Tinnitus: A Comprehensive Guide for MCCQE1

Introduction

Tinnitus is defined as the perception of sound in the absence of external acoustic stimulation. It is a symptom, not a disease entity itself. For MCCQE1 preparation, understanding the distinction between subjective and objective tinnitus, recognizing red flags requiring urgent ENT referral, and knowing the appropriate Canadian diagnostic algorithms is crucial.

In the context of the CanMEDS framework, the Medical Expert role requires you to differentiate benign causes from life-threatening pathologies (like vestibular schwannoma or glomus tumors), while the Health Advocate role involves addressing the significant psychological impact tinnitus can have on a patient’s quality of life.

Classification and Etiology

Tinnitus is broadly classified into Subjective (only the patient hears it) and Objective (the examiner can hear it).

Common Ototoxic Drugs in Canada

Knowledge of ototoxicity is high-yield for MCCQE1.

Clinical Assessment

1. History Taking

Focus on characterizing the sound and identifying associated symptoms.

• Character: Ringing, buzzing, hissing, clicking, or pulsing?
• Laterality: Unilateral vs. Bilateral (Unilateral is a Red Flag).
• Pattern: Constant, intermittent, or pulsatile (synchronous with heartbeat)?
• Associated Symptoms: Hearing loss, vertigo, aural fullness, otorrhea, facial weakness.
• History: Noise exposure, head trauma, medications, TMJ issues.

2. Physical Examination

A complete Head and Neck exam is required.

• Otoscopy: Rule out cerumen impaction, otitis media, or a retrotympanic mass (e.g., Reddish-blue mass = Glomus tumor; Schwartze sign = Otosclerosis).
• Auscultation: Listen over the orbit, mastoid, neck, and skull for bruits (Objective Tinnitus).
• Cranial Nerves: Focus on CN V, VII, and VIII. Test corneal reflex (early sign of acoustic neuroma).
• Tuning Fork Tests: Weber and Rinne to distinguish Conductive vs. Sensorineural Hearing Loss.
• Temporomandibular Joint (TMJ): Palpate for tenderness or clicks.

Diagnostic Approach

Follow this step-by-step approach for the MCCQE1 clinical reasoning process.

Management

Management depends entirely on the underlying cause.

Treatable Causes

• Cerumen: Removal.
• Medication: Stop or switch ototoxic drugs.
• Vascular/Tumor: Surgical intervention (e.g., glomus tumor resection).
• Depression/Anxiety: SSRIs/CBT (Treating the comorbidity often reduces tinnitus annoyance).

Idiopathic / Sensorineural Tinnitus

When no reversible cause is found (most common scenario), management shifts to habituation.

1. Hearing Aids:
   • Most effective treatment if hearing loss is associated. Amplifying ambient sound masks the tinnitus.
2. Sound Therapy (Masking):
   • White noise machines, fans, or music to decrease the contrast between the tinnitus and the environment.
3. Tinnitus Retraining Therapy (TRT):
   • A combination of directive counseling and sound therapy to facilitate habituation.
4. Cognitive Behavioral Therapy (CBT):
   • Highly evidenced-based for reducing the distress associated with tinnitus, even if the loudness remains unchanged.

Canadian Guidelines & Context

• Choosing Wisely Canada: Emphasizes avoiding routine imaging for symmetric, non-pulsatile tinnitus with normal hearing.
• Wait Times: In the Canadian system, MRI wait times can be long. For sudden sensorineural hearing loss (SSNHL) + tinnitus, immediate referral to an ENT or Emergency Department is required to initiate corticosteroids; do not wait for the MRI to treat SSNHL.
• Audiology Access: In many Canadian provinces, a referral is not strictly required to see a private audiologist, but a physician referral is needed for hospital-based audiology covered by provincial health plans.

Key Points to Remember for MCCQE1

• Unilateral Tinnitus + Asymmetric SNHL = Vestibular Schwannoma until proven otherwise (Order MRI).
• Pulsatile Tinnitus = Vascular etiology (Order CTA/MRA and Auscultate).
• Presbycusis is the most common cause of bilateral tinnitus in the elderly (High-frequency SNHL).
• Salicylate toxicity causes reversible tinnitus.
• Glomus Tympanicum presents as a pulsatile tinnitus with a reddish-blue mass behind the tympanic membrane.

Mnemonic: “PULSE” (For Pulsatile Tinnitus)

• P - Persistent stapedial artery
• U - Uneven vessel (Stenosis/Dissection)
• L - Lesion (Glomus tumor)
• S - Structural (High riding jugular bulb)
• E - Essential (Benign intracranial hypertension)

Sample Question

Stem: A 52-year-old male presents to his family physician complaining of a “ringing” sound in his right ear that has been present for the past 6 months. He notes that the sound is constant and high-pitched. He also reports difficulty understanding speech on the phone when using his right ear. He denies vertigo, facial weakness, or headache. He has no history of noise exposure or head trauma. Physical examination, including otoscopy and cranial nerve exam, is unremarkable. Weber test lateralizes to the left ear. Rinne test is positive (Air Conduction > Bone Conduction) bilaterally.

Lead-in: Which one of the following is the most appropriate next diagnostic step?

Options:

• A. Reassurance and follow-up in 6 months
• B. CT scan of the head without contrast
• C. MRI of the internal auditory canal with gadolinium
• D. Carotid Doppler ultrasound
• E. Oral corticosteroids

Explanation

The correct answer is:

• C. MRI of the internal auditory canal with gadolinium

Detailed Explanation:

This patient presents with unilateral tinnitus and clinical findings suggestive of asymmetric sensorineural hearing loss (SNHL).

• The Weber test lateralizes to the good ear in SNHL. Here it lateralizes to the left, implying right-sided SNHL (since the Rinne is positive, ruling out conductive loss).
• The combination of unilateral tinnitus and asymmetric SNHL is the classic presentation of a Vestibular Schwannoma (Acoustic Neuroma).
• The gold standard investigation to rule out retrocochlear pathology (like a vestibular schwannoma) is an MRI of the Internal Auditory Canal (IAC) with gadolinium.

Why other options are incorrect:

• A. Reassurance: Unilateral symptoms are a red flag and must be investigated.
• B. CT Head: CT is inferior to MRI for visualizing soft tissue tumors in the IAC and cerebellopontine angle. CT is better for bony pathology.
• D. Carotid Doppler: This would be appropriate for pulsatile tinnitus to rule out carotid stenosis, but this patient has constant, high-pitched tinnitus.
• E. Oral Steroids: These are indicated for Sudden Sensorineural Hearing Loss (SSNHL) presenting within 72 hours to 2 weeks. This patient’s symptoms have been chronic for 6 months.

References

1. Medical Council of Canada. MCCQE Part I Objectives: Hearing Loss and Tinnitus. Available at: mcc.ca 
2. Toronto Notes 2024. Otolaryngology Chapter: Tinnitus and Hearing Loss.
3. Choosing Wisely Canada. Otolaryngology - Head and Neck Surgery: Five Things Physicians and Patients Should Question. Available at: choosingwiselycanada.org 
4. Canadian Society of Otolaryngology - Head & Neck Surgery. Clinical Practice Guidelines.
5. CMAJ. Diagnostic approach to tinnitus. Can Med Assoc J.