USMLE USMLE-STEP-2 Online Practice Questions and Exam Preparation

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 631:

  A 19-year-old primigravida at term has been completely dilated for 21/2 hours. The vertex is at 2 to 3 station, and the position is occiput posterior. She complains of exhaustion and is unable to push effectively to expel the fetus. She has an anthropoid pelvis. Which of the following is the most appropriate management to deliver the fetus?

  A. immediate low transverse cesarean section
  B. immediate classical cesarean section
  C. apply forceps and deliver the baby as an occiput posterior
  D. apply Kielland forceps to rotate the baby to occiput anterior
  E. cut a generous episiotomy to make her pushing more effective
  C. apply forceps and deliver the baby as an occiput posterior

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  Explanation

  The station of the vertex indicates that the fetal head is on the perineum. A cesarean section, either low transverse or classical, is inappropriate unless an operative vaginal delivery is unsuccessful. In women with an anthropoid pelvis, the transverse, interspinous diameter of the bony pelvis is narrow, and the anteroposterior diameter of the pelvis is relatively long. In this circumstance, a forceps rotation should not be done and delivery should be in the occiput posterior. The indication for forceps is maternal exhaustion; women with an anthropoid pelvis usually have a spontaneous vaginal delivery. In women with a gynecoid pelvis, the transverse and anteroposterior diameters are more equal, and rotation of the fetal head to occiput anterior would be an acceptable choice. Soft-tissue resistance to delivery is not great enough that an episiotomy will permit slight expulsive efforts by the mother to deliver the fetal head

• Question 632:

  Identify the following personality disorders with the symptoms listed below. Preoccupied with feelings of superstitiousness; has a sixth sense; seems odd

  A. antisocial
  B. avoidant
  C. borderline
  D. dependent
  E. histrionic
  F. narcissistic
  G. obsessive-compulsive
  H. paranoid
  I. schizoid
  J. schizotypal
  J. schizotypal

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  Explanation

  Persons with personality disorders are rigidly bound to the use of patterns of defense and various traits that distinguish the disorders. All have problems with interpersonal relationships

• Question 633:

  A 50-year-old woman presents to the physician's office for evaluation of a right neck mass. The mass has been present for 3 years and is painless. On examination, a nontender, firm, 2.5-cm mass is noted slightly below and posterior to the angle of the mandible on the right. For the above patient with a neck mass, select the most likely diagnosis.

  A. thyroid carcinoma
  B. cystic hygroma
  C. acute suppurative lymphadenitis
  D. thyroglossal duct cyst
  E. lipoma
  F. carotid artery aneurysm
  G. mixed parotid tumor (pleomorphic adenoma)
  H. laryngeal carcinoma
  I. parathyroid adenoma
  J. branchial cleft cystK. tuberculosis
  G. mixed parotid tumor (pleomorphic adenoma)

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  Explanation

  Most tumors of the salivary glands present in the parotid, the most common of which is the pleomorphic adenoma. These occur most frequently in the fifth decade and present as a solitary painless mass in the superficial lobe of the parotid gland. Surgical treatment is complete excision with negative margins.

• Question 634:

  A60-year-old previously healthy man presents with massive rectal bleeding. Which of the following is the most likely diagnosis?

  A. diverticulosis of the colon
  B. ulcerative colitis
  C. external hemorrhoid
  D. ischemic colitis
  E. carcinoma of the colon
  A. diverticulosis of the colon

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  Explanation

  The causes of lower gastrointestinal (GI) bleeding include hemorrhoids and anal fissure diverticulosis, carcinoma, vascular ectasia, colitis, and polyps. Carcinoma of the colon usually causes chronic GI bleeding, resulting in anemia. Diverticulosis and vascular ectasia are common causes of massive GI bleeding in the elderly patient. Inflammatory bowel disease can also cause massive GI bleeding but is more frequent in younger age group patients. Most patients with ischemic colitis will be quite sick and will have had symptoms before the onset of bleeding.

• Question 635:

  Children with sickle cell anemia are at increased risk of developing overwhelming infection with certain microorganisms. Which of the following is the most reasonable step to prevent such infection?

  A. periodic injections of gamma globulin
  B. injection of VZIG after exposure to varicella
  C. withholding live virus vaccines
  D. prophylactic administration of oral penicillin daily
  E. early use of amoxicillin at home for episodes of fever
  D. prophylactic administration of oral penicillin daily

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  Explanation

  Children with sickle cell disease develop functional asplenia, presumably from repeated splenic infarction. This results in vulnerability to bacteremia and overwhelming infection, especially with encapsulated bacteria. The organism most commonly involved is S. pneumoniae. Daily prophylactic oral penicillin is indicated for young children. Because of the risk of bacteremia, these patients need careful medical evaluation when they develop fever. There are no data to support the use of gamma globulin in these children. They are not at higher risk for complications from live virus vaccines or from varicella.

• Question 636:

  A40-year-old alcoholic is brought to the emergency epartment with frostbite to both lower extremities. His core body temperature is 36°C. hich of the followin g is the most appropriate initial treatment for the patient's thermal injury?

  A. sympathectomy without any delay
  B. debridement of devitalized tissues
  C. slow rewarming at room temperature
  D. slow rewarming with dry heat
  E. rapid rewarming in warm water
  E. rapid rewarming in warm water

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  Explanation

  Frostbite is produced by formation of ice crystals in the tissue, with cessation of tissue perfusion. Appropriate initial treatment is rapid rewarming in warm water, to minimize further tissue damage. Dry heat can cause further tissue damage. With reperfusion, there is continuedprogression of tissue injury because of progressive microcirculatory thrombosis. Therefore, nonviable tissue should be allowed to demarcate over several weeks, with delayed debridement. A sympathectomy is not indicated acutely, because the vasculature in frozen tissue is already maximally dilated.

• Question 637:

  A 77-year-old male presents, accompanied by his wife to your clinic. She reports that the patient has been having visual hallucinations of little people in his room on and off for the past 3 months. Six months ago he developed a tremor and gait disturbance. Over this past year he has become more forgetful, and has had episodes of confusion.

  The most likely diagnosis is:

  A. Alzheimer dementia
  B. vascular dementia
  C. Parkinsion's disease with dementia
  D. Lewy body dementia
  E. Frontotemporal dementia
  D. Lewy body dementia

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  Explanation

  Though Alzheimer's dementia is the most common form, it is characterized by a gradual and progressive course typically starting with a loss of short-term memory. Vascular dementia is known for its stepwise progression. Frontotemporal dementia (Pick's) usually presents insidiously with behavior and personality changes. Lewy body dementia shares features with Alzheimer's dementia and dementia associated with Parkinson's disease, but is more progressive than the dementia associated with Parkinson's disease, and tends to exhibit cognitive decline soon after the Parkinson's symptoms present. Visual hallucinations and fluctuating cognition are also common with this type of dementia

• Question 638:

  A5-year-old pedestrian is hit by a car in a mall parking lot and he is brought to the emergency department. There was loss of consciousness for less than 1 minute. On evaluation, the child has no neurologic deficits and a CT scan of the head reveals no intracranial abnormalities and no obvious skull fractures. The parents want to know what possible long-term problems there might be. You remember that problems after head trauma may include the development of seizures and that the risk of developing posttraumatic epilepsy is increased by which of the following?

  A. a brief loss of consciousness
  B. an acute intracranial hemorrhage
  C. retrograde amnesia
  D. posttraumatic vomiting
  E. a small linear skull fracture
  B. an acute intracranial hemorrhage

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  Explanation

  Late posttraumatic epilepsy is diagnosed when a seizure occurs for the first time more than 1 week after a head injury. Factors that correlate with an increased risk of developing posttraumatic epilepsy include presence of a depressed skull fracture, acute intracranial hemorrhage, cerebral contusion, or unconsciousness lasting more than 24 hours. Because the risk of a subsequent seizure is approximately 75%, acute and chronic treatment with anticonvulsants is indicated. Loss of consciousness, retrograde amnesia, and vomiting are relatively common immediate consequences of head trauma. They are usually transient and are not highly correlated with a risk of subsequent posttraumatic seizures.

• Question 639:

  You make the diagnosis of Marfan syndrome in a very tall 22-year-old man with long, thin extremities.

  What other finding is associated with this disease?

  A. family history in 100% of the patients
  B. upward subluxation of the lenses
  C. mental retardation
  D. malar rash
  E. increased length of trunk compared with the limbs
  B. upward subluxation of the lenses

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  Explanation

  Marfan syndrome is an inherited disorder of connective tissue, but at least one-fourth of patients do not have an affected parent. Abnormal metabolism of collagen or elastin is suspected as the cause. Clinical features involve the eyes (upward subluxation of the lenses, myopia), cardiovascular system (aortic dilation, regurgitation, and aneurysms; mitral valve prolapse), and the skeleton (arachnodactyly, pectus deformity, joint laxity). Mental retardation and malar rash are not associated with Marfan. Afrequent finding is increased length of the limbs as compared with the trunk. Aortic root dilatation is a serious complication that can lead to aortic regurgitation, dissection, and even rupture.

  Mitral valve prolapse is also seen, but pulmonary stenosis, VSD, pulmonary hypertension, and CAD are not increased with Marfan syndrome. Echocardiography should be performed to follow the course of the heart. The other tests will not reveal aortic root dilatation or aneurysm formation.

• Question 640:

  Identify the defense mechanisms with the descriptions below. Working as a nurse in a pediatric ward because one would like to have children but cannot

  A. acting out
  B. altruism
  C. displacement
  D. intellectualization
  E. passive-aggressive behavior
  F. projection
  G. rationalization
  H. reaction formation
  I. sublimation
  J. suppression
  I. sublimation

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  Explanation

  Defense mechanisms provide a means for dealing with anxiety and affect. The mechanisms chosen range from the very narcissistic and immature to mature. In suppression, a person makes a conscious decision to put the conflict aside until it can be dealt with more appropriately. On the other hand, in acting out, there is little or no attempt to contain the affect, and it is directly expressed, as in name calling. Sublimation provides a channel for the indirect expression of a need or affect. Its use is positive and socially acceptable. In reaction formation, the person acts as if the strong need or affect did not exist and acts out the opposing feeling. In projection, unacceptable feelings and thoughts are denied as part of the self and instead are "put on" the other person.