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

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 441:

  An 8-year-old African American boy is brought in for evaluation of a mass on the scalp. On examination, he is afebrile and nontoxic. There is a boggy mass on his scalp with alopecia. His posterior cervical lymph nodes are enlarged but nontender. Which of the following is the most appropriate treatment?

  A. incision and drainage
  B. oral amoxicillin
  C. IV naficillin
  D. selenium sulfide shampoo twice a week
  E. oral griseofulvin and selenium sulfide shampoo twice weekly
  E. oral griseofulvin and selenium sulfide shampoo twice weekly

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  Explanation

  A tender, boggy mass on the scalp is most likely to be a kerion. This is an inflammatory form of tinea capitis. Tinea capitis is more common in African American children and is the most common cause of alopecia in children. In the United States, a majority of cases are caused by Trichophyton tonsurans; Microsporum canis may also be involved. Tinea capitis may present with diffuse scaling, a black dot form, and as the inflammatory form--kerion. The recommended treatment is 812 weeks of oral griseofulvin.

  Shampooing with selenium sulfide shampoo is a helpful adjunctive therapy which decreases spore shedding. Topical therapy alone is ineffective. Incision and drainage or antibiotic therapy are not recommended in treatment of tinea capitis.

• Question 442:

  A young mother seeks psychiatric help because she is unable to remember events surrounding her 3- year-old son's death after being struck by a car 2 months ago. She is worried that maybe she did something that put him at risk. Except for this brief time period, she is able to recall other events both before and after the tragedy.

  Of the following treatments, which is the most appropriate to help this patient regain her memory?

  A. electroshock therapy
  B. individual psychotherapy
  C. chlordiazepoxide
  D. sertraline
  E. aripiprazole
  B. individual psychotherapy

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  Explanation

  Individual therapy, which would include exploring the events recalled surrounding the incident, reactions to the child's death, feelings about motherhood, as well as other issues, is considered the most effective treatment for dissociative amnesia. If other symptoms indicate another disorder, then treatment would include appropriate drugs or ECT. In some cases, there is a role for hypnosis or sodium amobarbital interview to help recall. Benzodiazepines may be helpful to reduce anxiety. Integration through psychotherapy of the events of the traumatic episode into one's conscious state is important for recovery.

• Question 443:

  A 23-year-old man presents to the emergency department with a soft-tissue injury to the left lower extremity. The injury was sustained 8 hours earlier in a motorcycle accident on a gravel road. On examination, the patient has a 7-cm deep laceration to the calf, with visible road debris. He had full tetanus immunization as a child and a tetanus booster immunization at age 15. Appropriate management of this injury would include which of the following?

  A. irrigation and debridement of the wound
  B. irrigation and debridement of the wound; tetanus toxoid and tetanus immune globulin
  C. irrigation and debridement of the wound; tetanus toxoid
  D. irrigation and debridement of the wound; IV antibiotics
  E. tetanus toxoid and IV antibiotics
  C. irrigation and debridement of the wound; tetanus toxoid

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  Explanation

  All traumatic soft-tissue injuries should be managed with aggressive local wound care. Because this injury is greater than 6hours old, contaminated, and greater than 1 cm in depth, it is a tetanus-prone wound. Therefore, in addition, this patient should receive tetanus toxoid, because it has been more than 5 years since his last immunization. He had full immunization as a child and, therefore, does not require additional passive immunization with tetanus immune globulin. Prophylactic antibiotics are controversial in the absence of an established wound infection.

• Question 444:

  The mother of a 3-year-old girl brings her daughter to see you because the girl developed breasts 6 months ago. The girl has had no vaginal bleeding, and there is no pubic hair. She takes no medication

  Which of the following is the most appropriate management of this girl?

  A. pituitary suppression with a gonadotropin-releasing hormone (GnRH) agonist
  B. laparoscopy
  C. assurance that the condition is benign and self-limiting
  D. corticosteroid suppression of adrenal function
  E. breast biopsy
  C. assurance that the condition is benign and self-limiting

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  Explanation

  Premature thelarche is a benign, self-limited disorder that does not progress. Breast development may actually regress, though the regression may not be complete. The girl and her parents should be assured that the events of puberty will be normal at a normal age. Examination of the girl should be repeated at 3- to 6-month intervals for about 1 year to be certain that additional pubertal events do not occur (such as growth of pubic hair, accelerated linear growth, and vaginal bleeding). Because pituitary and adrenal functions are normal for a prepubertal girl, therapy with a GnRH agonist (Lupron, Synarel, and so forth) or a corticosteroid is ineffective and inappropriate. Although breast cancer is a rare possibility in prepubertal girls, the presence of bilateral breast buds effectively excludes this diagnosis. A breast biopsy may destroy breast analge, and these girls will not have breast development at puberty.

• Question 445:

  A 45-year-old woman comes to your office saying that she has once again got into a deep funk, losing sleep and weight, and feeling she is worthless. She reports this is the third time in her life that she has experienced such episodes, but she has never had periods of abnormally elevated moods. Identify the diagnosis below that best describes the situation.

  A. major depressive disorder, recurrent
  B. bipolar I disorder
  C. bipolar II disorder
  D. cyclothymia
  E. dysthymic disorder
  F. mood disorder due to a general medical condition
  G. substance-induced mood disorder
  A. major depressive disorder, recurrent

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  Explanation

  The criteria for mood disorders depend on the presence or absence and duration of depressive and hypomanic or manic symptoms as well as on their severity, and also on the presence or absence of a causative general medical condition or the ingestion of substances. Major depressive disorder, recurrent, is marked by the lifetime occurrence of two or more major depressive episodes without intervening hypomanic or manic episodes. A major depressive episode is a severe depression which has lasted at least 2 weeks. Bipolar I disorder is characterized by a history of at least one full-blown manic episode, during which the patient's mood has been abnormally and persistently elevated, expansive or irritable for at least 1 week with marked impairment in occupational functioning. Bipolar II disorder, on the other hand, is marked by a history of at least one major depressive episode and at least one hypomanic episode, during which a patient's mood has been elevated, but not to the extent of causing marked impairment in social or occupational functioning. Apatient with bipolar II disorder may not, by definition, have had a full- blown manic episode.

  Cyclothymia is marked by periods of hypomanic symptoms alternating with depressive symptoms that do not meet the criteria for a major depressive episode. Dysthymic disorder is marked by a persistent, low- grade depression occurring more days than not for at least 2 years. Amood disorder due to a general medical condition is a prominent and persistent disturbance in mood that is judged to be the direct physiologic effect of a general medical condition, such as hyperthyroidism. A substance-induced mood disorder is a prominent and persistent disturbance in mood that is judged to be due to the direct effects of a substance, but which continues beyond the usual period of intoxication or withdrawal from a substance.

• Question 446:

  Several groups of organic compounds are associated with serious toxic effects when used as insecticides and responsible for more deaths on a worldwide basis than any other group of insecticides

  A. nitrosamines
  B. epoxy compounds
  C. PCBs
  D. formaldehydes
  E. organophosphorus compounds
  E. organophosphorus compounds

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  Explanation

  Organophosphorus compounds have been widely used since the 1950s as insecticides, both in national pest control programs and domestically. They have been responsible for many deaths on a worldwide basis, despite the lives initially saved by control of mosquitoes and malaria. From the point of view of the environmental toxicologist, it was perhaps fortuitous that many pests began to develop resistance to the substances fairly early in the use of these compounds. More recently, concern for environmental control has further limited their use; studies have attributed carcinogenic properties to several of these pesticides.

• Question 447:

  A45-year-old woman, seen by her medical internist, has been experiencing fears that she may have a serious illness. She complains that after eating she experiences "a lot of gas" and abdominal pain, followed by diarrhea on occasion. Her heart at times seems to be beating rapidly, and she feels faint at times, has chest "discomfort," and wonders if she is having a heart attack. Multiple tests have identified only a mild irritable bowel syndrome. The woman's fears are not allayed by this. She makes repeated calls to be seen by her doctors as well as seeking consultation from other specialists. She insists that "there's something there" and believes the doctors are not taking her seriously.

  Which of the following is the most effective long-term management of this patient?

  A. Transfer her care to a psychiatrist.
  B. Prescribe alprazolam.
  C. Establish regular follow-up visits with regularly scheduled physical examinations.
  D. Refer for supportive group psychotherapy.
  E. Refer to a pain management clinic.
  C. Establish regular follow-up visits with regularly scheduled physical examinations.

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  Explanation

  Hypochondriasis is a somatoform disorder in which misperceptions or distortions of somatic signs and symptoms lead to preoccupation with fears of having a serious illness. In factitious disorders, one deliberately manufactures signs and symptoms to enter the sick role. The preoccupation with fear of serious illness is not part of factitious disorder. Major depression is characterized by symptoms of depression: sleep disturbance, appetite disturbance, and so forth.

  It may be complicated by hypochondriasis. In the case study, no supporting evidence for major depression (for which she would have been evaluated) is provided. This woman's symptoms as described are not of a psychotic level; thus, reactive psychosis would be inappropriate. In pain disorder, pain in a specific body site is the predominant focus, unlike the predominance of fear seen in hypochondriasis. Care of these patients is best managed supportively by developing a therapeutic alliance with them.

  Anticipating their needs by establishing regular office visits and physical examinations with them will help allay fears as well as reassure them of one's concern for them, and that if an occult condition becomes evident it will be diagnosed early. Certainly, regular consultation with other specialists is in order to manage these patients. Although the course of hypochondriasis tends to be chronic, there are indications that factor in for a good outcome. One of these is the absence of secondary gain. This disorder is seen equally in both men and women. The prevalence in a general medical practice is approximately 46%. There is no relationship between hypochondriasis and increased ESR.

• Question 448:

  A 35-year-old woman presents to the clinic for a discussion on breast cancer risk. Her family history is pertinent for a grandmother who died of breast cancer at age 53, a mother who died of premenopausal breast cancer, and one of three sisters with breast cancer diagnosed at age 42. The sister with breast cancer underwent genetic testing and was found to have a BRCA1 mutation. Subsequently, the 35- year- old woman underwent genetic testing and was found to be a carrier of the same deleterious BRCA1 mutation.

  Which of the following ranges represents the lifetime risk for breast cancer that should be quoted for this patient?

  A. 030%
  B. 1040%
  C. 2050%
  D. 5080%
  E. 70100%
  D. 5080%

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  Explanation

  Deleterious mutations in the BRCA1 and BRCA2 genes are associated with markedly elevated lifetime risks of breast cancer. The risk initially quoted was determined from families with high penetrance or expression of the disease, in the 8090% range. Asubsequent study, based on a larger population of gene mutation carriers, demonstrated a lower risk of 56%. Therefore, the risk generally quoted for mutation carriers is in the range of 5080%. Management options for known mutation carriers, or other high- risk women, include intensive surveillance with monthly self-breast examinations, annual or semiannual clinical breast examinations, annual mammography starting 10 years prior to the earliest age of onset of breast cancer in a family member, chemoprevention with tamoxifen, and prophylactic mastectomy. The data supporting these options in BRCA-mutation carriers, however, are limited to small series. Evidence for imaging of these high-risk women using MRI as a screening modality is promising.

• Question 449:

  A63-year-old woman has a 3-cm pruritic lesion on her right labia majora that she has noted for approximately 9 months. She has been treated with various topical creams and ointments for vulvar candidiasis without resolution of her symptoms or lesion. When you examine this woman, the lesion is still present. Which of the following is the most appropriate intervention?

  A. Papanicolaou (Pap) smear of the lesion
  B. colposcopy of the lesion
  C. biopsy of the lesion
  D. wide local excision of the lesion
  E. vulvectomy
  C. biopsy of the lesion

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  Explanation

  Vulvar carcinoma must be considered in any postmenopausal woman with pruritus, especially in the presence of a visible lesion. The appropriate management is to biopsy the lesion after disinfecting the area and infiltrating with 1% Xylocaine. A34 mm dermal punch is useful to obtain the biopsy. Colposcopy alone is less reliable for vulvar lesions compared to cervical abnormalities because the technique requires the topical application of 35% acetic acid, which penetrates a keratinized squamous epithelium (the vulva) less than a nonkeratinized squamous epithelium (the cervix). Multiple biopsies should be obtained for a large, confluent lesion or a multifocal vulvar lesion. Wide local excision may be appropriate for small lesions, but is more difficult in an outpatient setting. Vulvectomy is reserved for women with biopsy-proven vulvar carcinoma.

• Question 450:

  In this otherwise healthy adult woman, what is the most likely infecting organism?

  A. group B Streptococcus
  B. Staphylococcus aureus
  C. Haemophilus influenzae
  D. Streptococcus pneumoniae
  E. Listeria monocytogenes
  D. Streptococcus pneumoniae

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  Explanation

  S. pneumoniae is the most common cause of adult meningitis in people over 30 and accounts for about 15% of cases.

  H. influenzae is the most common cause in children over 1 month old. Group B Streptococcus is an important cause of neonatal meningitis, but is very rare in adults. Staphylococcus,

  E. coli, and Klebsiella may be seen with penetrating head wounds or postneurosurgical procedures.