Books on the topic 'Human abdominal sepsis][Sepsis'

Sepsis is common and has been the focus of recent large-scale, multi-centre trials internationally. Mortality rates have improved, largely due to a focus on early identification, key interventions, and close monitoring. Setting goals and resuscitation targets coupled with frequent reassessment is the essence of modern sepsis care. Retrieval services bring the intensive care unit to the patient. Specific conditions such as infective endocarditis, central nervous system infections, respiratory, gastrointestinal, abdominal, obstetric, and necrotizing soft tissue sepsis require special consideration. With newly emerging infections and increasing air travel, the importance of a travel history is emphasized. Sepsis in the immunocompromised host gets a special mention due to the complexity of patient, organism, and drug interactions. The chapter is completed by a table to guide empirical antibiotic choice.

Intra-abdominal infection encompasses a broad group of infections arising both within the peritoneal cavity and the retroperitoneum. The probable bacteriology reflects patterns of normal and pathological colonization of the gastrointestinal tract. Anaerobic bacteria are found in the distal small bowel and colon. The abdomen is the second most common site of infection leading to sepsis in critically-ill patients. Intra-abdominal infections can be complex to manage and require excellent collaboration between intensivists, diagnostic and interventional radiologists, surgeons, and sometimes gastroenterologists and infectious disease specialists. Prompt diagnosis, appropriate antimicrobial coverage and timely source control are the cornerstones of successful management. The spectrum of pathologic conditions responsible for intra-abdominal infection is broad, although some common biological features facilitate an understanding of their diagnosis and management.

Vomiting and gastric stasis/gastroparesis 318Gastric erosions 320Diarrhoea 322Upper gastrointestinal haemorrhage (non-variceal) 324Bleeding varices 326Intestinal perforation 328Intestinal obstruction 330Lower gastrointestinal bleeding 332Colitis 334Intra-abdominal sepsis 336Pancreatitis 338Acute acalculous cholecystitis 340Splanchnic ischaemia 342Abdominal hypertension (IAH) and abdominal compartment syndrome ...

This chapter begins by discussing the basic principles of Advanced Trauma Life Support, care of the critically ill surgical patient, shock, SIRS and sepsis, and blood products and transfusion, before focusing on the key areas of knowledge, namely traumatic head injury, spine and spinal cord trauma, maxillofacial trauma, cardiothoracic trauma, abdominal trauma, urological trauma, vascular trauma, assessment of the acute abdomen, acute appendicitis, acute upper gastrointestinal haemorrhage, lower gastrointestinal haemorrhage, gastrointestinal obstruction, gastrointestinal perforation, acute pancreatitis, and superficial sepsis. The chapter concludes with relevant case-based discussions.

Abdominal injuries are common following blunt and penetrating trauma. They can result in a spectrum of severity from benign to potentially life-threatening conditions. Soon after injury, haemorrhage is the predominant concern, and leading cause of morbidity and mortality. Active haemorrhage resulting in shock requires emergent operative intervention and aggressive haemostatic resuscitation. However haemodynamically-stable patients benefit from non-operative management of solid organ injuries with or without angiographic embolization. Sepsis usually occurs as a result of intra-abdominal infections from missed bowel perforations or anastomotic leaks. Sterile systemic hyperinflammatory conditions can result from major hepatic necrosis or pancreatic injuries, and closely mimic infectious conditions. Damage control surgery is a valuable adjunct to the operative management of major abdominal trauma. This concept recognizes that the time and procedures required to perform definitive operative repair may be detrimental when physiological derangements are excessive. By limiting operations to controlling haemorrhage and enteric contamination, further deterioration, and the ‘vicious bloody cycle of trauma’ can be avoided. The operative and critical care management of patients with abdominal trauma should be closely integrated to correct physiological derangements with rapid stabilization and reversal of hypoperfusion. Abdominal compartment syndrome, characterized by intra-abdominal hypertension and resultant remote organ dysfunction, is a risk in patients undergoing high-volume fluid resuscitation. Emergent decompressive laparotomy is indicated in patients with abdominal compartment syndrome and results in rapid reversal of physiological compromise. Paramount to optimal management of abdominal injuries is the close integration of operative and critical care approaches.

Management of the open abdomen and intestinal fistulae remains a significant challenge. Leaving the abdomen open when it is possible to close it confers no benefit and may increase morbidity. The abdomen may be left open as part of a ‘damage control’ strategy in an unstable patient with abdominal trauma, or in other conditions in which it may be impossible to close because swollen intestinal loops, retroperitoneal haematoma, or oedema may lead to abdominal compartment syndrome. It may also be inappropriate to close the abdomen when there has been infection that cannot be readily controlled. Intestinal fistulae are associated with considerable morbidity and mortality. Management is described by the four ‘R’s of resuscitation, restitution, reconstruction and rehabilitation. Eradication of sepsis, improved wound and skin care, safe nutritional support and appropriate timing of surgical intervention have reduced mortality related to enterocutaneous fistulae from 65 to <10% over the last 30 years. However, mortality from enteroatmospheric fistulae remains high. Fifty to eighty per cent of enterocutaneous fistulae close spontaneously, compared with only 10% of colonic fistulae. Refistulation rates are high despite operative repair.

Hand infections are common and range from minor nail fold or pulp infections to severe necrotizing sepsis (often in the presence of other significant co-morbidity). We discuss general principles of the surgical management of soft tissue infection, the microbiology of hand infection and antibiotic policy. Cellulitis, abscess, and specific hand infections are covered, including flexor tendon sheath infection, intra-articular sepsis, and bites (human and animal). The chapter concludes with osteomyelitis and chronic infections, including leprosy, and other conditions which can mimic infection.

Traditionally, the etiology of acute kidney injury (AKI) is considered in terms of prerenal, renal, and obstructive causes. However, this categorization is less useful in the ICU, where the etiology of AKI is usually multifactorial and often occurs in the context of multi-organ failure. Hypotension, nephrotoxic drugs, and severe sepsis or septic shock are the most important identifiable factors. Less frequently encountered causes include pancreatitis, abdominal compartment syndrome, and rhabdomyolysis. Primary intrinsic renal disease such as glomerulonephritis is extremely uncommon. A previous history of cirrhosis, cardiac failure, or haematological malignancy, and age >65 years, are important risk factors. This chapter covers symptoms, complications, diagnosis, investigations, prognosis, and treatment of renal failure in the ITU.

Emergency surgery in the elderly is needed even if elective surgery would not be considered. Often, it is due to trauma or to intra-abdominal, vascular, or neurosurgical emergencies. The time from onset of the cause of the emergency to operative treatment is directly related to complications and death. Delay to accurate diagnosis is common and may be masked by delirium. Sepsis, pain hypotension, and metabolic disorders may all trigger delirium. Resuscitation and optimization should be concurrent with operative management. Important factors considered include the possible cause of a fall (cardiac/neurologic), likelihood of severe hypovolaemia, electrolyte disorders, and ischaemic vascular disease (occlusive and embolic). Emergency laparotomy is reviewed with the possible reasons behind the appalling outcome data, such as delayed diagnosis and poor nutritional state.

Toxic infectious exfoliative conditions include staphylococcal toxic shock syndrome (TSS), streptococcal toxic shock syndrome (STSS), and staphylococcal scalded skin syndrome (SSSS). All three are mediated by bacterial toxin production and are considerations in the differential diagnosis of a febrile, hypotensive patient with a rash. Meningococcemia is potentially fatal and extremely contagious with a short incubation period. Disseminated gonococcal infection (DGI) presents with tenosynovitis, dermatitis, and polyarthralgias without purulent arthritis or with purulent arthritis but without skin lesions. Ecthyma gangrenosum (EG) is a cutaneous manifestation of Pseudomonas aeruginosa infection. Rocky Mountain Spotted Fever (RMSF) is caused by Rickettsia rickettsii, most commonly transmitted by the American dog tick. Patients present with nonspecific symptoms, such as fever, headache, myalgias, arthralgias, nausea, vomiting, and abdominal pain. Finally, vibrio vulnificus is a gram-negative bacterium that causes serious wound infections, sepsis, and diarrhea in patients exposed to shellfish or marine water.

This book is written for clinicians who are new to ultrasound and those who want to progress further from the basics to more advanced-level scanning. Consequently, it covers a broad range of subjects, and its text is divided into five sections. Section 1 is imaging-based. Chapters in Section 1, such as physics, machine setting, and sonoanatomy, provide the foundation that underpins the rest of the book. Section 2 is structure-based. Chapters in Section 2 cover cardiac, lung, abdominal, and vascular anatomy and enable the reader to start scanning in these areas. Section 3 is problem-based. Chapters in Section 3 cover the major differential diagnoses and algorithmic approaches to ultrasound assessment of the most common clinical presentations, including shock, dyspnoea, trauma, cardiac arrest, sepsis, acute respiratory distress syndrome, and many more. Section 4 is procedure-based. Chapters in Section 4, such as thoracocentesis, lumbar puncture, and percutaneous tracheostomy, cover the technical and non-technical aspects of invasive procedures performed in critically ill patients. Section 5 is governance-based and covers how to deliver a safe and effective service.

Infection of the urinary tract is one of the commonest human infections. It can vary in severity from asymptomatic colonization, through self-limiting but distressing lower tract infection, to life-threatening sepsis. Any site in the urinary tract can be affected. The site of infection determines the pattern of symptoms, but this is also influenced by the age at presentation. The age at presentation and the nature of symptoms will not only suggest a clinical diagnosis, but also guide investigation and treatment. This chapter acts as an introduction to others in this section which address the different presentations of infections of the lower and upper urinary tracts in adults.

Emergency general surgery comprises patients with surgical problems requiring surgical intervention or post-operative surgical patients who require further surgical intervention or symptom palliation at any time of the day or night. Beyond the cases discussed below, this will include also emergency presentations from all of the sub-specialty chapters covered so far. Over 600,000 emergency hospital admissions are made to general surgery. Of these patients, they comprise the sickest patient cohort relative to the majority of elective patients, which results from sepsis, shock, or organ dysfunction from the underlying causative pathology, as well as the impact of any pre-existant comorbid states. This often has a significant impact on patient outcome, with high rates of morbidity and mortality relative to elective surgery. With this in mind, a lot of work has been channelled into improving outcomes for these patients. Furthermore, emergency and trauma surgery is beginning to establish itself as a subspecialty in itself. This chapter starts by making applied discussion of the assessment and initial investigation of acute abdominal pain, a complaint that comprises half of the annual 600,000 emergency general surgical admissions. It covers the pertinent features of diagnosis, investigation, and management of a range of common or serious emergency surgical and trauma cases that will be encountered on the acute surgical take. Kidney transplantation is not in itself an emergency operation when you consider the degree of pre-operative preparation of recipient donors, but is included in this chapter as it is commonly encountered by junior trainees on the emergency theatre list when donors are found at short notice.

The neurohormonal physiological response to various stressors is pivotal for maintaining homeostasis. However, the advent of modern critical care has distorted evolutionary biology by generating the entirely new (patho)physiological entity of critical illness. By extending the biological features of the ‘fight or flight’ response beyond the acute phase, distinct neurohormonal, and immune profiles have become increasingly apparent. Both direct and off-target effects of neurohormonal control on immune function are implicated in the disruption of bidirectional links between neurohormones and immune effectors that limit organ dysfunction. Iatrogenic factors introduced by critical care therapy may exacerbate neurohormonal dysregulation, further distorting the biology of the ‘fight or flight’ response. Neural mechanisms underlying this newly-characterized clinical syndrome remain poorly understood. Furthermore, the same neurohormonal responses are chronically dysregulated in pre-existing comorbidities diseases associated with an increased risk of sepsis, multi-organ failure and critical illness. Off-target local immune effects may explain the failure of clinical trials aimed at altering systemic neurohormonal physiology. Recent laboratory and translational human clinical studies, particularly in diseases characterized by chronic neurohormonal dysregulation, have provided new insights into the possibility of therapeutic interventions that could minimize the pathophysiological features of critical illness.

Erysipeloid is an acute bacterial infection usually causing acute localised cellulitis as a secondary infection of traumatised skin. It is caused by Erysipelothrix rhusiopathiae (insidiosa), a non-sporulating Gram-positive rod-shaped bacterium, ubiquitous in the environment. It is the cause of swine erysipelas and also a pathogen or commensal in a variety of wild and domestic birds, animal and marine species. Human infection primarily associated with occupational exposure to infected or contaminated animals or handling animal products and therefore is commoner in farmers, butchers and abattoir workers and fisherman.Risk factors for the rare human invasive E. rhusiopathiae infection include conditions that affect the host immune response, such as alcoholism, cancer and diabetes. Treatment is with penicillin.Erysipelas can affect animals of all ages but is recognised more frequently in juveniles. Swine exhibit similar stages to the disease in man. Clinical manifestations in swine vary from the classical rhomboid urticaria (diamond skin), the condition of greatest prevalence and economic importance, to sepsis, polyarthritis, pneumonia and death.Prevention is largely a matter of good hygiene, herd management and by raising awareness in those at risk (especially butchers, farmers and fishermen); ensuring that clinicians are aware of E. rhusiopathiae as a possible cause of occupational skin lesions and bacterial endocarditis is important.

Drug dosing in acute kidney injury (AKI) is one of the broadest topics in human medicine. It requires an understanding of markedly altered and constantly changing physiology under many disease situations, the use of the drugs to treat those variety of diseases, and the concept of drug removal during blood cleansing therapies. Early in AKI kidney function may be supraphysiologic, while later in the course there may be no kidney function. As function deteriorates other metabolic pathways are altered in unpredictable ways. Furthermore, the underlying disorders that lead to AKI alter metabolic pathways. Heart failure is accompanied by vasoconstriction in the muscle, skin and splanchnic beds, while brain and cardiac blood flow proportionally increase. Third spacing occurs and lungs can become congested. As either kidney or liver function deteriorates, there may be increased or decreased drug sensitivity at the receptor level. Acidosis accompanies several failing organs. Protein synthesis is qualitatively and quantitatively altered. Sepsis affects tissue permeability. All these abnormalities influence drug pharmacokinetics and dynamics. AKI is accompanied by therapeutic interventions that alter intrinsic metabolism which is in turn complicated by kidney replacement therapy (KRT). So metabolism and removal are both altered and constantly changing. Drug management in AKI is exceedingly complex and is only beginning to be understood. Thus, we approach this discussion in a physiological manner. Critically ill patients pass through phases of illness, sometimes rapidly, other times slowly. The recognition of the phases and the need to adjust medication administration strategies is crucial to improving outcomes. An early phase involving supraphysiologic kidney function may be contributory to therapeutic failures that result in the complication of later AKI and kidney function failure.

En Medicina, el área de aplicación de Ginecología, la ciencia de la mujer condensa el estudio de las enfermedades frecuentes y graves, el diagnóstico, detección de los factores de riesgo y establecer mecanismos de prevención, prescribir los tratamientos médicos y quirúrgicos de las enfermedades del sis- tema reproductor femenino, entiéndase, todo lo relacionado con la vagina, las mamas, el útero y los ovarios. Durante el siglo XX, motivado por el crecimiento acelerado del conocimien- to científico y médico, se acrecienta la toma de conciencia del rol que le co- rresponde desempeñar a la medicina en el sector de la salud y la protección de la mujer embarazada. Los problemas del trato genital femenino cuando se asumen como responsabilidad de los ginecólogos, quienes incluyeron dentro del proceso de auscultación, diagnóstico y tratamiento aspectos fisiológicos y endocrinos. Las barreras de la formación académica se fueron difuminando y los ginecó- logos y obstetras comenzaron a estrechar su campo laboral y como resultante se constituyó la Ginecobstetricia. En el marco de estas reflexiones, surge la idea de la presentación de un tex- to titulado Ginecología – Obstetricia, mediante el cual se pretende hacer una contribución real a nivel teórico que permita apoyar a profesionales y estu- diantes en el área de salud humana, básicamente en algunas de las patologías o complicaciones médicas asociadas al embarazo, y tratadas por la especialidad obstétrica, así mismo, se abordan dos temas (1 y 2) de conocimiento general. Cabe indicar que el texto no pretende abordar la vasta información o literatura que sobre los temas se han tratado. El libro ha sido estructurado bajo el perfil de diez (10) temas que discurren estrictamente sobre contenidos específicos, a sa- ber: 1. El parto y sus fases, 2. Pruebas de Bienestar Fetal, 3. Amenaza de Parto Pretérmino, 4. Ruptura Prematura de Membranas, 5. Amenaza de aborto, 6. Desprendimiento de placenta, 7. Infecciones de vías urinarias en embarazadas, 8. Diabetes Gestacional, 9. Hipertension en las embarazadas y 10. Preeclamp- sia y eclampsia En el primer tema, el Parto y sus fases, se precisan diferentes nociones sobre 26 GINECOLOGIA - OBSTETRICIA el proceso y el resultado de parir (dar a luz). A lo largo de la historia ha evolu- cionado el conocimiento de este tema dando como resultado una terminología precisa sobre los diferentes tipos de parto: parto natural, parto normal, parto ins- trumental, parto pretérmino, parto humanizado, etc. Estas nociones obedecen a determinadas circunstancias específicas que lo circunscribe como el uso o no de instrumentos que ayuden al nacimiento de un feto. De manera general, el parto marca el final del embarazo y el nacimiento de la criatura que se engendraba en el útero de la madre. Este proceso por el que la mujer o la hembra de una especie vivípara expulsa el feto y la placenta al final de la gestación consta de tres fases: la fase de dilatación, la de expulsión y la placentaria o de alumbramiento. En el segundo tema titulado Pruebas de Bienestar Fetal, se destaca el desa- rrollo de diferentes pruebas para el control del bienestar fetal. Éstas constitu- yen las técnicas aplicadas a las madres que permiten predecir el posible riesgo fetal o hacer un pronóstico del estado actual del feto, es decir, que tratan de conseguir a través de una valoración del feto de forma sistemática, la identifi- cación de aquellos que están en peligro dentro del útero materno, para así to- mar las medidas apropiadas y prevenir un daño irreversible. Se abordan en este contexto las indicaciones y los métodos (clínicos, biofísicos y bioquímicos más utilizados para el control de bienestar fetal. En el tema tres (3) denominado Amenaza de Parto Pretérmino, el trabajo se centra, en el desarrollo de los siguientes ítems. La Definición de Parto Pretérmi- no, la Definición de amenaza de Parto Pretérmino, la Evaluación del riesgo, la etiología, la Clínica de la Amenaza de Parto Pretérmino, el Diagnóstico precoz de la Amenaza de Parto Pretérmino, la Evaluación de gestantes que acuden a emergencia por signos y síntomas de Amenaza de Parto Pretérmino y el trata- miento. El trabajo parte de la definición de Parto Pretérmino entendido como aquel que ocurre después de la semana 23 y antes de la semana 37 de gestación, para posteriormente, tratar lo relativo a la Amenaza de Parto Pretérmino (APP) definido como el proceso clínico sintomático (Aparición de dinámica uterina regular acompañado de modificaciones cervicales) que puede conducir a un parto pretérmino. Su etiología es compleja y multifactorial, en la que pueden intervenir de forma simultánea factores inflamatorios, isquémicos, inmunológi- cos, mecánicos y hormonales. 27 GINECOLOGIA - OBSTETRICIA Por otro parte, el tema cuatro (4) expone la Ruptura Prematura de Membra- nas, la cual constituye una complicación usual en la práctica obstétrica, esta puede aumentar la incidencia en la morbilidad y mortalidad materna – fetal. Múltiples estudios se están llevando a cabo para poder dilucidar completamente su fisiopatología, lo cual se hace cada vez más necesario para poder aplicar estos conceptos en la práctica clínica, la evidencia actual indica que la Ruptura Prematura de Membrana es un proceso que puede ser afectado por factores: bioquímicos, fisiológicos, patológicos y ambientales. El capítulo cinco (5) comprende la temática sobre la Amenaza de aborto. (AA) que es la complicación más común durante el embarazo, se define como el sangrado transvaginal antes de las 20 semanas de gestación (SDG) gestación o con un feto menor de 500g, con o sin contracciones uterinas, sin dilatación cervical y sin expulsión de productos de la concepción”. Es decir, se presenta hemorragia de origen intrauterino antes de la vigésima semana completa de ges- tación, con o sin contracciones uterinas, sin dilatación cervical y sin expulsión de los productos de la concepción. Los síntomas abarcan amenorrea secundaria, presencia de vitalidad fetal y cólica abdominales con o sin sangrado vaginal entre otros. Para el diagnóstico se puede hacer una ecografía abdominal o va- ginal, examen pélvico y de laboratorio. En un principio el tratamiento consiste en recomendar reposo en cama y reposo pélvico. La identificación de factores de riesgo, el Ultrasonido obstétrico y la medición de marcadores bioquímicos son de gran importancia para realizar un diagnóstico y establecer un pronóstico oportuno. Estos aspectos y otros relacionados con el tema como son: la clínica, el protocolo a seguir, el tratamiento y la prevención, son tratados en este capí- tulo. El tema Desprendimiento de placenta es desarrollado a lo largo del tema seis (6). Su contenido aborda los aspectos importes como los factores de riesgo, etiología, síntomas y signos, diagnóstico y tratamiento de esta complicación cuyo proceso se caracteriza por el desprendimiento total o parcial, antes del parto, de una placenta que esta insertada en su sitio normal. Este hecho que puede traer grandes consecuencias para el feto y para la madre, puede ocurrir en cualquier momento del embarazo. Los desprendimientos producidos antes de las 20 semanas, por su evolución, deberán ser tratados como abortos. Los que tienen lugar después de la semana 20 de gestación y antes del alumbramiento constituyen el cuadro conocido como desprendimiento prematuro de la placenta normalmente insertada. (abrptio plantae o accidente de Baudelocque). El pro- ceso ha tenido una variedad de denominaciones a lo largo del tiempo y son consecuencia de la diversidad de cuadros clínicos que pueden producirse, sien- do las más empleadas en la actualidad: abruptio placentae, ablatio placentae, desprendimiento prematuro de placenta normalmente inserta (DPPNI), junto con el término abreviado desprendimiento prematuro de placenta (DPP). Para hablar de otra importante complicación que aqueja a la gestante y su bebe por nacer se expone en el tema (7) relacionado con las Infecciones de vías urinarias en embarazadas. Los particulares cambios morfológicos y funcio- nales que se producen en el tracto urinario de la gestante hacen que la infec- ción del tracto urinario (ITU) sea la segunda patología médica más frecuente del embarazo, por detrás de la anemia. Las 3 entidades de mayor repercusión son: Bacteriuria asintomática (BA) (2-11%), cuya detección y tratamiento son fundamentales durante la gestación, pues se asocia a prematuridad, bajo peso y elevado riesgo de progresión a pielonefritis aguda (PA) y sepsis; la Cistitis aguda (CA) (1,5%) y la Pielonefritis aguda (1-2%), principal causa de ingreso no obstétrico en la gestante, que en el 10 al 20% de los casos supone alguna complicación grave que pone en riesgo la vida materna y la fetal. La Diabetes Gestacional se ubica y desarrolla en el tema ocho (8). Este tipo de diabetes que aparece o se diagnostica durante el embarazo ha aumentado su prevalencia y cobrado gran relevancia epidemiológica en los últimos años. La Diabetes Gestacional (DG) o Diabetes Mellitius Gestacional (DMG) se carac- teriza por una secreción de insulina insuficiente para compensar la resistencia a la hormona, propia del embarazo. Después del parto, los niveles de glucosa sanguínea suelen normalizarse; sin embargo, algunas mujeres desarrollan DM tipo 2 y se asocia con complicaciones graves en la madre y el hijo, incluso años después del nacimiento. La Hipertensión en las Embarazadas, tema tan tratado y controvertido en los últimos años por su significación a nivel de que es la complicación médica 29 GINECOLOGIA - OBSTETRICIA más frecuente de la gestación y ocurre según estudios comprobados en el 7% a 10% de los embarazos y constituye una causa importante de morbimortalidad materna y perinatal. De manera clásica, la HTA en el embarazo ha sido definida como el incremento, durante la gestación, de la presión arterial sistólica (PAS) en 30 mmHg o más y/o la presión arterial diastólica (PAD) en 15 mmHg o más comparado con el promedio de valores previos a la 20va. semana de gestación. Cuando no se conocen valores previos, una lectura de 140/90 mmHg o mayor es considerada como anormal. El tema desarrollado abarca una visión general sobre algunos aspectos relativos a la definición y su clasificación, los factores predisponentes, sintomatología, diagnóstico, tratamiento, etc. Por último, el tema 10 aborda dos alteraciones íntimamente ligadas a la hi- pertensión arterial en el embarazo: la preeclampsia y la eclampsia. Éstas son en ocasiones tratadas como componentes de un mismo síndrome ya que la pree- clampsia es la hipertensión de reciente comienzo con proteinuria después de las 20 semanas de gestación y la eclampsia es la presencia de convulsiones genera- lizadas inexplicables en pacientes con preeclampsia.