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ENT Ward End Viva - Complete Guide for 2nd Year MBBS

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PART 1: ENT ANATOMY

A. The Ear

External Ear

• Made of elastic cartilage covered by perichondrium and skin (except lobule which is fibrofatty).
• Landmarks: helix, antihelix, tragus, antitragus, concha, scapha, triangular fossa, lobule.
• Blood supply: superficial temporal artery (anterior), posterior auricular artery (posterior).
• Nerve supply:
  • Auriculotemporal nerve (V3) - anterior pinna
  • Greater auricular nerve (C2,C3) - lower pinna and lobule
  • Lesser occipital nerve (C2) - upper posterior
  • Auricular branch of vagus (Arnold's nerve) - concha/EAC (reflex cough from ear cleaning)
  • Facial nerve (VII) - small contribution

• Total length: ~24 mm
• Outer one-third: cartilaginous (contains hair follicles, sebaceous glands, ceruminous glands)
• Inner two-thirds: bony
• S-shaped: curves anteriorly then posteriorly
• Lined by stratified squamous epithelium with centrifugal migration (self-cleaning)
• The isthmus is the narrowest part
• Anterior wall related to temporomandibular joint
• Posterior wall related to mastoid air cells
• Roof (tegmen) related to middle cranial fossa
• Floor related to parotid gland

• Dimensions: 9-10 mm vertical, 8-9 mm horizontal; thickness ~0.1 mm
• Located at 55° angle to the EAC floor
• Parts:
  • Pars tensa (larger, inferior): 3 layers - outer squamous epithelium, middle fibrous layer (radial + circular fibers), inner mucosal layer
  • Pars flaccida / Shrapnell's membrane (smaller, superior): only 2 layers (no middle fibrous layer); lies above the malleolar folds - this is the weakest part, site of attic perforations
• Landmarks on TM: light reflex (antero-inferior quadrant, 5 o'clock in right ear), handle of malleus (umbo at tip), lateral process of malleus, anterior and posterior malleolar folds
• The TM is divided into 4 quadrants by 2 imaginary lines through the umbo
• Blood supply: deep auricular artery (outer), tympanic branch of maxillary artery (inner)
• Innervation: auriculotemporal nerve (V3) outer surface; tympanic branch of IX inner surface (Jacobson's nerve)

Middle Ear (Tympanic Cavity)

• Ossicles: Malleus (handle + head + lateral process), Incus (body + short process + long process), Stapes (head + crura + footplate in oval window)
• Ossicular lever ratio: 1.3:1
• Muscles: Tensor tympani (nerve: V3 via otic ganglion - TENSE Tensor Tympani Third nerve) - dampens TM; Stapedius (nerve: VII - Stapedius Seven) - stapedial reflex
• Chorda tympani: branch of VII, crosses medial surface of TM between malleus and incus, carries taste from anterior 2/3 tongue and parasympathetic to submandibular + sublingual glands
• Jacobson's nerve (IX): forms tympanic plexus on promontory - carries pain sensation, becomes lesser petrosal nerve (parasympathetic to parotid via auriculotemporal nerve)

• Epitympanum (attic): above level of TM, contains head of malleus and body of incus; Prussak's space is the lateral epitympanic recess here
• Mesotympanum: level of TM
• Hypotympanum: below level of TM
• Protympanum: anterior portion
• Retrotympanum (sinus tympani, facial recess)

Eustachian Tube

• Length: ~35 mm in adults (17-18 mm at birth)
• Angle: Horizontal at birth; 45° incline by adulthood (explains why children are more prone to OM)
• Parts: anteromedial cartilaginous portion (24 mm) + posterolateral bony portion (11 mm)
• Narrowest point: junction of bony and cartilaginous portions (isthmus)
• Functions: ventilation, drainage, protection of middle ear
• Lined by pseudostratified columnar ciliated epithelium (cartilaginous part); ciliated cuboidal near tympanic end
• Normally CLOSED at rest, opens with swallowing/yawning by tensor veli palatini (V3) and levator veli palatini (X)
• In children, only tensor palati works (levator veli palatini too far) - reason cleft palate causes ET dysfunction
• Tonsil of Gerlach: lymphoid tissue within the ET
• Fat pad of Ostmann: lateral fat pad that helps keep the ET closed at rest

Inner Ear

• 2.5 turns, 35 mm long
• Scala vestibuli (above, perilymph), Scala media/cochlear duct (middle, endolymph), Scala tympani (below, perilymph)
• Organ of Corti sits on basilar membrane in scala media - contains inner hair cells (IHC: 3500, single row) and outer hair cells (OHC: ~12,000, 3 rows)
• Tonotopic: high frequency at base, low frequency at apex
• Helicotrema: apex where scala vestibuli and tympani communicate
• Blood supply: labyrinthine artery (branch of AICA/basilar)

• 3 semicircular canals (superior, posterior, lateral/horizontal)
• Utricle (detects linear acceleration, horizontal) and Saccule (vertical)
• Hair cells: kinocilium (longest stereocilium) and stereocilia
• Lateral SCC: horizontal movement
• Superior SCC: parallel to head rotation in sagittal plane; posterior SCC: BPPV (posterior canal)

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B. The Nose and Paranasal Sinuses

• Perpendicular plate of ethmoid (posterosuperior)
• Vomer (posteroinferior)
• Septal cartilage (quadrilateral/anterior)
• Maxillary crest (floor)

• 3 turbinates (conchae): inferior (largest, most important - contains inferior turbinate bone), middle (part of ethmoid), superior (part of ethmoid)
• Supreme turbinate (vestigial, if present)
• Meatuses named below each turbinate:
  • Inferior meatus: nasolacrimal duct opens here
  • Middle meatus: drainage of frontal sinus (via frontonasal duct/infundibulum), maxillary sinus (via hiatus semilunaris), anterior ethmoidal cells - this is the OSTIOMEATAL COMPLEX
  • Superior meatus: posterior ethmoidal cells
  • Sphenoethmoidal recess: sphenoidal sinus

• Anterior ethmoidal artery (ophthalmic artery - ICA)
• Posterior ethmoidal artery (ophthalmic - ICA)
• Sphenopalatine artery (maxillary - ECA) - most important
• Greater palatine artery (maxillary - ECA)
• Superior labial artery (facial - ECA)
• Site of 90% of epistaxis

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C. The Pharynx and Larynx

• Nasopharynx (above soft palate): contains adenoids (pharyngeal tonsil), Eustachian tube openings (fossa of Rosenmuller behind), choanae anteriorly
• Oropharynx (between soft palate and epiglottis): palatine tonsils (faucial tonsils) in tonsillar fossa, bounded by palatoglossal fold (anterior) and palatopharyngeal fold (posterior), vallecula
• Hypopharynx (below epiglottis): pyriform sinuses, posterior pharyngeal wall, post-cricoid area - site of foreign body impaction

• C3-C6 level in adults
• Cartilages: thyroid (largest), cricoid (only complete ring - hyaline), arytenoids (hyaline), epiglottis (elastic fibrocartilage), corniculate, cuneiform
• Ligaments: thyrohyoid membrane, cricothyroid membrane (emergency airway access - cricothyrotomy site), cricotracheal ligament
• Vocal folds (true cords): at level of C5; mucosa = stratified squamous; ligament = vocal ligament; muscle = vocalis (thyroarytenoid)
• Vestibular folds (false cords): above true cords; mucosa = pseudostratified columnar epithelium
• Rima glottidis: space between two true vocal folds
• Piriform fossa: on either side of larynx - internal branch of SLN runs here (foreign bodies lodge here)

• Superior laryngeal nerve (SLN) from CN X: external branch - motor to cricothyroid (pitch); internal branch - sensory above cords
• Recurrent laryngeal nerve (RLN) from CN X: motor to all intrinsic muscles except cricothyroid; sensory below cords
• Left RLN loops under aorta; Right RLN loops under right subclavian

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PART 2: KEY PATHOLOGY

Ear Conditions

Nose Conditions

Throat Conditions

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PART 3: INVESTIGATIONS IN ENT

Hearing Tests

• Pure tone audiogram (PTA): air conduction, bone conduction; air-bone gap indicates conductive HL
• Speech audiogram: tests understanding of speech
• Tympanometry (impedance audiometry):
  • Type A: normal
  • Type B: flat - OME / perforation / cholesteatoma
  • Type C: negative peak - Eustachian tube dysfunction
  • Type As: shallow peak - otosclerosis
  • Type Ad: deep peak (compliance increased) - ossicular discontinuity
• Otoacoustic emissions (OAEs): test outer hair cell function; used in neonatal hearing screening
• BERA/ABR: brainstem evoked response; threshold estimation; retrocochlear testing

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PART 4: CHRONIC SUPPURATIVE OTITIS MEDIA (CSOM) - DETAILED OVERVIEW

Definition

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Types / Classification

Type 1: Tubotympanic (Mucosal) CSOM - "Safe" or "Benign" Type

• Perforation: Central perforation (within the pars tensa, with a rim of tympanic membrane all around - never reaches the annulus)
• Discharge: Mucoid or mucopurulent, NOT offensive smelling (no keratin)
• Pathology: Mucosal disease - hyperplastic mucosa, granulation tissue, polyps; NO cholesteatoma
• Hearing: Conductive hearing loss (usually mild-moderate)
• Mastoid: Usually pneumatized, antrum clear or with mucosa thickening
• Prognosis: "Safe" - lower risk of serious complications
• Treat with medical management and tympanoplasty when ear is dry

Type 2: Atticoantral (Squamosal) CSOM - "Dangerous" or "Unsafe" Type

• Perforation: Attic (in pars flaccida - hence "attic perforation") OR marginal perforation (reaches the annulus, usually posterosuperior in pars tensa)
• Discharge: Scanty, OFFENSIVE/foul-smelling (keratin debris - hallmark of cholesteatoma)
• Pathology: CHOLESTEATOMA - presence of keratinizing squamous epithelium in the middle ear cleft, with bone erosion
• Hearing: Conductive hearing loss (can be paradoxically good if cholesteatoma bridges ossicular gap)
• Mastoid: Sclerotic mastoid (poorly pneumatized), mastoid antrum involved
• Prognosis: "Dangerous" - high risk of complications due to bone erosion
• Treatment: ALWAYS surgical (tympanomastoid surgery)

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Pathogenesis

• Primary trigger for CSOM
• ET dysfunction leads to persistent negative pressure in the middle ear
• Causes: recurrent AOM, adenoid hypertrophy (blocks ET orifice in children), cleft palate, allergy, upper respiratory infections

• Negative pressure → transudation → serous effusion
• Bacterial infection converts this to a purulent effusion

• Purulent effusion generates inflammatory response
• Bacterial toxins + inflammatory mediators interact with edematous mucosa
• Ruptures of basement membrane of epithelia occur
• Inflammatory cells from lamina propria enter the middle ear lumen
• Angiogenic growth factors + epithelial growth factors stimulate fibroblast recruitment, neovascularization → granulation tissue and polyp formation
• Chronic inflammation leads to development of submucosal glands → secretory mucosa → perpetuates effusion

• Enzymes in granulation tissue and effusion break down the collagen skeleton of the TM
• Weakened TM + negative pressure → retraction pockets (especially in pars flaccida - weakest area)
• Deepening retraction pockets contact underlying mucosa → fibrous adhesions → perforation
• Perforation in pars tensa = central (tubotympanic type)
• Perforation/retraction in pars flaccida or marginal pars tensa = pathway to cholesteatoma

• Retraction pocket theory (most accepted): Pars flaccida retracts due to negative middle ear pressure → keratin accumulates in Prussak's space → self-cleaning mechanism fails → keratinous debris builds up → cholesteatoma
• Migration theory: Squamous epithelium migrates through marginal perforation into middle ear
• Metaplasia theory: Middle ear respiratory epithelium undergoes squamous metaplasia
• Implantation theory: Squamous cells implanted during trauma/surgery

• Tubotympanic CSOM: S. aureus, P. aeruginosa, Proteus, anaerobes, mixed flora
• Atticoantral CSOM: similar bacteria + anaerobes (Bacteroides, Peptostreptococcus)
• P. aeruginosa and S. aureus are the most common pathogens overall

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Symptomatology

• Tubotympanic: Mucopurulent, non-offensive, intermittent (worse with URTIs)
• Atticoantral: Scanty, offensive/foul-smelling (hallmark), purulent with keratin debris

• Conductive hearing loss in both types
• Degree depends on size of perforation and ossicular status
• Small central perforations: mild CHL (15-20 dB)
• Large perforations: moderate CHL (30-40 dB)
• Ossicular erosion: moderate-severe CHL (>40 dB)
• Paradoxical good hearing: cholesteatoma may act as a sound-conducting mass bridging an ossicular gap
• Sensorineural component: labyrinthine fistula or toxin spread through round window

• Usually ABSENT in uncomplicated CSOM
• Presence of otalgia/headache should raise RED FLAG for:
  • Intracranial complication (meningitis, extradural abscess, brain abscess)
  • Malignancy
  • Acute exacerbation on chronic

• May be present, usually low frequency in conductive HL

• Absent in uncomplicated CSOM
• Presence raises suspicion of:
  • Labyrinthine fistula (lateral SCC erosion by cholesteatoma - most common)
  • Labyrinthitis (toxic or suppurative)

• Facial palsy: erosion of fallopian canal (dehiscent facial nerve)
• Neck stiffness, photophobia: meningitis
• Persistent headache: extradural or subdural abscess
• Postauricular swelling: mastoid abscess
• Retroorbital pain: petrous apicitis (Gradenigo's syndrome: ipsilateral VI nerve palsy + retroorbital pain + otorrhoea)

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Local Examination Findings

External Ear

• Postauricular region: scar (previous surgery), swelling/redness (mastoiditis), fistula
• Pinna: pushed forward/downward if subperiosteal abscess
• Tragal tenderness: ABSENT (present in otitis externa - helps differentiate)
• External auditory canal: narrowed/edematous if secondary otitis externa; polypoid tissue may be seen; discharge (mucoid or purulent/offensive)

Otoscopy / Examination of Tympanic Membrane

• Perforation: Central, within pars tensa; annular rim of TM visible all around the perforation
• Types of central perforation: small/medium/large (subtotal); kidney-shaped, oval, or irregular
• Middle ear mucosa visible through perforation: may be pale/normal, hyperemic, or covered with granulation tissue/polyps
• Discharge: Mucoid or mucopurulent, non-offensive; may obscure the TM
• Retraction: May have associated retraction of remaining TM
• Ossicles: May be visible through large perforations; check for continuity
• No attic disease: Pars flaccida appears normal

• Attic perforation: Small crust or crust-covered defect in pars flaccida (superiorly, above the malleolar folds) - this is PATHOGNOMONIC
• OR Marginal perforation: In posterosuperior quadrant of pars tensa, reaching the annulus
• Cholesteatoma: Pearly white glistening mass of keratin debris visible in attic or through marginal perforation; has characteristic white sheen
• Discharge: Scanty but offensive/foul-smelling (due to keratin breakdown by bacteria - especially Pseudomonas)
• Scutum erosion: Blunting or erosion of the lateral attic wall (scutum) - best seen on coronal CT
• Granulation tissue/aural polyp: May fill the EAC and bleed easily on probing
• Retraction pockets: Deep retraction of pars flaccida; may not be easily visible if filled with keratin
• Ossicular erosion: Long process of incus (most commonly eroded), stapes suprastructure; causes increased CHL

Probing:

• Probe/curette through perforation may reveal:
  • Granulation tissue (bleeds easily)
  • Cholesteatoma (white, waxy, non-bleeding)
  • Ossicular chain integrity or absence
  • Bony ledge (scutum erosion)

Hearing Assessment:

• Tuning fork tests (Rinne negative, Weber to affected ear - both in CHL)
• PTA: air-bone gap (conductive component); bone conduction may be reduced if sensorineural involvement

Signs suggesting complications on examination:

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Investigations

1. Pure Tone Audiogram (PTA): Assess degree and type of hearing loss; air-bone gap quantification
2. Tympanometry: Type B (flat) or Type C in CSOM
3. Radiology:
   • CT Temporal Bone (HRCT): Investigation of choice for bone erosion, mastoid status, extent of cholesteatoma, scutum erosion, ossicular erosion, labyrinthine fistula
   • MRI (DWI - diffusion-weighted imaging): Best for detecting recurrent/residual cholesteatoma; cholesteatoma shows restricted diffusion (low water mobility due to packed keratin)
4. Swab for culture and sensitivity: To guide antibiotic therapy
5. X-ray mastoid (obsolete but still taught): Schuller's view (lateral oblique), Stenver's view, Towne's view

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Treatment

Medical Treatment (Conservative)

1. Aural Toilet: Dry mopping of the ear using twisted absorbent cotton-tipped probes; removes discharge, debris; essential before applying topical medications; syringing is CONTRAINDICATED in CSOM (risk of further contamination, labyrinthine damage)
2. Topical Antibiotic Ear Drops:
   • Fluoroquinolone ear drops (ciprofloxacin/ofloxacin): FIRST LINE - safe for middle ear (non-ototoxic)
   • Acetic acid 2%: antiseptic, effective, cheap
   • Avoid aminoglycoside ear drops (gentamicin, neomycin) - ototoxic through round window if TM is perforated
3. Systemic Antibiotics: Only if systemic features or failure of topical therapy
   • Based on culture/sensitivity; commonly amoxicillin-clavulanate, ciprofloxacin (for Pseudomonas)
4. Water precautions: No swimming, use petroleum jelly-soaked cotton plug while bathing
5. Treat underlying cause: Adenoid hypertrophy, allergic rhinitis, ET dysfunction

Surgical Treatment

• Myringoplasty: Repair of TM perforation alone (no mastoid surgery)
  • Graft materials: temporalis fascia (most commonly used), perichondrium, fat plug (small perforations)
  • Techniques: underlay (most common - graft placed medial to TM remnant) vs. overlay
  • Best results: dry ear, good Eustachian tube function
• Tympanoplasty Type I: Myringoplasty only (no ossicular reconstruction needed)
• Tympanoplasty Types II-V: Include ossicular reconstruction (ossiculoplasty)
• Combined approach tympanoplasty: Tympanoplasty + cortical mastoidectomy if mastoid disease present

• Canal Wall Up (CWU) / Closed technique (Combined approach tympanomastoidectomy):
  • Posterior canal wall preserved
  • Better cosmesis; normal-looking ear canal
  • Higher recurrence (cholesteatoma may be missed)
  • Requires planned second-look surgery
• Canal Wall Down (CWD) / Open technique (Modified radical mastoidectomy):
  • Posterior canal wall removed; mastoid + middle ear = single cavity (meatoplasty required)
  • Complete eradication of disease
  • Lower recurrence
  • Open cavity requires lifelong regular follow-up/cleaning
  • Patient cannot swim freely
• Radical Mastoidectomy: Removes all middle ear contents + ossicles + TM; sacrifices hearing; reserved for extensive/irreversible disease or malignancy
• Atticotomy / Attic exploration: For limited attic cholesteatoma
• Ossiculoplasty: Ossicular chain reconstruction at same or second-stage surgery using TORP (total ossicular replacement prosthesis), PORP (partial), or autologous ossicle/cartilage

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PART 5: COMPLICATIONS OF CSOM

Intratemporal (Extracranial) Complications:

1. Mastoiditis (acute/coalescent/chronic)
2. Labyrinthitis (toxic/suppurative) - vertigo, SNHL
3. Petrous apicitis (Gradenigo's syndrome): VI nerve palsy + retroorbital pain + otorrhoea (triad)
4. Facial nerve palsy (dehiscent fallopian canal eroded by cholesteatoma)
5. Labyrinthine fistula (lateral SCC most commonly - positive fistula test = Politzer's sign)

Intracranial Complications:

1. Extradural abscess (most common intracranial complication)
2. Subdural abscess/empyema (serious, rapid deterioration)
3. Meningitis (most common intracranial complication in some series - meningismus, Kernig's sign)
4. Brain abscess - temporal lobe (from middle ear) or cerebellar (from mastoid)
5. Lateral sinus thrombophlebitis (sigmoid sinus thrombosis) - Griesinger's sign (postauricular edema due to thrombosis of mastoid emissary vein)
6. Otitic hydrocephalus (raised ICP without brain abscess - rare)

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PART 6: QUICK REVISION - COMMON VIVA QUESTIONS

• Tubotympanic = safe (mucosal, no bone erosion). Atticoantral = dangerous (bone-eroding cholesteatoma, risk of serious complications).

• Pseudomonas aeruginosa and Staphylococcus aureus (most common); mixed flora including anaerobes.

• Fluoroquinolones (ciprofloxacin/ofloxacin ear drops). Aminoglycosides are CONTRAINDICATED (ototoxic through open perforation).

• Uncomplicated CSOM is painless. Pain suggests intracranial/intratemporal complication or malignancy.

• A collection of keratinizing squamous epithelium in the middle ear cleft with bony erosion. Types: congenital and acquired (primary acquired from pars flaccida retraction - most common; secondary acquired from marginal perforation).

• Triad: ipsilateral VIth nerve palsy (diplopia) + retroorbital pain (Vth nerve) + otorrhoea; caused by petrous apicitis.

• Rinne: Left ear negative (BC > AC). Right ear positive (normal). Weber: Lateralizes to LEFT (affected) ear.

• Positive if pressure in EAC (via pneumatic otoscope or Siegle speculum) produces nystagmus or vertigo, indicating a fistula between middle ear and labyrinth (usually lateral SCC eroded by cholesteatoma).

• HRCT temporal bone. MRI DWI is used for detecting residual/recurrent cholesteatoma postoperatively.

• Lateral epitympanic recess, between the pars flaccida and the neck of the malleus. The initial site of cholesteatoma accumulation in pars flaccida disease.

• Tensor veli palatini (V3); levator veli palatini (X) assists in adults.

• Arnold's nerve - auricular branch of vagus (X); stimulation of EAC/TM triggers cough via vagal reflex (Alderman's nerve or Arnold's reflex).

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Quick Summary Card: CSOM Comparison

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1. ENT Anatomy - Complete breakdown of the external/middle/inner ear (TM layers, middle ear walls, Eustachian tube facts, ossicles), nose (Kiesselbach's plexus, turbinates, paranasal sinus drainage), pharynx, and larynx with nerve supply.
2. Key ENT Pathology - Rapid-fire tables for common ear, nose, and throat conditions.
3. Investigations - Tuning fork interpretation (Rinne/Weber), tympanometry types, and audiological tests.
4. CSOM - Full Deep Dive:
   • Two types: Tubotympanic (safe/central perforation) vs. Atticoantral (dangerous/attic perforation + cholesteatoma)
   • Complete pathogenesis step-by-step from ET dysfunction → mucosal inflammation → retraction pocket → cholesteatoma
   • All symptoms with danger signs explained
   • Detailed local examination findings for both types
   • Medical (aural toilet + topical fluoroquinolones) and surgical (myringoplasty / CWU vs. CWD mastoidectomy) treatment
   • Full complications list: Gradenigo's syndrome, Griesinger's sign, lateral sinus thrombosis
5. High-Yield Viva Q&A - 12 rapid questions with model answers

• Attic perforation + offensive discharge = cholesteatoma = dangerous = surgery always
• Otalgia in CSOM = red flag (complication/malignancy)
• Only fluoroquinolone drops are safe (NOT aminoglycosides) when TM is perforated
• Prussak's space = where cholesteatoma starts in pars flaccida disease