical features of CSOM?

Symptoms:

Intermittent otorrhea - often foul-smelling (especially with cholesteatoma)
Hearing loss - typically conductive or mixed
Aural fullness

Warning signs (suggest complications):

Otalgia/headache - suspect intracranial involvement or malignancy
Vertigo - suspect labyrinthine fistula or labyrinthitis
Facial weakness - facial nerve involvement

Signs:

TM perforation (central in tubotympanic; marginal/attic in atticoantral)
Granulation tissue / aural polyps (aural polyp = cholesteatoma until proven otherwise)
Retraction pockets
White pearly debris (cholesteatoma)
Scutal erosion

8. What is the pathology of CSOM?

Pathological findings (Schuknecht's description):

Osteitis - osteoclastic bone resorption; most commonly involves the incus (81%), then stapes (57%), then malleus (43%)
Mucosal edema with submucosal gland formation (converts mucosa to secretory type)
Granulation tissue (present in 93-98% of CSOM specimens)
Tympanosclerosis
Cholesterol granulomas
TM retraction and perforation
Sclerotic mastoid - ongoing osteitis leads to dense, narrowed mastoid bone

9. What investigations are done in CSOM?

Otomicroscopy with pneumatic insufflation - key examination, look for cholesteatoma
Audiometry - conductive hearing loss; CHL >30 dB suggests ossicular erosion; SNHL if labyrinth involved
High-resolution CT scan of temporal bones - for:
- Surgical planning
- Complicated CSOM (facial nerve paralysis, vertigo)
- Cholesteatoma identified on examination
- Revision tympanomastoidectomy cases
MRI with contrast - suspected intracranial complications; diffusion-weighted MRI to detect cholesteatoma
Biopsy of granulation tissue unresponsive to topical therapy - to rule out malignancy

10. What is the treatment of CSOM?

Primary Goal = "Safe, Dry Ear"

Dry = no otorrhea
Safe = no keratin collection, reduced risk of suppurative complications

Medical Treatment:

Aural toilet (microsuction debridement)
Topical antibiotics (4-6 week course following debridement):
- Fluoroquinolones (ciprofloxacin - first choice, non-ototoxic)
- Polymyxin B or neomycin ± steroid
Note: Biofilms are frequently resistant to topical antibiotics
Systemic antibiotics if medical failure or complications

Indications for Surgery:

Cholesteatoma + medically refractory CSOM = nearly absolute indication for surgery
Failed multiple attempts at medical treatment
Symptoms suspicious of complications (vertigo, facial weakness, headache)
Retraction pockets at risk of cholesteatoma formation

11. What surgical procedures are done for CSOM?

Three primary indications for mastoidectomy:

Eradication of disease and infection
Approach for removal of cholesteatoma
Establishing aeration (less important)

Types of surgery:

Surgery	Description	Use
Tympanoplasty	TM repair ± ossicular reconstruction	CSOM without cholesteatoma; hearing restoration
CWU (Canal Wall Up) mastoidectomy	Preserve posterior EAC wall	Less extensive disease; better cosmesis; better hearing aids; less post-op care
CWD (Canal Wall Down) mastoidectomy	Remove posterior EAC wall; creates open cavity	Extensive cholesteatoma; lower recurrence; needs lifelong cavity care

12. What are the complications of CSOM?

Extracranial (Intratemporal):

Acute mastoiditis / Subperiosteal abscess
Facial nerve paralysis
Labyrinthitis (serous or suppurative) → vertigo, SNHL
Labyrinthine fistula (lateral SCC most common)
Petrositis → Gradenigo syndrome (deep retro-orbital pain + otorrhea + CN VI palsy)
Tympanosclerosis
Ossicular discontinuity

Intracranial:

Meningitis (most common intracranial complication)
Brain abscess (temporal lobe or cerebellar)
Sigmoid sinus thrombophlebitis
Subdural/Epidural abscess
Otic hydrocephalus

13. What is Gradenigo syndrome?

A triad resulting from petrositis (inflammation of the petrous apex):

Persistent otorrhea (from middle ear infection)
Deep retro-orbital pain (CN V - trigeminal irritation)
Diplopia / CN VI palsy (abducens nerve)

Treatment: IV antibiotics + surgical drainage.

14. What is aural polyp and its significance?

An aural polyp is granulation tissue or a polyp arising from the middle ear or EAC. It should be considered cholesteatoma until proven otherwise. Biopsy of granulation tissue unresponsive to topical therapy should be done to rule out malignancy.

15. What is the difference between Safe and Unsafe CSOM?

Feature	Safe (Tubotympanic)	Unsafe (Atticoantral)
Perforation	Central (pars tensa)	Marginal / Attic (pars flaccida)
Cholesteatoma	Absent	Present
Discharge	Mucopurulent, odourless	Foul-smelling, scanty
Bone erosion	Rare	Common
Complications	Less common	Common
Danger	Not dangerous	Dangerous
Surgery	Tympanoplasty	Mastoidectomy ± tympanoplasty

16. What are biofilms and their relevance in CSOM?

Biofilms are highly organized, communicative networks of sessile bacteria that:

Gain protection from changes in temperature and pH
Escape phagocytosis and humoral immunity (impenetrable matrix)
Are frequently polymicrobial
Produce efflux pumps for antibiotics
Can be intracellular (act as reservoirs)
Are found adherent to respiratory epithelium

This explains the antibiotic resistance seen in chronic CSOM and why medical treatment often fails.

17. What hearing loss pattern is seen in CSOM?

Conductive hearing loss (CHL) - most common
CHL >30 dB suggests ossicular erosion
Mixed hearing loss can occur if cochlea is affected
Sensorineural component (5-33 dB SNHL) from bacterial toxins crossing round window, labyrinthitis, or inner ear involvement
Interestingly, hearing can sometimes be preserved even with ossicular erosion if cholesteatoma transmits sound directly to the oval window

Sources: Shambaugh Surgery of the Ear | KJ Lee's Essential Otolaryngology | Cummings Otolaryngology | Scott-Brown's Otorhinolaryngology | Textbook of Family Medicine 9e

Create a comparison table of atticoantral vs tubotympanic CSOM

Here is a detailed comparison table based on the ENT textbooks consulted in the previous session:

Atticoantral vs Tubotympanic CSOM - Comparison Table

Feature	Tubotympanic (Safe/Mucosal)	Atticoantral (Unsafe/Squamous)
Also known as	Safe CSOM, Mucosal type, Inactive COM	Unsafe CSOM, Squamous type, Active squamous COM
Part of TM involved	Pars tensa	Pars flaccida (and posterosuperior pars tensa)
Type of perforation	Central perforation	Marginal perforation or attic (Shrapnell's membrane) perforation
Rim of perforation	Rim of TM present all around	No rim on one side (marginal)
Cholesteatoma	Absent	Present (hallmark feature)
Discharge	Mucopurulent, profuse, relatively odourless, intermittent	Scanty, foul-smelling (fetid), purulent - due to bone destruction by cholesteatoma
Hearing loss	Conductive hearing loss, usually mild to moderate	Conductive or mixed; can be severe if ossicular erosion
Bone erosion	Rare	Common - erodes ossicles, scutum, tegmen, canal wall
Ossicular involvement	Uncommon	Common - incus eroded most frequently (long process of incus)
Danger / Safety	Not dangerous	Dangerous - high risk of complications
Complications	Rare	Common - intracranial and extracranial
Granulation tissue	May be present (mucosal)	Often present; aural polyp common
Scutal erosion	Absent	Present (scutum = lateral wall of attic)
Middle ear mucosa	Congested, oedematous mucosa	Squamous epithelium lining (keratinizing)
Pathology	Chronic mucosal inflammation, submucosal gland formation	Bone-eroding cholesteatoma sac filled with keratin debris
Eustachian tube	Usually severely dysfunctional	Moderately dysfunctional; pars flaccida more susceptible
Retraction pocket	Pars tensa retraction	Pars flaccida retraction → attic cholesteatoma
Mastoid	Usually sclerotic	Variable; may have expanded or eroded cells
CT findings	Soft tissue in ME, no bony erosion	Soft tissue mass + bony erosion (scutum, ossicles, tegmen, canal wall)
Response to medical treatment	Often responds to aural toilet + topical antibiotics	Poor response; surgery required
Surgery required	Only if TM repair needed (tympanoplasty)	Always surgical - mastoidectomy mandatory
Surgery of choice	Tympanoplasty (type I-V)	Tympanomastoidectomy - CWU or CWD mastoidectomy
CWU vs CWD	CWU preferred	CWD for extensive/recurrent cholesteatoma; CWU for limited disease
Primary treatment goal	Dry, safe ear + hearing restoration	Eradication of cholesteatoma; safe ear is priority over hearing
Recurrence	Low after successful surgery	High - second-look surgery often needed at 12-18 months
Prognosis	Good	Guarded - risk of serious complications if untreated

Complications Comparison

Complication	Tubotympanic	Atticoantral
Mastoiditis	Rare	Common
Facial nerve palsy	Very rare	More common (cholesteatoma erodes facial canal)
Labyrinthine fistula	Rare	Common (lateral SCC most often eroded)
Labyrinthitis / SNHL	Rare	Can occur
Meningitis	Rare	Risk present
Brain abscess	Rare	Risk present
Sigmoid sinus thrombosis	Rare	Risk present
Petrositis / Gradenigo syndrome	Rare	Possible

Quick Memory Aid

Tubotympanic	Atticoantral
T = Tensa (pars tensa)	A = Attic / pars flaccida
T = Tame (safe)	A = Aggressive (unsafe)
T = Treatable medically	A = Always needs surgery
Central perforation	Marginal / attic perforation
No cholesteatoma	Cholesteatoma present

Sources: KJ Lee's Essential Otolaryngology | Shambaugh Surgery of the Ear | Cummings Otolaryngology | Scott-Brown's Otorhinolaryngology

Create a diagnostic flowchart for differentiating CSOM types

Generating Image

A clean, professional medical diagnostic flowchart for differentiating CSOM (Chronic Suppurative Otitis Media) types. The flowchart starts at the top with "Patient with Chronic Ear Discharge + Hearing Loss" in a rounded rectangle. Then flows down to "Otoscopic Examination" box. Then branches into two paths based on "Where is the perforation?". Left path: "Central Perforation (Pars Tensa)" leading to "Tubotympanic CSOM (Safe/Mucosal Type)" in a green box. Right path: "Marginal/Attic Perforation (Pars Flaccida)" leading to "Atticoantral CSOM (Unsafe/Squamous Type)" in a red/orange box. Under Tubotympanic box: bullet points - Profuse mucopurulent discharge, Odourless, No cholesteatoma, No bone erosion, Responds to medical treatment, Treatment: Tympanoplasty. Under Atticoantral box: bullet points - Scanty foul-smelling discharge, Cholesteatoma present, Scutal erosion, Bone erosion on CT, Surgery mandatory, Treatment: Mastoidectomy. Below both boxes, a "Check for Complications" diamond shape with arrows to complication lists. Atticoantral complications: Facial nerve palsy, Labyrinthine fistula, Meningitis, Brain abscess, Sigmoid sinus thrombosis. White background, blue header boxes, green for safe type, red/orange for unsafe type, clear arrows, medical illustration style, high resolution.

Here is a step-by-step walkthrough of the flowchart logic for viva purposes:

How to Use This Flowchart

Step 1 - Starting Point

Any patient presenting with chronic ear discharge + hearing loss lasting more than 6 weeks needs a systematic assessment.

Step 2 - Otoscopic Examination (Key Decision Point)

This is the most critical step. Use an otomicroscope if available.

What to look for:

Location of TM perforation
Nature of discharge
Presence of white/pearly debris (cholesteatoma)
Scutal erosion
Aural polyp (treat as cholesteatoma until proven otherwise)

Step 3 - Branch Decision

Finding	Go to
Central perforation, pars tensa, rim present all around	Tubotympanic (Safe)
Marginal/attic perforation, no rim on one side, pars flaccida involved	Atticoantral (Unsafe)

Step 4 - Confirm the Type

Tubotympanic (Safe) - Green Path:

Profuse, mucopurulent, odourless discharge
No cholesteatoma visible
No bone erosion on CT
Responds to aural toilet + topical fluoroquinolones
Treatment: Tympanoplasty

Atticoantral (Unsafe) - Red Path:

Scanty, foul-smelling discharge
White keratinous debris / cholesteatoma
Scutal erosion
Bone erosion on HRCT temporal bone
Does NOT respond to medical treatment
Treatment: Mastoidectomy (CWU or CWD)

Step 5 - Always Screen for Complications

Red flag symptoms requiring urgent imaging (HRCT + MRI):

Symptom	Suspect
Facial weakness	Facial nerve erosion
Vertigo	Labyrinthine fistula, lateral SCC erosion
Headache / neck stiffness	Meningitis, brain abscess
Diplopia + retro-orbital pain + otorrhea	Gradenigo syndrome (petrositis)
Postauricular swelling	Subperiosteal abscess

Sources: KJ Lee's Essential Otolaryngology | Shambaugh Surgery of the Ear | Cummings Otolaryngology

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