What are the diagnostic steps and treatment options for a patient experiencing a pulsation heard in their left ear?

Pulsatile Tinnitus in the Left Ear: Diagnostic and Treatment Approach

Immediate Clinical Assessment

A patient with pulsatile tinnitus in the left ear requires urgent imaging evaluation because this symptom indicates an underlying vascular or structural abnormality in over 70% of cases, and missing life-threatening causes like dural arteriovenous fistula or arterial dissection can result in catastrophic hemorrhage or stroke. 1, 2

Critical Initial Examination Steps

Perform a focused otoscopic examination to identify:

• Vascular retrotympanic mass (suggests paraganglioma or glomus tumor—16% of pulsatile tinnitus cases) 3
• Red, pulsating mass behind tympanic membrane (pathognomonic for glomus tympanicum) 1, 3

Assess for objective versus subjective tinnitus:

• Objective tinnitus (audible to examiner with stethoscope over neck/mastoid) strongly suggests vascular pathology requiring immediate workup 1, 3
• Subjective tinnitus (patient only) still warrants comprehensive imaging in nearly all unilateral cases 1, 4

Test for venous versus arterial etiology:

• Carotid or jugular compression that relieves symptoms suggests venous etiology (sigmoid sinus abnormalities, jugular bulb variants) or arterial dissection 3

Check for red flags requiring urgent escalation:

• Focal neurological deficits (suggests stroke risk from dural AVF or dissection) 5
• Asymmetric hearing loss (requires different imaging protocol per ACR criteria) 1, 4
• Severe headache in young overweight woman (idiopathic intracranial hypertension—second most common cause at 17.5% of cases—can cause vision loss) [3, @14@]

Audiometric Testing

Obtain comprehensive audiologic examination including:

• Pure tone audiometry to detect asymmetric sensorineural hearing loss 4
• This should be performed before imaging but should not delay urgent imaging if red flags present 4

First-Line Imaging Strategy

Initial Study Selection

Order high-resolution CT temporal bone (non-contrast) as the first-line study for evaluating:

• Paragangliomas and glomus tumors 1, 3
• Jugular bulb abnormalities (high-riding jugular bulb, dehiscence of sigmoid plate) 1, 3
• Superior semicircular canal dehiscence 1, 3
• Aberrant vascular anatomy 1

Alternatively, order CT angiography (CTA) of head and neck with contrast as first-line when suspecting:

• Dural arteriovenous fistulas (8% of cases—life-threatening if missed, can cause hemorrhagic stroke) 3
• Arterial dissection (potentially fatal, requires urgent identification) 3
• Atherosclerotic carotid artery disease (most common cause at 17.5% of cases) 3
• Sigmoid sinus diverticulum or dehiscence (associated with intracranial hypertension) 1, 3
• Arteriovenous malformations 1, 3

Important Technical Consideration

CTA source images can be reconstructed to create dedicated temporal bone CT images without additional radiation exposure, though there is no evidence supporting combined CTA/temporal bone examination over sequential studies 1

When to Use MRI/MRA

Reserve MRI with contrast and MR angiography for:

• Suspected cerebellopontine angle lesions or acoustic neuroma 1
• Vascular malformations not identified on CT/CTA 1, 3
• Patients with contraindications to iodinated contrast 1
• When CT/CTA are negative but clinical suspicion remains high 3

Specific MRI sequences for comprehensive evaluation include time-of-flight MRA, arterial spin labeling, and time-resolved imaging of contrast kinetics 6

Common Diagnostic Pitfalls to Avoid

Missing dural arteriovenous fistula is the most dangerous error:

• Requires high index of suspicion as it can present with isolated pulsatile tinnitus before catastrophic hemorrhage 3
• Demands appropriate vascular imaging (CTA or catheter angiography) 1, 3

Dismissing pulsatile tinnitus as benign:

• Unlike bilateral non-pulsatile tinnitus, unilateral pulsatile tinnitus almost always requires imaging 1, 3
• Identifiable causes exist in >70% of cases 2

Inadequate otoscopic examination:

• Leads to delayed diagnosis of vascular retrotympanic masses (paragangliomas) 1, 3
• Results in inappropriate imaging selection 3

Overlooking intracranial hypertension:

• Particularly in young, overweight women with headaches 3
• Can lead to permanent vision loss if missed 3

Treatment Approach Based on Etiology

Vascular Causes

• Dural AVF: Endovascular embolization or surgical repair 5
• Arterial dissection: Anticoagulation or endovascular intervention depending on severity 3
• Carotid stenosis: Medical management or revascularization based on degree of stenosis 3
• Petrous carotid aneurysm: Stent-assisted coiling has shown success in symptom resolution 7

Structural Causes

• Paragangliomas/glomus tumors: Surgical resection, radiation therapy, or observation depending on size and symptoms 1, 3
• Superior semicircular canal dehiscence: Surgical repair if symptoms are debilitating 1, 3
• Sigmoid sinus diverticulum: Surgical repair or stenting in severe cases 1, 3

Metabolic/Systemic Causes

• Idiopathic intracranial hypertension: Weight loss, acetazolamide, lumbar puncture, or venous sinus stenting [3, @14@]
• High cardiac output states: Treat underlying condition (anemia, hyperthyroidism) 2

When No Cause Identified

If imaging is negative but symptoms persist:

• Consider auditory masking therapy 8
• Cognitive behavioral therapy for tinnitus-related distress 5
• Sound therapy for auditory masking 5