Ogle.ENARM by JD-MD 12a PARTE
1101.- un hombre de 43 años inicio su padecimiento hace tres meses con un cuadro clínico caracterizado por dificultad para la visión cercana y cefalea ocasional. El diagnostico más probable es:
Ambliopia
Hipertensión arterial Miagraña
Astigmatismo Presbicia
La presbicia es la dificultad para el enfoque correcto de los objetos en distancias cortas, que ocurre en sujetos mayores de 40 años. Es debida al esclerosamiento del cristalino, lo que dificulta su flexibilidad y, por tanto, su capacidad para adaptarse en el enfoque de distintas distancias.
1102.- Caso clínico seriado: Una mujer de 48 años, con antecedentes de traumatismo nasal de hace 7 años, desde entonces ha padecido obstrucción nasal y cuadros esporádicos de cefalea frontal, hace 3 semanas inicia dolor en la región infraorbitaria de ambos lados, rinorrea mucoverdosa, hiposmia, fiebre, trismos y malestar general, se integra el diagnóstico de sinusitis aguda. Primer enunciado: El agente causal más probable del padecimiento de esta mujer es:
Streptococcus pneumoniae Bramhanella catarrhalis
Staphylococcus aureus Haemophylus influenzae Bacteroides fragilis
1103.- Segundo enunciado: al antimicrobiano más útil en este caso es: a) Cloranfenicol
b) Sulfametoxazol con trimetropin c) Gentamicina
d) Ceftriaxona e) Penicilina
The typical pathogens of bacterial sinusitis are the same as those that cause acute otitis media: S pneumoniae, other streptococci, H influenzae, and, less commonly, S aureus and M catarrhalis. Two-thirds of untreated patients will improve symptomatically within 2 weeks. Administration of antibiotics does, however, reduce by 50% the incidence of clinical failure and, coupled with clinical criteria-based diagnosis, represents the most cost-effective treatment strategy. Symptoms may be improved with oral or nasal decongestants (or both) eg, oral pseudoephedrine, 30-120 mg per dose, up to 240 mg/d; nasal oxymetazoline, 0.05%, or xylometazoline, 0.05-0.1%, one or two sprays in each nostril every 6-8 hours for up to 3 days.
Double-blinded studies exist to support any of the following antibiotic choices:
• Amoxicillin (500 mg orally three times a day), possibly with clavulanate (125 mg three times a day)
• Trimethoprim-sulfamethoxazole (4 mg/kg TMP and 20 mg/kg SMZ twice daily; available as tablets with 80 or 160 mg TMP and 160 or 800 mg SMZ)
• Cephalexin (250-500 mg orally four times a day) • Cefuroxime (250 mg orally twice daily)
• Cefaclor (250 mg orally three times a day) • Cefixime (400 mg orally daily)
• Quinolones, such as ciprofloxacin (500 mg twice daily), levofloxacin (500 mg once daily), moxifloxacin (400 mg once daily), and sparfloxacin (200 mg once daily after an initial dose of 400 mg)
• Macrolides, such as azithromycin (500 mg once daily, possibly for only 3 days) or clarithromycin (500 mg orally twice daily, for 14 days) Usually, amoxicillin or TMP-SMZ is adequate and most cost-effective and covers the common pathogens discussed earlier.
Treatment is usually for 10 days, although longer courses are sometimes required to prevent relapses. Recurrent sinusitis or sinusitis that does not appear to respond clinically warrants evaluation by a specialist. Selection of antibiotics is usually empiric, but if symptoms persist, obtaining a culture endoscopically or via maxillary sinus puncture may help narrow the choice based on culture and sensitivity tests. Resistance by H influenzae and S pneumoniae is a public health concern. Culture may also be helpful in nosocomial sinusitis, where the bacterial spectrum may be less typical and the potential complications greater. Failure of sinusitis to resolve after an adequate course of oral antibiotics may necessitate hospital admission for intravenous antibiotics and possible surgical drainage. Frontal sinusitis that does not promptly respond to outpatient care should be managed aggressively, because the posterior sinus wall is adjacent to the dura and because undertreated infection may lead to intracranial extension. If intravenous antibiotics fail to ameliorate symptoms, it may be necessary to surgically drill a small opening into the floor of the frontal sinus to drain and irrigate the sinus. Persistent maxillary empyema may be cultured and relieved with a needle inserted through the lateral wall of the nose or anterior wall of the antrum through the gingivobuccal sulcus.
1104.- El tratamiento del glaucoma agudo se debe efectuar utilizando: a) Espironolactona
b) Estreptomicina c) Pilocarpina d) Homatropina
e) Prostaglandina alfa F-2
Initial treatment in primary angle-closure glaucoma is control of intraocular pressure. A single 500-mg intravenous dose of acetazolamide, followed by 250 mg orally four times a day, is usually sufficient. Osmotic diuretics such as oral glycerol and intravenous urea or mannitol the dosage of all three being 1-2 g/kg may be necessary if there is no response to acetazolamide. Laser therapy to the peripheral iris (iridoplasty) or anterior chamber paracentesis is also effective. Once the intraocular pressure has started to fall, topical 4% pilocarpine, 1 drop every 15 minutes for 1 hour and then four times a day, is used to reverse the underlying angle closure. The definitive treatment is laser peripheral iridotomy or surgical peripheral iridectomy, which should also be performed prophylactically on the fellow eye. Cataract extraction is a possible alternative. If it is not possible to control the intraocular pressure medically, glaucoma drainage surgery as for uncontrolled open-angle glaucoma (see below) may be required. In secondary acute angle-closure glaucoma, systemic acetazolamide is also used, with or without osmotic agents. Further treatment is determined by the cause.
1105.- Tratamiento del cuadro agudo de gota: a) Prednisolona
b) Ácido acetilsalicílico c) Colchicina
d) Alopurinol e) Fenilbutazona
Arthritis is treated first and hyperuricemia later, if at all. Sudden reduction of serum uric acid often precipitates further episodes of gouty arthritis. NSAIDs have become the treatment of choice for acute gout. Traditionally, indomethacin has been the most frequently used agent, but all of the other newer NSAIDs are probably equally effective. Indomethacin is initiated at a dosage of 25-50 mg every 8 hours and continued until the symptoms have resolved (usually 5-10 days). Active peptic ulcer disease, impaired renal function, and a history of allergic reaction to NSAIDs are contraindications. For patients at high risk for upper gastrointestinal bleeding, a cyclooxygenase type 2 (COX-2) inhibitor may be an appropriate first choice for management of an acute gout attack. Long-term use of COX-2 inhibitors is not advised because of the association with increased risk of cardiovascular events, which has led to the removal of some drugs from the US market (e.g. rofecoxib and valdecoxib). Colchicine is no longer recommended for the treatment of acute gout flares. Its use during the intercritical period to prevent gout attacks. Corticosteroids often give dramatic symptomatic relief in acute episodes of gout and will control most attacks. They are most useful in patients with contraindications to the use of NSAIDs. If the patient's gout is monarticular, intra-articular administration (eg, triamcinolone, 10-40 mg depending on the size of the joint) is most effective. For polyarticular gout, corticosteroids may be given intravenously (eg, methylprednisolone, 40 mg/d tapered over 7 days) or orally (eg, prednisone, 40-60 mg/d tapered over 7 days). Gouty and septic arthritis can coexist, albeit rarely. Therefore, joint aspiration and Gram stain with culture of synovial fluid should be performed before corticosteroids are given.
1106.- En la artritis reumatoide que no responde satisfactoriamente al tratamiento con antiinflamatorios no esteroideos debe utilizarse:
a) Cloroquina b) Metotrexate c) D-penicilamina d) Nabumetona e) Prednisona
The first drug used to treat rheumatoid arthritis is an NSAID. These agents have analgesic and anti-inflammatory effects but do not prevent erosions or alter disease progression. A number of NSAIDs are available, including aspirin, ibuprofen, naproxen, sulindac, diclofenac, nabumetone, etodolac, ketoprofen, celecoxib, and others. Methotrexate is usually the treatment of choice for patients with rheumatoid arthritis who do not respond to NSAIDs. Methotrexate is generally well tolerated and often produces a beneficial effect in 2-6 weeks¾compared with the 2- to 6-month onset of action for drugs such as gold, penicillamine, and antimalarials. The usual initial dose is 7.5 mg of methotrexate orally once weekly. If the patient has tolerated methotrexate but has not responded in 1 month, the dose can be increased to 15 mg orally once per week. The maximal dose is approximately 25 mg/wk. The most frequent side effects are gastric irritation and stomatitis. If needed to minimize gastrointestinal toxicity, methotrexate can be administered by subcutaneous or intramuscular injection. A severe, potentially life-threatening interstitial pneumonitis occurs rarely and usually responds to cessation of the drug and institution of corticosteroids. Hepatotoxicity with fibrosis and cirrhosis is another important toxic effect that appears to be very rare, with a risk of approximately 1:1000 after 5 years of methotrexate therapy. Still, methotrexate is contraindicated in a patient with any form of chronic hepatitis. Diabetes, obesity, and renal disease increase the risk of hepatotoxicity. Liver function tests should be monitored every 4-8 weeks, along with the complete blood count,
serum creatinine, and serum albumin. Heavy alcohol use increases the hepatotoxicity, so patients should be advised to drink alcohol in extreme moderation, if at all. In a patient with no risk factors for hepatotoxicity, liver biopsy is not needed initially but is performed if aminotransferase levels are elevated, despite dosage reduction, in 6 out of 12 monthly determinations or if the serum albumin falls below normal. Cytopenia due to bone marrow suppression and infection are other important potential problems. The risk of developing cytopenia is much higher in patients with a serum creatinine of 2 mg/dL or higher. Side effects, including hepatotoxicity, may be reduced by prescribing either daily folate (1 mg) or weekly leucovorin calcium (2.5-5 mg taken 24 hours after the dose of methotrexate). Methotrexate is associated with an increased risk of B cell lymphomas, some of which resolve following the discontinuation of the medication. The combination of methotrexate and other folate antagonists, such as trimethoprim-sulfamethoxazole, should be used cautiously, since pancytopenia can result. Probenecid should also be avoided since it increases methotrexate drug levels and toxicity.
1107.- Cual de las siguientes parasitosis en el ser humano es transmitida por helminto: a) Ascariasis b) Amibiasis c) Cólera d) Botulismo e) Blastomicosis
La ascariasis es una infección producida por un helminto parásito, Ascaris lumbricoides, que en su fase de larva migra a los pulmones. Los huevos son eliminados a través de las heces humanas, contaminando así el suelo y permitiendo que el parásito se transmita a otras personas, a cuyas bocas accede a través de las manos, del agua o de los alimentos. Después de un período de incubación que transcurre en el intestino delgado, las larvas migran a través de la pared intestinal, pudiendo ser transportadas por medio de la sangre y de los linfáticos hasta los pulmones.
1108.- El mesotelioma se produce por la exposición a: a) Arsénico
b) Niquel c) Asbesto d) Cromo e) Silicio
Tumor maligno poco frecuente del mesotelio de la pleura o del peritoneo, que se asocia a una exposición previa al asbesto.
1109.- Qué fármaco es útil en la fiebre de Lassa en etapas tempranas: Amantadina
Vidarabina Aciclovir Ribavirina Zidovudina
Lassa fever, with its focus of endemicity in West Africa, is the best known of the arenavirus hemorrhagic fevers. Other agents, such as Junin and Machupo, cause similar syndromes in different geographic areas (Argentina and Bolivia, respectively).
Lymphocytic choriomeningitis virus (LCM) is an arenavirus that causes viral meningitis. Clinical illness is characterized by fever and coagulopathy. Hemorrhage and shock occur and occasionally cardiac and liver damage. Pharyngitis, diarrhea, and vomiting may be very prevalent, especially in patients with Lassa fever. The diagnosis is suggested by recent travel to endemic areas. Only supportive therapy for patients with arenavirus infection is currently available. Uncontrolled studies suggest that ribavirin may be useful for those with Lassa fever.
1110.- En la enfermedad de Lyme el agente etiológico es:
a)
Borrelia burgdorferib) Rickettsias c) Bartonella d) Micoplasma e) Treponema
Infección inflamatoria recurrente aguda, producida por una espiroqueta Borrelia
burgdorferi transmitida por garrapatas. El proceso fue descrito en principio en Lyme,
Connecticut (EE.UU.). Se afectan sobre todo las rodillas y otras grandes articulaciones y las articulaciones temporomandibulares, con inflamación y tumefacción local. A menudo las manifestaciones articulares están precedidas por escalofríos, fiebre, malestar general y una erupción cutánea eritematosa anular en expansión. A veces se asocian otros procesos como anomalías en la conducción cardíaca, meningitis aséptica y parálisis de Bell.
1111.- Tratamiento de elección para Pneumocystis carinii: a) Metronidazol
b) Trimetoprim con sulfametoxazol c) Atavacuona
d) Primaquina e) Clindamicina
The primary treatment of moderate to severe pulmonary or extrapulmonary infection caused by P carinii remains the combination of trimethoprim (TMP) and sulfamethoxazole (SMX), either orally or intravenously (IV). Several medications (atovaquone, trimetrexate, and pentamidine) and combination regimens (dapsone + TMP and clindamycin + primaquine) probably afford nearly equal efficacy to TMP-SMX in mild to moderate PCP and may be better tolerated in specific populations of patients. Prophylaxis for PCP has clearly been shown to be effective in reducing the incidence of disease and improving survival in patients at risk for developing the disease. No chemoprophylactic treatment regimen has been shown to be more effective than TMP-SMX. In addition, TMP-SMX provides protection against the bacteria that cause community-acquired pneumonia, as well as against toxoplasmosis. Aerosolized pentamidine isethionate and dapsone with or without pyrimethamine or TMP should continue to be regarded as second-line agents in the prevention of PCP.
1112.- Probable agente infeccioso en pacientes con VIH que se presenta con un cuadro de evacuaciones diarreicas:
a) Escherichia coli b) Cryptosporidium c) Salmonella tiphy d) Entamoeba histolytica e) Citomegalovirus
Bacteria may be responsible for secondary infections of the gastrointestinal tract. Infections with enteric pathogens such as Salmonella, Shigella, and Campylobacter are more common in homosexual men and are often more severe and more apt to relapse in patients with HIV infection. Patients with untreated HIV have approximately a 20-fold increased risk of infection with S. typhimurium. They may present with a variety of nonspecific symptoms including fever, anorexia, fatigue, and malaise of several weeks' duration. Diarrhea is common but may be absent. Diagnosis is made by culture of blood and stool. Long-term therapy with ciprofloxacin is the recommended treatment. HIV-infected patients also have an increased incidence of S. typhi infection in areas of the world where typhoid is a problem. Shigella spp., particularly S. flexneri, can cause severe intestinal disease in HIV-infected individuals. Up to 50% of patients will develop bacteremia. Campylobacter infections occur with an increased frequency in patients with HIV infection. While C. jejuni is the strain most frequently isolated, infections with many other strains have been reported. Patients usually present with crampy abdominal pain, fever, and bloody diarrhea. Infection may present as proctitis. Stool examination reveals the presence of fecal leukocytes. Systemic infection can occur, with up to 10% of infected patients exhibiting bacteremia. Most strains are sensitive to erythromycin. Abdominal pain and diarrhea may be seen with MAC infection. Fungal infections may also be a cause of diarrhea in patients with HIV infection. Histoplasmosis, coccidioidomycosis, and penicilliosis have all been identified as a cause of fever and diarrhea in patients with HIV infection. Peritonitis has been seen with C. immitis. Cryptosporidia, microsporidia, and Isospora belli are the most common opportunistic protozoa that infect the gastrointestinal tract and cause diarrhea in HIV-infected patients. CMV colitis was once seen in 5 to 10% of patients with AIDS. In addition to disease caused by specific secondary infections, patients with HIV infection may also experience a chronic diarrheal syndrome for which no etiologic agent other than HIV can be identified. This entity is referred to as AIDS enteropathy or HIV enteropathy. It is most likely a direct result of HIV infection in the gastrointestinal tract. Histologic examination of the small bowel in these patients reveals low-grade mucosal atrophy with a decrease in mitotic figures, suggesting a hyporegenerative state. Patients often have decreased or absent small-bowel lactase and malabsorption with accompanying weight loss. The initial evaluation of a patient with HIV infection and diarrhea should include a set of stool examinations, including culture, examination for ova and parasites, and examination for Clostridium difficile toxin. Approximately 50% of the time this workup will demonstrate infection with pathogenic bacteria, mycobacteria, or protozoa. If the initial stool examinations are negative, additional evaluation, including upper and/or lower endoscopy with biopsy, will yield a diagnosis of microsporidial or mycobacterial infection of the small intestine ~30% of the time. 1113.- Conforme a la norma oficial mexicana, para la prevención y control de la tuberculosis, que grupo de fármacos se utilizan como tratamiento primario acortado estrictamente supervisado:
a)
Piracinamida 60mg/kg e isoniacida 15 mg/kg fase de 60 dósisb)
Isoniacida y etambutol en 3 fases de 60 dosisc) Isoniacida y rifampicina en 2 fases de 60 dosis una cada día y otra de 45 dosis
d)
Estreptomicina y rifampicina en 4 fases de 45 dosis cada unae)
Rifampicina y etambutol durante 2 mesesTAES
Fase intensiva: diario de lunes a sábado, hasta completar 60 dosis. Administrar en una sola toma.
Medicame
nto Separados (dosis) Combinación fija (4 grageas) Rifampicin
a 600 mg 150 mg
Isoniacida 300 mg 75 mg dosis por gragea Pirazinami
da 1,500 a 2,000 mg 400 mg Etambutol 1,200 mg 400 mg
Fase de sostén: intermitente 3 veces por semana; lunes, miércoles y viernes. Hasta completar 45 dosis, administrar en una sola toma.
Medicam ento Separados (dosis) Combinación fija (4 cápsulas) Isoniacida 800 mg 200 mg Rifampicin a 600 mg 150 mg por cápsula
En niños y adultos de 50 kg, administrar dosis por kg de peso, con medicamentos en presentación separada. En todos los pacientes con tuberculosis del SNC, miliar u ósea, el tratamiento deberá ser administrado por un año, y los pacientes con diabetes serán tratados por 6 meses.
1114.- La anemia perniciosa se presenta por deficiencia de: Riboflavina
Hidroxicobalamina Cianocobalamina Factor intrínseco Factor extrínseco
Enfermedad crónica que afecta principalmente a los individuos mayores de 60 años, en la cual la vitamina B12 no se absorbe por ausencia de factor intrínseco (FI) en el jugo gástrico, como consecuencia de una posible predisposición genética. Asimismo, se ha sugerido una patogenia autoinmune por la presencia de anticuerpos antiparietales, la asociación con otras enfermedades autoinmunes y la presencia de anticuerpos antiFI. La anemia es macrocítica y en ocasiones se acompaña de trombocitopenia y, excepcionalmente, de leucopenia. La tríada clásica de palidez flavínica, glositis atrófica de Hunter y parestesias es la forma más habitual.
1115.- Cual es el riesgo de adquirir una infección por VIH después de una punción accidental con una jeringa hueca con sangre procedente de un paciente infectado: a) 1-30 b) 1-300 c) 1-1000 d) 1-3000 e) 1-100
There is a small, but definite, occupational risk of HIV2 transmission to health care workers and laboratory personnel and potentially others who work with HIV-containing materials, particularly when sharp objects are used. An estimated 600,000 to 800,000 health care workers are stuck with needles or other sharp medical instruments in the United States each year. Large, multi-institutional studies have indicated that the risk of HIV transmission following skin puncture from a needle or a sharp
object that was contaminated with blood from a person with documented HIV infection is ~0.3% and after a mucous membrane exposure it is 0.09% . HIV transmission after non-intact skin exposure has been documented, but the average risk for transmission by this route has not been precisely determined; however, it is estimated to be less than the risk for mucous membrane exposure. Transmission of HIV through intact skin has not been documented. An increased risk for HIV infection following percutaneous exposures to HIV-infected blood is associated with exposures involving a relatively large quantity of blood, as in the case of a device visibly contaminated with the patient's blood, a procedure that involves a needle placed directly in a vein or artery, or a deep injury. Factors that might be associated with mucocutaneous transmission of HIV include exposure to an unusually large volume of blood, prolonged contact, and a potential portal of entry. In addition, the risk increases for exposures to blood from patients with advanced-stage disease, probably owing to the higher titer of HIV in the blood as well as to other factors, such as the presence of more virulent strains of virus. The use of antiretroviral drugs as postexposure prophylaxis decreases the risk of infection compared to historic controls in occupationally exposed health care workers (see "HIV and the Health Care Worker"). The risk of hepatitis B virus (HBV) infection following a similar type of exposure is 6 to 30% in nonimmune individuals; if a susceptible worker is exposed to HBV, postexposure prophylaxis with hepatitis B immune globulin and initiation of HBV vaccine is >90% effective in preventing HBV infection. The risk of hepatitis C virus (HCV) infection following percutaneous injury is ~1.8%.
1116.- el VIH-SIDA continúa siendo problema de salud pública. El gobierno se preocupa por programas preventivos. De los siguientes aspectos: qué se debe tomar en cuenta para iniciar el tratamiento con antirretrovirales:
a) Cuantificación de CD4
b) Estadio clínico por infección de VIH c) Comorbilidades
d) Medir CD4, carga viral y presencia de condición desinhibitoria en SIDA e) Carga viral
Las recomendaciones para dar inicio al tratamiento con antirretrovirales son:
• Enfermedad por VIH sintomática (candidiasis mucosa recurrente, leucoplaquia pilosa bucal y fiebre inexplicable, sudores nocturnos y pérdida de peso).
• Asintomático, cuenta de células CD4+ <0.500 X 10-9/L • Asintomático, cuenta de células CD4+ >0.500 X 10-9/L 1117.- El colesterol es el precursor de todas las hormonas:
Tiroideas Hipofisiarias Pancreáticas Esteroideas Hipotalamicas
El colesterol es un alcohol esteroide con aspecto de grasa, presente en grasas animales, aceites, bilis, sangre, huevo (yema), etc. Es precursor de los ácidos biliares y constituye la materia prima para la síntesis de las hormonas esteroides.
1118.- El principal precursor circulante de la estrona placentaria y el 17-estradiol es:
a) Sulfato de dehidroisoandrosterona b) Testosterona
c) Androsterona
d) Dehidroisoandrosterona e) Pregnandiol
The naturally occurring estrogens are 17b-estradiol, estrone, and estriol. They are C18 steroids; ie, they do not have an angular methyl group attached to the 10 position or a D-3-keto configuration in the A ring. They are secreted primarily by the granulosa cells of the ovarian follicles, the corpus luteum, and the placenta. The biosynthetic pathway involves their formation from androgens (testosterona). They are also formed by aromatization of androstenedione in the circulation. Aromatase (CYP19) is the enzyme that catalyzes the conversion of androstenedione to estrone and the conversion of testosterone to estradiol.
1119.- Para el tratamiento de la escarlatina se debe utilizar la: a) Penicilina
b) Cefotaxima c) Eritromicina d) Lincomicina e) Dicloxacilina
During the last 30-40 years, outbreaks of scarlet fever in the Western world have been infrequent and notably mild, and the illness has been referred to as pharyngitis with a rash or benign scarlet fever. In contrast, in the latter half of the 19th century, mortalities of 25-35% were common in the United States, Western Europe, and Scandinavia. The fatal or malignant forms of scarlet fever have been described as either septic or toxic. Septic scarlet fever refers to patients who develop local invasion of the soft tissues of the neck and complications such as upper-airway obstruction, otitis media with perforation, meningitis, mastoiditis, invasion of the jugular vein or carotid artery, and bronchopneumonia. Toxic scarlet fever is rare today, but, historically, patients initially developed severe sore throat, marked fever, delirium, skin rash, and painful cervical lymph nodes. In severe toxic cases, fevers of 107°F, pulses of 130-160 beats per minute, severe headache, delirium, convulsions, little if any skin rash, and death within 24 hours were common. These cases occurred before the advent of antibiotics, antipyretics, and anticonvulsants, and deaths were acutely the result of uncontrolled seizures and hyperpyrexia. In contrast, children with septic scarlet fever had prolonged courses and succumbed 2-3 weeks after the onset of pharyngitis. Complications of streptococcal pharyngitis and malignant forms of scarlet fever have been less common in the antibiotic era. Even before antibiotics became available, necrotizing fasciitis and myositis were not described in association with scarlet fever. During epidemics, particularly when rheumatic fever or a post-streptococcal glomerulonephritis are prevalent, treatment of asymptomatic carriers may be necessary. Studies by the U.S. military have shown that monthly injections of benzathine penicillin greatly reduce the incidence of streptococcal pharyngitis and rheumatic fever in young soldiers living in crowded conditions. Erythromycin resistance of S pyogenes is currently 4% in Western countries; however, in Japan in 1974, the rate reached 72%. Sulfonamide resistance currently is reported in <1% of GAS isolates. Resistance to penicillin has not been described, yet in some settings there is a lack of in vivo efficacy despite in vitro susceptibility to penicillin. Three mechanisms may explain this lack of efficacy. Penicillin failure in pharyngitis, tonsillitis, or mixed infections may be caused by inactivation of penicillin in situ by beta lactamases produced by cocolonizing organisms such as Bacteroides fragilis, Haemophilus
influenzae, or S aureus. For example, the failure rate of penicillin treatment of GAS pharyngitis may approach 25%, and, if such patients are treated with a second course of penicillin, the failure rate may approach 80%, perhaps owing to selection of beta-lactamase-producing bacteria. In contrast, cures of 90% have been achieved when treatment consisted of amoxicillin plus clavulanate, oral cephalosporin, or clindamycin. Streptococcal cellulitis responds quickly to penicillin, although, in some cases in which staphylococcus is of concern, nafcillin or oxacillin may be a better choice. For treatment of streptococcal pneumonia, prolonged penicillin therapy, thoracoscopy, and decortication of the pleura may be necessary.
1120.- La profilaxis para los contactos de un caso de meningococcemia se debe efectuar con:
a) Ciprofloxacina b) Rifampicina c) Cloranfenicol d) Cefotaxima e) Vancomicina
Antimicrobial chemoprophylaxis should be given to close contacts of patients with meningococcal disease, because this is a primary means of prevention of disease. Close contacts are defined as household members, day care center contacts, and anyone directly exposed to the patient's oral secretions. Antimicrobial prophylaxis should be administered as soon as possible (ideally within 24 h) after case identification, because the secondary attack rate is highest within the first few days of onset of disease in the primary patient. Chemoprophylaxis given > 14 d after the onset of illness in the primary (index) case is of limited or no value. Nasal and oropharyngeal cultures are of no value in determining the need for chemoprophylaxis. The three antibiotics used for chemoprophylaxis against meningococcal disease are rifampin, ciprofloxacin, and ceftriaxone. Rifampin is the best studied and may be the most efficacious, but it is not the most convenient. It requires multiple dosing, is not recommended in pregnancy, and may cause gastrointestinal side effects. Ciprofloxacin is given as a single dose and is generally well tolerated, but it is not recommended in pregnancy or for children < 18 y of age. Ceftriaxone is also given as a one-time dose but requires intramuscular injection. A quadrivalent vaccine for meningococcal serogroups A, C, Y, and W-135 is available in the United States. Efficacy varies by age and serogroup. Protection against disease caused by serogroups A and C is 85-100% in older children and adults. The vaccine polysaccharides elicit bactericidal antibody that is serogroup specific. The serogroup B polysaccharide is poorly immunogenic in humans, and thus no useful vaccine against serogroup B is currently available; however, with the recent determination of the complete serogroup B meningococcus genome sequence, a set of immunogenic outer surface proteins from this organism has been revealed. A candidate vaccine has been created from some of these proteins. Serogroup B is the most common cause of meningococcal disease in Europe, North America, and several countries in Latin America. Vaccine protection decreases over time and more rapidly in young children. In children older than 4 y, one study documented an efficacy of 67% at 3 y after vaccination. The current vaccine is useful in controlling serogroup C meningococcal outbreaks. It is also recommended in the following high-risk groups: (1) complement-deficient hosts (C3, C5-C9), (2) asplenic individuals, (3) travelers to endemic areas, (4) research or laboratory personnel, and (5) military recruits.
1121.- Los índices eritrocitarios de la anemia aplasica corresponden a los de anemia:
a) Microcítica hipocromica b) Macrocitica
c) Normocítica normocromica d) Megaloblástica
e) Hemolítica
Aplastic anemia is a disease of the young, with a median age at onset of about 25 years (excluding aplasia secondary to cancer chemotherapy). It is the most common cause of pancytopenia in the adolescent or young adult. The bone marrow usually can be aspirated easily but appears dilute on smear. Bleeding is the most common early symptom of aplastic anemia. Patients commonly report days to weeks of easy bruising, including oozing from the gums, nose bleeds, or heavy menstrual flow; sometimes petechiae will have been noticed. With thrombocytopenia, massive hemorrhage is unusual, but small amounts of bleeding in the central nervous system can result in serious symptoms and signs of intracranial or retinal hemorrhage. In cases of more gradual onset, symptoms of anemia are described: usually lassitude, weakness, shortness of breath, and a pounding sensation in the ears. Infection is unusual as a first symptom in aplastic anemia, in contrast to agranulocytosis, in which pharyngitis, anorectal infection, and frank sepsis may be presenting syndromes. A striking feature of aplastic anemia is the restriction of symptoms to the hematologic system. Patients often feel and look remarkably well despite drastically reduced blood cell counts; systemic complaints and weight loss should point to other causes of pancytopenia. Drug use, chemical exposure, and preceding viral illnesses should be sought with repeated questioning; prompt cessation of drug or chemical exposure is especially important in agranulocytosis, which is usually self-limited. Petechiae and ecchymoses are frequently present, and there may be retinal hemorrhages. Pelvic and rectal examinations should be performed infrequently and gently to avoid trauma; these examinations may show bleeding from the cervical os and blood in the stool. Pallor of the skin and mucous membranes is also common except in the most acute cases or in those patients who have received transfusions. Infection is uncommon on presentation; however, by the time the patient reaches a referral center, fever and signs of systemic or local infection may well be present. Lymphadenopathy and splenomegaly are very unusual in aplastic anemia. Cafe-au-lait spots and short stature point to Fanconi's anemia; peculiar nails suggest dyskeratosis congenita. The smear typically shows large erythrocytes and a paucity of platelets and granulocytes. Macrocytosis, as determined by automated cell counting, is very common. Lymphocyte numbers may be normal or also reduced. The presence of immature myeloid forms should suggest leukemia or myelodysplasia; nucleated red cells suggest marrow fibrosis or invasion; and abnormal, or large, platelets suggest peripheral destruction, dysplasia, or fibrosis.
1122.- AL hablar de medición estadística de daños a la salud, cual es la diferencia entre tasa de mortalidad (TM) y la tasa de letalidad (LT):
a)
La TL mide la proporción de muertes ocurridas por una enfermedad mientras que la TM la mide solo por un grupo de edadb)
La TM mide la proporción de muertes ocurridas en la población en un periodo determinado y la TL mide la TRDc)
La TM mide el riesgo de fallecer por un determinado y la TL mide la proporción de muertes ocurridas por una enfermedadd)
La TM mide la proporción de muertes ocurridas en la población mientras que la TL mide el número de muertes ocurridas de un determinadoe)
La TM mide la probabilidad de morir de una persona a lo largo de su vida y la TL mide la probabilidad de morir por un determinadoLa tasa de mortalidad mide el número de muertes que se producen en una determinada población en un determinado período de tiempo, normalmente expresada en términos de muertes por 1.000 personas y año. La tasa de letalidad mide la proporción del número de muertes ocurridas por una enfermedad.
1123.- Cual es el agente causal del chancroide: Haemophylus ducreyi
Neisseria gonorrea Chlamydia
Trichomonas Candida albicans
El chancroide es una enfermedad de transmisión sexual altamente contagiosa producida por la infección por el bacilo Haemophilus ducreyi. Característicamente se origina como una pápula que asienta por lo general sobre la piel de los genitales externos; crece y se ulcera, se forman otras pápulas y, si no se trata, el bacilo se extiende produciendo bubones en la ingle.
1124.- Cual es el mecanismo de transmisión de la leishmaniasis: a) Agua contaminada
b) Ano-mano-boca c) Sexual
d) Salival
e) Hematógena
Género de protozoos parásitos pertenecientes a la familia Trypanosomatidae que causan importantes enfermedades en el hombre. Morfológicamente pueden presentarse como pequeñas células inmóviles de 2 a 4 m (amastigotes), que son parásitos intracelulares, o bien como formas móviles más alargadas, de 14-20 m, con un flagelo bien desarrollado (promastigotes). El género Leishmania incluye numerosas especies; aunque la sistemática del mismo ha sido objeto de debate durante años, en la actualidad se admiten unas 12 especies y subespecies agrupadas en complejos, siendo los más importantes el complejo Leishmania donovani, el complejo de L.
tropica, el complejo de L. mexicana y el de L. brasiliensis. Las leishmaniasis son un
conjunto de enfermedades producidas por las diferentes especies citadas y presentan características y distribución geográficas diferentes. Así, L. donovani y especies relacionadas producen la leishmaniasis visceral o «kala-azar», mientras que el resto de las especies producen leishmaniasis cutáneas y cutáneo-mucosas, o, en otras palabras, la leishmaniasis cutánea del Viejo Mundo, botón de Oriente producida por las especies del complejo L. tropica, y la leishmaniasis cutánea del Nuevo Mundo, que está causada por las especies de los complejos L. brasiliensis y L. mexicana. Todas las leishmaniasis se adquieren por picadura de dípteros pertenecientes al género Phlebotomus.
1125.- El agente causal más frecuente de meningitis en el adulto: a) S. pneumoniae
b) N meningitidis c) Listeria
d) Candida albicans e) Toxoplasma
La meningitis es la infección o inflamación de las membranas que envuelven el cerebro y la médula espinal. Normalmente es purulenta y afecta al líquido del espacio subaracnoideo. Se caracteriza por cefalea intensa, vómitos y dolor y rigidez de nuca. Su causa más frecuente es la infección bacteriana por Streptococcus pneumoniae,
Neisseria meningitidis o Haemophylus influenzae. La meningitis aséptica puede estar
provocada por otros tipos de bacterias, irritación química, neoplasias o virus. Muchas de estas enfermedades son benignas y autolimitadas, como las meningitis producidas por cepas de virus Coxsackie o ECHO. Otras son más graves, como en las que participan arbovirus, virus del herpes o de la poliomielitis. Levaduras como Candida u hongos como Cryptococcus pueden producir meningitis graves, con frecuencia mortales. La meningitis tuberculosa, siempre fatal si no se trata, puede producir distintas anomalías neurológicas, incluso con los mejores tratamientos disponibles. 1126.- Cuantas dosis se deben administrar en el tratamiento acortado para la tuberculosis: a) 120 b) 108 c) 96 d) 132 e) 60 TAES
Fase intensiva: diario de lunes a sábado, hasta completar 60 dosis. Administrar en una sola toma.
Medicame
nto Separados (dosis) Combinación fija (4 grageas) Rifampicina 600 mg 150 mg
Isoniacida 300 mg 75 mg dosis por gragea Pirazinamida 1,500 a 2,000 mg 400 mg
Etambutol 1,200 mg 400 mg
Fase de sostén: intermitente 3 veces por semana; lunes, miércoles y viernes. Hasta completar 45 dosis, administrar en una sola toma.
Medicam
ento Separados (dosis) Combinación fija (4 cápsulas) Isoniacida 800 mg 200 mg
Rifampicin
a 600 mg 150 mg por cápsula
En niños y adultos de 50 kg, administrar dosis por kg de peso, con medicamentos en presentación separada. En todos los pacientes con tuberculosis del SNC, miliar u ósea, el tratamiento deberá ser administrado por un año, y los pacientes con diabetes serán tratados por 6 meses.
1127.- La prevalencia de una enfermedad es la tasa de frecuencia que relaciona:
Total de casos en un brote localizado con la población expuesta al riesgo.
Número de casos nuevos entre los contactos y la población expuesta al contacto. Número total de casos existentes en un momento determinado y la
población estimada para la misma fecha.
Casos nuevos en la cantidad de tiempo y la población al centro del período. Numero de casos, más el brote localizado de la población en riesgo.
La prevalencia (en epidemiología) es el número de todos los casos nuevos y antiguos de una enfermedad o manifestaciones de un hecho durante un período determinado de tiempo.
1128.- En un paciente sometido a una operación proctológica que desarrolla una necrosis cutánea fulminante de los segmentos genitales y perineo. El diagnóstico más probable es:
a) Gangrena parietal bacteroides b) Celulitis subcutánea estreptococcica c) Enfermedad de Fournier
d) Tétanos quirúrgico e) Gangrena generalizada
La gangrena de Fournier es una fascitis necrosante que afecta a los genitales masculinos. Es de etiología bacteriana y están implicados múltiples gérmenes, especialmente anaerobios. Desde el punto de vista clínico, se presenta de forma brusca y aguda. Se consideran como factores predisponentes: la diabetes, los traumatismos locales, la parafimosis, la extravasación periuretral de la orina, las infecciones perirrectales o perianales y la cirugía local. El cuadro comienza con una lesión de celulitis, que se extiende y necrosa rápidamente, provocando un dolor intenso y fiebre, con marcada toxicidad sistémica. El tratamiento antibiótico endovenoso debe aplicarse de inmediato, como preparación para el precoz desbridamiento quirúrgico de los tejidos lesionados. La mortalidad puede alcanzar el 20%.
1129.- Indique con cuál de las siguientes patologías se asocia frecuentemente la colangitis esclerosante:
a) Panserositis tuberculosa b) Colitis ulcerativa c) Enfermedad de Wilson d) Seudomixoma peritoneal e) Pancretitis necrosante
Colangitis esclerosante (sclerosing cholangitis) es una colangitis crónica que produce múltiples estenosis y dilataciones preestenóticas de las vías biliares, y cursa con ictericia, episodios de colangitis aguda y finalmente insuficiencia hepática. Puede ser secundaria a infecciones ascendentes de repetición o, con más frecuencia, primarias, generalmente con sustrato autoinmune, sobre todo en la enfermedad inflamatoria intestinal.
1130.- A que se denomina periodo perinatal: a) Una semana antes y una después del embarazo
b) El periodo de gestación desde la semana 20 hasta el día 27 después del nacimiento
c) Desde la semana 28 de gestación hasta los 7 días después del nacimiento d) Desde la concepción hasta los 28 días después del nacimiento
e) Una semana después y una antes del embarazo
Es el período que se extiende, aproximadamente, desde la 28 semana de gestación hasta los 28 días después del nacimiento.
a) CA 19-9 b) CEA c) CA 15-3
d)
CA 125 e) CA 475Marcador tumoral Cáncer
CEA (antígeno carcinoembrionario) Cáncer de colon
AFP (alfa-feto proteína) Carcinoma hepatocelular CA 19-9 (antígeno carbohidrato) Cáncer de páncreas
CA 125 Cáncer de ovario
Beta-hCG Cáncer testicular
PSA (antígeno prostático especifico) Cáncer de próstata
CA 50 Cáncer de páncreas
Neuron-Enolasa especifica Cáncer pulmonar de células pequeñas
CA 15-3 Cáncer de mama
Ferritina Carcinoma hepatocelular
1132.- Un hombre de 25 años fue atropellado hace una hora y es traído al servicio de urgencias donde se le encuentra inconsciente, con presión arterial de 90/40 mm/hg, frecuencia cardiaca de 120 por minuto y resistencia muscular en todo el abdomen. Para establecer la causa de la hipotensión se debe practicar:
a)
Radiografía simple de abdomen de pie y en decúbito b) Arteriografía selectivac) Ultrasonido abdominal d) Lavado peritoneal e) Tomografía computarizada
El lavado peritoneal es una exploración diagnóstica y maniobra terapéutica. Como exploración diagnóstica se realiza de urgencia ante la sospecha de patología abdominal grave que requiere un diagnóstico rápido y un tratamiento quirúrgico urgente. La principal indicación son los traumatismos abdominales y politraumatismos en los que hay sospecha, por el estado general del paciente o por la exploración abdominal, de lesiones graves del abdomen (fundamentalmente, hemorragia intrabdominal y rotura de víscera hueca), o en los que por un estado de deterioro de conciencia no es valorable la exploración física del abdomen. La prueba se realiza puncionando con un trócar la línea media del abdomen por debajo del ombligo, aspirando primero con jeringa (punción-lavado peritoneal), y administrando un litro de suero salino en la cavidad peritoneal y dejándolo salir después por gravedad. Del aspecto macroscópico del líquido y de su análisis en el laboratorio depende la indicación de laparotomía urgente, que se realiza cuando hay bilis, restos alimenticios, o bien más de 500 leucocitos o 100.000 hematíes por milímetro cúbico. Estos hallazgos de laboratorio se correlacionan en más del 90% de los casos con lesiones intrabdominales que requieren cirugía urgente.
1133.- Criterio mayor de la fiebre reumática según Jones: a) Fiebre
b) Datos electrocardiográficos
c) Velocidad de sedimentación elevada d) Antecedentes de valvulopatía
e) Eritema marginado
Conjunto de criterios mayores (carditis, poliartritis, corea minor, nódulos subcutáneos, eritema anular de Leiner-Lehndorff) y menores (fiebre; artralgias; prolongación PR en el electrocardiograma; aumento de la velocidad de sedimentación globular, proteína C reactiva o leucocitosis; signos de infección previa por estreptococo -hemolítico; fiebre reumática previa, cardiopatía reumática inactiva), que sirven para diagnosticar la fiebre reumática. La presencia de dos criterios mayores o un criterio mayor y dos menores, hace altamente probable el diagnóstico.
1134.- La administración intravenosa de hierro produce: a) Reacción anafiláctica
b) Crisis hipertensiva c) Edema pulmonar d) Onicolisis
e) Epidermolisis
The indications of parenteral iron are intolerance to oral iron, refractoriness to oral iron, gastrointestinal disease (usually inflammatory bowel disease) precluding the use of oral iron, and continued blood loss that cannot be corrected. Because of the possibility of anaphylactic reactions, parenteral iron therapy should be used only in cases of persistent anemia after a reasonable course of oral therapy. Until recently, iron dextran had been the only form of parenteral iron available in the United States. Now, sodium ferric gluconate is available, and has been shown to result in a lower incidence of severe anaphylaxis. To date, no deaths have been reported with the use of this preparation. The dose (total 1.5-2 g) may be calculated by estimating the decrease in volume of red blood cell mass and then supplying 1 mg of iron for each milliliter of volume of red blood cells below normal. Approximately 1 g should then be added for storage iron. The entire dose may be given as an intravenous infusion over 4-6 hours. A test dose of a dilute solution is given first, and the patient should be observed during the entire infusion for anaphylaxis.
1135.- Un paciente con choque séptico que no responde a la administración de líquidos y se encuentra con datos de hiperdinamia e hipotensión arterial, los fármacos más útiles para el tratamiento son:
a) Amrinona y dopamina b) Dobutamina y amrinona c) Dobutamina y norepinefrina d) Epinefrina y dopamina e) Isoproterenol y dobutamina
Sepsis is the most common cause of distributive shock and carries a mortality of 40-80%. Typically, patients present with fever, chills, hypotension, hyperglycemia, and altered mental status due to gram-negative bacteremia (Escherichia coli, Klebsiella, Proteus, and Pseudomonas). Gram-positive cocci and gram-negative anaerobes (bacteroides) are less often implicated. Risk factors include extremes of age, diabetes, immunosuppression, and recent urinary, biliary, or gynecologic manipulation, such as placement of a percutaneous nephrostomy or biliary drain in an obstructed system. Hypovolemic shock is treated with fluid resuscitation. Initial response is gauged after bolus administration of 2 L of crystalloid, and additional fluid requirements are then estimated from measurement of ongoing losses, CVP or PCWP, and urine output. Selection of the proper fluid for restoration and maintenance of hemodynamic stability is controversial. Blood products are indicated in hemorrhagic shock; type-specific or
type O negative packed red blood cells (PRBC) are given to maintain the hematocrit above 30%. Whole blood provides extra volume and clotting factors. Each unit of PRBC or whole blood is expected to raise the hematocrit by 3%. With abnormal coagulation studies, platelet count less than 10,000/mcL, or transfusion of over six units of PRBC, fresh frozen plasma and platelets should be administered. When hematocrit is greater than 30% and CVP is less than 8 mm Hg, crystalloid solutions are generally the preferred resuscitation fluid. Isotonic (0.9%) sodium chloride or lactated Ringer's solution (which contains potassium, calcium, and bicarbonate as well as sodium chloride) is given in boluses of 500 or 1000 mL. Dextrose-containing solutions are generally not needed initially except in the treatment of hypoglycemic shock. Hypertonic (7.5%) saline is being investigated for use in the prehospital setting and in the hypotensive patient with closed head injury. Plasma expanders¾or colloids such as albumin, dextran, and hetastarch¾are high-molecular-weight substances that increase plasma oncotic pressure. Increased capillary permeability in the lung accompanying septic shock or SIRS may result in increased pulmonary edema in patients administered colloids, so use of these agents warrants careful consideration. Side effects include coagulopathy and anaphylaxis. Oxygen-carrying synthetic plasma expanders ("artificial blood") have been used with success in some trauma centers for treatment of hypovolemic shock. Large-volume resuscitation with unwarmed fluids produces hypothermia, which must be treated to avoid hypothermia-induced coagulopathy. Calcium should be administered to maintain an ionized calcium level greater than 1.15 mmol/L. Sodium bicarbonate may be considered in patients with arterial pH less than 7.20. Pressors are administered only after adequate fluid resuscitation. Dopamine hydrochloride has variable effects according to dosage. At low doses (2-3 mcg/kg/min), stimulation of dopaminergic and b-agonist receptors produces increased glomerular filtration rate, heart rate, and contractility. At higher doses (> 5 mcg/kg/min), a-adrenergic effects predominate, resulting in peripheral vasoconstriction. Dobutamine (2-20 mcg/kg/min), a synthetic catecholamine with greater inotropic effect and afterload reduction than dopamine, is the first-line drug for cardiogenic shock. Because tachyphylaxis can occur after 48 hours, the phosphodiesterase inhibitor amrinone (5-15 mcg/kg/min) is often substituted. Diuretics, thrombolytics, morphine, nitroglycerin, antiarrhythmics, and antiplatelet agents may be part of a multimodality approach to treatment of cardiogenic shock secondary to acute myocardial infarction. Distributive shock or neurogenic shock may require peripheral vasoconstrictors such as epinephrine (2-10 mcg/min) or norepinephrine (0.5-30 mcg/min). Phenylephrine is avoided in neurogenic shock because of the potential for reflex bradycardia. Vasopressin (antidiuretic hormone [ADH]) is gaining widespread acceptance in the treatment of distributive shock and has been added to the ACLS algorithm for ventricular fibrillation cardiac arrest. Shock due to sepsis or SIRS is associated with low levels of endogenous vasopressin; in hemorrhagic shock, vasopressin is initially elevated and then drops to subnormal levels. Vasopressin has multiple therapeutic effects: peripheral vasoconstriction, decreased heart rate, hemostasis, increased serum cortisol, and coronary, cerebral, and pulmonary vasodilation. It has also been shown to potentiate the effects of other peripheral vasoconstrictors. Paradoxically, at low doses (0.01-0.04 units/min), it acts as a diuretic. The dose is regulated to maintain normal physiologic serum levels of 20-30 pg/mL. The effect on mortality rate in septic shock is as yet unknown. Vasopressin-induced vasoconstriction may be mediated by effects on nitric oxide synthesis. Methylene blue is another inhibitor of the nitric oxide pathway being investigated for use in distributive shock. Broad-spectrum antibiotics are administered in septic shock until blood cultures and sensitivities become available. Sedation, anxiolytics, and pain medications are tailored for each individual case. Corticosteroids are lifesaving in the treatment of shock associated with acute adrenal insufficiency and decrease inflammation associated with acute spinal shock, but they are of no benefit in other types of shock. Research has focused on regulation of specific inhibitors of the inflammatory response.
Protein C levels are diminished in septic shock, and recombinant protein C (drotrecogin alfa) is now in phase 3 trials. It has been shown to significantly decrease 28-day mortality in septic shock when given as a continuous infusion of 24 mcg/kg/h for 96 hours. Its mechanism of action is reduction of systemic inflammation by inhibition of thrombosis. Administration of recombinant protein C has been correlated with lower D-dimer and interleukin-6 levels in this setting.
1136.- Complicación grave de la cirrosis hepática con ascitis: a) Nefritis perdedora de potasio
b) Síndrome hepatorrenal c) Trombosis de la vena renal d) Necrosis papilar aguda e) Nefritis túbulo-intersticial
Hepatorenal syndrome occurs in up to 10% of patients with advanced cirrhosis and ascites and is characterized by azotemia in the absence of shock or significant proteinuria and by failure of renal function to improve following intravenous infusion of 1.5 L of isotonic saline. Oliguria, hyponatremia, and low urinary sodium are typical features. Hepatorenal syndrome is diagnosed only when other causes of renal failure (including prerenal azotemia and acute tubular necrosis) have been excluded. Type I hepatorenal syndrome is characterized by doubling of the serum creatinine to a level greater than 2.5 mg/dL or by halving of the creatinine clearance to less than 20 mL/min in less than 2 weeks. Type II hepatorenal syndrome is more slowly progressive and chronic. The cause is unknown, but the pathogenesis involves intense renal vasoconstriction, possibly because of impaired synthesis of renal vasodilators such as prostaglandin E2 and decreased total renal blood flow; histologically, the kidneys are normal. Treatment is often ineffective. Improvement may follow intravenous infusion of the long-acting vasoconstrictor ornipressin and albumin (but with a high rate of ischemic side effects), ornipressin and dopamine, terlipressin (a long-acting vasopressin analog not available in the United States) and albumin, norepinephrine and albumin, or administration of the somatostatin analog octreotide subcutaneously, midodrine, an a-adrenergic drug, orally, and albumin intravenously. Prolongation of survival has been associated with use of the molecular adsorbent recirculating system (MARS), a modified dialysis method that selectively removes albumin-bound substances. Improvement and sometimes normalization of renal function may also follow placement of a TIPS. Mortality is high without liver transplantation, death being due to complicating infection or hemorrhage.
1137.- La enfermedad causada por las bacterias del género shiguelas se debe a:
a) Producción de enterotóxinas
b) Capacidad de invadir las células epiteliales del colon c) Adherencia a las células HP2
d) Producción de hemolisina e) Producción de verotoxina
Shigellosis may produce either predominantly watery diarrhea or watery diarrhea that progresses to dysentery. The severity of disease is largely determined by the invading organism. S dysenteriae and S flexneri are the agents most commonly associated with bacillary dysentery, whereas the other Shigella species more often produce watery diarrhea. The pathogenesis of the watery-diarrhea phase of bacillary dysentery is caused by a combination of lumenal bacterial replication and superficial mucosal invasion in the small intestine. During this phase of disease, large numbers of shigellae
are present in the lumen of the small intestine. This phase of the disease is correlated with the onset of cramping abdominal pain, fever, and toxemia. Within days, the lumenal contents of the small intestine do not contain shigellae, and the site of infection is the colon. The shigellae invade colonic mucosa and occasionally invade to the level of the submucosa. Factors that are important for invasion are present on the bacterial chromosome, as well as on a 140-MDa plasmid. Eventually, epithelial cell death occurs, and the mucosa sloughs, possibly secondarily to shigatoxin production. The loss of mucosa evokes an intense inflammatory response and allows for the introduction of coliform bacteria. Microabscesses, epithelial ulcerations, and pseudomembranes that consist of sloughed epithelial cells, bacteria, fibrin, and inflammatory cells may be seen. This phase of the disease correlates with tenesmus and fractionated stools that contain blood, mucus, and inflammatory debris.
1138.- Si existe salida de líquido amniótico y dilatación cervical, se trata de un aborto: a) Inminente b) Incompleto c) Diferido d) Inevitable e) En evolución
About three-fourths of spontaneous abortions occur before the 16th week; of these, three-fourths occur before the eighth week. Almost 20% of all clinically recognized pregnancies terminate in spontaneous abortion. More than 60% of spontaneous abortions result from chromosomal defects due to maternal or paternal factors; about 15% appear to be associated with maternal trauma, infections, dietary deficiencies, diabetes mellitus, hypothyroidism, or anatomic malformations. There is no reliable evidence that abortion may be induced by psychic stimuli such as severe fright, grief, anger, or anxiety. In about one-fourth of cases, the cause of abortion cannot be determined. There is no evidence that video display terminals or associated electromagnetic fields are related to an increased risk of spontaneous abortion. It is important to distinguish women with a history of incompetent cervix from those with more typical early abortion and those with premature labor or rupture of the membranes. Characteristically, incompetent cervix presents as "silent" cervical dilation (ie, with minimal uterine contractions) between 16 and 28 weeks of gestation. Women with incompetent cervix often present with significant cervical dilation (2 cm or more) and minimal symptoms. When the cervix reaches 4 cm or more, active uterine contractions or rupture of the membranes may occur secondary to the degree of cervical dilation. This does not change the primary diagnosis. Factors that predispose to incompetent cervix are a history of incompetent cervix with a previous pregnancy, cervical conization or surgery, cervical injury, diethylstilbestrol (DES) exposure, and anatomic abnormalities of the cervix. Prior to pregnancy or during the first trimester, there are no methods for determining whether the cervix will eventually be incompetent. After 14-16 weeks, ultrasound may be used to evaluate the internal anatomy of the lower uterine segment and cervix for the funneling and shortening abnormalities consistent with cervical incompetence.
1. Threatened Abortion: Bleeding or cramping occurs, but the pregnancy continues. The cervix is not dilated.
2. Inevitable Abortion: The cervix is dilated and the membranes may be ruptured, but passage of the products of conception has not occurred. Bleeding and cramping persist, and passage of the products of conception is considered inevitable.
3. Complete Abortion: The fetus and placenta are completely expelled. Pain ceases, but spotting may persist.
4. Incomplete Abortion: Some portion of the products of conception (usually placental) remain in the uterus. Only mild cramps are reported, but bleeding is persistent and often excessive.
5. Missed Abortion: The pregnancy has ceased to develop, but the conceptus has not been expelled. Symptoms of pregnancy disappear. There is a brownish vaginal discharge but no free bleeding. Pain does not develop. The cervix is semifirm and slightly patulous; the uterus becomes smaller and irregularly softened; the adnexa are normal.
1139.- Enfermedad exantemática común de la infancia qué causa sordera, catarata congénita y cardiopatía:
a) Sarampión b) Varicela c) Rubéola
d) Exantema súbito e) Erisipela
La rubéola es una infección aguda, benigna, predominantemente infantil. Se caracteriza por dolor de garganta, fiebre, inflamación de los ganglios cefálicos y cervicales y la aparición de una erupción rosada, que se inicia en la cara y después se extiende a todo el cuerpo. Está producida por un togavirus, que cuando afecta a una embarazada puede anidar en la placenta y, rompiendo la barrera placentaria, llegar a la circulación fetal e infectar al feto. Si esta infección se produce en el periodo de embriogénesis puede generar malformaciones en el feto. Embriopatía rubeólica: Conjunto de malformaciones fetales provocadas por el virus de la rubeola cuando infectó a la madre en el periodo de organogénesis. Suele afectar sobre todo al corazón y al cristalino (catarata rubeólica).
1140.- Parvovirus B-19 es el causante de la enfermedad exantemática conocida como:
a) Erisipela
b) 5ª enfermedad o eritema infeccioso c) Varicela
d) Escarlatina e) Rubéola
Pequeño virus con ácido desoxirribonucleico monocatenario de la familia Parvoviridae que infecta a seres humanos, causando eritema infeccioso y crisis aplásicas en la anemia hemolítica. Otra cepa de Parvoviridae, la cepa canina P2, causa enteritis aguda y miocarditis en perros. El eritema infeccioso es una enfermedad infecciosa aguda benigna, sobre todo de niños, caracterizada por fiebre y por una erupción eritematosa que comienza en las mejillas y que luego aparece en brazos, muslos, nalgas y tronco. 1141.- Una complicación grave del sarampión es:
a) Meningitis basal b) Neumonía
c) Pancreatitis d) Orquiepididimitis e) Otomastoiditis
Acute complications can include meningoencephalitis, pneumonia, otitis media, and laryngotracheitis. Measles meningoencephalitis occurs in 1 per 1000 cases. It
has a high morbidity and mortality rate. "Black measles" is a severe, hemorrhagic variation of typical measles. It is extremely rare in the postvaccination era. It has a high mortality rate. Patients present with a confluent hemorrhagic skin rash, encephalitis, and pneumonia. Bleeding often occurs via nose, mouth, and gastrointestinal tract. Measles infection during pregnancy produces significant fetal morbidity and mortality, especially if infection occurs during the first trimester. Measles uncommonly produces severe abdominal pain during the acute febrile phase. Etiologies for this pain can be mesenteric lymphadenitis or appendicitis. Evidence of peritonitis warrants prompt surgical evaluation. Subacute sclerosing panencephalitis (SSPE) is a rare, late-onset, lethal neurodegenerative sequela of measles infection. It occurs with an incidence of 0.6-2.2 cases/100,000 infections and 1 case/1 million vaccinations. SSPE results from a slowly progressive chronic infection with the virus. SSPE becomes clinically evident an average of 7 years after initial measles exposure. Symptoms include unusual behavior, developmental regression, ataxia, myoclonic jerks, visual impairment, and aphasia. All of these symptoms are progressive, leading ultimately to decorticate rigidity and death, which usually occurs 6-9 months after onset of symptoms. Confirmation of the diagnosis can be made by electroencephalogram, serology, and analysis of the cerebrospinal fluid. Cerebrospinal fluid shows high IgG as does serum. No current therapy is effective.
1142.- Una mujer de 65 años presenta una masa tumoral en la mama izquierda, fija a la pared torácica, y ganglios palpables en la región axilar ipsilateral en la evaluación inicial de la paciente se debe incluir:
a) Biopsia incisional
b) Aspiración con aguja fina c) Biopsia excisional
d) Tomografia axial computada e) Ultrasonido
The diagnosis of breast cancer depends ultimately upon examination of tissue or cells removed by biopsy. Treatment should never be undertaken without an unequivocal histologic or cytologic diagnosis of cancer. The safest course is biopsy examination of all suspicious masses found on physical examination and of suspicious lesions demonstrated by mammography. About 60% of lesions clinically thought to be cancer prove on biopsy to be benign, and about 30% of lesions believed to be benign are found to be malignant. These findings demonstrate the fallibility of clinical judgment and the necessity for biopsy. A breast mass should not be followed without histologic diagnosis, except perhaps in the premenopausal woman with a nonsuspicious mass presumed to be a fibrocystic condition. A lesion such as this could be observed through one or two menstrual cycles. The simplest method is needle biopsy, either by aspiration of tumor cells (fine-needle aspiration cytology) or by obtaining a small core of tissue with a hollow needle. Fine-needle aspiration cytology is a useful technique whereby cells are aspirated with a small needle and examined by the pathologist. This technique can be performed easily with no morbidity and is much less expensive than excisional or open biopsy. The main disadvantages are that it requires a pathologist skilled in the cytologic diagnosis of breast cancer and that it is subject to sampling problems, particularly because deep lesions may be missed. Furthermore, noninvasive cancers usually cannot be distinguished from invasive cancers. The incidence of false-positive diagnoses is extremely low, perhaps 1-2%. The false-negative rate is as high as 10%. Most experienced clinicians would not leave a suspicious dominant mass in the breast even when fine-needle aspiration cytology is negative unless the clinical diagnosis, breast imaging studies, and cytologic studies were all in agreement. Large-needle (core Large-needle) biopsy removes a core of tissue with a large cutting Large-needle. Hand-held biopsy devices make large-core needle biopsy of a palpable mass easy and cost
