Noise induced hearing loss
Noise-Induced Hearing Loss (NIHL) 🎧🔊:
A preventable form of sensorineural hearing loss caused by loud sound exposure that damages cochlear hair cells.
Once hair cells are lost, the damage is irreversible.
About ℹ️
- Results from acoustic trauma (single loud blast 💥) or chronic loud sound exposure (e.g. concerts, workplaces 🏗️).
- One of the most common causes of acquired hearing loss worldwide 🌍.
- Prevention with ear protection is key! 🎧🛡️
Aetiology 🧬
- Acute Exposure 💥: Explosion, gunshot, firework.
- Chronic Exposure 🎶⚙️: Repeated loud noise (factories, concerts, headphones at high volume).
- Pathology: Cochlear hair cell damage → apoptosis → permanent loss (no regeneration 🚫).
Risk Factors ⚠️
- Recreational:
- Target shooting 🎯 / hunting.
- Motorsports 🏍️ / snowmobiles.
- Headphones/earbuds at high volume 🎧.
- Concerts / musicians 🎸🎤.
- Occupational:
- Construction sites 🏗️, factories 🏭, workshops 🔧.
- Power tools, lawnmowers, leaf blowers, woodworking equipment 🪚.
Clinical Features 👂
- Progressive hearing loss — first noticed as difficulty following speech in noisy environments 🍻.
- Tinnitus 🔔 (ringing/buzzing) — may precede or accompany loss.
- Typically bilateral, symmetrical, high-frequency hearing loss.
Differential Diagnoses 🔍
- Presbycusis 👵 (age-related high-frequency loss).
- Ototoxic drug exposure 💊 (aminoglycosides, loop diuretics, cisplatin).
- Sudden sensorineural hearing loss ⚡.
- Middle ear pathology 🦻 (otosclerosis, chronic otitis media).
Investigations 🧪
- Audiometry 🎧:
- Classic “4 kHz notch” 📉 — maximum loss at 4000 Hz.
- Pattern persists even in advanced NIHL.
Management 💊🛠️
- Prevention 🛡️:
- Earplugs / earmuffs 🎧.
- Safe listening practices: lower device volume 📱🎶.
- Occupational noise controls (soundproofing, equipment maintenance 🏗️).
- Hearing Rehabilitation 👂:
- Hearing aids for significant loss.
- Counselling + education on hearing conservation.
- Tinnitus Management 🔔: Sound therapy, CBT/counselling, relaxation techniques 🧘.
References 📚
💡 Clinical Pearls
- Classic “4 kHz notch” = exam clue for NIHL 🎯.
- NIHL is preventable but irreversible — patient education is crucial 📢.
- Differentiate from presbycusis (age-related, gradual, symmetric high-frequency loss 👵).
