Month June 2016

Why do doctor’s check for the pulse and heart beat during consultation? What does it indicate and why is it felt only on the wrist and neck regions?

Pulse and heart beat are checked primarily to have a simple and quick assessment of the condition of the heart and other system of the body. By checking the pulse the doctor can know the rate, rhythm and wave pattern of the arterial pulse. The normal arterial pulse will have certain characteristic features and any deviation from this pattern suggests an underlying problem.

For example normal, adult resting person’s pulse rate/heart rate is around 72 beats per minute. Here the words normal, adult resting all have significance as children’s heart rate is more compared to adults and a person who did some exercise like running, cycling and swimming will have a higher pulse/heart rate compared to other persons at rest. These are all physiological variations.

 Even at rest if a person’s pulse rate grossly deviates from the beat it signifies some underlying problem. In the same way if the rate of the rhythm or wave pattern of the pulse deviates from the normal it also denotes some underlying problem. Normal heartbeat consists of two heart sounds. In addition if any other sounds or murmurs (peculiar noises heard in between or along with the heart sounds) are heard, it also signifies some problem in the heart.

The arterial pulse can be felt at several places viz near the wrist, elbow, armpit, neck, groin, popletial fossa (area behind the knee joint) and foot. The wrist and neck are the most easily accessible places for the doctor to check the pulse with little discomfort to the patient. Hence these regions are usually preferred. In certain special conditions or diseases the pulse at the other regions are also checked. 

Why do people catch colds and flu more often in the winter? Are viruses transmitted more easily in damp air, is the resistance of the population reduced by the cold and lack of sunlight, or do the vir

            There is no one reason why we get more colds and flu in winter. The rhinovirus, which is responsible for up to 40 per cent of colds, cultures better at a temperature of 32 degrees C rather than the normal body temperature of 37 degrees C. However, 32 degrees C is the normal temperature of the lining of the nose, which is good news for the virus.

We do tend to be indoors more often in poorly ventilated areas during the winter and this aids the airborne transmission of the virus. Similarly, ultraviolet rays will kill viruses and this may be another factor as there is obviously much less sunlight in winter. However, it is believed that one of the biggest factors for the great increase in colds that occurs in early autumn and just after Christmas is the return of school children and students to schools and colleges.

Children and teenagers are far more susceptible to infection as their immune system learns how to combat more infections as they get older and have been exposed to more of the 200 or so viruses responsible for the common cold. Densely packed nurseries, schools and colleges provide an ideal breeding ground for viruses which then spread out into the community, aided by the cold damp weather. 

How does antidandruff shampoo work?

Dandruff is thought to be caused by overgrowth of yeast such as Pityrosporum ovale which live on normal skin. This overgrowth causes local irritation resulting in hyper proliferation of the cells (keratinocytes) forming the outer layer of the skin. These form scales which accumulate and are shed as dandruff flakes.

Antidandruff shampoos work by three mechanisms. Ingredients such as coal tar are antikeratostatic and they inhibit keratinocyte cell division. Detergents in the shampoo are keratolytic: they break up accumulation of scale. Finally, antifungal agents such as ketoconozole inhibit growth of the yeast itself. Other components such as selenium sulphide also inhibit yeast growth and therefore scaling. 

What is dandruff?

Dandruff is a condition of excessive scaliness of the scalp. There are two varieties – dry and greasy. In the dry variety, the scales are fine, thin, white or grayish, and dry or slightly greasy. Such type of hair lacks lusture. People with this type of hair will have mild to moderate itching. The scales will fall freely on the shoulders.

This dandruff will be more common in winter than in summer. It signifies exaggeration of normal exfoliation of the horny layer of the epidermis. It usually affects people with dry integument and scalp. Such people are rather reluctant to use oil, on their scalp. In the greasy variety both the scalp and the integument are oily. It diffuses all over the scalp. Later the condition also extends to other hairy regions. It may extend typically to the eyebrows, eyelids, beard and other regions. The basic defect in this case is over production and/or change in composition of the sebaceous secretion. Dandruff is common at puberty and it occurs due to endocrine disorders, familial predisposition, unbalanced diet and constipation. Effective treatments for these conditions are prescribed, in Siddha medicine, based on commonly available plant products.

Why do people get cramps and how does massage help?

Cramp is a sudden, painful, involuntary contraction of a muscle. It generally affects the legs and hands. It can occur due to various reasons such as metabolic abnormality, sever cold, lack of blood flow and mineral deficiency. All these elicit pain or other types of sensory impulses that are transmitted from the muscle to the spinal cord, thus causing reflex muscle contraction. Thus, a positive feedback mechanism occurs so that a small amount of initial irritation leads to more and more contraction until a full-blown muscle cramp ensues.

Massage helps to overcome cramp mainly by stretching the cramped muscle. In other words, it elicits what can be termed as ‘reciprocal inhibition’ of the muscle. This can at times relieve the cramp.

Cramp can occur due to localized muscle spasm. The pain or uneasiness is caused by nervous irritation due to accumulation of some ‘metabolites; or chemicals’ in that area. Massage, external compression of muscle, improves blood supply.  Helps in washing away these metabolites and thus relives the cramp. However, not all cramps can be relieved by massage. 

What causes myopia? Can it be cured with the latest medical techniques?

Myopia is defined as an eye defect where the image of the object falls before the retina of the eye. The person affected with myopia cannot see distant objects clearly, but can see objects that are close to him. Myopia is also known as short sight. It may be caused due to: Increased Anterio Posterior length of the eyeball, Increased curvature of cornea or lens, Increased refractive index of the media particularly of lens sclerosis (early cataract).

Myopia can be broadly classified into three main types: Congenital myopia: It is present since birth and may be unilateral or bilateral. Simple or developmental myopia is common type where the defect increases usually as age advances,

Pathological myopia or degenerative myopia was the condition rapidly increases and there may be high myopia up to 20 D or more. Degenerative changes occur in post segment and fundus like myopic crescent choroidal sclerosis, post staphyloma due to stretching or sclera, vitreous degeneration retinal detachment and development of nuclear cataract seen.

 Latest technologies that are available for the treatment of myopia are: Radial Keratectomy, where the problem is corrected by making a series of radial cuts around outer edges of the cornea by a handheld small blade thereby reducing corneal curvature and reduction of myopia.

Photorefractive Keratectomy, where laser rays are used to correct the defect by gently removing corneal tissues from the central area of the cornea thereby reducing the corned curvature

 Lasik procedure combined with laser where small layer of the cornea are removed microscopically and then laser rays are applied to correct the defect. 

What is dry eye syndrome? Would it help to have an air purifier in the house?

Our eyes are lubricated by tears that are produced by glands around the eye.

There are two types of tears: moisturizing tears and reflex tears. Moisturizing tears are produced continuously

 

, while reflex tears are produced in response to irritation or emotion. Dry eye syndrome is a condition in which production of moisturizing tears is dramatically reduced, making the eyes feel scratchy and look red. When the eyes become irritated, some people experience reflex tearing, which is why tearing can also be a symptom of dry eye syndrome. In addition, people with dry eyes sometimes find they can no

 longer comfortably wear contact lenses. There are many possible causes’ dry eyes. The most common cause is age, because production of moisturizing tears decreases as people grow older. In women, hormonal changes – especially those associated with pregnancy or menopause – can result in dry eyes. Environment irritants may also play a role. The treatment is lubrication.

Continue reading “What is dry eye syndrome? Would it help to have an air purifier in the house?”

Why is alcohol used in cough syrups?

Most cough syrups contain menthol and natural extracts, for carminative and antitussive actions. These substances are water-insoluble and so alcohol is used as a solvent.

Alcohol is miscible in all proportions with many of the syrups and so is the solvent of choice for many preparations. This property is rendered by its R-OH (hydroxyl) group which increases miscibility via inter molecular hydrogen bonding with solute particles. This enables the syrup to be absorbed easily by the body. It is used as a preservative in pharmaceutical preparations to prevent microbial growth. In addition syrups are mainly made of gels which in turn contain a liquid (as dispersed phase) and a solid (as dispersion medium). In them, alcohols play the role of stabilizers by preventing coagulation of solute particles during storage.

Sucrose is used as a vehicle in most of the medicated syrups. If the syrup is completely saturated with sucrose, under cool storage conditions some sucrose might crystallize from the esolution and, by acting as nuclei, initiate a type of chain reaction that would result in the separation of an amount of sucrose disproportionate to its solubility at the storage temperature. The syrup would then be very much unsaturated and probably support microbial growth. Many of them are not intended to be as nearly saturated as simple syrup (85g of sucrose is dissolved in 100 ml of purified water) and therefore need preservatives to ensure their stability   during storage. Sucrose may be substituted in whole e or in part by other agents in the preparation of medicated syrups. Polyols like sorbitol or a mixture of polyols like sorbitol and glycerin are commonly used. Here, alcohol serves as a preservative and stabilizer.

Alcohols are good sedatives and hypnotics as they depress the activity of the central not nervous system and lead to sleep. As a result they reduce the irritation in the throat and also reduce coughing.

Hypnotic property of alcohols increase with increase in molecular weight. Heavy doses of some of these alcohols can lead to anesthesia and coma.

Why is the air we breathe out on a cold day visible?

The air we exhale on a cold day is visible because of the formation of dew. Actually, the main constituents of the air exhaled from the lungs, are water vapour and carbon dioxide. The temperature of this air is about 40 degrees Centigrade while that of the outside atmosphere is about 10 degrees Centigrade or less. Cold air cannot hold as much water vapour as warm air. Dew is formed when air is cooled to the point where it cannot hold all its water vapour, so the moisture in it begins to condense forming tiny water droplets. The temperature at which the moisture in the air begins to condense is called dew point. If relative humidity is100 per cent, then dew point is nearly equal to the atmospheric temperature.

On a cold day when we breathe out air with water vapour, it is cooled from 40 degrees Centigrade to less than 10 degrees Centigrade. That is, it is cooled to below the dew point but above its freezing point. Hence the tiny water droplets float in the air and are visible.

How long can we survive without oxygen?

Humans can survive only for a few minutes without oxygen. This is because of the susceptibility of the brain is only about 2 percent of the body’s weight, it consumes about 20 per cent of the oxygen we breath in.

Hence if oxygen supplied (by the blood) is stopped for a few minutes, the brain ceases its function resulting in death. We will lose consciousness in 8-10 seconds after the blood supply to the brain is cut.

Brain cells can survive for long periods without oxygen at very low temperatures, as oxygen consumption is reduced. This technique, induced hypothermia, is made use of during major surgeries. Other tissues can survive for long periods without oxygen and that is why it is possible to remove organs, from brain dead persons, for transplantation.