Pulsatile tinnitus

Pulsatile tinnitus is a specific type of tinnitus and refers to the perception of rhythmic noise, usually in time with the patient's heartbeat, in the absence of an external source, which is most commonly, but not exclusively, due to underlying vascular pathology.

Clinical presentation

Patients describe a pulsing noise that sounds like rushing, flowing, or humming. Some recognise synchronization with their pulse and an increase in the sensation with physical activity or in a recumbent position ¹⁰.

Tinnitus, including pulsatile tinnitus, is subcategorized as subjective or objective ¹⁰:

• subjective tinnitus: heard only by the patient

• objective tinnitus: heard by the clinician on auscultation (neck or mastoid region)

Non-pulsatile tinnitus is almost always subjective, but some cases of pulsatile tinnitus are objective ¹¹.

Additional findings on the clinical history and physical examination can narrow the differential diagnosis ¹¹:

• autophony (hearing one's voice loudly in the affected ear) on top of pulsatile tinnitus suggests either patulous Eustachian tube dysfunction or dehiscent semicircular canal syndrome ¹¹

• a low-pitched hum on auscultation and suppression of symptoms with manual pressure on the ipsilateral internal jugular vein suggests a venous aetiology

• obesity and papilloedema on fundoscopy raise the suspicion for idiopathic intracranial hypertension

• a retrotympanic vascular mass on otoscopy suggests a neoplasm or vascular anomalies protruding into the middle ear cavity

Pathology

Numerous causes of pulsatile tinnitus are recognised ^4,7-11:

Vascular

• venous

  • idiopathic intracranial hypertension (most common in this category) with or without transverse sinus stenosis

  • transverse sinus stenosis without idiopathic intracranial hypertension

  • variant/anomalous vessel within the temporal bone

    • sigmoid sinus diverticulum or laterally placed sigmoid sinus ², with or without sigmoid plate dehiscence (most common in this category)

    • jugular bulb diverticulum or high riding jugular bulb, with or without jugular plate dehiscence

    • abnormal mastoid emissary veins

• arterial

  • arterial stenosis (usually involving internal carotid artery)

    • atherosclerosis (most common in this category, especially in the elderly)

    • dissection

    • fibromuscular dysplasia

  • variant/anomalous vessel within the temporal bone

    • aberrant internal carotid artery (most common in this category)

    • lateralised internal carotid artery

    • persistent stapedial artery

  • aneurysm of the internal carotid artery, less commonly vertebral or anterior inferior cerebellar artery

• arteriovenous transition

  • dural arteriovenous fistula (most common in this category), including caroticocavernous fistula

  • arteriovenous malformation

Hypervascular tumours

• paraganglioma (most common in this category)

  • tympanic paraganglioma

  • jugulotympanic paraganglioma

• haemangioma

• meningioma

• Langerhans cell histiocytosis

• hypervascular metastasis

• intralabyrinthine schwannoma (tinnitus is common, only a minority have pulsatile tinnitus) ¹⁵

Non-vascular

• temporal bone pathology: e.g. superior semicircular canal dehiscence syndrome, otosclerosis, Paget disease ^4,12

• patulous eustachian tube dysfunction ^11-13

• palatal myoclonus involving the tensor veli palatini, levator veli palatini, salpingopharyngeus, and/or superior pharyngeal constrictor muscles (most common in this category)

• middle ear myoclonus involving the stapedius or tensor tympani muscles

Radiographic features

CT, MRI, ultrasound, and digital subtraction angiography (DSA) provide complementary information in the evaluation of pulsatile tinnitus given the diversity of causes. In patients with pulsatile tinnitus without myoclonus or Eustachian tube dysfunction, the American College of Radiology in 2017 rated the following imaging exams as "usually appropriate" ¹⁴:

• CTA of the head with contrast

• CTA of the head and neck with contrast

• CT venography of the head with contrast

• CT of the temporal bone without contrast

• MRI of the head and internal auditory canal without and with contrast

• MRA of the head without and with contrast

The following imaging exams were rated as "may be appropriate" ¹⁴:

• MRI of the head and internal auditory canal without contrast

• MRA of the head without contrast

• MR venography of the head without and with contrast

• MR venography of the head without contrast

• arteriography of the cervicocerebral vessels

• ultrasound duplex Doppler of the carotid arteries

Given the wide range of entities that may present with pulsatile tinnitus, it is beyond the scope of this article to discuss each in turn. Rather, please refer to the articles for the specific entities above for individual imaging findings.