By Q. Kayor. Alabama State University.
Such binding leads to the opening of ion channels and often order cleocin gel 20gm without prescription, in turn buy cleocin gel 20gm lowest price, to the generation of action potentials in the postsynaptic neuron. Many different kinds of neurotransmitters have been identified in the brain, and this variety has enormous implications for brain function. This level of analysis at the synaptic level is particularly relevant for psychiatric and neurological disorders that shed light on the workings of the mind. Further insight into the chemical basis of thinking and behavior depends on obtaining more precise data at multiple levels of neural organization - from the mind all the way down to molecules. The power of the molecule-to-mind approach is evident in many recent advances in the pharmacologic treatment of many debilitating mental disorders such as schizophrenia, anxiety, amnesia, etc. For instance a change in the personality of a patient may either be due to depression or brain tumor (frontal or corpus callosal region). At times head injuries in cases of road accidents, falling from a height, or injury due to an instrument, demand immediate emergency treatment. In such cases it is essential that the patient is immediately shifted to a hospital without wasting any time, and given emergency treatment by a neurosurgeon. After this basic information about the brain, we will now try to understand the various diseases of the brain in detail, in the subsequent chapters. I would like to clarity that above mentioned psychiatric disorders being out of context, they are not discussed here. Finally, a most important point - It has been observed from experience that, though timely, correct diagnosis and proper medications are important for curing a patient, there are other equally important factors to bring a patient to a state of total healing & health which are unfortunately not being given proper importance in modern medicine. It is important for the patient to have faith in his doctor and have will power, a desire to live, a positive attitude and a disciplined and simple lifestyle, for a quick and complete recovery. This apart, the sympathy of the doctor towards his patient, his honest dedication towards his profession as well as his skill and high character are vital. All these points are worth taking into consideration and due emphasis should be given to each of them, in the management of a patient. In short, the aim should be healing of a patient and not merely eradication of the disease - symptoms. Many a times when it becomes necessary to know the location, extent and damage caused by a disease lying inside the body, radiology- neuroradiology becomes helpful and and necessary. X-Ray : The “miraculous rays” X-Rays which could look-make structures inside the body were discovered in 1895 by a German scientist Mr: Roentegen. Radio and television waves do not have much energy and so though they are present all around us in innumerable numbers, they cannot harm us and we are still alive. The energy from the X-Rays is 10,000 to 15,000 times more powerful than light and therefore can penetrate through objects. An amazing fact of nature is that the human eye can perceive only the sun rays and the rest of the rays are invisible to us. The common X-Rays only give a rough picture of the skull or a one dimensional picture, but the depth of any feature cannot be judged, e. However, since we are now discussing about the diseases of the brain, it is necessary to know how X-Rays are helpful in this context. In the previous chapter we learned that the brain is well protected in the skull and therefore X- Rays are only able to give us the information of the skull. If there is a tumor in the brain, its depth and position can be determined by dividing the brain into imaginary parts like slices of bread, and each part is X-Rayed from various angles. The computer then calculates and creates a three- dimensional picture, which determines the depth and the size of the tumor very accurately. The stretcher like table on which the patient lies, can be moved in all directions upward, downward and side ways. The X-Ray tube lies in the middle of the tunnel, and rotates in a circular motion photographing the body part from each angle. These photographs are reflected on the detector, a computer carries out accurate calculations, divides the area into slices and then with the help of laser camera photographs are taken. The scanning procedure is painless and the patient just has to lie down still for a short period of time. In the diseases of brain like tumor or infection, a special drug called the Contrast Agent is injected intravenously to figure out the circulation of blood inside the diseased part. This iodine-based drug (Iodinised contrast) sometimes can make a person nauseate or temporarily increase his body temperature. In 1972,a scientist called Damadian discovered the use of magnetic field in the examination of the human body. The patient is positioned in such a way that the organ to be examined remains at the centre of the machine. Here the X-Rays are not used, instead radio frequency waves and strong magnetic field are used, this eliminates the fear of harmful radiation. Each cell has a different number of protons and with the help of radio signals and advanced computers one can accurately calculate the various numbers of protons and thus differentiate each and every type of cell which can be photographed from every angle, with the help of a laser camera on a 14" x 17" photo film. Thus, in 30 to 45 minutes, 80 to 100 photographs of the brain from the different angles (X, Y, Z, axis) can be taken, which an expert radiologist analyzes and a report is given. In some diseases, a special drug (contrast) has to be used to specify some defects; this drug has very few side effects.
For care of sick patients buy generic cleocin gel 20 gm on-line, certain guidelines are given in chapter 24 purchase 20gm cleocin gel mastercard, which may be followed strictly by the care taker. Subarachnoid Hemorrhage : This type of hemorrhage is completely different from the one discussed before. These which rupture at a particular age due to sudden exertion or unknown causes, with oozing of blood into the subarachnoid spaces between the membranes of the brain. It is worth noting that out of every 100 people, at least one may be harboring such a congenital aneurysm in the blood vessels of the brain, but it can never be predicted when it may rupture and in many cases it may not rupture during the entire course of life. This disease is extremely dangerous and hence it is not only important to understand the disease but also have its early diagnosis before it ruptures. This test can detect aneurysms of the blood vessels of the brain with an accuracy of 95 to 98%, without any invasive procedure. But in my personal opinion and experience, in migraines, which constantly affect only one particular side of the brain, it is better to get this test done, to exclude aneurysm or A Vmalformation. Usually the patient regains consciousness in a short while, but may again start losing consciousness after some time, suffer from paralysis and there may be irregularities in the vital functions like respiration, blood pressure or heart. Therefore, if the patient feels that he/she has never experienced such a splitting headache before along with other signs and symptoms, it is all the more important for the patient to see a neurologist so that timely treatment may save his / her life. Investigation of Blood Vessels of the Brain : The test known as Angiography is the most important test. In 15% cases more than one aneurysm can be present and so it is imperative that the angiography is done on all the four blood vessels of the brain, so that if surgery becomes necessary it can be planned keeping all the aneurysms in mind. Similarly, between 4 to 12 days of primary bleeding, there is a spasm in the vessel distal to aneurysm - so called vasospasm. Now-a-days gamma knife is more frequently used where gamma rays generated from a cobalt source are focused by a gamma knife and the cauterization is done with precision. Luckily, all these surgical techniques and procedures are available in major cities in India and hence the mortality and morbidity are reduced very significantly. It is said that everyone suffers from a headache at least once in his or her life while some suffer from it frequently. Some people may complain of a unilateral headache, which occurs every few days or months and can be migraine. If the headache is of recent origin, then changes in daily lifestyle such as the pattern of working, eating habits or sleeping habits may also be a cause. If the headache has been there for some months then it has to be noted what prompted the patient to seek treatment. Thus, it is very necessary for patients with headache, to undergo complete history, neurological and physical check-up and investigations. The various alarming diseases, which could cause headache, are meningitis, brain hemorrhage, brain tumor, arteritis, edema of the brain and impaired blood circulation in the brain. Luckily very few patients with headache may be suffering from such serious diseases with associated other. In these cases of headache patient’s reports are completely normal and there are practically no possibilities or danger of any disability or paralysis. In addition to above reasons of headache; depression, alcohol addiction, spondylosis, sinus infection, weakness of eyes, glaucoma, or neuralgia, etc can also cause headache. Nausea, vomiting, blackouts and photophobia may accompany and it is difficult to look directly towards light. Therefore discipline in life and food habits, mental peace, sufficient rest, prevention of constipation and less exposure to sun, (and if it is essential to go out in full sun wearing goggles) etc. Important Medicines : The medicines to be taken during attack : When the attack starts, the drugs to be used immediately are paracetamol, antiemetic drugs (to stop vomiting), painkillers like nimesulide, ibuprofen, or in some cases ergotamine, (oral, inj ectable or as suppository) can help decrease the intensity of the attack. Among the new medicines, sumatriptan (pill or injection) naratriptan have proved to be very effective. As mentioned ahead in the chapter on stress and -its management; relief from mental stress benefits the patient. Appropriate treatment by a neurophysician or physician and if required psychotherapy by a psychotherapist can relieve the patient from spastic headache. It is also essential to rule out easily curable diseases which cause headaches like sinusitis, ophthalmic disorders etc. The serious symptoms : The symptoms usually associated with headache of serious origin are given below. In such cases immediate diagnosis and treatment can save lives, which is the main intention of this chapter. Seizure, vertigo, blackout, stumbling or paralysis on one side of the body, speech loss or memory loss, unconsciousness. If the temporal artery becomes thick or starts paining with symptoms like exhaustion, low-grade fever, weakness, temporal arteritis may be the cause. It is worth noting that Herpes Zoster viral infection occurring on the skin affects and inflames the nearby nerve causing very painful neuralgia. This pain is shooting and momentary like an electric shock, which is very painful and keeps recurring frequently.
Myogenic control of blood flow The smooth muscles present in the walls of the terminal arterioles of the microcirculation respond to changes in vascular pressure by vasomotion order 20 gm cleocin gel amex. Vascular distention induced by increased pressure in the arteriole generic 20gm cleocin gel visa, and increases their tone, resulting in vasoconstriction. Conversely, decreased arteriolar pressure is followed by relaxation of the smooth muscles and a consequent vasodilatation. The fine tuning regulation of blood flow depends upon different combinations of humoral and local vasoactive substances, changes in the proportion of vasoconstriction and vasodilatation, and balance between sympathetic and parasympathetic activity, plus the myogenic responses to changes in arterial blood pressure. Autoregulation assures relatively adequate blood flow even when large fluctuations in blood pressure occur. An increase in blood pressure briefly increases blood flow through the tissues, but it will also rapidly remove tissue vasodilators and increase the oxygen supply. A fall in blood pressure transiently decreases blood flow, increases metabolic and humoral accumulation of metabolic vasodilators, decreases oxygen content, and initiates the myogenic response of vasodilation. Blood flow through the tissue increases and the increased venous return to the heart raises the cardiac output. The coronary circulation is an excellent example of auto regulation, whereby the volume of blood flowing through the heart is adapted to the need of cardiac muscle fibers. When the stroke volume of the heart is increased, more blood is immediately pushed into coronary arteries at the same time that the blood is ejected into the aorta. During ventricular systole, the contracting ventricles compress the small coronary vessels. At rest, the coronary circulation 197 receives about 5% of the total cardiac output; it increases four to five times during strenuous exercise. Regulation of arterial blood flow In the elastic arterial vessels the blood inflow is intermittent, that is, only during the systole of the cardiac cycle, whereas the outflow from the arterioles to the capillaries is continuous. Then as the elastic arterial wall distends, the ventricles begin to relax (diastole) & the semi-lunar valves close due to pressure gradient. During diastole the aortic /pulmonary pressure continues to fall and as the elastic aorta recoils, blood is pushed to the periphery. Higher brain centers, such as hypothalamus and cerebral cortex, coordinate the cardiovascular responses depending on the stimulus. A stressful stimulus may result in the following autonomic changes: • Shunting of blood to active skeletal muscles • Restriction of blood flow to abdominal & pelvic viscera, & skin • Increased rate & depth of respiration • Increased sweating 198 These features are evident in fear, rage, or excitement. It has to be maintained for the following reasons: • It must be high enough ensuring sufficient driving pressure in the capillaries where exchange of fluid occurs across the wall; • Without sufficient pressure, brain & other tissues will not get enough blood flow, no matter what local auto regulation are made; • This pressure must not be too high to create extra work-load for the heart & increase the risk of rupturing blood vessels. Same neural & humoral factors are involved in short-term blood pressure regulation (minutes to hours) e. Short- term (within Seconds) adjustments are accomplished by alterations in cardiac output, total peripheral resistance, mediated by means of autonomic nervous system on the heart, Veins and arterioles. Long-term (Regulating minutes to days) control system involves adjustments of blood volume by restoring normal salt and water balance, through mechanisms that regulate urine output & thirst. These 200 receptors are fine nerve endings present in the arterial wall that are stimulated by tension/stretch of the arterial wall evolved by blood pressure. Vasomotor center: its location, input from the higher centers and output to the effector. The cardiac inhibitory center lies in medulla and includes the dorsal nucleus of vagus. It slows the heart rate and decreases the contractility of the heart through the impulses sent through the efferent fibers of the vagii. They are regulated by higher hypothalamus and cerebral cortical regions and in turn, the heart and blood vessels, are capable of some intricate auto regulation. Cardiovascular control areas receive information from many peripheral inputs, including arterial baroreceptors, mechanoreceptors in the heart and 202 lungs, arterial chemoreceptors (Carotid and aortic bodies), and input from skeletal muscles. The high-pressure baroreceptors are the most important source of peripheral input. The baroreceptor afferents also lead to suprapontine structures: the reticular formation, limbic system, and the fronto-orbital cortex. The carotid sinus and aortic arch baroreceptors increase the rate of firing in their afferent nerve. These efferent signals decrease heart rate, decrease stroke volume, and produce arteriolar and venous dilation, which in turn lead to decrease in cardiac output and decrease in total peripheral resistance, with a consequent decrease in blood pressure back towards normal. Conversely, when blood pressure falls below normal baroreceptor activity decreases, inducing the cardiovascular center to increase sympathetic cardiac and vasoconstrictor nerve activity, while the parasympathetic output is decreased. This efferent activity pattern leads to an increase in heart rate and cardiac output coupled with arteriolar and venous vasoconstriction. These changes result in an increase in both cardiac output and total peripheral resistance, producing an elevation in blood pressure back towards normal. These include: sympathetic cholinergic vasodilatation in 203 skeletal muscle which promote immediate increase in blood flow to the muscles to be used, sympathetic vasoconstriction else where which increase blood pressure, increase heart rate and contractility, increased catecholamines production, increased respiratory rate, piloerection (in animals). The heart slows (bradycardia), blood pressure falls, and a state similar to fainting occurs.
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