stroke

Berry Aneurysm

Posted on 03/09/201209/03/2019 by Jinavie

Stroke is a disease often associated with the elderly, but this is not necessarily true. As much as 5% of the population carry a ticking time bomb in their brain, known as a berry aneurysm. An aneurysm is a weakening of the arterial wall, causing a localised ballooning of the vessel. A berry aneurysm is a common type of aneurysm where the ballooning resembles a berry. What is most troubling is that a large proportion of these aneurysms can present very early (usually congenital, meaning you are born with it), with one research suggesting that 1.3% of the population in the age group of 20 to 39 has a berry aneurysm. If this berry aneurysm was to burst, no matter how young and fit you are, you will bleed into the area around your brain (subarachnoid haemorrhage), suddenly develop a severe, crippling headache (“thunderclap headache”), become confused, show signs of stroke such as speech or movement problems, or simply drop dead.

Fortunately, only 10% of people carrying a berry aneurysm suffer a ruptured aneurysm and subsequent brain bleed. The other 90% will carry on living their lives, without ever knowing that they had a time bomb in their brain.

Certain factors make the risk of the aneurysm bursting go up, such as high blood pressure, which can be caused by a stressful lifestyle or smoking. But in some cases, as explained above, even a healthy teenager could suddenly drop to the ground with a massive brain haemorrhage.

Berry aneurysms are only one of many ways death could strike unnoticed, no matter how young you may be. You could live a long and healthy life and die peacefully in your sleep when you are 90 years old, or you may have a stroke and drop dead in a few minutes’ time. For all you know, a bus might run you over tomorrow, with no warning whatsoever. Ergo, youth is not an excuse to waste the day you are given. You do not have to achieve something great, or be productive, but at least spend your day knowing that you are doing everything in your power to make yourself happy, without harming your health, your future or other people.

Carpe diem. Seize the day.

Science & Nature

Seven Bridges Of Konigsberg

Posted on 22/05/201216/02/2019 by Jinavie

The city of Königsberg (capital of Prussia, now Kaliningrad, Russia) has the Pregel River running through the middle, with islands at the centre of the river connected by seven bridges. Is it possible to cross all of these bridges while only crossing them only once each?

If you try to solve this problem, you soon discover that it is incredibly difficult not to cross the same bridge twice. But it is difficult to tackle this problem in a brute force manner. To calculate all of the permutations in the order of bridges, you use 7! = 7 x 6 x 5 x 4 x 3 x 2 x 1 = 5040, meaning that there are 5040 possible arrangements of bridges. Then how can you prove if the problem is solvable or not?

The great mathematician Leonhard Euler, upon being asked to solve the problem, is reported to have said that the problem is impossible to solve on the spot. In 1735, he proved his answer by modelling the seven bridges of Königsberg in a diagram of four dots connected by lines (representing the bridges).

By using this model, the problem is converted into a “draw in one stroke” problem, which is also called a Euler walk to honour Euler’s contributions. Euler discovered many properties and laws regarding such problems. If a certain point is the starting point, then the line must first leave the point, then even if it comes back to the point, it must leave again. Ergo, the starting point must have an odd number of lines connected to it. The opposite applies to the ending point, where a line must enter the point, and if it leaves the point it must come back to it. Ergo, the ending point must also have an odd number of lines connected to it. In the case of a Euler walk, the starting and ending points are identical, so the number of lines is the sum of two odd numbers, making it an even number. Thus, to find out whether a picture can be drawn using one line, use the following laws:

If there are no points of odd degree (odd number of lines), the starting and ending points are identical.
If there are two points of odd degree, the starting and ending points are different.
If there are one of more than two points of odd degree, it is impossible to draw using one stroke.

Thus, a Euler walk is only possible if there are 0 or 2 points of odd degree. Looking at the seven bridges of Königsberg problem, we can see that A is connected to 5 lines and B, C and D are connected to 3 lines each. As there are four points of odd degree, we have thus proved that it is impossible to draw a path that crosses all the bridges while not crossing any bridge more than once.

Psychology & Medicine

Trepanation

Posted on 31/03/201215/02/2019 by Jinavie

When and what was the first surgery performed by mankind? Many would believe it to be a simple procedure such as suturing a wound. But would you believe that the earliest surgical procedure was brain surgery in 6500BC? Surprisingly, this is true.

Archaeologists have found a large amount of skulls with a large, round hole in them. Some of the oldest skulls with holes were found in France, where 40 skulls from the Neolithic era were excavated. Archaeologists believed these holes to be from a battle leading to a dent in the skull. However, these holes were actually the results of a surgery (signs of bone recovery can be seen around the edges of the hole, suggesting the patients were alive for some time even after the operation). These skulls all belonged to trepanation patients.

Trepanation is the surgical opening of the skull by drilling a hole in it. This is an ancient surgery that can be found throughout history. Hippocrates and Galen from ancient Greece both recorded detailed instructions on trepanation, ancient Incans performed the surgery and it was also common during the Middle Ages and the Renaissance in Europe. These surgeries were most likely indicated for skull fractures where fragments were embedded in the brain. During the Middle Ages when it was better known that the brain was the seat of the soul, trepanation was used for psychiatric treatments too. For example, in 15th century Netherlands, trepanation was used to excise a so-called stone of madness that was supposedly the cause of insanity. Like this, it was believed that trepanation could release the demons and insanity trapped in the skull.

Although this operation sounds hilariously misled, it is still used in modern medicine. Of course, it is not known to treat insanity, but rather to treat brain bleeds. Extradural and subdural haemorrhages occur when a rupture of an artery in the brain causes a collection of blood in the skull, compressing the brain. This is a dangerous situation which can lead to a stroke or even death. One treatment of this condition is trepanation, or a burr hole, where a small hole is drilled in the skull to relieve the pressure, lowering intracranial pressure and stabilising the patient. Trepanation is an excellent example of how we can learn from the past and how medical knowledge from ancient times is sometimes still valid.

Psychology & Medicine

Posted on 08/11/201114/02/2019 by Jinavie

A stroke is caused by a disruption in the supply of blood to the brain, which leads to cell death as oxygen is required. There are two types: ischaemic (where a clot cuts off blood supply to an area of the brain by blocking an artery) or haemorrhagic (when a blood vessel ruptures and leaks blood instead of delivering it to tissue). The most common cause of a stroke is a clot that made its way up to carotid arteries into the brain until it wedges in small vessel. There are many risk factors for blood clots, such as smoking, high cholesterol levels, atrial fibrillation and long distance flights.

Because the brain is always in high demand of oxygen (taking 20% of the total oxygen available), strokes can produce devastating effects within minutes. 5 minutes of oxygen deprivation can lead to irreversible cell death, a principle that is also used in cases of shock, where the blood pressure is too low to supply organs, or cardiac arrest. Therefore, it is crucial to recognise a stroke early so that an ambulance may arrive and deliver clot-busting medication such as streptokinase.

The FAST mnemonic is an effective way of remembering the common signs of a stroke. It is also useful in reminding people to respond fast.

F – Facial weakness: Is the person’s smile crooked? Disrupted brain function causes facial weakness on the opposite side. The weakness is usually seen around the mouth or eyes.
A – Arm weakness: Can the person keep both arms outstretched? This is related to motor function of the brain.
S – Speech difficulty: Is the person’s speech slurring or are they having problems understanding speech? This is a combined result of impaired motor function and speech centres of the brain.
T – Time to act: Call an ambulance. NOW.

Psychology & Medicine

Gait

Posted on 30/05/201112/02/2019 by Jinavie

In medicine, a person’s way of walking is termed gait. By analysing a person’s gait, a trained professional can gain insight into what pathologies the person may be suffering from. For example, just from the way the patient limps, the doctor may discover that the patient has an incurable degenerative brain disease.

The most common gait abnormality is the antalgic gait, or limping due to pain. Most people would have experienced the difficulty of walking with a sprained or broken ankle, muscle ache or knee problems. This is easy to spot as the patient quickly switches to the other feet when leaning on the affected leg due to the pain. Therefore, the side that stays on the ground less than the other is the affected leg.

Sometimes, you can see a person “waddling” along as they swing from one side to the other. This may be a waddling gait, also known as Trendelenburg’s gait, caused by a weakness in the hip muscles that support the pelvic girdle, either due to muscle or nerve damage. As the patient cannot support their weight on the affected side, their pelvis tilts towards the opposite side. To avoid falling over, the patient lurches their body towards the other side, causing them to waddle. Looking at the tilt and lurch gives insight into what side is affected.
Another rather common gait is the steppage gait, where the person lifts one leg higher than the other, while their foot drags on the ground. This is caused by nerve damage leading to the loss of ability to lift the foot up (termed foot drop).

As the brain controls the motor system, damage to the brain also leads to motor dysfunction. A common example is a stroke.
If the stroke damages a significant part of the motor cortex, the patient suffers from hemiparesis/hemiplegia, or weakness/paralysis of one half of the body. This causes the limbs on the affected side to stiffen, as seen by an extended leg pointing inwards and retracted arm. The patient has to swing the affected leg around while they walk as they cannot flex the hip, known as a hemiplegic gait.
If the cerebellum is damaged, balancing becomes an issue. This causes the patient to suffer from ataxia, where they cannot coordinate their movements and are prone to toppling over. These patients tend to sway violently from side to side as they try to walk in a straight line.

Lastly, degenerative brain diseases can also affect gait. There are two main examples.
In Parkinson’s disease, the patient suffers from what is called hypokinesia and bradykinesia – reduced and slow movement. This leads to a shuffling gait where the patient walks slowly by shuffling their feet in small steps. They are also stooped over and are often seen with a pill-rolling tremor of their hands – a cardinal symptom of the disease.
In Huntington’s chorea, the opposite (hyperkinesia) occurs. This causes flailing as the muscles contract in an uncoordinated manner, including both the arms and legs. Ergo, their gait is quite jerky and interrupted by bouts of flailing, termed choreiform gait, but their balance is fine so walking in a straight line is still possible.

Knowledge of these disorders may help one appreciate the suffering a patient walking along the street has to undergo everyday of their life.

(Video demonstrations: http://stanford25.wordpress.com/gait-abnormalities/)