Vascular (pulse-synchronous) tinnitus

What it is

Vascular tinnitus is the pulse synchronous half of the para-auditory group in the tinnitus differential diagnosis. The other half, non-pulse synchronous, is TMJ dysfunction and palatal myoclonus.

Causes and risk

The pulse synchronous causes are vascular ones, that is carotid bruits, a hyperdynamic state, aneurysm and venous hum, together with glomus tumor.

• Arterial bruits: arteries near the temporal bone transmit sounds associated with turbulent blood flow, and the petrous carotid system is the most common source, with carotid body tumors behind it. The tinnitus is greatest in a quiet environment, for example at night, and there are no other otologic complaints.
• Venous hums: caused by abnormally high placement of the jugular bulb. The risk factors given are hypertension, increased ICP, and a dehiscent or dominant jugular bulb. The sound is described as a soft, low-pitched hum that decreases or stops with pressure over the jugular vein, that is compression of the ipsilateral jugular vein, with a change in head position, or with activity.
• Paraganglioma: benign highly vascular neoplasms, either tympanic paragangliomas or jugular bulb paragangliomas, both called glomus. Both cause a loud pulsing tinnitus with hearing loss. Glomus tympanicum is a vascular, reddish bluish mass behind the TM, with blanching of the TM on pneumatic otoscopy, which is Brown's sign, and it is diagnosed by CT. Glomus jugulare appears as the tip of the iceberg, with the majority of the tumor hidden below the eardrum.

Pulsatile tinnitus, a swishing sound, is also one of the common symptoms of idiopathic intracranial hypertension, in which intracranial pressure is chronically elevated.