Infectious disease is disease caused by a pathogen which enters the body and triggers the development of an infection. Infectious diseases have a range of causes, and they can be found all over the world. These diseases are considered contagious or communicable, meaning that they can be passed from person to person. It is also possible for such diseases to spread indirectly through unhygienic conditions, or from animals to people, in which case they are known as zoonotic diseases.
A variety of pathogens can be responsible for infectious disease, including viruses, bacteria, fungi, protozoans, and prions. Within these large categories of infectious organisms, there are numerous modes of transmission and a colorful assortment of symptoms, although surprisingly few organisms cause infectious disease, when one considers the diversity of viral, bacterial, fungal, and protozoan life. In order to treat an infectious disease, doctors must be able to knock out the source of the infection and repair the damage it has done to the body. Many infectious diseases make the body vulnerable to secondary infections, in which other organisms move in to take advantage of a weakened immune system, and this can be very problematic.
The study of infectious disease is known as epidemiology. Epidemiologists work to determine the source of an infectious disease so that they can develop new treatment approaches. They also identify emerging outbreaks, which may develop into epidemics or pandemics, and areas where a disease is endemic, meaning that it occurs regularly. Malaria, for example, is endemic to some regions of Africa and Southeast Asia. Read more »
Tags: access, advantage, Africa, AIDS, Antivirals, assortment, body, case, clean drinking water, colorful assortment, contact, damage, development, diarrheal, disease, diversity, drinking, education, effort, Epidemiologists, epidemiology, example, fight, fungal, fungi, HIV, hygiene, incidence, infection, Infectious, infectious disease, infectious disease doctors, infectious diseases, infectious organisms, killer, life, loss, malaria, medical facilities, modes of transmission, order, Pandemics, pathogen, person, person to person, prevention, prions, protozoan, protozoans, range, Reduction, rodents, Screening, secondary infections, source, Southeast Asia, spread, study, surgery, system, transmission, treatment, use, variety, vectors, water, weakened immune system, work, world, worldwide, zoonotic diseases
Posted in medicalmatrix | February 13, 2010 | 
Comments (0)
Background
Anemia, like a fever, is a symptom of disease that requires investigation to determine the underlying etiology. Often, practicing physicians overlook mild anemia. This is similar to failing to seek the etiology of a fever. The purpose of this article is to provide a method of determining the etiology of an anemia.
Anemia is strictly defined as a decrease in red blood cell (RBC) mass. Methods for measuring RBC mass are time consuming, are expensive, and usually require transfusion of radiolabeled erythrocytes. Thus, in practice, anemia is usually discovered and quantified by measurement of the RBC count, hemoglobin (Hb) concentration, and hematocrit (Hct). These values should be interpreted cautiously because they are concentrations affected by changes in plasma volume. For example, dehydration elevates these values, and increased plasma volume in pregnancy can diminish them without affecting the RBC mass.
Pathophysiology
Erythroid precursors develop in bone marrow at rates usually determined by the requirement for sufficient circulating Hb to oxygenate tissues adequately. Erythroid precursors differentiate sequentially from stem cells to progenitor cells to erythroblasts to normoblasts in a process requiring growth factors and cytokines. This process of differentiation requires several days. Normally, erythroid precursors are released into circulation as reticulocytes.
Reticulocytes remain in the circulation for approximately 1 day before reticulin is excised by reticuloendothelial cells with the delivery of the mature erythrocyte into circulation. The mature erythrocyte remains in circulation for about 120 days before being engulfed and destroyed by phagocytic cells of the reticuloendothelial system. Read more »
Tags: Abnormal, abnormality, absorption, access, addition, adulthood, African, age, AIDS, anemia, Arabians, area, aspirin, attemp, availability, average, Bleeding, blood, body, bone, bone marrow, bowel, calf, capability, care, Carefully, cell, Clinical, colon, color, contrast, Coumadin, decade, deficiency, deficient, dehydration, depletion, description, development, diet, difference, differentiation, disease, disorder, diverticula, document, donor, duration, equilibrium, erythrocyte, estimate, Etiology, examination, example, extent, factor, family, Fanconi, fault, food, gastrointestinal, Gram, growth factors, hair, Hbs, health, hematocrit, hemoglobin, Hemorrhoidal, hiatal, history, household, ice, incidence, inquiry, instance, investigation, iron, jaundice, life, loss, malaria, man, marrow, mass, meat, mild anemia, Morbidity, Mortality, mother, Neoplasia, nonsteroidal, northern Europe, NSAIDs, Obtain, occupation, part, Pathophysiology, patient, phagocytic cells, plasma volume, pregnancy, premenopausal, prescription, prevalence, quantity, Race, rate, RBC, red blood cell, rejection, replacement, reticulocytes, reticuloendothelial cells, reticuloendothelial system, Saudi, Severe, Sex, Sicilians, sickle, significance, Socioeconomic, splenectomy, standpoint, status, stem cells, symptom of disease, Symptoms, syndrome, tarry, thalassemia, tolerance, treatment, tumor, United States, urine, use, woman, Women, work, world
Posted in medicalmatrix | | Comments (0)
Background
Acute rheumatic fever (ARF) is an autoimmune inflammatory process that develops as a sequela of streptococcal infection. ARF has extremely variable manifestations and remains a clinical syndrome for which no specific diagnostic test exists. Persons who have experienced an episode of ARF are predisposed to recurrence following subsequent (rheumatogenic) group A streptococcal infections. The most significant complication of ARF is rheumatic heart disease, which usually occurs after repeated bouts of acute illness.
Pathophysiology
ARF is characterized by nonsuppurative inflammatory lesions of the joints, heart, subcutaneous tissue, and central nervous system. An extensive literature search has shown that, at least in developed countries, rheumatic fever follows pharyngeal infection with rheumatogenic group A streptococci. The risk of developing rheumatic fever after an episode of streptococcal pharyngitis has been estimated at 0.3-3%. More recent investigations of rheumatic fever occurring in the aboriginal populations of Australia suggest that streptococcal skin infections might also be associated with the development of rheumatic fever. In Oceania and Hawaii, streptococcal strains that are not typically associated with rheumatic fever have been found to cause the disease.
Molecular mimicry accounts for the tissue injury that occurs in rheumatic fever. Both the humoral and cellular host defenses of a genetically vulnerable host are involved. In this process, the patient’s immune responses (both B- and T-cell mediated) are unable to distinguish between the invading microbe and certain host tissues.The resultant inflammation may persist well beyond the acute infection and produces the protean manifestations of rheumatic fever.
Frequency
United States
The incidence of ARF has declined markedly in the past 50 years in both the United States and Western Europe. Most Western physicians see only the late sequelae of rheumatic heart disease; the diagnosis of an acute case is usually reason enough for a ground rounds presentation. This remarkable decline of rheumatic fever likely reflects improved socioeconomic conditions, as well the decline in prevalence of the classically described rheumatogenic strains of group A streptococci.
Following two decades of almost total absence, a resurgence of ARF occurred in the 1980s among middle-class white children in Salt Lake City, Utah. Clusters were also reported in US Army and Navy training camps during the same period. These limited outbreaks were associated with mucoid rheumatogenic strains that were rarely seen in the preceding 20 years. Today, ARF remains a rarity in most of the United States, although Hawaii and American Samoa continue to see a significant number of cases, many of which are caused by streptococcal strains not usually associated with rheumatic fever in persons of Polynesian descent. Read more »
Tags: abdominal, aboriginal populations, acute case, acute illness, acute infection, acute rheumatic fever, adolescence, age, and, appearance, area, ARF, arthralgia, arthritis, attention, auscultation, bout, brain, breath, Carditis, Carey, central nervous system, Characteristic, chest, CHF, chorea, Clinical, cohort, Coombs, cough, damage, death, decrescendo, development, diagnosis, disability, disease, due, dyspnea, echocardiography, effusion, endocardium, enlargement, eruption, Erythema, Europe, evidence, evolution, exertion, failure, fair, family, featu, fever, flow, form, friction, ganglioside, gonococcal, group a streptococci, Hand, heart, history, host defenses, host tissues, incidence, infection, inflammation, inflammatory lesions, inflammatory process, involvement, Isolated, Jaccoud, Joint, laboratory, likelihood, literature search, locale, malaise, manifestation, marginatum, migratory, mimicry, mitral, murmur, Murmurs, myocardium, New Zealand, nocturnal, orthopnea, pain, patient, pattern, periarticular, pericardial, pericardium, pharyngitis, Physical, Polyarthritis, poststreptococcal, potential, predilection, predisposition, prevention, problem, process, puberty, rate, recall, Recurrent, regurgitation, Rheumatic, rheumatic heart disease, risk, rub, sequela, Severe, Sex, Sore, spine, streptococcal, streptococcal infections, streptococcal skin infections, streptococcal strains, Subcutaneous, subside, Sydenham, syndrome, tenderness, Tenosynovitis, throat, trunk, United States, valvular, variable manifestations, warmth, week, western physicians
Posted in medicalmatrix | | Comments (0)
Background
Typhus refers to a group of infectious diseases that are caused by rickettsial organisms and that result in an acute febrile illness. Arthropod vectors transmit the etiologic agents to humans. The principle diseases of this group are epidemic or louse-borne typhus and its recrudescent form known as Brill-Zinsser disease, murine typhus, and scrub typhus. (For more information on pediatric scrub typhus, see the eMedicine article Scrub Typhus in the Pediatric: General Medicine volume.)
Pathophysiology
Epidemic typhus is the prototypical infection of the typhus group of diseases, and the pathophysiology of this illness is representative of the entire category. The arthropod vector of epidemic typhus is the body louse (Pediculus corporis). This is the only vector of the typhus group in which humans are the usual host. Rickettsia prowazekii, which is the etiologic agent of typhus, lives in the alimentary tract of the louse. A Rickettsia- harboring louse bites a human to engage in a blood meal and causes a pruritic reaction on the host’s skin. The louse defecates as it eats; when the host scratches the site, the lice are crushed, and the Rickettsia- laden excrement is inoculated into the bite wound. The Rickettsia travel to the bloodstream and rickettsemia develops.
Rickettsia parasitize the endothelial cells of the small venous, arterial, and capillary vessels. The organisms proliferate and cause endothelial cellular enlargement with resultant multiorgan vasculitis. This process may cause thrombosis, and the deposition of leukocytes, macrophages, and platelets may result in small nodules. Thrombosis of supplying blood vessels may cause gangrene of the distal portions of the extremities, nose, ear lobes, and genitalia. This vasculitic process may also result in loss of intravascular colloid with subsequent hypovolemia and decreased tissue perfusion and, possibly, organ failure. Loss of electrolytes is common.
Some people with a history of typhus may develop a recrudescent type of typhus known as Brill-Zinsser disease. After a patient with typhus is treated with antibiotics and the disease appears to be cured, Rickettsia may linger in the body tissues. Months, years, or even decades after treatment, organisms may reemerge and cause a recurrence of typhus. How the Rickettsia organisms linger silently in a person and by what mechanism recrudescence is mediated are unknown. The presentation of Brill-Zinsser disease is less severe than epidemic typhus, and the associated mortality rate is much lower. Risk factors that may predispose to recrudescent typhus include improper or incomplete antibiotic therapy and malnutrition.
Murine typhus and scrub typhus share the same pathophysiology as epidemic typhus, although they are somewhat milder. The incubation period is approximately 12 days for the typhus group. Prior infection with Rickettsia typhi provides subsequent and long-lasting immunity to reinfection. Read more »
Tags: acute febrile illness, advent, Africa, age, alimentary tract, Appropriate, area, array, arthropod, axilla, bathing, bite, blood meal, body, body louse, bradycardia, Brill, California, Central, changing, chigger, Clinical, CNS, Cold, colloid, coma, contact, cough, death, development, diagnose, disaster, disease, distal portions, dullness, duration, dysfunction, ear lobes, eir, endothelial cells, environment, Epidemic, epidemic typhus, eschar, etiologic agent, etiologic agents, excrement, exposure, failure, fall, fatigue, favor, fever, flea, formation, gangrene, general medicine, group, headache, Himalayas, history, hygiene, hypovolemia, illness, immunity, incidence, infection, infectious diseases, Infrequent, initiation, International, involvement, laboratory, lack, loss, lymph, lymphadenopathy, macular, maculopapu, maculopapular, malaise, Malaysia, Medical, mentation, month, Morbidity, Mortality, multiorgan, multisystem, murine, northern Australia, northern China, Occupational, onset, organ failure, organism, Orientia, Outbreaks, Overcrowding, papule, Pathophysiology, petech, petechial, Physical, population, Populations, port, predilection, presentation, process, propagation, Rash, rate, Rats, recovery, region, reinfection, rickettsia prowazekii, rickettsial, rickettsial organisms, risk, RMSF, Rocky Mountain, scrub, scrub typhus, season, section, Sex, site, South America, southern California, southern Texas, spread, spring, study, subcontinent, summer, system, Tachypnea, temperate, tender, testing, Texas, therapy, tissue perfusion, transmission, treatment, trunk, tsutsugamushi, typhi, United States, Untreated, vector, war, weather, western Pacific, world, Zinsser
Posted in medicalmatrix | | Comments (0)
The development of the world is fast. All people will able to do all things that they want. They can get everything in very easy way. When you feel bad because you have curly hair, you can get your straight hair in very fast time. It is the result of technology and technology really helps us to get better life. You need to know that everything is possible. When you are never confident because you have bad nose, you better get perfect nose by doing non-surgical nose job Rhinoplasty. It is the best way to find your perfect nose.
This nose injection London will be good for people who have problem with crooked nose and want to make it better. Some people usually have problems because their nose is small. They can improve it in very easy and instant time. When you ever get some accident and it makes your nose look bad, they will happy to help you to get perfect nose too. It will not make you in hard pain. You just need short time to get your best nose. It is usually will take 15 minutes. It will only last for six up to 12 months. You better always do treatment regularly.
Tags: 12 months, 15 minutes, accident, better life, crooked nose, curly hair, development, everything, fast time, hair, injection, job, life, London, look, non surgical nose job, nose, pain, problem, result, Rhinoplasty, short time, straight hair, technology, time, treatment, way, world
Posted in medicalmatrix | October 14, 2006 | Comments (0)