Preguntas y Respuestas 3

Preguntas y Respuestas 3CIRUGA GENERALPaciente originario de Chiapas, con dificultad para la deglucin. Los estudios de imagen muestran dilatacin esofgica importante. Cual de los siguientes rganos podra estar tambin afectado?A. VejigaB. CerebroC. CoraznD. PulmonesE. IDRespuesta correcta CLa enfermedad de Chagas es originada por un parasito protozoario intracelular (Tripanosoma cruzi). Causa de megaesfago, megacolon e insuficiencia cardiaca por cardiopata dilatada.A 55-year-old woman complains to her physician that the skin of her armpits and groin "keeps getting darker and darker." Physical examination demonstrates velvety brown and warty skin in the axilla and groin. Biopsy of these lesions shows a variably hyperplastic epidermis with many sharp peaks and valleys. Aside from cosmetic considerations, which of the following is the primary medical significance of these lesions?A. They may be a sign of immunosuppressionB. They may be a sign of visceral carcinomaC. They may be easily superinfectedD. They may be malignantE. They may be premalignant

The correct answer is B. The lesions are acanthosis nigricans, which looks somewhat like a mole or wart, but is actually due to epidermal hyperplasia. Acanthosis nigricans can be seen in obesity, diabetes, and in patients with underlying cancers, often adenocarcinomas of the chest or abdomen.A 2-year-old child is seen for a welI-child visit in a pediatric clinic. Abdominal examination demonstrates a palpable, non-tender mass on the Ieft side of the abdomen. The mother had no idea the mass was present and the pediatrician did not note the presence of the mass at the child's 18-month welI-child visit. Physical examination is otherwise unremarkable.Question CT examination demonstrates an 8-cm diameter, roughly round, mass involving the lower pole of the kidney. Which of the following is the most likely cause of this mass?A. Ewing sarcomaB. NeuroblastomaC. Renal cell carcinomaD. Transitional cell carcinomaE. Wilms tumor

The correct answer is E. Wilms tumor is an embryonal malignancy of the kidney that most commonly affects children from birth to age 4, but can affect children up to about age 15. This tumor is the second most common extracranial solid tumor in children and tends to form large, round, solitary masses of the kidney, although bilaterality and multicentricity may also occur. Wilms tumors usually present with a palpable abdominal mass, with less common presentations including abdominal pain, hematuria (indicating invasion of the collecting system), hypertension, fever, nausea, and vomiting.A 67-year-old man with an 18-year history of type 2 DM presents for a routine physical examination. His temperature is 36.9 C, his blood pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On examination, the physician notes a nontender, pulsatile, mass in the mid-abdomen. A plain abdominal x-ray film with the patient in the lateral position reveals spotty calcification of a markedly dilated abdominal aortic walI.Question Which of the following is most likely pathogenetically related to this patient's aortic disease?A. AtherosclerosisB. Cystic medial necrosisC. Kawasaki diseaseD. Mnckeberg arteriosclerosisE. Syphilis

The correct answer is A. This patient has an abdominal aortic aneurysm (AAA); these are most commonly the result of atherosclerosis. Hypertension and cigarette smoking are also risk factors. AAA may be asymptomatic, or may be associated with pain. Some aortic aneurysms are palpable as pulsating masses in the abdomen. Abdominal aortic aneurysms typically begin below the renal arteries and may extend well into the iliac system bilaterally. Calcified atherosclerotic plaques on plain films of the abdomen can be seen in the majority of cases. A 67-year-old man with an 18-year history of type 2 DM presents for a routine physical examination. His temperature is 36.9 C, his blood pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On examination, the physician notes a nontender, pulsatile, mass in the mid-abdomen. A plain abdominal x-ray film with the patient in the lateral position reveals spotty calcification of a markedly dilated abdominal aortic walI.Question The patient is taken to surgery and the abdominal aorta and proximal common iliac arteries are replaced with a graft. Which of the following aneurysm diameters is usually considered the threshold above which elective surgery is recommended, unless contraindicated by other disease?A. 1 cmB. 2 cmC. 6 cmD. 10 cmE. 15 cmThe correct answer is C. This recommendation is made because larger aneurysms have a much greater chance of rupture, and emergency repair carries a high mortality rate. For aneurysms larger than 5 cm, the risk of rupture is 5-10% per yearA 3-year-old girl is seen in the emergency department with acute abdominal pain. She has a 5-day history of vomiting and abdominal distension. She has not passed stool during this time, and during the past day, has been vomiting bilious materiaI. On physical examination, she is lethargic, with a firm and tender abdomen, and peritoneal signs are present. She is immediately referred for laparotomy for suspected diagnoses of intussusception vs. volvulus. At surgery, approximately 20 cm of small intestine is found to be markedly distended, and is resected. The section contains a tightly knotted ball of nematodes that are about 15 to 35 cm in length. The worms have tapered ends without hooks.Question The worms are most likely which of the following?A. Ancylostoma duodenaleB. Ascaris lumbricoidesC. Enterobius vermicularisD. Strongyloides stercolarisE. Trichuris trichiura

The correct answer is B. Ascaris lumbricoides is the only parasitic worm that is likely to cause intestinal obstruction, and then only if the worm burden is high. The description given of the worms in the case presentation is typical. All of the other worms listed in the choices are also nematodes or roundworms.

A 47-year-old woman presents to the emergency department with cramping/colicky abdominal pain. The current episode of pain began several hours ago, following a fatty meaI. The pain began slowly, and rose in intensity to a plateau over the course of several hours. The patient reports that she had had several other episodes of similar pain during the past several months, with long intervening periods of freedom from pain. On physical examination, she is noted to have tenderness to deep palpation in the right upper quadrant of the abdomen near the rib cage. The patient also reports that she is experiencing shoulder/back pain at a site she identifies near the right lower scapula, but no tenderness can be elicited during the back and shoulder examination.Question If this patient had refused surgical treatment, which of the following would be the most appropriate pharmacotherapy to provide definitive treatment and thereby relieve associated pain?A. AmpicillinB. CIofibrateC. MeperidineD. OxycodoneE. UrsodiolThe correct answer is E. The question is asking, "Which of the following will eradicate a gallstone?" When a gallstone is eliminated the pain will subsequently be eliminated. This question is NOT asking, "which of the following is the most appropriate form of pain control?". Ursodiol (ursodeoxycholic acid) is a hydrophilic bile acid that is used to dissolve small (< 20 mm), non-calcified, radiolucent cholesterol gallstones in patients with functioning gallbladders who cannot undergo (or refuse) cholecystectomy.A 64-year-old man with a history of coronary artery disease comes to the emergency department with the acute onset of severe, constant, Iower abdominal pain and rectal bleeding. He reports that he previously has had several episodes of similar, but less severe pain. About 12 hours after the onset of pain, the patient began passing copious bright red blood per rectum. He denies nausea, vomiting, sick contacts, or foreign traveI. Initial physical examination reveals a distressed man, who is afebrile, but tachypneic, with scant diffuse abdominal tenderness to palpation. Rectal examination is positive for blood. Laboratory studies reveal a metabolic acidosis with an elevated serum Iactate.Question Which of the following is the most likely diagnosis?A. Colon carcinomaB. Infectious colitisC. Inflammatory bowel diseaseD. Ischemic colitisE. Necrotizing enterocolitis

The correct answer is D. A patient with severe abdominal pain and rectal bleeding with an unremarkable physical examination is likely suffering from ischemic colitis. "Pain out-of-proportion to examination" is a classic finding for ischemic colitis. The previous episodes of less severe pain represent ischemic angina. An infarction has occurred, as indicated by the rise in serum lactate secondary to the colon's anaerobic metabolism. The history of coronary artery disease also suggests this diagnosis, as the atherosclerotic processes that contribute to his CAD are also likely present in his abdominal vasculature.

A 27-year-old woman goes to an emergency room with severe abdominal pain. She had previously experienced similar episodes of pain that Iasted several hours to a few days, but this episode is the most severe. She has also been experiencing nausea, vomiting, and constipation. The physician is left with the impression that she is agitated and somewhat confused, and an accurate history is difficult to elucidate. The patient is sent for emergency laparotomy, but no pathology is noted at surgery. Following the unrevealing surgery, an older surgeon comments that he had once seen a similar case that was actually due to porphyria.Question The porphyrias are biochemical abnormalities in which of the following pathways?A. GIycogen degradationB. Heme synthesisC. Lipoprotein degradationD. Nucleotide degradationE. Urea cycleThe correct answer is B. The porphyrias are a group of rare, related diseases that have in common a block in the heme synthesis pathway. The block is usually partial rather than complete, and thus many of these patients have only intermittent symptoms. Most cases of porphyria present with either a neurovisceral pattern (including both psychiatric symptoms and abdominal pain) or with photosensitive skin lesions. These two patterns are associated with different forms of porphyria.A 27-year-old woman goes to an emergency room with severe abdominal pain. She had previously experienced similar episodes of pain that Iasted several hours to a few days, but this episode is the most severe. She has also been experiencing nausea, vomiting, and constipation. The physician is left with the impression that she is agitated and somewhat confused, and an accurate history is difficult to elucidate. The patient is sent for emergency laparotomy, but no pathology is noted at surgery. Following the unrevealing surgery, an older surgeon comments that he had once seen a similar case that was actually due to porphyria.Question Following the surgery, the decision is made to screen for the porphyrias that cause acute neurovisceral symptoms. Which of the following tests would be most likely to be used?A. Erythrocyte porphyrinsB. Total fecal porphyrinsC. Total plasma porphyrinsD. Total urinary porphyrinsE. Urinary porphobilinogen

The correct answer is E. The acute neurovisceral porphyrias are those that tend to present with severe abdominal pain, often accompanied by neuropsychiatric symptoms. The best tests to use for screening of these diseases are urinary porphobilinogen (PBG, either random or 24 hour) and urinary delta-aminolevulinic acid (ALA, either random or 24 hour).