Tag: medicine

Posted in Science & Nature

Cordyceps sinensis

Posted on by Jinavie

Cordyceps sinensis is a fungus known as dongchoong-hacho(동충하초, 冬蟲夏草) in Korea, with the same characters used in China and Japan. It literally translates to “worm in the winter, herb in the summer”. It is a peculiar fungus with an interesting life cycle. In the summer when the weather is warm, the fungus infects its host (usually ghost moth larvae) through spores. The infected caterpillar is slowly filled with mycelium (thready part of fungi), until it becomes mummified with only the shell remaining. The fungus keeps replicating until it bursts out of the caterpillar’s head with a club-like fruit body (which holds the fungus’ spores). This makes it look as if the caterpillar, which was an insect in the winter, turned into a fungus in the summer (technically it is at this stage, but the caterpillar is long dead). In English, it is also called caterpillar fungus or vegetable worm (which is a misnomer as fungi are not vegetables).

Cordyceps sinensis is an important ingredient in traditional Eastern medicine as it is believed to be a perfect balance between yin and yang due to it possessing both animal and plant (actually a fungus) properties. It is used to treat many diseases from fatigue to cancer.

Although Western medicine usually looks down on and ignores Eastern medicine, research shows that Cordyceps sinensis actually has medicinal properties. Cordycepin, a chemical extracted from the fungus, has been shown to inhibit the growth of viruses, fungi and tumours through its inhibitory actions on a certain protein. There is also research that suggests it can protect the body against radiation poisoning.

Posted in Psychology & Medicine

Symptom Reporting

Posted on by Jinavie

Some people always complain of symptoms, claiming that they are sick, while some people never seem to complain even if they have a whole list of symptoms. Why is there a difference in symptom reporting between people? For example, women are more likely to recognise symptoms and report them compared to men. This is because men are generally under the social pressure of needing to appear strong and healthy, so they become stoic and less sensitive to pain and disease. Women are usually more sensitive to internal bodily changes and worry more about their health.

According to a psychological theory called the competition for cues hypothesis, there are two signals that compete for attention when we recognise symptoms. The first is bodily changes, i.e. internal cues, while the other is external stimuli from what happens around us. Awareness of symptoms follows a ratio between these two signals: if there is a strong internal cue such as severe pain, we notice symptoms more quickly, while if there are many distractions, we may not notice the symptom. For example, according to a study people can run faster when listening to music and running through a forest with plenty to see. This is because music and the scenery distract the runner from internal cues. As we can only process a certain amount of information at a given moment, the more distractions there are the less sensitive we become to signals from inside our body.

Another factor that affects symptom reporting is illness labelling. The more information we have about a disease, the more we search for those symptoms. For example, if you yawn or scratch yourself, people around you will do the same. This is because they see you yawning and subconsciously believe that they should yawn too. This can be a powerful effect, as seen in mass hysteria. This strange phenomenon occurs when a person observes a sick person and their brain believes they are sick too, beginning to show symptoms despite being healthy. A similar example is seen in medical student disease, where medical students, with their extensive knowledge of diseases, match their own symptoms to symptom lists of rare diseases. For example, they might think that their high blood pressure is due to a phaeochromocytoma or renal artery stenosis, rather than just hypertension.

However, the opposite can occur where people fail to notice important symptoms and suffer serious consequences as a result. For instance, not all cases of heart attacks (myocardial infarction) cause unconsciousness and a patient may believe they are fine when only chest pain occurs. Failure to get treated as soon as possible at a hospital may result in ventricular fibrillation, leading to sudden death.

Posted in Psychology & Medicine

Sudden Death

Posted on by Jinavie

Unlike diseases such as tuberculosis or cancer, some disease processes are known to kill a human being within an hour of onset. Other than the obvious causes such as decapitation, massive bleeding or any other trauma-related injuries, these diseases tend to be cardiac or respiratory in origin.

A common example is coronary artery disease, where the blood vessel providing blood to an area of the heart becomes completely blocked by stenosis (narrowing, often by atherosclerosis) or a clot. This results in immediate ischaemia (lack of oxygen) to heart muscles, which causes cell death. This produces scar tissue which disrupts the electrical activity of the heart, which may lead to a condition called ventricular fibrillation where the heart beats in an uncontrolled, erratic manner. When in VF, the heart effectively becomes useless as it cannot coordinate proper pumping function. Blood circulation stops and the patient goes in to multiple organ failure (the brain goes first) within a very short time. Although it can kill within a short time, early identification and treatment may be able to prevent VF from occurring and save the patient’s life. If VF does occur, it is crucial to begin CPR or use a defibrillator if available.

VF can also occur in other situations. For example, there is a genetic condition called long QT syndrome which predisposes the patient to spontaneous arrhythmias (electrical abnormalities in the heart). Even becoming too excited can sometimes set off a VF in some LQTS patients, thus they require an implantable cardioverter-defibrillator (ICD) to shock their heart back in to normal rhythm every time they develop an arrhythmia.

Some other causes of sudden death include: aortic dissection (tearing of the aorta that may cause massive internal bleeding), pulmonary embolism (a clot obstructs blood flow in the lung, stopping circulation), commotio cordis (a blow to the heart at a certain moment in the heart rhythm triggers VF), ruptured brain aneurysm (ballooning of an artery in the brain), anaphylaxis (severe allergic reaction that cuts off airflow to the lungs) and poisoning (various mechanisms, mainly related to disrupting cellular function).

Death can strike swiftly, even from within your body.

Posted in Psychology & Medicine

Stroke

Posted on 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.

Posted in Psychology & Medicine

Tetanus

Posted on by Jinavie

Tetanus is an infectious disease caused by a soil-borne bacteria called Clostridium tetani. Patients are often infected soil entering the blood through deep wounds, such as a cut. The bacteria produces a toxin called tetanospasmin which leads to the characteristic symptoms of tetanus involving muscle.

The term tetanus actually refers to a state where skeletal muscle remains contracted and cannot relax due to maximum signalling from the nervous system. Tetanus is associated with some distinct symptoms involving tetanised muscles.

Tetanus starts in the face in the form of lockjaw (jaw clamps shut and cannot be opened) and sardonic risus sardonicus. Risus sardonicus, also known as sardonic grin, is a contorted, malicious-looking smile that is caused by spasms of muscles in the face. A good portrayal of the grin is seen in the Joker’s face from the Batman comic book series.
The disease then progresses to cause stiff neck, spasming of chest and leg muscles and difficulty swallowing. 

A dramatic symptom is opisthotonos, where the patient experiences extremely painful contractions of back muscles causing them to arch their back against their will. Along with lockjaw and risus sardonicus, it is a characteristic sign of tetanus and has been known for centuries. Before it was attributed to tetanus, people used to think the person was possessed by a demon due to the agonised screams and involuntary spasming of the body.

The disease is especially devastating in infants and can be spread to the fetus within the womb. This is because babies do not have a developed passive immune system that can combat the infection. Neonatal tetanus carries a mortality rate of over 90% and is responsible for 15% of all neonatal deaths.

Tetanus is a preventable disease through immunisation. Immunisation is done by injecting an inactive form of the toxin (i.e. cannot cause disease), inducing a reaction by the immune system. This essentially “teaches” the immune system to defend the body against tetanus. By completing a course of three doses and receiving occasional booster shots throughout life, tetanus can be prevented. Pregnant women must be immunised against tetanus to prevent neonatal tetanus (the babies receive scheduled immunisations soon after birth too).

This is one example of how immunisation can effectively prevent fatal diseases in a population.

Posted in Psychology & Medicine

Phantom Limb Pain

Posted on by Jinavie

In up to 80% cases of amputations, a strange phenomenon occurs where the amputee reports sensation or even severe pain where the limb has been amputated. It was noticed in field hospitals during wars when a soldier would wake up and ask someone to scratch his leg – which was no longer attached to his body. The sensation can be so powerful that victims actively believe that their phantom limb can interact with real objects. For example, there have been case reports of patients trying to pick up a cup with an amputated arm and becoming frustrated with their inability to.

Phantom limb pain may persist even after the amputee realises the limb is no longer there. The basis for phantom limb pain is a neurological system called the cortical homunculus. The cortical homunculus is a concept that the part of the brain responsible for sensation and movement is mapped out so that each part corresponds to a part of the body (see picture). For example, the top of the primary somatosensory and motor cortices (said parts of the brain) is responsible for foot sensation and movement while the side receives information from and sends signals to the face. It lets the brain construct an image of what the body looks like from sensory information it collates from various body parts. It is suggested that phantom limb pain is caused by a remapping of the cortical homunculus, fooling the brain to think that the limb is there even if it has been physically cut off. This also explains a similar condition called supernumerary phantom limb, where the brain believes there is an extra limb (e.g. a third arm).

As the homunculus concept is a recent idea, treatment options had not advanced much until the late 1990s. In 1998, a neuroscientist called Dr. Vilayanur S. Ramachandran devised a method called the mirror box treatment. He noticed that victims of phantom limb pain (PLP) had paralysis or pain in the limb just before the amputation (such as tightly gripping something before the arm got blown up by a mine), suggesting that PLP may be a form of learned paralysis. This means that the brain believes that the arm is still paralysed and any movement causes an uncomfortable sensation as the brain thinks the limb is contorted into a painful position. To fix this problem, Dr. Ramachandran invented a box with two holes, each going into a separate compartment. One compartment is for the good arm while the other has a mirror positioned on an angle to reflect the other arm (instead of seeing the stub they put in the hole). He would then instruct the patient to perform symmetric movements with both hands while looking at the reflected arm. For example, he would tell the patient to squeeze their “fists” tightly as possible and then let go. Through this procedure, the brain is retrained to let go of the perceived paralysis and pain as it is tricked in to thinking that the arm is healthy again. The mirror box therapy drastically improved the outcome and quality of life of PLP patients through the power of illusions.

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Posted in Psychology & Medicine

Alien Hand Syndrome

Posted on by Jinavie

There is a very rare, disturbing and interesting medical condition called alien hand syndrome (AHS). An individual with this neurological disorder has full sensation in the rogue hand, but is unable to control its movements and does not feel that it is a part of their body. The hand becomes personified, as if it has a will of its own, and its owner will usually deny ownership of the limb.

Though AHS was first identified in 1908, it was not clearly defined until 1972. Depending on the cause of the injury, the movements may be random or purposeful, and may affect the dominant or non-dominant hand. The symptoms are brought on by an injury to the brain, such as head trauma, stroke, tumour, or infection. It can also be a side effect of a certain kind of brain surgery where the patient has the two hemispheres of the brain separated to relieve severe epilepsy.

If the AHS is caused by separation of the corpus callosum (the area of the brain that connects the two halves of the brain) by surgery or injury, the movements are usually complex purposeful behaviour, such as compulsive manipulation of tools, undoing buttons, or tearing clothes. For example, a right-handed person is left-hemisphere-dominant, thus their left hand (controlled by the right hemisphere) will become “alien”. Sometimes the sufferer is completely unaware of what the hand is doing until it is brought to his or her attention, or until they happen to see it themselves. 

Strangely, many of the alien hand’s actions are the complete opposite of what the person is doing with the other hand. For example, if they start packing a suitcase, the alien hand will unpack it. It is believed that one half of the brain (usually the right brain) is unaware of why the other hand is doing something (due to the lack of connection between the two hemispheres) and so proceeds to “correct” it. There are also reports of the alien hand attacking the patient by hitting them or even trying to strangle them in their sleep. 

There is currently no treatment for alien hand syndrome, but the symptoms can often be relieved by giving the rogue hand an object to manipulate, to keep it occupied. One patient whose alien hand had a compulsion of holding on to door handles or other objects to stop the man from walking was given a cane. The alien hand would grab on to the cane and not interfere with the patient’s walking.

There is currently no treatment for alien hand syndrome, but the symptoms can often be relieved by giving the rogue hand an object to manipulate to keep it occupied. One patient whose alien hand had a compulsion of holding on to door handles or other objects to stop the man from walking was given a cane. The alien hand would grab on to the cane and not interfere with the patient’s walking.

Although it is a distressing condition, some patients learn to live with the disease. For instance, when one patient’s alien hand kept throwing away the cigarette her dominant hand put in her mouth, she shrugged and said: “I guess ‘he’ doesn’t want me to smoke that”. Perhaps the alien hand is simply a way for the subconscious mind to physically act on the conscious mind.

Posted in Psychology & Medicine

Kuru

Posted on by Jinavie

European explorers who visited the island of Papua New Guinea in the 1950’s noticed that the Fore tribe suffered from a strange disease. The patient would initially have headaches, joint pains and tremors. They then show signs of weakness and are unable to stand.  The shaking of limbs, a classic symptom of the disease, becomes progressively worse as the disease progresses (“kuru” is a Fore word for “to shake”). In the late stages, the patient shows other neurological symptoms such as uncontrollable laughter and emotional instability. By this point, their tremors and ataxia (lack of coordination) is so severe that they cannot sit without support. They may also suffer from inability to speak or swallow, become unresponsive to their surroundings, develop ulcers on the skin and become incontinent (cannot hold urine/faeces). Within 3 months to 2 years after the symptoms develop, the patient dies.

Kuru is exclusive to the Fore tribe and medical researchers were puzzled by the nature of this disease. It is incurable and takes more than 10 years to develop (from the time of infection). In 1961, Dr Michael Alpers discovered that kuru was spread due to a certain cultural behaviour within the tribe – cannibalism. The Fore tribe had a tradition of eating the corpse of a deceased tribe member at the funeral as to return their life force back in to the tribe. Of course, this involved the consumption of the brain as well.

It was discovered that kuru is caused by a strange pathogen known as a prion. Prions are misfolded pieces of proteins that cause disease by converting the body’s proteins into “wrong” proteins. These new prions then convert more proteins until the body is filled with deposits of such proteins. Prions mainly affect the brain and cause spongiform encephalopathy – meaning that the brain becomes sponge-like and full of holes. The most famous example of prion disease is mad cow disease.

After colonists took over Papua New Guinea, cannibalism was banned and kuru faded away. This was proof that cannibalism was what spread the prion from one victim to another. It was also discovered that women and children had a higher incidence as men would have priority in choosing what part of the body to eat first. As with lions, the men always chose muscles first and women and children would often finish the organs such as the brain. As prions are indestructible, it cannot be treated, cured or prevented (other than not eating brains). It also means that it transmits perfectly from a dead patient to an unsuspecting victim who is feasting on the infected brain.

A disease that causes the brain to disintegrate, causing limb shaking and inability to walk, spread by the ingestion of brains. Is it possible that zombies are caused by eating brains and not the other way around?

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Posted in Psychology & Medicine

Munchausen’s Syndrome

Posted on by Jinavie

Some people are known to overreact regarding their health, such as a hypochondriac thinking that she has kidney failure because her urine looks slightly frothier. However, some people far surpass the level of hypochondrias to the level of psychiatric disease.
Münchausen’s syndrome patients are known to exaggerate or create symptoms so that the doctor would pay attention to them. When the doctor investigates, treats and sympathises with the patient they gain satisfaction from all the attention they are receiving.
Although this may sound like hypochondrias, Münchausen’s is far more serious.

A Münchausen’s patients are known to cause symptoms just to get attention from others. For example, a common manoeuvre used is the injection of insulin to induce a hypoglycaemic seizure. When their symptoms are “treated”, the patient will most likely invent another factitious disease to be treated for a longer time. They will also seek out many different doctors when the attending doctor catches on to their act. In fact, a Münchausen’s patient will do almost anything to prolong medical care, even accepting unnecessary and risky procedures such as surgeries.

The key difference between Münchausen’s syndrome and hypochondriasis is that the patient is aware that they are not actually sick (hypochondriacs actually believe they are sick). The fundamental basis for Münchausen’s syndrome is the desire for attention. Thus, the main risk factor for developing Münchausen’s is childhood experience of seeing someone close (typically a family member) suffering a debilitating disease. For example, if a girl sees her sister suffering from leukaemia and receiving all the attention of everyone around her, she may develop feelings of jealousy and later try to duplicate the scenario. As a patient, the person feels safe and comfortable and this feeds their addiction to medical care.

As Münchausen’s patients are very proficient liars and act completely like an actual patient, doctors must rule out any diseases before suspecting that their patients have a psychiatric problem. However, some signs such as the patient being overly keen on receiving procedures such as biopsies or continuously developing random symptoms may indicate Münchausen’s.

Interestingly, a similar condition called Münchausen’s syndrome by proxy also exists, where a caregiver (e.g. mother) convinces a doctor that the person they are caring for (e.g. child) are sick. Unfortunately, as these patients actually cause illness in the child, it is considered a form of child abuse. Common “symptoms” include: growth problems, asthma, allergies, vomiting, diarrhoea, seizures and infections. This may lead to the child developing Münchausen’s syndrome in the future.

Posted in Science & Nature

Murphy’s Law

Posted on by Jinavie

In 1947, an aerospace engineer named Edward A. Murphy Jr was involved in high-speed rocket sled experiments led by the US Air Force. The aim of the experiment was to research the effect of sudden deceleration on the human body so to improve the safety of jet fighter pilots. To study this, a flight surgeon named Dr John Stapp devised a “sled” attached to a rocket that could be used on a long track. The rocket would propel the sled to a massive speed and brakes would induce as sudden deceleration. However, they found that the machines that were used to measure the G-force (force of deceleration relative to the force of gravity) were unreliable. Murphy proposed that they use electronic strain gauges attached to the harness of the test subject to measure the G-force, something he learned while working with centrifuges.

The idea was great but there was one problem: the gear kept failing, showing no reading whatsoever. Murphy soon found that the sensors were attached correctly but were wired backwards. This simple mistake frustrated Murphy, who blamed the incompetency of his assistant, stating that “if that guy has any way of making a mistake, he will.” This became the famous Murphy’s law, now simplified to “Anything that can go wrong will go wrong”.

Murphy’s law actually played a fundamental role in defensive design, where the worst-case scenario is always assumed and prepared for. Thanks to this system, the rocket sled experiment was successful and in 1954 Dr Stapp became the fastest man in the world – travelling at a speed of 1011km per hour and decelerating at a force of 46G (it was hypothesised that a human being could not survive past 18G). Not only did he survive (albeit with broken limbs, ribs, hernias, detached retina and temporary blindness), Dr Stapp went to build bigger rockets to further test the limits of the human body.

Interestingly, there’s another side to the Murphy’s law involving psychology. People suffer from a fallacy called appeal to probability, where they believe that because there is a possibility of something can happen, it will happen. The brain is surprisingly inefficient in dealing with probabilities and has a tendency to ignore that there is a relatively miniscule possibility and instead focuses on the absolute fact that there “is” a probability. This is the best explanation for why people are compelled to buy lottery tickets and why every student believes they will grow up to be rich and successful.