USMLE USMLE Certifications USMLE-STEP-3 Questions & Answers

• Question 261:

  A 67-year-old man is seen in the clinic for a scheduled visit. He complains of walking difficulties that have progressively worsened over many months. He also has noticed "shaking" of his hands, resulting in his dropping objects occasionally. He is greatly upset by these problems and admits to frequent crying spells. His only chronic medical illnesses are gastroesophageal reflux disease and hyperlipidemia. He is currently prescribed a proton pump inhibitor and cholesterol-lowering agent. His MSE is notable for little expression or range of affect. His vitals signs are within normal limits. On physical examination, there is a noticeable coarse tremor of his hands, left greater than right. His gait is slow moving and broad-based.

  Which of the following brain structures is most likely affected in this man's condition?

  A. caudal raphe nuclei

  B. hippocampus

  C. locus ceruleus

  D. nucleus basalis of Meynert

  E. substantia nigra

  Correct Answer: E Section: (none)

  Explanation:

  This patient suffers from Parkinson's disease, a disorder involving decreased dopaminergic transmission. The nigrostriatal system originates in the substantia nigra. It is the primary dopaminergic tract in the central nervous system and is significantly affected in Parkinson's disease. The caudal raphe nuclei are the origin of the serotonergic system in the brain. The hippocampus is responsible for emotional and memory processing. The locus ceruleus is the location of the norepinephrine cell bodies. The nucleus basalis of Meynert is where the neurotransmitter acetylcholine originates.

  The concern with treating agitation and psychosis in patients with Parkinson's disease is that antipsychotics block certain dopamine receptors, which can subsequently worsen the Parkinson's symptoms. While clozapine has minimal extrapyramidal symptoms (EPS), its risk of agranulocytosis and need for regular blood monitoring make it less practical as a first-line agent. Haloperidol is a high potency neuroleptic. It is efficacious in treating psychotic symptoms and reducing agitation, but its potency also presents a significant risk of worsening the Parkinson's disease. Risperidone is an atypical, or second-generation, antipsychotic. Although the risk of EPS at low doses is less than with haloperidol, risperidone tends to still be more of a problem when compared with other atypical medications. Thioridazine is another older antipsychotic. While its lower potency creates less EPS and, therefore, less likelihood of worsening Parkinson symptoms, it has significant anticholinergic side effects that may worsen the confusion. A more concerning risk is prolongation of the QTc interval on ECG, potentially causing a ventricular arrhythmia. Quetiapine is a second-generation antipsychotic medication with essentially no EPS. This gives it a unique advantage in treating the psychosis and/or agitation in Parkinson's patients without also worsening the movement disorder.

• Question 262:

  An 86-year-old woman is brought to the emergency room by her daughter. The patient is a poor historian with limited insight. Her daughter understands that she has a history of high BP and is treated with an unknown medication. The patient has been living by herself in a retirement community. The daughter became concerned a year prior, when she noticed that her mother seemed more confused. She had attributed this to "old age," but 2 weeks ago she noticed an abrupt worsening in her condition. Her mother now has difficulty recognizing close relatives and remembering information. For the past 2 weeks, she has been getting lost, forgetting to turn off the stove, and has been unable to bathe herself. The daughter is concerned that she may inadvertently harm herself.

  Which of the following will be the most likely course of her illness?

  A. gradual improvement

  B. rapid decline

  C. stable course

  D. steady worsening

  E. stepwise deterioration

  Correct Answer: E Section: (none)

  Explanation:

  This is a case of dementia, vascular type (multiinfarct dementia), caused by poorly controlled hypertension. Atrophy of the caudate nucleus is seen in Huntington chorea, which accounts for the movement disorder and dementia that are seen in that illness. Dilated ventricles without atrophy are characteristic of normal pressure hydrocephalus (NPH), one of the potentially reversible causes of dementia. The triad seen in NPH consists of dementia, gait disturbance, and urinary incontinence. Pick's disease is a gradually progressing dementia, displaying marked but preferential atrophy of the frontal and temporal lobes of the brain. Generalized atrophy can often be seen with neuroimaging in Alzheimer dementia. Vascular dementia classically will show lacunar infarcts of the white matter on MRI. With the exception of reversible causes (e.g., NPH, metabolic causes, or heavy metal toxicity), improvement is unusual in dementing illnesses. A rapid decline is common in dementias due to prion infection, such as Creutzfeldt-Jakob disease. Stable dementias are also unusual, most notably seen in dementia due to a head injury. Both Alzheimer's and Pick's dementias demonstrate a steady worsening of the illness over many years. The multiple small infarcts causing vascular dementia correspond to a stepwise deterioration in functioning of the patient

• Question 263:

  An 86-year-old woman is brought to the emergency room by her daughter. The patient is a poor historian with limited insight. Her daughter understands that she has a history of high BP and is treated with an unknown medication. The patient has been living by herself in a retirement community. The daughter became concerned a year prior, when she noticed that her mother seemed more confused. She had attributed this to "old age," but 2 weeks ago she noticed an abrupt worsening in her condition. Her mother now has difficulty recognizing close relatives and remembering information. For the past 2 weeks, she has been getting lost, forgetting to turn off the stove, and has been unable to bathe herself. The daughter is concerned that she may inadvertently harm herself.

  An MRI of the brain would most likely demonstrate which of the following findings?

  A. caudate nucleus atrophy

  B. dilated ventricles without atrophy

  C. frontotemporal atrophy

  D. generalized atrophy

  E. white matter infarcts

  Correct Answer: E Section: (none)

  Explanation:

  This is a case of dementia, vascular type (multiinfarct dementia), caused by poorly controlled hypertension. Atrophy of the caudate nucleus is seen in Huntington chorea, which accounts for the movement disorder and dementia that are seen in that illness. Dilated ventricles without atrophy are characteristic of normal pressure hydrocephalus (NPH), one of the potentially reversible causes of dementia. The triad seen in NPH consists of dementia, gait disturbance, and urinary incontinence. Pick's disease is a gradually progressing dementia, displaying marked but preferential atrophy of the frontal and temporal lobes of the brain. Generalized atrophy can often be seen with neuroimaging in Alzheimer dementia. Vascular dementia classically will show lacunar infarcts of the white matter on MRI. With the exception of reversible causes (e.g., NPH, metabolic causes, or heavy metal toxicity), improvement is unusual in dementing illnesses. A rapid decline is common in dementias due to prion infection, such as Creutzfeldt-Jakob disease. Stable dementias are also unusual, most notably seen in dementia due to a head injury. Both Alzheimer's and Pick's dementias demonstrate a steady worsening of the illness over many years. The multiple small infarcts causing vascular dementia correspond to a stepwise deterioration in functioning of the patient.

• Question 264:

  A 30-year-old married male with a history of depression presents to the family medicine clinic. He appears embarrassed and somewhat anxious during his appointment. He denies significant sadness or crying spells. He is sleeping adequately and eating well, without recent changes in his weight. His energy and concentration are normal, and he denies any suicidal or homicidal ideation. He claims to be compliant with his citalopram (Celexa), which he is taking for his depression, but he complains of "problems with sex."

  Consideration is given to switching the patient to another antidepressant in order to minimize his side effects. Which of the following would be the most appropriate medication to choose?

  A. desipramine (Norpramin)

  B. fluoxetine (Prozac)

  C. mirtazepine (Remeron)

  D. phenelzine (Nardil)

  E. venlafaxine (Effexor)

  Correct Answer: C Section: (none)

  Explanation:

  Many psychotropic medications, including most of the antidepressants, cause a variety of sexual dysfunction symptoms. Both painful intercourse and retrograde ejaculation are not seen with antidepressant therapy. These are usually caused by other classes of medications, medical conditions, or surgical procedures. Premature ejaculation is not caused by antidepressants and, in fact, may actually be helped by antidepressants, especially SSRIs. Priapism is an uncommon side effect seen in patients treated with trazodone and even more rarely with the other antidepressants. Decreased libido is a frequent sexual side effect seen in individuals taking antidepressants, especially SSRIs. Other sexual problems caused by these medications include decreased erection and delayed ejaculation.

  Almost all of the antidepressants, including the tricyclic antidepressants such as desipramine and the monoamine oxidase inhibitors such as phenelzine, can cause sexual dysfunction. Fluoxetine is a SSRI that commonly causes sexual dysfunction. Venlafaxine is a serotonin and norepinephrine reuptake inhibitor that has also been shown to cause similar problems with sexual performance. Mirtazapine, a novel antidepressant which blocks serotonin and noradrenergic receptors, causes little to no sexual dysfunction. Bupropion has likely dopaminergic properties, and it not only causes little sexual dysfunction, but it also is used to help treat antidepressantinduced sexual dysfunction in some patients.

• Question 265:

  A 30-year-old married male with a history of depression presents to the family medicine clinic. He appears embarrassed and somewhat anxious during his appointment. He denies significant sadness or crying spells. He is sleeping adequately and eating well, without recent changes in his weight. His energy and concentration are normal, and he denies any suicidal or homicidal ideation. He claims to be compliant with his citalopram (Celexa), which he is taking for his depression, but he complains of "problems with sex."

  Which of the following symptoms would this patient most likely exhibit?

  A. decreased libido

  B. painful intercourse

  C. premature ejaculation

  D. priapism

  E. retrograde ejaculation

  Correct Answer: A Section: (none)

  Explanation:

  Many psychotropic medications, including most of the antidepressants, cause a variety of sexual dysfunction symptoms. Both painful intercourse and retrograde ejaculation are not seen with antidepressant therapy. These are usually caused by other classes of medications, medical conditions, or surgical procedures. Premature ejaculation is not caused by antidepressants and, in fact, may actually be helped by antidepressants, especially SSRIs. Priapism is an uncommon side effect seen in patients treated with trazodone and even more rarely with the other antidepressants. Decreased libido is a frequent sexual side effect seen in individuals taking antidepressants, especially SSRIs. Other sexual problems caused by these medications include decreased erection and delayed ejaculation.

  Almost all of the antidepressants, including the tricyclic antidepressants such as desipramine and the monoamine oxidase inhibitors such as phenelzine, can cause sexual dysfunction. Fluoxetine is a SSRI that commonly causes sexual dysfunction. Venlafaxine is a serotonin and norepinephrine reuptake inhibitor that has also been shown to cause similar problems with sexual performance. Mirtazapine, a novel antidepressant which blocks serotonin and noradrenergic receptors, causes little to no sexual dysfunction. Bupropion has likely dopaminergic properties, and it not only causes little sexual dysfunction, but it also is used to help treat antidepressantinduced sexual dysfunction in some patients.

• Question 266:

  A young White female, age unknown, is brought into the emergency room after being found unresponsive at the bus station. She is obtunded and her vitals signs are temperature 97.8°F, blood pressure (BP) 9 4/60, pulse 55, and respirations 8. Her physical examination is notable for a markedly underweight, poorly groomed woman. She appears pale with cold, dry skin and mucous membranes. She is uncooperative with the examination. Her pupils are pinpoint and minimally reactive to light. Her cardiac examination demonstrates bradycardia without murmurs or rubs. Her lungs are clear with shallow breathing. Her abdomen appears to be slightly distended.

  Administration of which of the following would be most appropriate?

  A. disulfiram (Antabuse)

  B. flumazenil (Romazicon)

  C. naloxone (Narcan)

  D. physostigmine

  E. thiamine

  Correct Answer: C Section: (none)

  Explanation:

  Alcohol and benzodiazepine intoxication commonly present with disinhibited behavior, slurred speech, poor coordination, and nystagmus, but not typically with dry mucous membranes or constricted pupils. Patients with anticholinergic overdose classically demonstrate psychotic symptoms and dry skin, similar to the above case. However, physical examination usually shows dilated pupils, warm skin, and tachycardia. PCP intoxication also manifests itself with vertical or horizontal nystagmus, dysarthria, and even coma, but it will usually cause hypertension or tachycardia (DSM IV-TR). This case is a typical presentation of opiate (such as heroin) overdose. The clinical triad is coma/unresponsiveness, pinpoint pupils, and respiratory depression. Other signs may include hypothermia, hypotension, and bradycardia. Disulfiram is an oral, nonemergent medication that blocks aldehyde dehydrogenase to cause a noxious reaction in those who consume alcohol while taking it. It is useful as a deterrent to drinking alcohol but not indicated for alcohol or opiate overdose.

  Flumazenil is a benzodiazepine receptor antagonist used to reverse the symptoms of overdose with benzodiazepines, especially the sedation and respiratory depression. It would have no effect on overdose on opiates unless benzodiazepines have been ingested concurrently. Intravenous thiamine is indicated for the treatment of Wernicke's encephalopathy, due to the thiamine deficiency seen in alcoholics. The classic triad seen in Wernicke encephalopathy consists of oculomotor disturbances, ataxia, and delirium. Although individuals with chronic opiate dependence are often malnourished, thiamine would not prevent complications seen with overdose. Physostigmine is an anticholinesterase inhibitor used in the emergent treatment of anticholinergic toxicity, but it could be dangerous in opiate overdose since it can cause further hypotension. Intravenous naloxone, an opiate antagonist, is the treatment of choice for the urgent management of heroin overdose, as it rapidly reverses the sedation, respiratory depression, hypotension, and bradycardia seen in cases similar to the patient above.

• Question 267:

  A young White female, age unknown, is brought into the emergency room after being found unresponsive at the bus station. She is obtunded and her vitals signs are temperature 97.8°F, blood pressure (BP) 9 4/60, pulse 55, and respirations 8. Her physical examination is notable for a markedly underweight, poorly groomed woman. She appears pale with cold, dry skin and mucous membranes. She is uncooperative with the examination. Her pupils are pinpoint and minimally reactive to light. Her cardiac examination demonstrates bradycardia without murmurs or rubs. Her lungs are clear with shallow breathing. Her abdomen appears to be slightly distended.

  Intake of which of the following substances would most likely account for her presentation?

  A. alcohol

  B. anticholinergic

  C. benzodiazepine

  D. heroin

  E. phencyclidine (PCP)

  Correct Answer: D Section: (none)

  Explanation:

  Alcohol and benzodiazepine intoxication commonly present with disinhibited behavior, slurred speech, poor coordination, and nystagmus, but not typically with dry mucous membranes or constricted pupils. Patients with anticholinergic overdose classically demonstrate psychotic symptoms and dry skin, similar to the above case. However, physical examination usually shows dilated pupils, warm skin, and tachycardia. PCP intoxication also manifests itself with vertical or horizontal nystagmus, dysarthria, and even coma, but it will usually cause hypertension or tachycardia (DSM IV-TR). This case is a typical presentation of opiate (such as heroin) overdose. The clinical triad is coma/unresponsiveness, pinpoint pupils, and respiratory depression. Other signs may include hypothermia, hypotension, and bradycardia. Disulfiram is an oral, nonemergent medication that blocks aldehyde dehydrogenase to cause a noxious reaction in those who consume alcohol while taking it. It is useful as a deterrent to drinking alcohol but not indicated for alcohol or opiate overdose. Flumazenil is a benzodiazepine receptor antagonist used to reverse the symptoms of overdose with benzodiazepines, especially the sedation and respiratory depression. It would have no effect on overdose on opiates unless benzodiazepines have been ingested concurrently. Intravenous thiamine is indicated for the treatment of Wernicke's encephalopathy, due to the thiamine deficiency seen in alcoholics. The classic triad seen in Wernicke encephalopathy consists of oculomotor disturbances, ataxia, and delirium. Although individuals with chronic opiate dependence are often malnourished, thiamine would not prevent complications seen with overdose. Physostigmine is an anticholinesterase inhibitor used in the emergent treatment of anticholinergic toxicity, but it could be dangerous in opiate overdose since it can cause further hypotension. Intravenous naloxone, an opiate antagonist, is the treatment of choice for the urgent management of heroin overdose, as it rapidly reverses the sedation, respiratory depression, hypotension, and bradycardia seen in cases similar to the patient above.

• Question 268:

  An 80-year-old woman is admitted to the medical service for treatment of a UTI. While she is hospitalized, she is evaluated for confusion. On her mental status examination (MSE), she appears somnolent at times, fluctuating with an alert state. She is not cooperative, is hostile, and clearly is hallucinating at times. Her insight and memory are poor. The differential diagnosis includes both delirium and dementia.

  Which of the following is the most appropriate pharmacotherapy for her behavioral management?

  A. low-dose diphenhydramine (Benadryl)

  B. low-dose donepezil (Aricept)

  C. low-dose haloperidol (Haldol)

  D. low-dose lorazepam (Ativan)

  E. low-dose risperidone (Risperdal)

  Correct Answer: E Section: (none)

  Explanation:

  This case demonstrates a classic presentationfor delirium. Delirium can present with many symptoms, including aggressiveness, hostility, memory impairment, psychotic symptoms (especially visual hallucinations), and overall uncooperativeness, such as pulling out IVs and getting out of bed. While these symptoms are common in delirious patients, they are not specific for delirium and can be seen in many psychiatric illnesses, including dementias, psychotic disorders, substance use disorders, personality disorders, and others.

  The hallmark of delirium is a fluctuating level of consciousness over time, ranging from sedation to agitation. Diphenhydramine can be sedating but, due to its anticholinergic side effects, can also worsen delirium and cause urinary retention and constipation, especially in the elderly. Anticholinesterase inhibitors such as donepezil may be indicated for mild-tomoderate dementias, especially Alzheimer dementia. It is not indicated for the treatment of delirium and it would be difficult to diagnose a dementing illness in the context of a delirious state. Giving benzodiazepines such as lorazepam may be useful for agitation caused by a delirium, but they can also disinhibit a patient and cause further agitation, especially in older individuals. A benzodiazepine would be the preferred treatment of alcohol withdrawal delirium (delirium tremens [DTs]), however. A low dose of antipsychotic would be the best choice to decrease the agitation in a delirious patient. While a high-potency medication such as haloperidol can be used, it is more likely to cause extrapyramidal side effects than a second-generation (or atypical) antipsychotic such as risperidone.

• Question 269:

  An 80-year-old woman is admitted to the medical service for treatment of a UTI. While she is hospitalized, she is evaluated for confusion. On her mental status examination (MSE), she appears somnolent at times, fluctuating with an alert state. She is not cooperative, is hostile, and clearly is hallucinating at times. Her

  insight and memory are poor. The differential diagnosis includes both delirium and dementia.

  Which of the following signs/symptoms is the most specific for delirium?

  A. aggressiveness

  B. fluctuating consciousness

  C. poor memory

  D. psychosis

  E. uncooperativeness

  Correct Answer: B Section: (none)

  Explanation:

  This case demonstrates a classic presentationfor delirium. Delirium can present with many symptoms, including aggressiveness, hostility, memory impairment, psychotic symptoms (especially visual hallucinations), and overall uncooperativeness, such as pulling out IVs and getting out of bed. While these symptoms are common in delirious patients, they are not specific for delirium and can be seen in many psychiatric illnesses, including dementias, psychotic disorders, substance use disorders, personality disorders, and others.

  The hallmark of delirium is a fluctuating level of consciousness over time, ranging from sedation to agitation. Diphenhydramine can be sedating but, due to its anticholinergic side effects, can also worsen delirium and cause urinary retention and constipation, especially in the elderly. Anticholinesterase inhibitors such as donepezil may be indicated for mild-tomoderate dementias, especially Alzheimer dementia. It is not indicated for the treatment of delirium and it would be difficult to diagnose a dementing illness in the context of a delirious state. Giving benzodiazepines such as lorazepam may be useful for agitation caused by a delirium, but they can also disinhibit a patient and cause further agitation, especially in older individuals. A benzodiazepine would be the preferred treatment of alcohol withdrawal delirium (delirium tremens [DTs]), however. A low dose of antipsychotic would be the best choice to decrease the agitation in a delirious patient. While a high-potency medication such as haloperidol can be used, it is more likely to cause extrapyramidal side effects than a second-generation (or atypical) antipsychotic such as risperidone.

• Question 270:

  A 30-year-old woman with a prior history of depression is attending her postpartum followup appointment after the birth of her first child. She has no physical complaints and her examination demonstrates no significant problems. She appears anxious. When asked, she describes intrusive thoughts of wanting to harm her baby but quickly states, "I'm not like that. I would never do anything to hurt him."

  Which of the following is the most appropriate next step in her management?

  A. assess further for symptoms of psychosis and support system

  B. begin immediate treatment with an antidepressant

  C. call child protective services in order to have the child removed

  D. hospitalize the woman immediately for further evaluation

  E. reassure her that these thoughts are normal

  Correct Answer: A Section: (none)

  Explanation:

  Although antidepressant treatment may be appropriate if the patient is suffering from a depressive illness, further questioning would have to be made prior to that determination. Postpartum depressive symptoms are not uncommon and they may not require treatment. If there is felt to be immediate danger to the child, calling child protective services would certainly be indicated. Having intrusive thoughts does not equate with acting on the thoughts, and thoughts similar to those in this case are not unusual given the stress of a newborn. Again, more information would need to be obtained. On the other hand, premature reassurance regarding the thoughts of harm without knowing additional facts might be dangerous if the patient is harboring a plan or intent to harm her child. Hospitalization may be necessary if the patient is suffering from postpartum psychosis or is suicidal. Only by gathering further history and symptoms, especially focusing on a support system and possible psychotic symptoms, can the clinician determine if there is significant cause for concern. Postpartum psychosis is considered a psychiatric emergency because of the risk of harm to the infant and usually requires immediate hospitalization (DSM IV-TR).