By M. Aidan. Upper Iowa University. 2018.
The tonsils are compressed against the margins of the foramen magnum 100 mg dilantin overnight delivery, causing tonsillar necrosis discount dilantin 100 mg line. More importantly dilantin 100mg on line, the herniating tonsils squeeze the medulla order 100mg dilantin with mastercard, producing medullary paralysis and death (loss of consciousness, bradycardia, irregular respirations or apneic periods, and hypotension). Cerebellar masses may produce signs of lower midbrain and of pontine compression also. The most appropriate treatment is removal of the mass lesion, but there are many instances when, because of the location of lesions, the rapidity with which brain swelling occurs or because of the presence of hemorrhages, such intervention is not feasible. In critical situations, the use of osmotically active substances is often life saving. Brain capillaries are impermeable to most substances, the exceptions being gases (02, C02, N20, anesthetics, etc. These agents dehydrate the brain; areas of cerebral edema are less easily dehydrated than normal brain tissue, but the net effect in reducing intracranial pressure is, nevertheless, beneficial. Corticosteroids are most important in treating cerebral edema, especially the synthetic steroids prednisolone and dexamethasone. The beneficial effects of steroid therapy in patients with cerebral edema secondary to tumors and in pseudotumor cerebri are well established. There is controversy as to whether steroids are effective in ischemic edema associated with strokes, but their use in patients with stroke is widespread. Improvement becomes evident within 24 hours after initiation of treatment and can be maintained for prolonged periods of time. Steroids may exert their beneficial effects by more than one mechanism: for example, they may also affect cerebral function directly or decrease the size of the primary lesion, such as a tumor. It has been demonstrated that steroids suppress activation of lysosomal hydrolyzing enzymes. They reduce disruption of brain capillaries in areas adjacent to lesions and restrict the spread of cerebral edema from a site of injury. This is performed by insertion of a catheter into a lateral ventricle or into the subdural or epidural space; the catheter is then attached to a pressure transducer. The patient must receive artificial ventilation, of course, and be very closely monitored. About one-third are mildly impaired, another third are moderately impaired and the remainder are severely impaired. Approximately one-third of these survivors will have another stroke within 5 years. From a pathophysiologic and anatomic standpoint, it is convenient to consider cerebrovascular disease as processes that lead to infarction (encephalomalacia) or hemorrhage. The two most important predisposing conditions are atherosclerosis and systemic hypertension. Anatomic Review The right and left internal carotid and vertebral arteries supply the brain. The carotid and vertebral arteries feed, respectively, the anterior and posterior circulation systems of the 21 brain. From the circle, three pairs of branches emerge to supply the two cerebral hemispheres in toto. The vertebrobasilar arterial trunks give off branches to supply the cerebellum and the brain stem. Anterior circulation: Each internal carotid artery enters the floor of the middle cranial fossa and makes a cephalad and caudad hairpin turn as it passes through the cavernous sinus in the lateral margin of the sella turcica. The postcavernous or suprasellar segment divides into the large middle and anterior cerebral arteries that, together with the short anterior communicating artery and the two posterior communicating arteries, form the anterior portion of the circle of Willis. Its branches emerge laterally to fan out over virtually the entire convexity of the hemisphere. The anterior cerebral artery enters the interhemispheric fissure to supply all of the medial and apical convolutions of the frontal and parietal lobes, as well as the corpus callosum.
It may also occur in conditions affecting venous draining and systemic hypotension dilantin 100mg otc. The extent of damage depends on speed of onset order 100mg dilantin free shipping, completeness of blockage buy generic dilantin 100 mg on line, anatomy of the local blood supply buy dilantin 100 mg cheap, and the nature of the underperfused tissue. Ischaemia can also lead to plasma membrane damage by accelerating phospholipids metabolism (by activation of phospholipases). An infarct is a localised area of necrosis resulting from ischaemic injury – the majority of these are due to obstruction of the arterial supply to a tissue. The appearance depends on the amount of blood that escapes through damaged vessels, the solidity of the tissue, and the length of survival of the patient. Pale infarcts occur in solid tissue – with complete arterial occlusion with no collateral supply, red cells rapidly lyse. Initially the infracted tissue swells, but within 48 hrs the tissue become demarcated and the surrounding tissue forms granulation tissue. Haemorrhagic infarcts occur in loose expansile tissue due to bleeding or reperfusion. Note that any organ can have a haemorrhagic infarct due to venous congestion – typical examples are torsion of the testis, bowel volvulus and strangulated hernia. They are characterised by coagulation necrosis and inflammatory cell infiltration – repair is by fibrosis 530. Contraction band necrosis may be seen at the margin where blood flow persists or following reperfusion. Areas of liquefactive or colliquative necrosis are excavated by phagocytes but are not repaired by fibrosis – the lesion becomes a permanent cyst surrounded by glial fibres produced by reactive astrocytes. The blood vessels in the necrotic area are dilated, leaky and engorged due to retrograde filling, and the alveolar spaces become filled with erythrocytes and fibrin. The margins of the infarct show an inflammatory reaction, and the infarct is gradually converted to collagenous scar tissue. At the venous end, however, plasma oncotic pressure (due to albumin) sucks water into capillary beds. Oedema occurs when the rate of formation of interstitial fluid exceeds its rate of draining through the lymphatics: 1. Note that death from any cause is typically associated with pulmonary oedema – this may confound initial investigation. Acute pulmonary oedema is often referred to as acute left ventricular failure (common cause). High pulmonary vein pressure (mitral valve disease) Cardiac oedema is mainly caused by excess retention of sodium and water in the renal tubules. This is due to decreased perfusion pressure in the kidneys, though increased capillary hydrostatic pressure contributes. Differentiation of tissue occurs mainly in the embryo, though differentiation of cells continues in some tissues – e. Disorders of growth are due to abnormalities in the regulations of cell size, proliferation or differentiation resulting in abnormality of tissue mass, function or morphological appearance: 1. Abnormal immune stimulation in Graves disease Æ hyperthyroidism (not premalignant) ii. Some types carry an increased risk of malignancy – this may be due to acquired genetic abnormalities, or due to the irritative stimuli and tissue damage. Genetic alteration to the cell, with loss of tumour suppressor genes (and/or activation of oncogenes) but not sufficient for malignancy ii. May occur with increase in tissue mass, or may be associated with a microscopic lesion iii. He was the first to recognise that cancer was a cellular disorder, and showed how it could be diagnosed at the microscopic level on the basis of cellular appearance and arrangement. The conversion of a single cell to a cancerous cell occurs in steps, with each step governed by a mutation – several subclones may appear before one that has cancerous characteristics. Mutation of a specific cancer gene throughout the tumour The incidence of each type of cancer varies according to age, gender, social class, ethnic origin, geographical location and time. The commonest cancers in adult western populations are those of the lung, breast, bowel, prostate, bladder and stomach. Studies done on people who migrate between risk areas suggest that most variation is environmental (as opposed to inherited or constitutional), and often highlight environmental factors.
Therefore the satellite modules are prepared to strengthen the professional training of each category purchase dilantin 100 mg amex. This module does show clearly that it is essential to consider the teacher purchase dilantin 100 mg without prescription, the students buy dilantin 100 mg lowest price, the learning materials and the circumstances together generic 100 mg dilantin otc. It is hoped that the reading of this module will stimulate teachers to produce teaching materials that are problem-based and learner centered. Although most of the dermatological conditions do not result in death, they lead to misery and incapacitations. Apart from the morbidity that is usually chronic, patients face a lot of agony from social stigma and low self-esteem due to deformities and disabilities of various degrees. The intent of this module is to highlight the Health Officers, Nurses, Medical Laboratory Technicians and Environmental Health Technicians with the diagnosis, management, control, and prevention of common dermatological conditions in our setting. Preparation of such teaching materials is an important milestone in an effort towards achieving these long-term goals. Therefore, this module is prepared to facilitate the process of equipping trainees with adequate knowledge and skills through interactive teaching mainly focused on the most common skin diseases. The module can be used in the basic training of health center teams in the training institutions and training of health center teams who are already working in the community, health workers and care givers. All of the following are primary skin lesions except a) papule b) Vesicle c) macule d) pustule e) ulcer 3. Bullous impetigo is most commonly seen in: a) Adults b) Adolescents c) Neonates and Infants d) Pre school children e) Elderly 4. An acute, deep-seated, red, hot, tender nodule or abscess that evolves from a staphylococcal folliculitis is a) Ichthyma b) Cellulitis c) Furuncle d) Erysipelas e) Necrotizing fascitis 3 5. The factors associated with increased colonization rate of Candida include/s a) Usage of broad spectrum antibiotics for long periods b) Diabetes mellitus c) Depressed cell mediated immunity d) Pregnancy e) All of the above 6. In some areas discoid lupus erythematosus is common and lichen planus is seen far more frequently than in temperate countries. Then there are the more chronic infections: Leprosy, Leishmaniasis, scabies and onchocericiasis– which affect the skin so distinctively; the whole range of ulcers of the skin; and the serious effects on the skin of protein malnutrition. Skin diseases affect all segments of the population with out ethnic variability but are more prevalent among children and in low socioeconomic groups, essentially due to poor hygienic practices. Different studies also suggest that skin infections are more prevalent in extreme climatic conditions. Another study carried out in 1996 to determine the prevalence of skin diseases among school children in rural Ethiopia, showed that 80. It is formed by an ordered arrangement of cells called keratinocytes, the basic function of which is to synthesize keratin, a filamentous protein that serves a protective function. The dermis is the middle layer, composed of collagen, tough and resilient part of the skin lies on the subcutaneous tissue which is principally composed of lobules of fat cells. Although there is a considerable regional variation in their relative thickness: the epidermis is thickest on the palms and soles and very thin on the eyelids. Cells of the epidermis Keratinocyte - produces keratin which forms the outer most skin layer covered by thin lipids to give the skin protective capacity from water and heat loss, penetration of microbial agents, and other trauma by physical mechanisms. The number of melanocytes in the epidermis is the same, regardless of the person’s race or skin color; it is the number , shape and size of melanosomes (melanin containing granules) and the type of melanin that determine difference in skin color. They are found in the epidermis but they constantly move as a result, they transport antigens to the regional lymph nodes and present them to naïve T lymphocytes in the regional lymph nodes and consequently the naive T lymphocytes become recruited to the specific antigen and the resultant immunologic response occurs. In this way, the skin is very crucial part of the immune system because of the large surface area that it spans. Protection: it protects the body from many environmentally unfavorable factors; such as, thermal, chemical, ultra violet radiation and different disease-causing microorganisms. Immunologic: the skin is an end organ for many immunologically mediated disorders as well as a tool for immunologic research.