An embolism occurs when a blood vessel is obstructed by a foreign substance or blood clot.
Although it was a rare fatal case as severe side effects are uncommon, when liquid silicone - also called silicone oil - is not injected properly, it can travel through the bloodstream and block blood vessels supplying the lungs, causing lung tissue to die.
This is called silicone embolism syndrome and can result in fatal respiratory distress.
Dr Kevin Teh, medical director of Singapore Lipo, Body & Face Centre, said that liquid silicone is known to break up into smaller globules and obstruct blood vessels leading to the lungs or the brain.
He added that having an embolism in the lungs is akin to drowning on land. The embolism can block blood flow to the lungs, causing permanent damage to part of the lungs as well as other organs in the body as they will not get enough oxygen too.
If it happens in the brain, the patient will suffer a stroke. Silicone can also cause blindness if it is injected near the eye and ends up blocking the arteries to the eye.
Silicone injections are banned in Singapore and the United States.
However, doctors here have treated patients for clandestine treatments that they had received here and in the region which went wrong.
Silicone injections have been used to firm, plump up or enlarge parts of the body like the chin, breasts, thighs and penis.
On the risks of having silicone injections, Dr Teh said: 'It's a permanent substance that can't be broken down by the body. If injected into your face, the silicone can migrate to your neck and form unsightly lumps under the skin.'
Dr Ivor Lim, a consultant plastic and cosmetic surgeon at Ivor J. Lim Plastic Surgery, said: 'Your body will recognise silicone oil as a foreign body and try to wall it off by forming a fibrous capsule around it.
'Over time, other cells surround the foreign body to try and break it down and a lump called a granuloma is formed.'
A 2006 American study of 44 patients who had illegal silicone injections found that all experienced respiratory difficulties later and a quarter of those died from bleeding in the lungs. The side effects typically turn up after a day or two.
Dr Teh said: 'What we see commonly in America and in the region are illegal practitioners, like beauticians, using this substance because it's cheap. They shockingly often use industrial grade silicone.'???Industrial grade silicone can be bought from most hardware stores.
While silicone oil may be potentially deadly in an injection, silicone gel is perfectly safe, especially when encased within a silicone shell as an implant.
Other fillers like Macrolane, which is made of a compound that occurs naturally in the skin called hyaluronic acid, are also safe. However, the effects of Macrolane are temporary, lasting typically one to two years as the hyaluronic acid is broken down by the body over time.
Although such procedures carry less risk, they also cost more.
Macrolane injections cost $8,000 and upwards while silicone and saline implants cost $12,000 and upwards.
According to The New York Times, a cup of silicone for injection costs US$800 (S$1,164) and Ms Pichardo had had between half a cup and two cups injected in a single session.
