What is the initial workup for a patient presenting with pulsatile tinnitus?

Initial Workup for Pulsatile Tinnitus

For patients presenting with pulsatile tinnitus, the initial workup should include a comprehensive otologic examination, audiometric evaluation, and contrast-enhanced CT angiography (CTA) of the head and neck as the first-line imaging modality. 1, 2

Diagnostic Approach

Step 1: Clinical Assessment

• Determine if tinnitus is:
  • Objective (audible to examiner) or subjective (perceived only by patient)
  • Unilateral or bilateral
  • Associated with hearing loss
  • Associated with focal neurological abnormalities
• Complete otologic examination to identify possible vascular retrotympanic mass
• Review medical history and medications (including over-the-counter)
• Measure blood pressure (to rule out hypertension as a cause)

Step 2: Audiologic Evaluation

• Pure tone audiometry
• Speech audiometry
• Tympanometry
• Acoustic reflex testing
• Otoacoustic emissions (when indicated)

Step 3: Imaging

Based on the American College of Radiology guidelines, the following imaging approach is recommended:

• First-line imaging options:

  • Contrast-enhanced CT angiography (CTA) of head and neck - preferred initial study to evaluate vascular causes 1
  • Dedicated temporal bone CT - particularly useful when a vascular retrotympanic mass is identified on examination 1

• Alternative or additional imaging:

  • MRI with contrast of internal auditory canals - when suspecting vestibular schwannoma
  • MR angiography (MRA) - may be used as an alternative to CTA in certain cases

Differential Diagnosis Categories

Pulsatile tinnitus causes can be classified into three main categories 3:

1. Vascular Causes (Most Common)

   • Idiopathic intracranial hypertension
   • Dural arteriovenous fistulas
   • Atherosclerotic carotid artery disease
   • Jugular bulb abnormalities
   • Vascular stenoses
   • Persistent stapedial artery
   • Aberrant arterial or venous anatomy

2. Structural Causes

   • Glomus tumors (paragangliomas)
   • Other vascular temporal bone tumors
   • Semicircular canal dehiscence
   • Sigmoid sinus wall anomalies

3. Metabolic/Systemic Causes

   • Hyperthyroidism
   • Anemia
   • Pregnancy
   • High cardiac output states
   • Medication-induced

Important Considerations

• More than 70% of pulsatile tinnitus cases have an identifiable cause with thorough evaluation 3
• Failure to diagnose the underlying cause may have serious consequences, as some etiologies (like dural AVFs) can lead to hemorrhagic or ischemic stroke 3, 4
• Benign intracranial hypertension (pseudotumor cerebri) is one of the most common diagnoses in patients with pulsatile tinnitus 5
• Depression and anxiety screening is recommended, as patients with severe tinnitus and coexisting psychiatric illness require prompt intervention 1, 2

Pitfalls to Avoid

• Don't miss dangerous causes: Thorough evaluation is essential as pulsatile tinnitus can be a symptom of potentially life-threatening conditions 4
• Don't confuse with non-pulsatile tinnitus: Management differs significantly between pulsatile and non-pulsatile tinnitus
• Don't overlook systemic causes: Always check blood pressure and consider systemic conditions that can cause high cardiac output states 6
• Don't rely solely on a single imaging modality: Some vascular abnormalities may be missed if only one type of imaging is performed

By following this systematic approach, clinicians can efficiently identify the underlying cause of pulsatile tinnitus and direct patients to appropriate treatment options.