Författare: Theresa Larkin Associate professor of Medical Sciences Unive

Australian radio host Kyle Sandilands announced on air yesterday that he has a brain aneurysm and needs urgent brain surgery.

Typically an aneurysm occurs when a part of the wall of an artery (a type of blood vessel) becomes stretched and bulges out.

You can get an aneurysm in any blood vessel, but they are most common in the brain’s arteries and the aorta, the large artery that leaves the heart.

Many people can have a brain aneurysm and never know. But a brain (or aortic) aneurysm that ruptures and bursts can be fatal.

So, what causes a brain aneurysm? And what’s the risk of rupture?

Weakness in the artery wall

Our arteries need strong walls because blood is constantly pumped through them and pushed against the walls.

An aneurysm can develop if there is a weak part of an artery wall.

The walls of arteries are made of three layers: an inner lining of cells, a middle layer of muscle and elastic fibres, and a tough outer layer of mostly collagen (a type of protein). Damage to any of these layers causes the wall to become thin and stretched. It can then balloon outward, leading to an aneurysm.

Genetics and certain inherited disorders can cause weak artery walls and brain aneurysms in some people.

For all of us, our artery walls become weaker as we age, and brain aneurysms are more common as we get older. The average age for a brain aneurysm to be detected is 50 (Sandilands is 53).

Females have a higher risk of brain aneurysm than males after about age 50. Declining oestrogen around menopause reduces the collagen in the artery wall, causing it to become weaker.

A brain aneurysm occurs when a part of the wall of an artery balloons out.
Alfmaler/Shutterstock

High blood pressure can increase the risk of a brain aneurysm. In someone with high blood pressure, blood inside the arteries is pushed against the walls with greater force. This can stretch and weaken the artery walls.

Another common condition called atherosclerosis can also cause brain aneurysms. In atherosclerosis, plaques made mostly of fat build up in arteries and stick to the artery walls. This directly damages the cell lining, and weakens the muscle and elastic fibres in the middle layer of the artery wall.

Several lifestyle factors increase risk

Anything that increases inflammation or causes atherosclerosis or high blood pressure in turn increases your risk of a brain aneurysm.

Smoking and heavy drinking affect all of these, and nicotine directly damages the artery wall.

Sandilands mentioned his cocaine use in discussing his diagnosis. He said:

The facts are, a life of cocaine abuse and partying are not the way to go.

Indeed, cocaine abuse increases the risk of a brain aneurysm. It causes very high blood pressure because it causes arteries to spasm and constrict. Cocaine use is also linked to worse outcomes if a brain aneurysm ruptures.

Stress and a high-fat diet also increase inflammation. High cholesterol can also cause atherosclerosis. And being overweight increases your blood pressure.

A study of more than 60,000 people found smoking and high blood pressure were the strongest risk factors for a brain aneurysm.

Is it always a medical emergency?

About three in 100 people will have a brain aneurysm, varying in size from less than 5mm to more than 25mm in diameter. The majority are only discovered while undergoing imaging for something else (for example, head trauma), because small aneurysms may not cause any symptoms.

Larger aneurysms can cause symptoms because they can press against brain tissues and nerves.

Sandilands described “a lot of headache problems” leading up to his diagnosis. Headaches can be due to minor leaks of blood from the aneurysm. They indicate a risk of the aneurysm rupturing in subsequent days or weeks.

Less than one in 100 brain aneurysms will rupture, often called a “brain bleed”. This causes a subarachnoid haemorrhage, which is a type of stroke.

If it does occur, rupture of a brain aneurysm is life-threatening: nearly one in four people will die within 24 hours, and one in two within three months.

If someone’s brain aneurysm ruptures, they usually experience a sudden, severe headache, often described as a “thunderclap headache”. They may also have other symptoms of a stroke such as changes in vision, loss of movement, nausea, vomiting and loss of consciousness.

Surgery can repair a brain aneurysm, and stop it from rupturing.
Roman Zaiets/Shutterstock

Surgery can prevent a rupture

Whether surgery will be used to treat a brain aneurysm depends on its size and location, as well as the age and health of the patient. The medical team will balance the potential benefits with the risks of the surgery.

A small aneurysm with low risk of rupture will usually just be monitored.

However, once a brain aneurysm reaches 7mm or more, surgery is generally needed.

In surgery to repair a brain aneurysm, the surgeon will temporarily remove a small part of the skull, then cut through the coverings of the brain to place a tiny metal clip to close off the bulging part of the aneurysm.

Another option is endovascular (meaning within the vessel) coiling. A surgeon can pass a catheter into the femoral artery in the thigh, through the aorta to the brain. They can then place a coil inside the aneurysm which forms a clot to close off the aneurysm sac.

After either surgery, usually the person will stay in hospital for up to a week. It can take 6–8 weeks for full recovery, though doctors may continue monitoring with annual imaging tests for a few years afterwards.

You can lower your risk of a brain aneurysm by not smoking, moderating alcohol intake, eating a healthy diet, exercising regularly and maintaining a healthy weight. Läs mer…

When you’re in a car, train or bus, do you choose a seat to avoid being in the sun or do you like the sunny side?

You can definitely feel the sun’s heat through a window. But can you get sunburn or skin damage when in your car or inside with the windows closed?

Let’s look at how much UV (ultraviolet) radiation passes through different types of glass, how tinting can help block UV, and whether we need sunscreen when driving or indoors.

What’s the difference between UVA and UVB?

Of the total UV radiation that reaches Earth, about 95% is UVA and 5% is UVB.

UVB only reaches the upper layers of our skin but is the major cause of sunburn, cataracts and skin cancer.

UVA penetrates deeper into our skin and causes cell damage that leads to skin cancer.

UVA penetrates deeper than UVB.
Shutterstock/solar22

Glass blocks UVA and UVB radiation differently

All glass used in house, office and car windows completely blocks UVB from passing through.

But only laminated glass can completely block UVA. UVA can pass through other glass used in car, house and office windows and cause skin damage, increasing the risk of cancer.

Car windscreens block UVA, but the side and rear windows don’t

A car’s front windscreen lets in lots of sunshine and light. Luckily it blocks 98% of UVA radiation because it is made of two layers of laminated glass.

But the side and rear car windows are made of tempered glass, which doesn’t completely block UVA. A study of 29 cars found a range from 4% to almost 56% of UVA passed through the side and rear windows.

The UVA protection was not related to the car’s age or cost, but to the type of glass, its colour and whether it has been tinted or coated in a protective film. Grey or bronze coloured glass, and window tinting, all increase UVA protection. Window tinting blocks around 95% of UVA radiation.

In a separate study from Saudi Arabia, researchers fitted drivers with a wearable radiation monitor. They found drivers were exposed to UV index ratings up to 3.5. (In Australia, sun protection is generally recommended when the UV index is 3 or above – at this level it takes pale skin about 20 minutes to burn.)

So if you have your windows tinted, you should not have to wear sunscreen in the car. But without tinted windows, you can accumulate skin damage.

UV exposure while driving increases skin cancer risk

Many people spend a lot of time in the car – for work, commuting, holiday travel and general transport. Repeated UVA radiation exposure through car side windows might go unnoticed, but it can affect our skin.

Indeed, skin cancer is more common on the driver’s side of the body. A study in the United States (where drivers sit on the left side) found more skin cancers on the left than the right side for the face, scalp, arm and leg, including 20 times more for the arm.

Another US study found this effect was higher in men. For melanoma in situ, an early form of melanoma, 74% of these cancers were on the on the left versus 26% on the right.

Earlier Australian studies reported more skin damage and more skin cancer on the right side.

Cataracts and other eye damage are also more common on the driver’s side of the body.

What about UV exposure through home or office windows?

We see UV damage from sunlight through our home windows in faded materials, furniture or plastics.

Most glass used in residential windows lets a lot of UVA pass through, between 45 and 75%.

Residential windows can let varied amounts of UVA through.
Sherman Trotz/Pexels

Single-pane glass lets through the most UVA, while thicker, tinted or coated glass blocks more UVA.

The best options are laminated glass, or double-glazed, tinted windows that allow less than 1% of UVA through.

Skylights are made from laminated glass, which completely stops UVA from passing through.

Most office and commercial window glass has better UVA protection than residential windows, allowing less than 25% of UVA transmission. These windows are usually double-glazed and tinted, with reflective properties or UV-absorbent chemicals.

Some smart windows that reduce heat using chemical treatments to darken the glass can also block UVA.

So when should you wear sunscreen and sunglasses?

The biggest risk with skin damage while driving is having the windows down or your arm out the window in direct sun. Even untinted windows will reduce UVA exposure to some extent, so it’s better to have the car window up.

For home windows, window films or tint can increase UVA protection of single pane glass. UVA blocking by glass is similar to protection by sunscreen.

When you need to use sunscreen depends on your skin type, latitude and time of the year. In a car without tinted windows, you could burn after one hour in the middle of the day in summer, and two hours in the middle of a winter’s day.

But in the middle of the day next to a home window that allows more UVA to pass through, it could take only 30 minutes to burn in summer and one hour in winter.

When the UV index is above three, it is recommended you wear protective sunglasses while driving or next to a sunny window to avoid eye damage. Läs mer…