@marimphil wrote:
1>A 25-year-old male presents to his family physician with the following
statement: "Doctor, I can't urinate in public restrooms. I can if
there is no one around, but if I go to the restroom in a movie, an
airport, at the ball park or anywhere that someone else comes in,
I can't urinate. Even if I have already started, it just stops and
I can't get it going until the other person leaves. I am so
Answer
2>Autopsy of an elderly individual who died in a nursing home with no
known genetic diseases reveals small amounts of amyloid deposition
in the heart. Amyloid deposition is not seen in other organs. There
is no history of long-standing inflammatory disease. This type of
Answer
3>A family is referred to a genetic specialist because of mild mental
retardation in several of the school-age children. Laboratory evaluation
demonstrates a specific chromosomal breakage site in metaphase studies
of lymphocytes cultured with methotrexate. Which of the following
Answer
4>A 5-year-old male with no previous medical history is brought to the
ER by his mother because he accidentally ingested a large dose of rat
poison. He is conscious but appears quite agitated. On physical exam,
he is found to have a blood pressure of 110/70 and a heart rate of 90.
Answer
5>A 67-year-old man is evaluated for persistent shooting pains, lower
limb ataxia, and bladder dysfunction. Physical examination demonstrates
small irregular pupils that constrict with accommodation but not in
response to light. A VDRL test is positive. A CT scan of the spinal
cord would most likely demonstrate atrophy of which of the following
structures?
Answer
6>What is the earliest age at which toilet training is likely to be
successful?
Answer
7>A 13-year-old boy is brought to a rural clinic because of poor school
performance. His parents state that he did not begin talking until after
three years of age, and still does not use language as effectively as
his sister, who is 6-years-old. A careful family history reveals that
a maternal grandfather was mildly retarded. The mother has two sisters,
Answer
8>A 15-year-old is brought to the emergency department in a coma. An alert
ambulance attendant notes that the patient's breath smells like acetone.
This would be most consistent with which of the following?
Answer
9>A 28-year-old male with history of mood disorder presents with a decreased
need for sleep, irritability, recklessness, and increased energy. Which of
the following is the most likely additional presenting symptom?
Answer
10 A 10-year-old girl who is a suspected victim of child abuse
is referred to a psychologist for evaluation. As part of her
workup, the patient is asked to construct a story based on pictures
. Which of the following psychometric measures was utilized?
Answer
11>
A 65-year-old woman has a long-standing dementing disorder characterized
by deterioration in personality, neglect of personal hygiene, impaired
judgment, and disinhibited behavior. MRI demonstrates severe cortical
atrophy limited to the frontal lobes and anterior two thirds of the
temporal lobes, while the remaining cortex is preserved. No evidence
of recent or remote infarcts is found. Which of the following diagnoses
Answer
12>
A 50-year-old woman who works as a paralegal in a law firm comes to her
local doctor because of problems with sleep. The patient says that over
the past several weeks, she hasn't slept well, feels tired, and has had
headaches. She does not smoke or drink alcohol, except on special
occasions, and does not take any medications. The patient's pupils
are 5 mm in size, equal and reactive, with both the direct and
Answer
13>A one-year-old baby presents with increasing flaccid paralysis, lack
of coordination, and hyporeflexia. Over the next several years, the
child's condition deteriorates to a bedridden vegetative state.
Funduscopic examination reveals optic atrophy. Extensive enzymological
Answer
14>A 60-year-old male executive with a history of angina pectoris and
depression had bypass surgery the previous day. His depression has
responded well to selective serotonin reuptake inhibitors (SSRIs)
and there is no history of psychosis in the past. He now presents
with confusion, agitation, irritability, and tries to remove his
IV lines. His level of consciousness fluctuates, and at times he
Answer
15>A 38-year-old woman with a history of multiple sexual partners is most
at risk for which of the following?
Answer
16>Which of the following chemotherapeutic agents is specific for the M
phase of the cell cycle?
Answer
17>A 47-year-old man with a history of type 2 diabetes, depression, and
hypertension presents to the emergency department with spontaneous
priapism. Which of the following drugs is the most likely cause of
his current condition?
Answer
18>Tay-Sachs disease, an autosomal recessive disease caused by a deficiency
of hexosaminidase A, is lethal in childhood. In a population of Ashkenazi
Jews, blood testing shows the frequency of heterozygotes to be 0.1. What
is the probability that the first child of two individuals from this
population with no family history of the disease will have Tay-Sachs?
Answer
19>A 44-year-old male with a history of polysubstance abuse presents with
nausea, vomiting, increased heart rate, high blood pressure, sweating,
agitation, and weakness. He also complains of seeing monsters on the
wall during the interview. Which of the following best accounts for
Answer
20>In which of the following laboratory tests would you expect to find the
greatest disparity in reference intervals between men and (non-pregnant)
women?
Answer
21>A 7-year-old girl is walking across a vacant lot and steps on a nail. The
next day, her foot is sore and the wound appears inflamed. During these
early stages of infection, which of the following compounds exert the
most powerful chemotactic effect on neutrophils, causing them to migrate
into the inflamed area?
Answer
22>A 23-year-old woman with a history of sickle cell disease presents with
fever and severe bone pain localized to her left tibia. X-ray reveals a
lytic lesion and blood cultures reveal infection. A bone culture grows
gram-negative rods. Which of the following best describes the infecting
organism?
Answer
23>A 17-year-old girl loses her best friend in an automobile accident. After
the death, she starts writing for hours daily in her diary. This would
most likely be an example of which of the following defense mechanisms?
Answer
24>Physical examination of a neonate demonstrates abnormal facies with a
small lower jaw, low-set ears, and a prominent occiput. The feet have a
rocker-bottom deformation, and the infant is hypertonic. Cardiac
evaluation demonstrates a ventricular septal defect. Which of the
following is the average life-span for infants with this neonate's
syndrome?
Answer
25>A biopsy of a brain tumor from a 42-year-old man reveals a glial neoplasm
consisting of atypical astrocytes with scattered mitoses. Besides mitotic
activity, which of the following markers can provide information about
the neoplasm's proliferative activity?
Answer
26>A pharmacologist is determining the pharmacokinetic parameters of a novel
antibiotic in order to determine the proper dosage. The drug is a
weak organic acid with a pKa of 3.0. Assuming a pH of 2.0 in the
stomach, approximately what percent of the drug will be in a form
that can be rapidly absorbed from the stomach?
Answer
27>A 38-year-old woman vacationing in Connecticut is bitten by a tick.
She does not seek medical treatment and eventually develops chronic
arthritis of the knee and hip joints and paralysis of the left facial
muscles. A physical examination during the early stages of the disorder
would most likely have revealed
Answer
28>A 20-year-old man with new onset of seizures and no history of hypertension
is evaluated with a contrast-enhanced CT scan of the head, which
demonstrates a mixed parenchymal and subarachnoid hemorrhage. The
parenchymal hemorrhage is centered over one cerebral hemisphere.
Which of the following is the most likely source of the hemorrhage?
Answer
29>A baby is born with a small head, small eyes, and 6 fingers on each hand.
Two dimensional echocardiography reveals congenital heart defects.
Which of the following genetic conditions is most likely to be the
cause of this child's presentation?
Answer
30>A 35-year-old male presents to an infectious disease specialist with
recurrent infections with encapsulated bacterial organisms. The history
indicates that these infections have become apparent in the last
6 months. Laboratory findings indicates that the total immunoglobulin
Answer
31>A researcher develops a specific antibody to the complement component C3b
. Assume that intravenous administration of the antibody prevents the
biological effects of C3b. Administration of the antibody would be
expected to interfere with which of the following biological functions?
Answer
32>A 42-year-old man previously diagnosed with kidney stones complains
of gnawing, burning epigastric pain. On questioning, he also notes
moderate to severe diarrhea. Measurement of the patient's basal gastric
acid output reveals that it is markedly elevated. These symptoms are
likely the result of which of the following neoplastic syndromes?
Answer
33>During the isolation of Met-enkephalin (Tyr-Gly-Gly-Phe-Met) from
post-mortem human brain tissue, researchers find that the peptide
is rapidly degraded by peptidases in 1 minute at 37 C. Detailed
analysis of the peptide cleavage pattern of Met-enkephalin is
investigated with two candidate enzymes. Using the drug bestatin,
the investigators found no detectable Tyr-Gly-Gly-Phe-Met but did
find significant concentrations of Tyr-Gly-Gly. Using thiorphan,
there was no detectable Tyr-Gly-Gly-Phe-Met, but there was a
high concentration of Tyr. Which of the following is the best
Answer
34>The pharmacokinetic properties of a new drug are being studied in
normal volunteers during phase I clinical trials. The volume of
distribution and clearance determined in the first subject are
40 L and 2.0 L/hour, respectively. The half-life of the drug
in this subject is approximately
Answer
35>The pregnant mother of a 6-year-old son with glucose-6-phosphate
dehydrogenase deficiency is very worried that her female fetus
will have the disease. The father and mother are clinically normal.
Which of the following is true about her baby?
Answer
36>Medical students at a major teaching hospital are routinely assigned
to observe obstetric patients and to assist during delivery. When a male
medical student introduces himself to an obstetric patient, the patient
becomes agitated and requests that no students be present during her
delivery. The patient had been informed, prior to admission, that this
was a teaching hospital and that a student would be assigned to her
Answer
37>A 24-year-old migrant farm worker is rushed to a nearby emergency room
after an accidental exposure to parathion. He is in respiratory distress
and is bradycardic. Which of the following drugs can be given to increase
the activity of his acetylcholinesterase?
Answer
38>A 74-year-old woman with multiple myeloma is being treated with high
doses of doxorubicin (Adriamycin). She has also received
cyclophosphamide and prednisone recently. During his examination,
the physician should check the patient for
Answer
39>A 60-year-old man hospitalized with metastatic colon cancer signs a
DNR order. This means that the medical staff treating him is required
to
Answer
40>A 27-year-old swimmer who feels insecure about her athletic abilities
harshly criticizes her teammates' techniques. Which of the following
ego defense mechanisms is she displaying?
Answer
41>In a certain population, the frequency of color-blind males is 1 in 100.
Assuming that the population is in Hardy-Weinberg equilibrium at this
locus, the frequency of color-blind females is approximately
Answer
42>A newborn presents with severe acidosis, vomiting, hypotonia, and
neurologic deficits. Serum analysis reveals elevated levels of lactate
and alanine. These observations suggest a deficiency in which of the
following enzymes?
Answer
43>A 5-year-old boy who has been diagnosed with a mucopolysaccharidosis is
given an IQ test and found to have nearly normal intellectual functioning.
Which of the following are possible diagnoses for this patient?
Answer
44>A 72-year-old female patient with Alzheimer's disease, but no other
medical problems, suddenly becomes comatose and dies due to an intracranial
hemorrhage that caused severe damage to her entire left cerebral
hemisphere. There was no evidence or history of trauma. What is the
most
likely cause of this hemorrhage?
Answer
45>A 23-year-old man living in a group home for the developmentally
challenged has an IQ of 73. He does not read or write, and communicates
with one or two word utterances. He will not interact with other group
home members, and since birth he has "pulled back" and becomes agitated
Answer
46>Which of the following amino acids is most responsible for the buffering
capacity of hemoglobin and other proteins?
Answer
47>Addition of which of the following exhaustively 14C labeled substrates
would lead to evolution of 14CO2 from a cell-free suspension containing
all the enzymes and substrates required for the synthesis of uridylic
acid?
Answer
48>A 54-year-old college professor is diagnosed with colon cancer and has
it resected. Tumor is found extending from the mucosa to the serosal
surface of the colon and in three regional lymph nodes. Histological
examination demonstrates that the tumor is composed of cells with
ovoid, relatively small nuclei that form well-defined glands. Which
of the following best describes this tumor?
Answer
49> A 52-year-old man presents to his physician after a community health
screening test reveals a fasting glucose of 170 mg/dL. Physical
examination is remarkable for bronze skin pigmentation, hepatomegaly,
Answer
50> Which of the following enzymes is located at arrow 1 in
the electron micrograph above?
Answer
Answers
(39)
1 The correct answer is C. In the condition described, a person is in a
social situation and fears that he or she will not be able to perform
in the same manner as most everyone else can. The two most common social
phobias concern public speaking and restroom performance (sometimes
called "shy bladder".)
Anxiety disorder due to a general medical condition (choice A) is
diagnosed when a medical condition precipitates anxiety, e.g.,
hypoglycemia.
Panic disorder (choice B) is characterized by sudden paroxysms of
anxiety. It can strike unexpectedly in uncued situations so it would not
occur only when others are present.
Specific phobias (choice D) are unreasonable fears of some identifiable thing, not situation (e.g., elevators).
Substance-induced anxiety disorder (choice E) is diagnosed when anxiety
is precipitated by ingestion of a psychoactive substance, e.g.,
hallucinogens.
2The correct answer is E. This patient has senile cardiac amyloidosis,
which is usually a clinically insignificant condition due to deposition
of structurally normal transthyretin (formerly called prealbumin). The
transthyretin is a normal serum protein used to transport thyroxin and
retinal. In addition to causing senile cardiac amyloidosis,
transthyretin, in a mutant rather than normal form, is deposited as
amyloid in the familial amyloid polyneuropathies.
Amyloid-associated protein (choice A) is a more common protein deposited
as amyloid, and precipitates in secondary amyloidosis associated with
underlying chronic inflammatory conditions.
Amyloid light chain protein (choice B) is a common protein deposited as
amyloid, and precipitates in amyloidosis related to multiple myeloma and
other monoclonal B cell proliferations.
Beta-2-amyloid protein (choice C) is deposited as amyloid in the brain
(notably in blood vessels and cerebral plaques) of patients with
Alzheimer's disease.
Beta-2-microglobulin (choice D) is a normal serum protein that is deposited in amyloidosis complicating long-term hemodialysis.
3The correct answer is A. The heritable mental retardation condition
associated with chromosomal breakage is fragile X syndrome. The break
point is at q27.3 on the X chromosome. The test for this condition
involves culturing lymphocytes in either folate-deficient medium or with
chemical agents such as methotrexate that tend to break chromosomes. To
make the diagnosis, at least 4% of metaphase chromosomes must show the
specific break-point on the X chromosome. The percentage of defective
X-chromosomes above 4% does not correlate well with the degree of mental
retardation. The breakage point is a site of CGG trinucleotide repeats,
which tend to expand in successive generations, producing the clinical
feature of worsening mental retardation in each generation.
Y chromosome (choice B) damage is not part of fragile X syndrome, but
loss of this chromosome is one mechanism of producing 45, X0 (Turner
syndrome), characterized by mental retardation.
Trisomy 13 (choice C, Patau syndrome), trisomy 16 (choice D, Edward's
syndrome) and trisomy 21 (choice E, Down's syndrome) are all associated
with mental retardation, but not chromosomal breakage syndromes.
4The correct answer is E. As you might have guessed from his elevated PT
level, the active ingredient in rat poison is warfarin. It acts as an
anticoagulant by interfering with the normal hepatic synthesis of the
vitamin K-dependent clotting factors II, VII, IX, and X. The most
important adverse effect of warfarin is bleeding. The action of warfarin
can be reversed with vitamin K.
Atropine (choice A) is used as an antidote for anticholinesterase toxicity (e.g., ingestion of organophosphates).
Flumazenil (choice B) is used as an antidote for benzodiazepine toxicity (e.g., Valium).
N-acetylcysteine (choice C) is used as an antidote for acetaminophen toxicity.
Protamine (choice D) is used as an antidote for heparin overdose. Note
that heparin enhances the activity of antithrombin III, producing its
anticoagulant effect. Heparin toxicity would have resulted in an
elevated PTT.
5The correct answer is A. The patient has tabes dorsalis, which is a
form of neurosyphilis seen 10 to 25 years or longer after primary
disease. The pupils described are Argyll Robertson pupils, and are
considered diagnostic for neurosyphilis. Characteristically, the dorsal
columns, which contain the ascending tracts for sensory information,
become atrophic, probably as a result of damage to the dorsal root
ganglion cells.
The dorsal gray horn (choice B) contains neurons that respond to sensory input.
The lateral column (choice C) contains both descending (e.g., lateral
corticospinal, rubrospinal) and ascending (e.g., spinocerebellar,
spinothalamic) tracts.
The ventral column (choice D) contains both descending (e.g., anterior
corticospinal, tectospinal) and ascending (e.g., spinothalamic) tracts.
The ventral horn (choice E) contains lower motor neurons.
6The correct answer is D. Toilet training is not possible before the age
of 18 months because the long nerve fibers have not yet myelinated and
sphincter control is not possible. Toilet training should be completed
by 4 years of age.
7The correct answer is A. The features described are typical of the
familial form of mental retardation known as fragile X syndrome. This
disorder is the second most common heritable cause of mental
retardation, second only to Down syndrome. Striking features of this
disease are that the clinical features tend to worsen with each
successive generation, and that males are usually much more severely
affected than females, although nearly 50% of carrier females are at
least slightly mentally retarded. The explanation appears to involve a
region of DNA on the X chromosome that normally contains 6-54 tandem
repeats of the sequence CGG. Carrier females for fragile X syndrome may
have up to 200 CGG repeats. Clinically affected individuals have
250-4,000 repeats of the CGG sequence. The greater the number of
repeats, the more severe the retardation tends to be. Amplification of
premutations to full mutations appears much more likely to occur during
oogenesis than spermatogenesis.
Genomic imprinting (choice B) is a phenomenon in which the phenotypic
expression of a gene differs if the gene is inherited from the mother,
rather than the father. An example of this effect is Angelman ("happy
puppet") syndrome, caused by a deletion of band q12 in the maternal copy
of chromosome 15. A similar deletion in the paternal chromosome 15
produces a different disease called Prader-Willi syndrome.
A Robertsonian translocation (choice C) causes about 5% of cases of Down
syndrome. Generally the mother [typically with genotype 45, XX, -14,
-21, +t(14q; 21q)] has normal mentation, but some of her children may
carry the translocation in addition to the normal maternal chromosome 21
and normal paternal chromosome 21, producing partial trisomy 21. This
form of Down syndrome can appear to be a recessive genetic disease.
Trisomy 13 (Patau syndrome; choice D) is characterized by microcephaly,
mental retardation, cleft lip and palate, polydactyly, and rocker-bottom
feet. Survival is rare beyond one year.
Trisomy 18 (Edwards syndrome; choice E) is characterized by mental
retardation, micrognathia, low-set ears, cardiac defects, renal defects,
and rocker-bottom feet. Survival is rare beyond one year.
8The correct answer is C. The smell of acetone on the breath of a
comatose patient is an important, rapid diagnostic clue that strongly
suggests ketoacidosis and is usually seen in patients with poorly
controlled type 1 diabetes. Other features of diabetic ketoacidosis
include high blood glucose, increased serum osmolality, hypovolemia,
acidosis, and electrolyte imbalance.
In alcohol intoxication (choice A), the breath will smell like alcohol.
Diabetic hyperosmolar coma (choice B) usually is seen in older patients
with type 2 diabetes and is not characterized by ketoacidosis. Since
there is no acetone production, there is no specific scent to the
breath.
In heroin overdose (choice D), no acetone production occurs and there is no specific scent to the breath.
In hypoglycemic coma (choice E), which can occur in diabetics with
insulin overdose, no acetone production occurs and there is no specific
scent to the breath.
9The correct answer is D. The presentation suggests a manic or hypomanic
episode of a mood disorder. Patients in a manic episode often have an
elated or euphoric mood and racing thoughts. Other symptoms of mania
include increased energy, hypersexuality, grandiosity, and increased
talkativeness. In some patients, irritability, rather than euphoria, is
characteristic.
Depressed mood (choice A) can include anhedonia, decreased self-esteem,
energy, concentration, appetite, and libido, as well as increased guilt
and sucidality.
An unreasonable fear that one might die (choice B) may be associated
with panic disorder. Neurovegetative symptoms including severe anxiety,
palpitation, shortness of breath, chest pain, trembling, and
paresthesias may also occur.
Despite poor sleep, manic patients do not complain of insomnia (choice
C). Their need for sleep is decreased. During depressive episodes,
patients complain of insomnia or hypersomnia.
Obsessive-compulsive disorder is characterized by distressing recurrent
thoughts (obsession) and actions (compulsion) (choice E) that relieve
anxiety when carried out.
10>***
11The correct answer is D. Not all dementing disorders manifest with the
same clinical features. Although there is considerable overlap in
clinical symptomatology among different types of dementias, making
clinical diagnosis somewhat problematic, there are classic presentations
that allow identification of a specific form of dementia with a high
degree of confidence. In this case, the patient has symptoms due to
frontal lobe damage, eg, disinhibition, impaired judgment, and
personality changes. Furthermore, MRI demonstrates a specific pattern of
cortical atrophy, restricted to the frontal lobes and anterior portion
of the temporal lobes. This combination points toward a group of
dementias called frontotemporal dementia, the most frequent form of
which is Pick disease. Other forms of frontotemporal dementia are very
infrequent. Remember: frontal symptoms in conjunction with
frontotemporal atrophy = frontotemporal dementia/Pick disease.
Alzheimer disease (choice A) is the most frequent form of dementia in
industrialized countries. Although symptoms due to frontal damage may be
present in Alzheimer disease, they are usually associated with a more
generalized impairment of higher neurologic functions, eg, language,
memory, and learned movements. In addition, cortical atrophy in
Alzheimer disease is widespread and not limited to the frontal and
anterior temporal lobes.
Creutzfeldt-Jacob disease (choice B) represents the prototype of prion
diseases. Cortical atrophy is not a prominent feature of
Creutzfeldt-Jacob disease, which manifests with personality changes,
memory loss, and seizures, leading to death after a rapid clinical
course (a few months to 1 year).
Dementia with Lewy bodies, also known as diffuse Lewy body disease
(choice C), is one of the most common forms of dementia in Western
countries, possibly more common than vascular dementia. It is
characterized by widespread formation of Lewy bodies in the substantia
nigra, limbic cortex, and subcortical nuclei, such as the basal nucleus
of Meynert. Extrapyramidal symptoms similar to Parkinson disease
manifest in this form of dementia as a result of degeneration of
dopaminergic pathways.
Vascular dementia (choice E) is an umbrella term encompassing dementing
conditions that arise from pathology of large or small cerebral vessels.
It manifests with memory loss associated with focal neurologic symptoms
depending on the location of damage. MRI would identify old or recent
infarcts, as well as white matter disease. Conditions associated with
vascular dementia include the following:
Multi-infarct dementia, which is caused by multiple, scattered brain
infarcts secondary to atherosclerosis of large arteries of the circle of
Willis and/or carotid arteries.
Binswanger disease, which involves rarefaction of cerebral white matter
and is caused by hypertension-related arteriolosclerosis.
Lacunar infarcts, which consist of small (< 1 cm) infarcts in the
striatum and thalamus; this condition is related to arteriolosclerosis.
12The correct answer is E. This patient has a pinealoma. Tumors of the
pineal gland compress the vertical gaze center in the tectum of the
midbrain. The pineal gland manufactures melatonin from its precursor
serotonin; an inadequate supply of melatonin results in insomnia. Tumors
of the pineal gland will not compress the cerebral cortex or the rest
of the brainstem. Frequently, the only physical sign noted is failure of
upward gaze.
An acoustic neuroma (choice A) is a schwannoma of the eighth cranial
nerve. It results in deafness, ataxia, and dysarthria. Nystagmus may be
present. The gaze centers are not affected.
Astrocytomas of the cerebellum (choice B) are usually seen in children.
These tumors present with headache, nausea, vomiting, papilledema, and
cerebellar signs such as ataxia, dysarthria, nystagmus, and intention
tremor. The gaze centers are not affected.
Craniopharyngiomas (choice C) are usually seen in children. There is failure of growth, headaches, and bitemporal hemianopia.
Parasagittal meningiomas (choice D) usually result in headache, spastic paresis, and urinary incontinence
13The correct answer is C. There are a number of hereditary
sphingolipidoses that have devastating clinical courses. In practice,
these diseases may have a variable course and may be difficult to
specifically diagnose reliably on clinical grounds alone. The most
useful clue to the specific diagnosis in this case is the comment about
the deficient arylsulfatase A. Deficiency of this enzyme produces
metachromatic leukodystrophy, characterized by accumulation of
cerebroside sulfates (galactosyl sulfatide). The cerebroside sulfates
accumulate as intra- and extracellular spherical masses that stain
metachromatically (purplish rather than bluish) with acid cresyl violet,
particularly in the nervous system. The biochemical diagnosis can be
made by evaluating cultured cells from a variety of sources, including
leukocytes, fibroblasts, and hair bulbs. The most common presentation is
that described in the question stem; adolescent and adult variants also
occur.
Gaucher's disease (choice A) is a sphingolipidosis caused by deficient beta-glucocerebrosidase.
Krabbe's disease (choice B) is a sphingolipidosis caused by deficient beta-galactocerebrosidase.
Niemann-Pick disease (choice D) is a sphingolipidosis caused by deficient sphingomyelinase.
Tay-Sachs disease (choice E) is a sphingolipidosis caused by deficient hexosaminidase A (alpha subunit).
14The correct answer is B. Delirium is a common complication of general
anesthesia and surgery. It is manifested by acute changes in mental
status with waxing and waning level of consciousness, agitation,
irritability, and psychosis. Patients usually respond to low-dose
neuroleptics to achieve sedation. The course is self-limited.
Any psychosocial or biological stressor can lead to adjustment disorder
(choice A). This patient's surgery will restrict his level of
functioning, at least in the short term. This will be difficult for a
high-functioning individual to accept. Adjustment disorder may present
with depressive mood, anxiety, and irritability, but a fluctuating level
of consciousness is not a feature of this disorder.
Dementia (choice C) can present with irritability, confusion, and
agitation, but usually has an insidious course and affects mainly
cognition. In contrast to delirium, it does not have a fluctuating
course.
Severe depression can present with irritability, suicidal ideation, and
psychotic features (choice D). The patient has a history of depression
that responded well to SSRIs and he has no prior history of psychosis.
He was motivated to undergo cardiac surgery, so removing his IV lines is
unlikely to be a manifestation of suicidal ideation.
Schizophrenia (choice E) presents with bizarre behavior, hallucinations,
and delusions. It usually starts at a younger age than the acute
symptoms in this patient, and is characterized by progressive
deterioration in functioning. It is unlikely for a schizophrenic to
achieve the functional level of an executive.
15The correct answer is B. In a sense, cervical carcinoma can be
considered a "sexually transmitted disease," since human papilloma virus
(typically strains HPV-16 or HPV- 18) is transmitted venereally. In our
culture, HPV-related dysplasia of the cervix is common, even in the
18-28 year old group, and carcinomas of the cervix (more rare now than
in the past due to screening and aggressive therapy of dysplasia) can
occur in the 35-45 age group. The other cancers listed typically occur
in older age groups and are not as clearly related to venereal agents.
16The correct answer is E. Vincristine (and vinblastine) are Vinca
alkaloids that bind to tubulin, a component of cellular microtubules.
This leads to disruption of the mitotic spindle apparatus and results in
metaphase arrest since the chromosomes are unable to segregate. Since
these drugs interfere with mitosis, they are considered cell-cycle
specific for the M phase.
Cytarabine (choice A) belongs to the class of antineoplastics that are
antimetabolites. This drug class interferes with normal metabolic
pathways by competing for enzymatic sites. Specifically, cytarabine
(Ara-C) is a pyrimidine nucleoside analog. It interrupts DNA synthesis
and function by inhibiting DNA polymerase and incorporating into the DNA
or RNA of the cell. As you would expect, this drug is cell-cycle
specific for the S phase.
Daunorubicin (choice B) is one of the antibiotic antineoplastic agents
(others include dactinomycin, doxorubicin, bleomycin, plicamycin, and
mitomycin). These agents work by disrupting DNA functioning.
Daunorubicin binds to DNA between base pairs on adjacent strands,
resulting in uncoiling of the helix and destruction of the DNA template.
While this drug has its maximum effect during the S phase, it is not
cell-cycle specific. (Note: the only antibiotic that is cell-cycle
specific is bleomycin.)
Hydroxyurea (choice C) works by interfering with ribonucleoside
diphosphate reductase, the enzyme responsible for generating the
deoxyribonucleotides needed for DNA synthesis. It is S-phase specific.
Mechlorethamine (choice D) is a nitrogen mustard. The nitrogen mustards
(mechlorethamine, cyclophosphamide, melphalan, chlorambucil) belong to
the larger class of alkylating agents. These agents work by alkylating
DNA (along with RNA and proteins). The alkylating agents are generally
NOT cell-cycle specific.
17The correct answer is E. Priapism is characterized by the development
of a painful erection for an extended period of time. When untreated,
priapism can cause severe penile damage that can culminate in impotence.
Administration of the antidepressant drug trazodone has been associated
with priapism in a number of patients. In patients with prolonged or
inappropriate penile erection, this medication should be discontinued
and medical attention should be sought immediately. Injection of
alpha-adrenergic stimulants, such as norepinephrine or epinephrine, may
be successful in treating the priapism. Surgical intervention is
necessary for the treatment of trazodone-induced priapism in many
instances.
Atenolol (choice A) is a beta-1 adrenergic antagonist indicated for the
treatment of hypertension. This agent is commonly associated with
impotence in males.
Furosemide (choice B) is a loop diuretic indicated for the treatment of
edema and hypertension; electrolyte abnormalities are the most common
side effects seen with this agent.
The sulfonylurea glyburide (choice C) is an oral hypoglycemic agent
indicated for the treatment of type 2 diabetes; hypoglycemia is the most
common side effect of this agent.
Paroxetine (choice D) is a selective serotonin reuptake inhibitor (SSRI)
used for the treatment of depression. This agent is commonly associated
with impotence in males.
18The correct answer is D. Since Tay-Sachs is lethal in childhood, the
only adults carrying the gene are heterozygotes. The only mating that
will produce progeny with the disease is the mating between two
heterozygotes. Using the blood test data, the probability that a random
individual is a heterozygote is 0.1. The probability that two
heterozygotes will produce a child with Tay-Sachs disease is 0.25. So,
the overall probability that two individuals in the population will
produce a child with Tay-Sachs is (0.1)(0.1)(0.25), or 0.0025.
Choice A, 0.25, could be obtained if the parents are carriers, so the
probability of a Tay-Sachs child is equal to the probability that two
heterozygotes will produce a child with the disease, or 0.25.
Choice B, 0.11, could be obtained if both of the parents had a sibling
with Tay-Sachs. This would mean that the grandparents must have carried
the disease, and that their normal children had a 0.67 chance of
carrying the allele. This gives the probability that the parent's child
would have Tay-Sachs as (0.67)(0.67)(0.25), or 0.11.
Choice C, 0.0625, is also incorrect. It is the product of (0.25)(0.25).
Choice E incorrectly assumes that because q2, the frequency of the
disease, cannot be calculated, and hence the allele frequencies cannot
be calculated, that an estimate of the frequency of heterozygotes cannot
be made. The problem can be done, however, because the heterozygote
frequency (0.1) was given in the question stem.
19The correct answer is D. This man's presentation can be explained
either by alcohol withdrawal or by cocaine intoxication. Nausea,
vomiting, sympathetic nervous system activation, and weakness could be
produced in either case. Visual hallucinations (seeing monsters) can
also be accompanied by tactile and auditory hallucinations. In severe
cases, either alcohol withdrawal or cocaine intoxication can cause
convulsions.
Alcohol intoxication (choice A and B) is characterized by disinhibition,
aggression, impaired attention and judgment, unsteady gait and
imbalance, slurred speech, nystagmus, and a decreased level of
consciousness.
Other symptoms associated with alcohol withdrawal (choices C and D)
include insomnia, headache, and tremors of the tongue, eyelids, and
outstretched hands.
Withdrawal from cocaine (choices B and F) is characterized by dysphoria,
lethargy, psychomotor retardation or agitation, increased appetite,
sleep disturbances, and bizarre or unpleasant dreams.
Other symptoms associated with cocaine intoxication (choices D and E)
include grandiosity, paranoid ideation, and pupillary dilatation.
Orientation usually remains intact.
20The correct answer is C. Men have higher reference intervals than
women in tests related to iron and hemoglobin (Hb) concentration in
blood. The normal reference interval for Hb concentration in women is
lower (12.0-16.0 gm/dL) than that for men (13.5-17.5 gm/dL) due to lower
serum testosterone levels (testosterone is higher in men and stimulates
erythropoiesis) and blood loss during menses. Furthermore, women
normally have about 400 mg of iron (as ferritin) in their bone marrow
iron stores versus an average of 1000 mg of iron for men. In the absence
of inflammation, the small circulating fraction of ferritin (choice C)
correlates well with ferritin stores in the bone marrow. Hence, men have
different reference intervals for serum ferritin than do women (15-200
ng/mL in men versus 12-150 ng/mL in women).
The mean corpuscular volume (choice A), serum alkaline phosphatase
(choice B), serum glucose (choice D), and serum sodium (choice E) are
similar in both sexes.
21The correct answer is A. The most important chemotactic factors for
neutrophils are the complement factor C5a and the interleukin IL-8.
The cytokines IL-1 and tumor necrosis factor (choice B) have complex,
similar actions, including stimulation of production of many acute-phase
reactions, stimulation of fibroblasts, and stimulation of endothelium.
Leukotrienes LTC4 and LTD4 (choice C) cause increased vascular permeability.
Prostaglandins PGI2 and PGD2 (choice D) mediate vasodilation and pain.
Thromboxane and platelet activating factor (choice E) induce platelet changes
22The correct answer is D. The presence of sickle cell disease in a
question stem is usually a significant clue. This question tests if you
know that patients with sickle cell anemia are more susceptible to
osteomyelitis caused by Salmonella. (The patient's fever, bone pain, and
x-ray results indicate osteomyelitis). But note that Staphylococcus
aureus (gram-positive coccus) is the most common cause of osteomyelitis
in both sicklers and nonsicklers. If it had not been ruled out on bone
culture, you should have looked for it in the answer choices. Notice
that you were required to know more than just the organism's name; you
needed to know its distinguishing features. Choice D describes
Salmonella (a gram-negative rod) accurately. Salmonella exists in over
1800 serotypes and is known to contaminate poultry.
A facultative intracellular parasite (choice A) is Legionella, a
catalase-positive gram-negative rod. It contaminates air-conditioning
cooling towers and causes Legionnaire's disease (a type of pneumonia).
A nonmotile, facultative anaerobe (choice B) is Shigella, a
gram-negative rod that does not produce H2S. All Shigella contain an
endotoxic lipopolysaccharide. The organism causes bacillary dysentery,
with abdominal cramps, fever, and mucoid, bloody diarrhea.
A comma-shaped organism that is sensitive to acidic pH (choice C) is
Vibrio cholerae, a gram-negative rod that causes severe
enterotoxin-induced diarrhea, with "rice-water" stools and dehydration.
The toxin acts by stimulating adenylyl cyclase to overproduce cAMP in
the brush border of the small intestine.
A motile and oxidase positive organism (choice E) is Pseudomonas, a
gram-negative rod with pili that sometimes produces a polysaccharide
slime layer. P. aeruginosa is the prototype and commonly colonizes the
lungs of patients with cystic fibrosis. It is associated with blue-green
pus.
23The correct answer is E. Sublimation is the diversion of unacceptable
impulses into more acceptable ones. In this case, the girl would like to
continue to talk to her best friend, but since that is not possible,
she substitutes writing in her diary. An example of sublimation seen
fairly frequently in medical settings is the mother whose child died of a
disease who becomes active in a state or national organization designed
to help families with the disease.
Identification (choice A) is the adoption of characteristics or activities of another person.
Projection (choice B) occurs when someone attributes their own thoughts to a different person.
Rationalization (choice C) is the offering of a false, but acceptable, explanation for behavior.
Regression (choice D) is the adoption of behavior more appropriate to a younger age.
24The correct answer is A. The syndrome described is Edwards' syndrome
(trisomy 18), which is typically characterized by the features noted and
additionally causes severe mental retardation, which would not be
recognizable in the neonatal period. This disease is relatively common,
with an incidence of about 1 in 5000 births (Down syndrome has an
incidence of 1 in 2000 births). The average life span is only 2-3
months.
25The correct answer is C. Ki-67 is a nuclear factor (of uncertain
function) whose expression correlates with neoplastic replicative
activity. Its expression can be visualized by immunostaining of
formalin-fixed, paraffin-embedded sections. Ki-67 labeling correlates
with a neoplasm's rate of growth and, therefore, with prognosis.
The bcl-2 gene (choice A) suppresses apoptosis by different mechanisms.
Its abnormal activation is involved in the pathogenesis of low-grade
lymphomas but not astrocytomas.
GFAP (choice B) is an intermediate cytoskeletal filament (analogue of
keratin and vimentin) expressed exclusively by certain types of glial
cells, e.g., astrocytes and ependymal cells. Immunohistochemistry for
GFAP is used diagnostically to confirm an astrocytic origin of a
neoplasm, but gives no information about mitotic or proliferative rate.
The gene p53 (choice D) encodes a protein that blocks the cell cycle
when damage to DNA occurs. If the damage is successfully repaired, p53
allows the cell cycle to resume; if not, p53 induces apoptosis, thus
eliminating dangerous DNA mutations. Mutations of p53 have been found in
the great majority of human neoplasms, including gliomas. However, its
expression gives no information concerning neoplastic replicative
activity.
Ubiquitin (choice E) is a low-molecular-weight heat-shock protein. Its
function is to tag aberrant proteins for degradation. It is present in
many abnormal intraneuronal inclusions associated with neurodegenerative
disorders, such as Lewy bodies, Pick bodies, and neurofibrillary
tangles. It has no relationship with mitotic activity or growth rate.
26The correct answer is E. First, it is necessary to know that it is the
uncharged, lipid-soluble form that can be rapidly absorbed. For an
acid: HA <-------> H+ + A-. Therefore, the protonated form is
uncharged. The Henderson-Hasselbalch equation is:
pH = pKa - log[protonated form/unprotonated form]
In this case,
2.0 = 3.0 - log [HA/A-]
1.0 = log [HA/A-]
10 = HA/A- = 10/1
HA/(HA + A-) = 10/(10 + 1) = 91%, or approximately 90%
27The correct answer is B. Lyme disease should be suspected in a patient
who is bitten by a tick in the northeastern U.S. Lyme disease was named
after a township in eastern Connecticut where the disease was endemic.
The disease is spread via a tick vector of the genus Ixodes, which
transmits a spirochete that causes a systemic illness. Erythema
chronicum migrans is usually the first sign of the illness. This is a
large red patch on the buttocks or chest that slowly expands as the
center blanches. Generally, patients also have constitutional symptoms,
such as fever and chills, during this phase. Stiff neck may develop,
along with other signs of meningeal irritation, because of an aseptic
meningitis. Other neurologic complications of Lyme disease include
Bell's palsy due to involvement of branches of the facial nerve.
Arthritis is a prominent feature in about half the patients with Lyme
disease. It tends to appear several months after the infection but may
persist for several years. The course of the chronic arthritis shows
exacerbations and remissions; the most commonly affected joints are the
knees and hips. Cardiac abnormalities in Lyme disease include
pericarditis and heart block.
Skin manifestations do not include aphthous ulcers (choice A).
Flaccid or spastic paralysis of limbs (choices C and E) does not
accompany Lyme disease; neurologic involvement is generally limited to
cranial nerves and meningitis.
Purpura (choice D) is associated with vasculitis and does not occur in Lyme disease.
28The correct answer is A. Arteriovenous malformations are composed of
complex tangles of congenitally malformed vessels that typically involve
the superficial or deep cerebral hemispheres. There is a slight male
predominance, and bleeding typically occurs in adolescence or young
adulthood. Symptoms may be those of subarachnoid hemorrhage (headache,
increased intracranial pressure) and/or seizures. Surgical resection is
usually required for therapy.
Berry aneurysms (choice B) can produce both subarachnoid and parenchymal
hemorrhage, but are usually centered near the base of the brain.
Bleeding from bridging veins (choice C) causes subdural hematoma.
Charcot-Bouchard aneurysms (choice D) are small, intraparenchymal aneurysms that are related to hypertension.
Rupture of the middle meningeal artery (choice E) causes epidural hematoma.
29The correct answer is A. This is Patau syndrome, or trisomy 13. This
disorder is also associated with severe mental retardation, abnor