American rap legend and record producer Dr Dre remains hospitalised this week after initially seeking treatment for a brain aneurysm last Tuesday.

According to a TMZ report on Monday (January 11), doctors at the Cedars-Sinai Medical Center in Los Angeles are keeping the entertainer under observation out of caution in case he suffers another episode.

But what exactly is a brain aneurysm?

The medical event is a bulge or ballooning in a blood vessel in the brain, according to not-for-profit hospital Mayo Clinic.

Although aneurysms can appear anywhere in the brain, these events are most common in arteries at the base of the brain.

Normally not life-threatening, a brain aneurysm often looks like a berry hanging on a stem when observed through non-invasive examinations such as an X-ray or CAT scan.

Most brain aneurysms, however, don’t rupture, create health problems or cause symptoms. The medical anomalies are often detected during tests for other conditions.

The Minnesota-headquartered Mayo Clinic further noted that brain aneurysms can leak or rupture, causing bleeding into the brain (haemorrhagic stroke). 

“Most often, a ruptured brain aneurysm occurs in the space between the brain and the thin tissues covering the brain. This type of haemorrhagic stroke is called a subarachnoid haemorrhage,” the organisation added.

Persons at risk of experiencing a ruptured aneurysm have very little time to seek medical treatment—by which time one’s condition could deteriorate rapidly.

With “the worst headache of your life” being the calling card of symptoms, brain aneurysms, if ignored or left untreated, could lead to death.

Here are a few known signs of a ruptured brain aneurysm:

• sudden, extremely severe headache
• nausea and vomiting
• stiff neck
• light sensitivity
• drooping eyelid(s)
• confusion
• loss of consciousness
• blurred or double vision
• seizures

See related story below:

• Rap legend Dr Dre says he’s ‘doing great’ in hospital after reported aneurysm