When patients are able to hear the sound of their own pulse they are diagnosed with pulsatile tinnitus. Unlike the very common tonal tinnitus which is rarely sign of concern, pulsatile tinnitus is usually due to an underlying pathologic condition that needs to be addressed. In its simplest form it could be from conductive hearing loss from fluid in the middle ear from a common cold or allergies. In the more complex form it could be from narrowing of the carotid arteries to vascular tumors.
Pulsatile tinnitus is divided into arterial phase and venous phase categories. To distinguish the 2 entities the internal jugular vein is compressed by pressure on the neck to see if this sound would disappear. If this sound disappears while the physician is compressing the internal jugular vein and returns louder when the hand is removed, this is a venous phase pulsatile tinnitus. Many patients have observed this phenomenon themselves and use something to compressed her neck to soft in the sound and allow them to go to sleep. This is not recommended since obstructing the internal jugular vein impedes the drainage of the blood from the brain back to the heart.
Venous phase pulsatile tinnitus
The most common cause of venous phase pulsatile tinnitus is increased pressure of the fluid around the brain known as cerebrospinal fluid. This condition used to be called pseudotumor cerebri because the increased pressure in the brain was not caused by an actual mass occupying tumor. More correctly the condition is now called idiopathic intracranial hypertension since the majority of the cases the cause is never identified. Although some patients with this condition have progressive headaches and physical findings on ophthalmologic examination, many do not have any other neurologic symptoms and a spinal tap is necessary to measure the pressure. If a cause could be identified for the intracranial hypertension it may be treated such as certain medications including anti-acne antibiotics and birth control pills. Many of the patient’s with intracranial hypertension are woman in childbearing age who are overweight. It is obviously not the obesity that is causing the intracranial hypertension rather than a confounding factor. However, many of these patients respond very well to massive weight loss. At times the increased fluid pressure finds a way to decompress through small dehiscences in the bone that separates the brain from the nose or the ear. The middle image below is one of Dr. Monfared’s patients presenting with chornic ear drainage that would not respond to treatment. On further evaluation it was found that the fluid leaking through the ear is actually cerebrospinal fluid (CSF). Her body had found a way to decompress the high pressure through the roof of the ear. She underwent surgery to correct the defect and is now on medication to prevent increase pressure again.
Sagital T1 image of a patient without intracranial hypertension. Pituitary gland (white arrow) fills 1/2 of the sella
Sagital T1 image of a patient with intracranial hypertension. Pituitary gland (white arrow) is completely compressed to the floor of the sella. This finding is known as “empty sella”
Although vascular anomalies and anatomic findings on CT scans have been associated with venous phase pulsatile tinnitus, they are most likely not the cause of the condition rather the reason patient hears the sound. For example some patients present with diverticula or outpouchings of the venous structure draining the blood from the brain known as the sigmoid sinus. Although it is due to turbulent flow within the diverticula as perceived by the patient as pulsatile tinnitus, the actual cause is usually intracranial hypertension. When patients have increased pressure around the brain, the venous structures narrow in certain segments and may produce these diverticula in other segments creating a turbulent flow. Dr. Monfared obtains a lumbar puncture or spinal tap in most patients with venous phase pulsatile tinnitus unless the diagnosis is made through an ophthalmologic examination or other causes are identified.
Arterial phase pulsatile tinnitus
Unlikely venous phase, compression of the internal jugular vein does not make this sound of the pulse disappear.the most common causes of arterial phase pulsatile tinnitus include narrowing of the carotid artery, transmission of heart murmur sound into the ear, vascular tumors such as glomus tympanicum and glomus jugulare, or vascular anomalies such as arteriovenous malformation or arterio venous fistula. In Dr. Monfared’s experience if the sound of pulsatile tinnitus is heard by examiner it is usually a vascular anomaly such as arteriovenous fistula. Sometimes patient’s significant others can hear the sound when lying in bed in a quiet room and is the reason that the patient has been brought to doctor’s office.
Treatment of pulsatile tinnitus is dependent on the cause and has to be customized to the patient. Intracranial hypertentions could be managed with massive weight loss, stopping the medication causing the problem, medications that would decrease production of CSF, and shunts that drain the excess fluid into the abdomen. Glomus jugulare tumors are either treated with surgery or radiation. Please see here for futher detail. Most vascular malformations (AVM or AVF) are treated using endovascular techniques (angiography).