Pediatric Deafness and NPPCD

MS ENT University Examination Answer - 20 Marks

PART A: PEDIATRIC DEAFNESS (10 marks)

Definition and Epidemiology

Classification of Hearing Loss

• Congenital (present at birth) - prelingual
• Perinatal
• Postnatal - may be prelingual (< 2 yrs) or postlingual (> 2 yrs)

• Mild (26-40 dB), Moderate (41-55 dB), Moderately severe (56-70 dB)
• Severe (71-90 dB), Profound (> 90 dB)

Etiology

I. GENETIC CAUSES (70-80% in developed countries)

• Autosomal Recessive (DFNB) - 75-80%: GJB2 gene (Connexin 26) accounts for up to 50% of severe-to-profound congenital AR non-syndromic deafness. STRC gene deletions account for the majority of mild-to-moderate AR non-syndromic deafness.
• Autosomal Dominant (DFNA) - 20-25%: Usually later onset, progressive
• X-linked (DFNX) - < 2%: Males affected more severely
• Mitochondrial: Maternal inheritance; associated with aminoglycoside ototoxicity (MT-RNR1/A1555G mutation)

II. ACQUIRED CAUSES

• TORCH infections: Toxoplasma, Rubella, CMV (most common congenital viral cause; congenital CMV = cCMV), HSV, Syphilis
• Ototoxic drugs in pregnancy: aminoglycosides, quinine, thalidomide
• Alcohol (fetal alcohol syndrome)

• Prematurity, Low birth weight (< 1500 g)
• Birth asphyxia / hypoxia
• Hyperbilirubinemia (kernicterus)
• NICU stay > 5 days

• Bacterial meningitis (most common cause of acquired SNHL in children - Streptococcus pneumoniae most damaging)
• Viral: Mumps (unilateral sudden profound SNHL), Measles, CMV
• Ototoxic drugs: aminoglycosides, cisplatin
• Noise exposure
• Head trauma
• Chronic otitis media (conductive HL)

Diagnosis

Universal Newborn Hearing Screening (UNHS)

• All newborns screened before hospital discharge
• OAE (Otoacoustic Emissions) - first-line screen; tests outer hair cell function
• AABR (Automated ABR) - used for NICU babies; detects ANSD
• "Refer" result -> diagnostic ABR within 3 months

Diagnostic Workup ("1-3-6 rule")

• Screen by 1 month, diagnose by 3 months, fit hearing aid and enroll in early intervention by 6 months

Audiological Tests

• BERA/ABR (Brainstem Evoked Response Audiometry) - gold standard in infants
• ASSR (Auditory Steady State Response) - frequency-specific thresholds
• VRA (Visual Reinforcement Audiometry) - 6 months to 2.5 years
• CPA (Conditioned Play Audiometry) - 2.5 to 5 years
• Pure Tone Audiometry - from 5 years onwards
• Tympanometry - assess middle ear

Investigations

• Ophthalmology assessment (Usher, Alport, Stickler)
• ECG (Jervell and Lange-Nielsen)
• Renal ultrasound (BOR, Alport)
• Thyroid function (Pendred)
• Genetic testing - first test after history, examination, and audiometry; highest diagnostic rate (GJB2/STRC sequencing, gene panels)
• HRCT temporal bone - inner ear malformations (Mondini deformity, EVA)
• MRI IAM - cochlear nerve aplasia, ANSD

Management

A. Medical / Conservative

• Treat underlying cause (OM with effusion - watchful waiting, grommets)
• Treat congenital infections (CMV - valganciclovir within first month)

B. Amplification

• Hearing aids - fitted as early as possible (< 6 months); all degrees of HL; binaural fitting preferred
• BAHA (Bone-Anchored Hearing Aid) - for atresia, unilateral deafness, chronic discharge preventing use of conventional HA
• CROS/BiCROS - single-sided deafness

C. Cochlear Implantation

• Indicated in severe-to-profound bilateral SNHL where hearing aids provide inadequate benefit
• Criteria: Usually > 12 months age (some centers < 12 months in bilateral profound deafness)
• Best outcomes with early implantation (within sensitive period before 3 years)
• Bilateral CI superior to unilateral
• Cross-modal neuroplasticity is a key concern: prolonged auditory deprivation leads to visual/somatosensory cortex "takeover" of auditory cortex, reducing CI outcomes - underlining urgency of early implantation (Cummings, p. 3042-3079)

D. Habilitation

• Speech and language therapy
• Auditory Verbal Therapy (AVT)
• Special education / mainstream education with support
• Sign language (Deaf community, capital "D")

PART B: NPPCD - NON-PURULENT PERFORATION OF CHRONIC EAR DISEASE (10 marks)

Definition

A permanent central perforation of the pars tensa of the tympanic membrane in which the middle ear and mastoid mucosa are NOT inflamed and there is no active infection or discharge at the time of examination.

• Inactive Mucosal COM
• Dry Central Perforation
• Tubotympanic disease (inactive) - older terminology
• "Safe" or "Benign" type of CSOM

Pathophysiology

Sites of Perforation

• Anterior central - Anteroinferior pars tensa
• Posterior central - Posteroinferior
• Subtotal - Large, single rim remaining
• Total - Involving entire pars tensa (annulus intact)

Etiology

1. Acute Otitis Media (AOM) where TM perforation fails to heal (most common)
2. Ventilation (grommet) tubes which fail to close after removal
3. Ascending Eustachian tube infections (chronic)
4. Trauma (barotrauma, direct)
5. Rarely: food allergies

Clinical Features

• Hearing loss - typically Conductive Hearing Loss (CHL) - degree depends on size and site of perforation; posterior perforations cause more HL due to loss of "round window baffling effect"
• Intermittent ear discharge (during URTI or water ingress) - mucoid, non-foul, non-offensive
• No pain (otalgia would suggest acute infection or complication)
• No tinnitus, no vertigo in uncomplicated cases

• Dry central perforation of pars tensa
• Middle ear mucosa appears pale/normal through perforation (contrast: inflamed/edematous mucosa = active disease)
• No polyp, no cholesteatoma
• No marginal or attic perforation
• Ossicular chain may be partially visible through large perforations

Investigations

1. Pure Tone Audiometry (PTA) - Conductive HL (air-bone gap); typically 20-45 dB; bone conduction normal
2. Tympanometry - Type B or flat curve; large volume
3. Tuning fork tests - Rinne negative (BC > AC); Weber lateralizes to affected (worse) ear in unilateral CHL
4. HRCT Temporal Bone - Before surgery; assesses:
   • Ossicular chain integrity
   • Mastoid pneumatization
   • Tegmen / sinus plate / facial nerve canal
   • Rules out hidden cholesteatoma
5. Culture & sensitivity of any discharge if active phase
6. BERA if sensorineural component suspected

Management

Conservative (Initial)

1. Dry ear precautions - avoid water entry (cotton wool with petroleum jelly while bathing)
2. Treat URTI promptly to prevent recurrent active episodes
3. Aural toilet (microsuction, dry mopping) if any discharge
4. Topical antibiotics (e.g., ciprofloxacin drops) during active exacerbation
5. Hearing aid if patient is not a surgical candidate or declines surgery

Surgical - Myringoplasty / Tympanoplasty

• Dry ear for minimum 6-8 weeks (quiescent phase)
• Desire for hearing improvement
• Recurrent episodes of active discharge
• Pre-surgical requirement for hearing aid fitting (CROS/BAHA consideration)
• Prevention of complications

• Temporalis fascia - most common; excellent results
• Tragal perichondrium
• Cartilage + perichondrium (for large perforations, revision surgery, high-risk ears)

• Underlay technique - graft placed medial to TM remnant; most commonly used
• Overlay technique - graft placed lateral to remnant; better for anterior perforations
• Transcanal (for small posterior perforations) vs. Postauricular (for large/anterior perforations)

• Success rate 85-95% in dry ears
• Hearing improvement expected 10-15 dB (air-bone gap closure) in uncomplicated cases
• Poorer outcomes: anterior perforations, poor Eustachian tube function, revision surgery, wet ears

Complications of Neglected NPPCD

1. Permanent conductive HL - ossicular erosion (long process of incus most vulnerable)
2. Tympanosclerosis - chalky deposits in TM/middle ear
3. Adhesive otitis media - fibrosis obliterating middle ear space
4. Secretory OM - mucosal metaplasia
5. Serious complications (rare but possible during active phase): mastoiditis, labyrinthitis, facial nerve palsy, intracranial complications

Key Distinguishing Points: NPPCD vs. Dangerous Ear

Summary Table for Quick Revision