Chapter 18: Tinnitus

Introduction

Two categories based on whether observer can hear the tinnitus (objective) or not (subjective).

• Objective—much less common than subjective

  1. Vascular—typically corresponds to pulse (aka, pulse synchronous tinnitus); may be venous, arterial, or combination (arteriovenous) source or secondary to high-output cardiac state, tumors, other; (pulse synchronous tinnitus may be subjective also)

     • Pathogenesis:

       • – Venous sources

         • Jugular bulb: high riding and large, turbulent flow, dehiscent jugular plate at level of middle ear

         • Sigmoid sinus: diverticulum, turbulent flow, dehiscent sigmoid plate

         • Other venous structures: aberrant condylar vein, superior petrosal sinus, inferior petrosal sinus; aberrant vein contacting labyrinthine structures

       • – Arterial sources

         • Carotid artery: cervical carotid dissection, aneurysm, or stenosis; aberrant carotid artery; carotid body tumor; dehiscent carotid plate within the middle ear

         • Persistent stapedial artery: derived from internal carotid artery, passes through obturator foramen of stapes superstructure

       • – Arteriovenous (AV) malformations and dural AV fistulas

         • May be associated with venous drainage leading to enlarged cortical veins (high rate of bleeding)

         • Often associated with sigmoid/transverse sinus and prior craniotomy

       • – Tumors

         • Paraganglioma, middle ear adenoma, choristoma, facial nerve neuroma, hemangioma

         • Any tumor (or encephalocele) contacting the ossicular chain or TM may lead to pulse synchronous tinnitus (subjective or objective)

       • – High cardiac output states: anemia, thyrotoxicosis, pregnancy, beriberi, etc.

     • Diagnosis: Auscultation with stethoscope, Toynbee tube, palpation of peri-auricular tissue

       • – CT angiography

       • – Magnetic resonance angiography (MRA)/magnetic resonance venography (MRV)

       • – Formal cerebral angiography (small risk of stroke)

     • Treatment: based on etiology and severity of symptoms

       • – Selective embolization, surgical resection/clipping, and radiosurgery are options for dural AV fistulas and malformations.

       • – Surgical excision or combination of surgery and radiosurgery may be used for tumors.

       • – High output states should be medically corrected.

       • – Anatomic vascular abnormalities may or may not be amenable to intervention.

  2. Nonvascular—typically presents as clicking sensation

     • Palatal myoclonus—rapid (50-200 beats/min) irregular clicking caused by eustachian tube opening and closing from palatal musculature contraction.

       • – Symptoms often worse during times of stress

       • – Diagnosed by prolonged tympanogram showing movement with palatal contraction; may visualize palate with nasopharyngoscope as well; Toynbee tube may be used to auscultate rhythmic sound

       • – Treated with muscle relaxants or botox in refractory cases

       • – Often associated with central nervous system disease; MRI of posterior fossa should be performed to assess

     • Stapedial or tensor tympani muscle spasm

       • – Can be heard as clicking or crackling noise

       • – Diagnosis similar to above, but without observed palatal muscle contractions

       • – Treated with muscle relaxants or sectioning of tendons if refractory

     • Patulous eustachian tube—symptoms worsen with respiration and are often described as roaring sensation; autophony

       • – Can be diagnosed by TM movement with respiration, but not always visualized. Prolonged tympanometry may also be helpful

       • – Placement of head in dependent position for relief of symptoms

     • May be associated with temporomandibular joint disorders, normal swallowing that leads to TM movement (latter may be heard as single click with Toynbee tube)

• Subjective

  1. Incidence: 10% of population

  2. Can arise due to ...