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 | February 13, 2010 | 
Comments (0)
Background
Malaria, which predominantly occurs in tropical areas, is a potentially life-threatening disease caused by infection with Plasmodium protozoa transmitted by an infective female Anopheles mosquito vector. Individuals with malaria may present with fever and a wide range of symptoms.
The 4 Plasmodium species known to cause malaria include Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. A fifth species, Plasmodium knowlesi, has recently been identified as a clinically significant pathogen in humans. Timely identification of the infecting species is extremely important, as P falciparum infection can be fatal and is often resistant to standard chloroquine treatment. In some cases, individuals with malaria are infected with multiple Plasmodium species. P falciparum and P vivax are responsible for most new infections. Each Plasmodium species has a defined area of endemicity, although geographic overlap is common. Species can usually be distinguished by morphology on a blood smear. P falciparum is distinguished from the rest of plasmodia by its high level of parasitemia and the banana shape of its gametocytes.
Malaria in travelers typically manifests weeks after the individual leaves the endemic area. Presentation more than 4 weeks after returning from the endemic area is unusual. In some individuals, disease manifests months or years later, usually due to the presence of P vivax or P ovale hypnozoites, which can remain dormant in the liver and reactivate years after infection. Relapse with P vivax or P ovale infection is rare more than 5 years after initial infection. Because symptomatic delay is common, history of even a remote exposure to an endemic area should be elicited. Symptoms of malaria are nonspecific, and, because timely diagnosis and treatment are necessary, malaria should be considered in all patients from tropical areas who present with fever. Read more »
Tags: addition, Adherence, Africa, age, agent, airport, anemia, antimalarial, area, Asking, basis, blood, blood smear, burden, cell, chloroquine, Clinical, clue, CNS, coma, compliance, cycle, damage, death, die, disease, disease manifests, dysfunction, End-organ, endemic area, exposure, factor, falciparum, female anopheles, fever, fifth species, form, Frequency, gene, headache, history, host, hour, hypnozoite, hypoglycemia, hypoxia, illness, immunity, Importantly, incubation, India, infection, initial infection, International, latent, life, likelihood, liver, malaria, malariae, meal, mind, month, Morbidity, Mortality, mosquito, mosquito vector, multiorgan, New, none, organism, ovale, parasite, parasitemia, pathogen, patient, pattern, period, Physical, plane, plasmodia, Plasmodium, plasmodium malariae, plasmodium ovale, plasmodium species, population, Populations, posttravel, primaquine, primigravida, property, protection, protozoa, quartan, reason, recurrence, relapse, resident, return, Reviews, risk, Saharan, sequestration, severity, sickle, southern United States, stage, stream, sub, susceptibility, symptomatology, symptoms of malaria, system, temperate, Tertian, timely diagnosis, timely identification, TNF, travel, traveler, Travelers, tropical areas, tumor, United States, US, virulent, vivax, world, year, Young
Posted in medicalmatrix | | Comments (0)
Background
Rabies is a viral disease that affects the CNS. The genus Lyssavirus contains more than 80 viruses. Classic rabies, the focus of this article, is the prototypical human Lyssavirus pathogen. Ten viruses are in the rabies serogroup, most of which only rarely cause human disease. The genus Lyssavirus, rabies serogroup, includes the classic rabies virus, Mokola virus, Duvenhage virus, Obodhiang virus, Kotonkan virus, Rochambeau virus, European bat Lyssavirus types 1 and 2, and Australian bat Lyssavirus. In 1997, an unusual bat Lyssavirus caused a brief outbreak of a rabieslike illness in Australia.
The fatal madness of rabies has been described throughout recorded history, and its association with rabid canines is well known. For centuries, dog bites were treated prophylactically with cautery, unfortunately, with predictable results. In the 19th century, Pasteur developed a vaccine that successfully prevented rabies after inoculation and launched a new era of hope in the management of this uniformly fatal disease. Rabies is recognized as a zoonosis worldwide. Animal-control and vaccination strategies currently supersede postexposure prophylaxis in preventing the spread of rabies. Through such programs, rabies has been eliminated in several nations and some areas in the US territories.
Human rabies reflects the prevalence of animal infection and the extent of contact this population has with humans. Less than 5% of cases in developed nations occur in domesticated dogs; however, unvaccinated dogs serve as the main reservoir worldwide. Undomesticated canines, such as coyotes, wolves, jackals, and foxes, are most prone to rabies and serve as reservoirs. These reservoirs allow rabies to remain an indefinite public health concern, and ongoing public health measures are critical to its control. Raccoons, skunks, and insect-eating bats remain the prime vectors in the United States, followed by cats and cattle. Increasingly in the United States, the source of exposures cannot be identified, but the risk of death from rabies is exceedingly low, with fewer than 5 cases documented per year. Opossums are rarely infected and are not considered a likely risk for exposure. Read more »
Tags: absence, Acute, addition, Adherence, aerophobia, age, agitation, air, airway, amantadine, animal control, anisocoria, anorexia, antibody, anxiety, aphasia, arrest, Attempting, attention, auditory, australian bat lyssavirus, Autonomic, awareness, bat, bite, calm, cardiorespiratory, care, case, cautery, CDC, cerebrospinal, Clinical, CNS, coma, confusion, Control, cranial, CSF, death, delirium, depression, developed nations, diarrhea, diplopia, disease, dog bites, domesticated dogs, drinking, duration, Episodes, exposure, face, fact, fever, form, Furious, girl, Hand, head, headache, health, history, human rabies, Hydrophobia, hyperactivity, hypertension, hyperventilation, hypotension, incubation, individual, infection, inoculation, inoculum, insomnia, instability, International, involvement, irritant, jackals, lacrimation, laryngeal, main reservoir, malaise, Morbidity, Mortality, Nausea, neck, need, nerve, Neurologic, neurovirulent, Nonspecific, objective, October, onset, Organization, outset, pain, palsy, paralysis, Paralytic, Paresthesia, patient, percent, period, person, perspiration, phase, Physical, postexposure, postural, predictable results, predilection, preexposure, prevention, Prodromal, public health concern, public health measures, rabid canines, Rabies, rabies virus, raccoons, Race, recovery, regimen, response, Ribavirin, risk, saliva, salivation, scratch, Seizures, sensation, Sex, sign, site, skunks, spasm, suggestion, survival, survivor, Symptoms, system, tachycardia, tactile, therapy, thrashing, tissue, treatment, US, vaccination, vaccination strategies, victim, viral disease, virus, Wisconsin, world, worldwide, year, zoonosis
Posted in medicalmatrix | | Comments (0)
This article focuses on common bacterial infections in pregnancy and describes the manifestations of these infections and the therapies used to treat them.
Bacterial infections can affect pregnant women from implantation of the fertilized ovum through the time of delivery and peripartum period. They may also affect the fetus and newborn. Many women with these infections are asymptomatic, necessitating both a high degree of clinical awareness and adequate screening.
Grop B Streptococcus
Group B Streptococcus (GBS) is the most common cause of life-threatening infections in newborns; thus, GBS is the primary focus of any discussion about infections and pregnancy. Infections caused by GBS affect both mother and child. Since the emergence of this pathogen in the 1970s, the increased use of intrapartum prophylaxis has decreased the infection rate by 70%.
Etiology
Streptococcus agalactiae, or GBS, is a facultative, beta-hemolytic, fastidious, gram-positive coccus. GBS can be found as part of normal vaginal, rectal, and oral flora. The virulence of the organism depends largely on the polysaccharide capsule.
Transmission
Twenty to 25% of pregnant women are asymptomatic carriers of vaginal or rectal GBS. Intrapartum transmission occurs via ascending spread or at the time of delivery.
Clinical spectrum
Because only 0.5-1% of mothers who carry GBS develop signs and symptoms of disease, clinical diagnosis of GBS infection can be problematic.
In pregnant women, GBS is a cause of cystitis, amnionitis, endometritis, and stillbirth. Occasionally, GBS has caused endocarditis and meningitis in pregnant women, while, in postpartum women, GBS has been identified as a cause of urinary tract infections (UTIs) and pelvic abscesses. Read more »
Tags: abscesses, absorption, addition, alternative, Ampicillin, antenatal, antibody, Antitreponemal, assay, asymptomatic carriers, Avoid, azithromycin, bacteremia, benzathine, blood, care, Ceftriaxone, cervix, Chlamydia, choice, Clinical, clinical diagnosis, clinical spectrum, CNS, common bacterial infections, congenital, Consume, context, course, CSF, culture, cystitis, death, delivery, diagnose, diagnosis, disease, dose, drug, endometritis, equivalent, Erythromycin, Etiology, examination, failure, fetus, fever, fluorescent, focus, food, FTA-ABS, gbs, gestation, group b streptococcus, Herxheimer, HIV, increase, infection, intramuscular, Jarisch, labor, laboratory, lack, latent, lesion, life, lumbar, lymphadenopathy, material, maternal, meat, MHA-TP, microhemagglutination, milk, Morbidity, mother, mother and child, motile, neonatal, Neurosyphilis, nonpregnant, nontreponemal, ovum, pain, pallidum, patient, penicillin, plasmin, polysaccharide capsule, postpartum women, pregnancy, prenatal, preparation, preterm, prevention, prophylaxis, puncture, Rash, rate, reaction, reagin, Research, risk, Screening, screening group, seafood, Serological, show, site, spectrum, spilling, spirochete, stage, stillbirth, stool, streptococcus agalactiae, streptococcus group b, sulfamethoxazole, surveillance, symptom onset, Syphilis, test, testing, therapy, third, treatment, Treponema, treponemal, trimester, Trimethoprim, ulcer, United States, Untreated, urinary tract infections, uterine, vagina, VDRL, Venereal, virulence, visit, vulva, Wash, week, Women
Posted in medicalmatrix | | Comments (0)
Background
Intracranial abscesses are uncommon, serious, life-threatening infections. They include brain abscess and subdural or extradural empyema and are classified according to the anatomical location or the etiologic agent. The term brain abscess is used in this article to represent all types of intracranial abscesses.
Intracranial abscesses can originate from infection of contiguous structures (eg, otitis media, dental infection, mastoiditis, sinusitis) secondary to hematogenous spread from a remote site (especially in patients with cyanotic congenital heart disease), after skull trauma or surgery, and, rarely, following meningitis. In at least 15% of cases, no source can be identified.
In recent years, the complex array of etiologic agents that cause brain abscess has become better understood.
Pathophysiology
Brain abscess is caused by intracranial inflammation with subsequent abscess formation. In at least 15% of cases, the source of the infection is unknown (cryptogenic). Infection may enter the intracranial compartment directly or indirectly via 3 routes.
Contiguous suppurative focus (45-50% of cases)
Direct extension may occur through necrotic areas of osteomyelitis in the posterior wall of the frontal sinus, as well as through the sphenoid and ethmoid sinuses.This direct route of intracranial extension is more commonly associated with chronic otitic infection and mastoiditis than with sinusitis. Odontogenic infections can spread to the intracranial space via direct extension or a hematogenous route. Contiguous spread could extend to various sites in the central nervous system, causing cavernous sinus thrombosis; retrograde meningitis; and epidural, subdural, and brain abscess. Read more »
Tags: abdominal, abscess formation, abscesses, administration, age, agent, AIDS, array, artery, article, availability, Background, body, brain, brain abscess, cause, cavernous sinus thrombosis, central nervous system, cerebellum, Chronic, Clinical, compartment, complication, congenital, congenital heart disease, contamination, Contiguous, contiguous structures, course, decrease, dental infection, diagnosis, dilatation, disease, distribution, drug, dural, emergence, emissary veins, empyema, entry, epidural, esophageal, ethmoid, ethmoid sinuses, etiologic agent, etiologic agents, evidence, exacerbation, extension, extradural, focus, formation, fracture, Frequency, frontal sinus, fulmi, fulminant, fungal, Haemophilus, heart, Hematogenous, history, HIV, hospital, imaging, indolent, infection, inflammation, influenzae, injection, International, Intracranial, introduction, life, lobe, location, lung, mode, Morbidity, Mortality, MRI, mucosa, mucosal, necrotic areas, network, neutropenia, Odontogenic, odontogenic infections, osteomyelitis, paranasal, Pathophysiology, posterior, prevalence, problem, rate, resul, retrograde, route, Rupture, seed, sequelae, Sex, shrapnel, site, skin, skull, source, space, sphenoid, spread, structure, subdural, surgery, system, term, Thrombophlebitis, transplantation, trauma, United States, use, vaccine, vasculature, wall, world
Posted in medicalmatrix | | Comments (0)