31. A patient presents with cervical lymphadenopathy. Biopsy demonstrates a nodular lymphoma with follicle formation. This lesion would most likely be associated with which of the following?

(A)       bcr-c-abl

(B)       bcl-2 activation

(C)       c-myc activation

(D)       t(8, 14)

(E)       t(9, 22)

31. The correct answer is B. Nodular lymphomas of all types are derived from the B-cell line. The translocation t(14, 18), with bcl-2 activation, is associated with these lymphomas.

An abl-bcr hybrid (bcr-c-abl; choice A) and t(9, 22) translocation (choice E) are associated with chronic myeloid leukemia (CML).

c-myc activation (choice C) and t(8, 14) (choice D) are associated with Burkitt lymphoma.

32. A 25-year-old woman presents with pain and tenosynovitis of the wrists and ankles, and arthralgias of other joints. She notes two prior episodes similar to the present one. She just had her menstrual period during the previous week. Physical examination reveals ulcerated lesions overlying the wrists and ankles. These symptoms are likely due to deficiency of which of the following?

(A)       C1 esterase inhibitor

(B)       Ciliary function

(C)            Complement (C6-C8) components

(D)            Endothelial adhesion molecules

(E)            Eosinophils

32. The correct answer is C. This patient has disseminated gonococcemia. Gonococcal arthritis and tenosynovitis typically involve both the upper and lower extremities equally. Vesicular skin lesions are characteristic of disseminated gonococcal disease. Females are at particular risk of gonococcemia during menstruation, since sloughing of the endometrium allows access to the blood supply, necrotic tissue enhances the growth of Neisseria gonorrhoeae, and there is an alteration of the pH. Patients who have a C6-8 deficiency have an increased risk of disseminated gonococcemia and tend to have multiple episodes. These patients are also at risk for bacteremia from Neisseria meningitidis.

C1 esterase inhibitor deficiency (choice A) can occur as an autosomal dominant disorder or is acquired. Patients have angioedema without urticaria. The syndrome is also associated with recurrent attacks of colic and episodes of laryngeal edema.

Ciliary dysfunction (choice B) is a marker of Kartagener syndrome (immotile cilia syndrome). The syndrome includes infertility, bronchiectasis, sinusitis, and situs inversus. It is an autosomal recessive disorder caused by abnormalities in the dynein arm of the cilia.

Endothelial adhesion molecule deficiency (choice D), or beta 2 integrin deficiency, is characterized by failure of neutrophils to express CD18 integrins on their surface. Patients have impaired phagocyte adherence, aggregation, chemotaxis, and phagocytosis of C3b-coated particles. Clinically, there is delayed separation of the umbilical cord, sustained agranulocytosis, recurrent infections of skin and mucosa, gingivitis, and periodontal disease.

Eosinophil deficiency (choice E), or eosinopenia, occurs with stressors such as acute bacterial infection and following administration of glucocorticoids. There is no known adverse effect of eosinopenia.

33. A 5-year-old girl is thoroughly evaluated because of growth failure. The child has been complaining of headaches, which are exacerbated when she tries to read. Funduscopic examination reveals papilledema. CT scan demonstrates a mass involving the area above and within the sella turcica. Surgical resection of the mass yields a multiloculated cystic and solid tumor containing dark brown, oily fluid. This tumor is thought to arise from epithelial rests derived from which of the following structures?

(A)            Hypothalamus

(B)       Pineal gland

(C)            Posterior pituitary gland

(D)            Rathke’s pouch

(E)            Superior colliculus

33. The correct answer is D. The tumor described is a craniopharyngioma, which is one of the more common brain tumors of children. These tumors arise from epithelial rests derived from Rathke’s pouch, which is an oral invagination that gives rise to the cells that form the anterior pituitary gland. Histologically, craniopharyngiomas can resemble ameloblastomas, which are tumors derived from dental epithelium.

Note that this question could also have been answered very simply by noting that the hypothalamus, pineal gland, pituitary gland, and the superior colliculus are all adult structures; only Rathke’s pouch is an embryonic structure. Therefore, only Rathke’s pouch could be the source of epithelial rests, which are remnants of embryonic tissues that persist in the adult.

Although craniopharyngiomas often occur near the hypothalamus (choice A) and posterior portion of the pituitary gland (choice C), they do not arise from neural tissue.

The pineal gland (choice B) and superior colliculus (choice E) are found on the posterior aspect of the brain stem.

34. A new antifungal medication is being tested in Phase I clinical trials. Examination of the pharmacokinetic properties of the drug reveals that the half-life of the drug is 6 hours. If a continuous intravenous infusion of this drug were started on a research subject, how long would it take to reach 75% of steady state?

(A)       3 hours

(B)       6 hours

(C)       9 hours

(D)       12 hours

(E)       18 hours

(F)       24 hours

34. The correct answer is D. The rule of thumb is that the plasma concentration will reach 50% in one half-life, 75% in two half-lives, 87.5% in three half-lives, etc., so that the difference between the current drug level and 100% halves with each half-life. In this instance, it takes two half-lives to reach 75%. The half-live of this drug is 6 hours, so two half-lives is 12 hours.

35. A patient presents to a physician with jaundice. Physical examination reveals a nodular, enlarged liver. CT of the abdomen shows a cirrhotic liver with a large mass. CT-guided biopsy of the mass demonstrates a malignant tumor derived from hepatic parenchymal cells. Infection with which of the following viruses would most likely be directly related to the development of this tumor?

(A)            Epstein-Barr virus (EBV)

(B)            Hepatitis B virus (HBV)

(C)       Human herpesvirus type 8 (HHV 8)

(D)       Human papillomavirus (HPV)

(E)       Human T-lymphocyte virus (HTLV-1)

35. The correct answer is B. The tumor is hepatocellular carcinoma, which usually develops in the setting of cirrhosis owing to a variety of damaging agents, including hepatitis B virus (HBV) infection, alcohol use, and hemachromatosis.

Epstein-Barr virus (EBV; choice A) is associated with Burkitt lymphoma and nasopharyngeal carcinoma.

Human herpesvirus type 8 (HHV 8; choice C), a member of the herpes family, is associated with Kaposi sarcoma.

Human papillomavirus (HPV; choice D) is associated with cervical, penile, and anal carcinoma.

Human T-lymphocyte virus (HTLV-1; choice E) is associated with adult T-cell leukemia.

36. A man brings his 45-year-old wife to the emergency department. He states she has been ill for 3 days and has been running a temperature of 99.8 to 100.5 F. Today she is having difficulty staying awake, is talking to persons who are not there, and at times appears to be frightened of something. She is restless and somewhat combative when restrained. What is the most likely diagnosis?

(A)       Acute stress disorder

(B)       Bipolar I disorder, manic type

(C)       Brief psychotic disorder

(D)            Delirium

(E)            Dementia

36. The correct answer is D. This is a psychotic level disorder (the patient is hallucinating). The patient has a fluctuating level of consciousness and is disoriented. Also, there is a clear history of a febrile condition that developed rather rapidly, all of which suggest delirium.          

In acute stress disorder (choice A) a traumatic event occurs that precipitates an anxiety-type reaction, not a change in the sensorium.

In both bipolar I disorder, manic type (choice B) and brief psychotic disorder (choice C), patients may reach a level of behavioral disruption of psychotic proportion. They do not, however, demonstrate changes in level of consciousness or major disorientation.

Persons with dementia (choice E) demonstrate a clear sensorium with no fluctuations in the level of consciousness. In addition, persons with dementia predominantly show symptoms of impairment of cognitive functions (e.g., memory impairment).

37. A patient consults a physician because of a small lesion on the lips that, on biopsy, proves to be a mucosal neuroma. The patient’s mother had medullary carcinoma of the thyroid. In addition to medullary carcinoma of the thyroid, to which of the following conditions would this patient be particularly vulnerable?

(A)            Gastrinoma

(B)            Insulinoma

(C)            Parathyroid adenoma

(D)            Pheochromocytoma

(E)            Pituitary adenoma

37. The correct answer is D. You should recognize this as a probable case of multiple endocrine neoplasia, specifically, MEN III (formerly MEN II b). Features of this autosomal dominant condition include medullary carcinoma of the thyroid, pheochromocytoma, and oral and intestinal ganglioneuromatosis (including mucosal neuromas).

Gastrinomas (choice A), insulinomas (choice B), and pituitary adenomas (choice E) are found in MEN I.

Parathyroid adenomas (choice C) are found in MEN I and II.

38. A 2-year-old boy has a CT scan of the head performed after a pediatrician notices a disproportionate growth in his head circumference compared with the rest of the body. The scan demonstrates a large choroid plexus papilloma involving the body of the right lateral ventricle. Which of the following brain structures might be affected by direct extension of this tumor?

(A)            Caudate nucleus

(B)            Cerebellum

(C)            Hippocampus

(D)            Hypothalamus

(E)       Pons

38. The correct answer is A. Tumors of the ventricular system of the brain can affect the brain tissue either directly, via pressure on or invasion into a physically close structure, or indirectly, by obstructing CSF flow and causing hydrocephalus. Choroid plexus papillomas are highly differentiated, benign tumors that can involve any ventricle but have a predilection for involving the lateral ventricles of small children, particularly boys. The caudate nucleus is a C-shaped structure that comprises part of the wall of the lateral ventricle throughout its extent. The only structure listed that is adjacent to the body of the lateral ventricle, and would therefore be directly affected by the large tumor described in the question, is the caudate nucleus.

The cerebellum (choice B) overlies the fourth ventricle.

The hippocampus (choice C) is adjacent to the inferior (temporal) horn of the lateral ventricle.

The hypothalamus (choice D) abuts the third ventricle.

The pons (choice E) forms part of the floor of the fourth ventricle.

39. A premature infant develops progressive difficulty breathing over the first few days of life. Deficient surfactant synthesis by which of the following cell types may be contributing to the infant’s respiratory problems?

(A)            Alveolar capillary endothelial cells

(B)            Bronchial mucous cells

(C)            Bronchial respiratory epithelium

(D)       Type I pneumocytes

(E)       Type II pneumocytes

39. The correct answer is E. The child has neonatal respiratory distress syndrome (hyaline membrane disease). This condition is caused by the inability of the immature lungs to synthesize adequate amounts of surfactant. Surfactant, which reduces surface tension, helps keep alveoli dry, and aids in expansion of the lungs, is synthesized by type II pneumocytes.

Alveolar capillary endothelial cells (choice A) are important in maintaining the capillary structure and permitting flow of gases into and out of the bloodstream.

Bronchial mucous cells (choice B) produce the usually thin (in healthy individuals) coat of mucus that lines the bronchi.

The ciliated bronchial respiratory epithelium (choice C) is responsible for moving the dust-coated mucus layer out of the bronchi.

Type I pneumocytes (choice D) are the squamous cells that line alveoli and permit easy gas exchange. These cells tend to be immature (and thick) in premature infants but are not the producers of surfactant.

40. A 67-year-old woman who has been in very good health is brought to her physician's office by her husband. He states that over the course of the past 5 years she has had difficulty recognizing her grandchildren, she has not been able to plan their daily activities, she has forgotten things left cooking on the stove, and at night she has been wandering through the house with an “absent” look on her face. She is beginning to demonstrate difficulty in recalling the names of common objects, and her speech is limited to simple two- or three-word sentences. Which of the following is the most likely diagnosis?

(A)            Alzheimer disease

(B)            Amnestic disorder

(C)            Pseudodementia

(D)            Substance-induced persisting dementia

(E)            Vascular dementia

40. The correct answer is A. This woman has dementia of the Alzheimer type. A gradual onset of symptoms, general pervasive memory deficit, difficulties with language, and inability to plan, leading to severe impairment of daily functioning, are all characteristic of this dementia.

Amnestic disorder (choice B) is limited to memory problems, and this woman is demonstrating cognitive dysfunction, such as alterations in language and the loss of the ability to plan.

Pseudodementia (choice C) is incorrect since it is a major depressive disorder rather than a dementing condition. There is no evidence for a depressive syndrome in this patient’s presentation.

The diagnosis of substance-induced persisting dementia (choice D) requires evidence of a history of substance abuse. However, it is the second most likely diagnosis and should be carefully explored with the husband and other close relatives and friends.

Vascular dementia (choice E) is generally characterized by a stepwise deterioration, not the gradual presentation of this case.

 Back to USMLE Test Sampler

Like this Site? Save it & Share it! del.icio.us

Share on Facebook

Seed Newsvine

HOME | JOB BOARD | FORUMS | PHYSICIAN | MEDICAL STUDENT | PREMEDICAL STUDENT
JOIN MOMMD | EDUCATION | CAREERS | RESOURCES | PRODUCTS
NEWS | ABOUT MOMMD | CONTACT | ADVERTISING | LINKS

©1999 - 2008 MomMD, LLC. MomMD is a registered service mark of MomMD, LLC.
The use of this site is governed by a Terms of Use Agreement and Privacy Policy.
Problems or site comments to webmaster@mommd.com.

MomMD does not provide medical advice or information.