@marimphil wrote:
(11) <1>A 61-year-old woman with leukemia abruptly
develops an intensely
itchy rash. Physical examination demonstrates multiple erythematous patches
of the distal arms and legs, some of which involve the palms and soles.
Some of the patches show central clearing with surrounding erythematous
rings. Which of the following is the most likely diagnosis?
A. Erythema migrans chronicum
B. Erythema multiforme
C. Kaposi's sarcoma
D. Psoriasis
E. Urticaria
Answer
<2>A 52-year-old woman presents to her physician for a check-up. She is
recovering from a wrist fracture after a fall. Dual energy x-ray
absorptiometry of the hip had shown her to have osteoporosis. She
became menopausal at age 50 and did not begin hormone replacement
therapy because of a strong family history of breast cancer. She
now fears a future hip fracture and would like to begin a bone
loss prevention regime.Which of the following pharmaceutical
agents is most appropriate for this patient?
A. Calcitonin nasal spray
B. Oral conjugated estrogen
C. Raloxifene
D. Tamoxifen
E. Transdermal estradiol
Answer
<3>A fracture of the humerus neck damages a nerve running around the
humeral neck. After the fracture heals, the patient notices a marked
decrease in his ability to raise his arm over his head. The denervated
muscle arises from which of the following?
A. Acromion alone
B. Clavicle and acromion
C. Clavicle and coracoid
D. Coracoid alone
E. Coracoid and acromion
Answer
<4>A patient is admitted to a psychiatric hospital after having been
picked
up by the police for making inappropriate sexual advances. A detailed
psychiatric interview demonstrates deficits in memory, insight,
judgement, personal appearance, and social behavior. The patient
is witnessed experiencing a possible epileptic seizure. Over a
period of several years, motor findings also develop, including
relaxed, but expressionless facies, tremor, dysarthria,
and pupillary abnormalities. Which of the following tests performed on his
cerebrospinal fluid would most likely be diagnostic?
A. CSF glucose
B. FTA-ABS
C. Gram's stain
D. Lymphocyte count
E. Neutrophil count
Answer
5>A 29-year-old single man seeks psychiatric treatment to help him deal
with difficulties in his personal life. Although the man is a successful
computer programmer, he feels unsatisfied with his interpersonal
relationships. He reports being attracted to several of his female
coworkers, but is "too shy" to talk to them about anything other
than superficial subjects such as the weather. He would like to ask
one of the women out on a date, but is afraid of being rejected.
Which of the following diagnoses is most appropriate?
A. Avoidant personality disorder
B. Borderline personality disorder
C. Dependent personality disorder
D. Narcissistic personality disorder
E. Schizotypal personality disorder
Answer
<6>A 3-month-old infant presents with a 3-day history of fever, cough,
and poor feeding. On examination, the baby appears ill and has a
temperature of 102 F and a respiratory rate of 32. A chest x-ray
film shows bilateral patchy infiltrates in the lungs. Which of
the following is the most likely etiologic agent?
A. Coronavirus
B. Influenza type A
C. Parainfluenza type 1
D. Respiratory syncytial virus
E. Rhinovirus
Answer
<7>A 35-year-old male presents to the urologist for an infertility
evaluation. A biopsy of his testis is performed to check sperm
production and maturation. A microscopic section reveals only
a few germ cells near the basal lamina in the seminiferous
tubule. Which of the following cells is the germ cell closest
to the basal lamina in the seminiferous tubule?
A. Primary spermatocyte
B. Secondary spermatocyte
C. Spermatid
D. Spermatogonia
E. Spermatozoa
Answer
<8>A 30-year-old otherwise healthy woman presents to her physician
with complaints of fatigue and dyspnea. Physical examination reveals
normal breath sounds and the presence of third and fourth heart sounds.
Chest x-ray shows clear lung fields but right ventricular enlargement,
main pulmonary artery enlargement, and "pruning" of the peripheral
vasculature. Electrocardiogram shows right axis deviation and right
ventricular hypertrophy. Left ventricular function appears normal
on echocardiography. Serologic studies show antinuclear antibodies.
Which of the following pathological findings would this patient
also show, either at autopsy or if an appropriate biopsy was taken?
A. Mural thrombus of the right atrium
B. Necrosis and scarring of the left ventricle
C. Plexogenic pulmonary vasculopathy
D. Pulmonary artery stenosis
E. Severe pulmonary fibrosis
Answer
<9>During an abdominal surgical procedure, the surgeon wishes to locate
the ureter in order to ensure that it is not injured. The ureter may be
found immediately anterior to the origin of the
A. common iliac artery
B. external iliac artery
C. internal iliac artery
D. gonadal artery
E. renal artery
Answer
<10>A patient with mild congestive heart failure is treated with
high-dose
furosemide and diureses 25 pounds of fluid. A complete blood count (CBC)
taken before the diuresis shows an RBC count of 4 million/mm3; a CBC
taken after diuresis shows a RBC count of 7 million/mm3. Which of the
following is the most likely explanation?
A. Cyanotic heart disease
B. Increased erythropoietin
C. Polycythemia vera
D. Relative polycythemia
E. Renal cell carcinoma
Answer
<11>A newborn male child is noted to have hypospadias. A complete
evaluation determines that the child has no other genitourinary
anomalies. Nonetheless, hypospadias repair will be performed to
prevent which of the following possible sequelae?
A. Bladder exstrophy
B. Hydrocele
C. Phimosis
D. Urachal cysts
E. Urinary tract infection
Answer
<12>During the passage of an intravenous catheter, numerous endothelial
cells are dislodged from the lining of the popliteal vein. What substance
allows platelet adhesion to the exposed collagen fibers?
A. Factor VIII
B. Factor IX
C. Fibronectin
D. Tissue factor
E. Von Willebrand factor
Answer
<13>A 57-year-old man presents to the emergency department with a
nosebleed for the past 2 hours. The patient received a prosthetic
heart valve 5 months ago and is currently taking warfarin (7.5 mg per day)
and oral antibiotics. Laboratory evaluation reveals
an INR (international normalized ratio, the ratio of
patient to normal prothrombin times) of 6.4. Which of
the following antibiotics is the patient most likely taking?
A. Ampicillin
B. Cephalexin
C. Nitrofurantoin
D. Norfloxacin
E. Phenazopyridine
Answer
<14>A 47-year-old woman presents with complaints of nervousness and
increased sensitivity to hot weather. She is diagnosed with
hyperthyroidism and prescribed propylthiouracil. What is
the principal mechanism by which this drug acts?
A. Decreasing the efficacy of TSH binding to the thyroid TSH receptor
B. Decreasing the rate of proteolysis of thyroglobulin
C. Increasing the amount of 3,3',5'-triiodothyronine (reverse T3; rT3)
D. Inhibiting deiodination of thyroxine (T4)
E. Inhibiting the uptake of iodide into the thyroid gland
Answer
<15>Which of the following neurotransmitters is most important for the
induction of REMsleep?
A. Acetylcholine
B. Dopamine
C. Epinephrine
D. Norepinephrine
E. Serotonin
Answer
<16>A 37-year-old woman presents with 3 days of progressive joint pain
in her ankles, knees, and wrists. She had three similar episodes
over the past several years. On examination, she has a temperature
of 38.7 C, her blood pressure is 110/70 mm Hg, and her heart rate
is 90/min. She has a diffuse petechial rash over her trunk and extensor
surfaces. Her ankles and knees are swollen, red, and tender with
decreased range of motion, and there is tenderness over the tendon
sheaths of her hands and forearms. Blood cultures are negative.
Aspiration of joint fluid reveals a white cell count of
22,000/mm3 with no visible organisms, but culture on
chocolate agar is positive. Which of the following
is an attribute of the causative organism that allows
it to produce recurrent infections?
A. It is an intracellular pathogen
B. It is resistant to ceftriaxone
C. It is resistant to complement-mediated lysis
D. Its capsule is not immunogenic
E. Its pili undergo antigenic and phase variation
Answer
<17>The data presented below compares the results of a diagnostic
test in the presence and absence of a disease.
Disease present Disease absent
Positive test 40 5
Negative test 10 95
Total 50 100
The specificity of the test is
A. 0.05
B. 0.40
C. 0.80
D. 0.90
E. 0.95
Answer
<18>Blood stored in a blood bank tends, with time, to become relatively
depleted of 2,3-diphosphoglycerate. What effect does this have on the
hemoglobin-oxygen dissociation curve?
A. Shifts the curve to the left, so that the hemoglobin has a decreased oxygen
affinity
B. Shifts the curve to the left, so that the hemoglobin has an increased oxygen
affinity
C. Shifts the curve to the right, so that the hemoglobin has a decreased oxygen
affinity
D. Shifts the curve to the right, so that the hemoglobin has an increased
oxygen affinity
E. Does not change the dissociation curve
Answer
<19>A psychotic, indigent man with a history of multisubstance
abuse has been involuntarily hospitalized for 1 week. Because of
persistent diarrhea, stools are sent for ova and parasites,
revealing numerous granular, spherical, thin-walled cysts
measuring 10-20 mm in diameter. Trichrome stains show up to
four nuclei in most of the cysts. These finding are consistent
with an infection by which of the following organisms?
A. Cryptosporidium parvum
B. Dientamoeba fragilis
C. Entamoeba histolytica
D. Giardia lamblia
E. Isospora belli
Answer
<20>A child who understands that the volume of a liquid poured out of
a narrow glass remains the same when poured into a wider glass is at
which of Piaget's stages of intellectual development?
A. Concrete operations
B. Formal operations
C. Preoperational
D. Sensorimotor
Answer
<21>A 4-year-old girl is brought to a specialty clinic by her foster
parents because of a limp in her right leg and a serum alkaline phosphatase
(ALP) that is 10 times the adult upper limit of normal for the test. The child
is withdrawn and clinging to her foster mother. Physical examination is
remarkable for a blue-green discoloration of the skin overlying a tender, 3-cm
mass on the anterior portion of the right mid-thigh. An x-ray of the right
thigh reveals a dense mass within the femur that extends into the surrounding
tissue. Which of the following best describes the increased alkaline
phosphatase and physical findings in this case?
A. ALP is abnormal for her age and the bone lesion represents an area of aseptic
necrosis
B. ALP is abnormal for her age and the bone lesion represents repair of a
femoral fracture
C. ALP is abnormal for her age and is unrelated to the bone lesion
D. ALP is normal for her age and the bone lesion is an osteogenic sarcoma
E. ALP is normal for her age and is unrelated to the bone lesion
Answer
<22>Which of the following drugs antagonizes both the vascular and
cardiac
actions of norepinephrine?
A. Atenolol
B. Esmolol
C. Labetalol
D. Metaproterenol
E. Prazosin
Answer
<23>During surgery to treat an ischioanal abscess, the inferior rectal
nerve is damaged. This nerve is a direct branch of which of the following
nerves?
A. Inferior gluteal nerve
B. Pelvic splanchnic nerve
C. Pudendal nerve
D. Sciatic nerve
E. Superior gluteal nerve
Answer
<24>A 15-year-old girl is evaluated for failure to begin menstruation.
Physical examination demonstrates short stature and a webbed neck.
Chromosomal analysis demonstrates a lack of one X chromosome. This
patient should be specifically evaluated for which of the following
cardiovascular anomalies?
A. Coarctation of the aorta
B. Dextrocardia
C. Ostium primum septal defect
D. Pulmonary stenosis
E. Tetralogy of Fallot
Answer
<25>A baby is born with a testicular mass. Histologic sections made of
the
homogeneous yellow-white mass after its removal demonstrate
epithelial-lined spaces that have flattened-to-cuboidal epithelial
cells with vacuolated cytoplasm containing eosinophilic, hyaline-like
globules. Scattered structures resembling primitive glomeruli
(endodermal sinuses) are also seen. If appropriate
immunohistochemical stains are performed, the eosinophilic
cytoplasmic globules would most likely contain which of the following?
A. Alpha-fetoprotein
B. Estrogen receptors
C. Human chorionic gonadotropin
D. Human papilloma virus
E. Melanin
Answer
<26>A surgeon wishes to perform a splenectomy on a patient who has
been in an automobile accident. Before removing the spleen, the
splenic artery and splenic vein are ligated. Within which of the
following peritoneal structures are the splenic artery and vein found?
A. Gastrocolic ligament
B. Gastrosplenic ligament
C. Lesser omentum
D. Splenorenal ligament
Answer
<27>A 65-year-old woman with a long-standing disease has bone marrow
fibrosis and increased bone remodeling, with bone resorption exceeding
bone formation. She has a history of passing calcium-oxalate kidney
stones. Which of the following lab result profiles would be expected
in the serum of this patient?
Calcium Phosphate PTH
A. decreased decreased increased
B. decreased increased decreased
C. decreased increased increased
D. increased decreased increased
E. increased increased increased
Answer
<28>Upon examination of a newborn male, a cystic structure is found
in the scrotum. It is determined that there is a hydrocele of the
spermatic cord. Which of the following is the most likely etiology
of this finding?
A. Communication between the epididymis and the tunica vaginalis
B. Failure of the processus vaginalis to form
C. Failure of the processus vaginalis to fuse
D. Incomplete fusion of the processus vaginalis
E. Varicosities of the spermatic vein
Answer
<29>A Brazilian immigrant is hired at a meat-packing plant, and undergoes
an employment physical. Chest x-ray demonstrates a patchy, bilateral
pneumonia and a lung mass, and he is referred to a specialist. Biopsy
of the mass demonstrates fungal organisms with a few very distinctive
"pilot's wheel" yeast forms. Which of the following is the most
likely
diagnosis?
A. Blastomycosis
B. Coccidioidomycosis
C. Histoplasmosis
D. Paracoccidioidomycosis
E. Sporotrichosis
Answer
<30>A 34-year-old female is brought to the emergency room with severe
muscle cramps and carpopedal spasms. The patient was noted to be extremely
irritable and was complaining of tingling around the mouth and in the hands
and feet. A few hours later, laboratory examination reveals
sodium 140 mEq/L, potassium 4.2 mEq/L, chloride 101 mEq/L,
calcium 6.4 mg/dL, phosphate 5.1 mg/dL,
magnesium 2.4 (normal 1.8-3.8 mg/dL) and alkaline phosphatase 67 U/L. A CT scan
of the head shows basal ganglia calcifications. Prolonged QT intervals and T
wave abnormalities are noted on electrocardiogram. The history is pertinent for
a thyroidectomy two months prior to admission. Which of the following
conclusions is most consistent with these data?
A. An increase in dietary vitamin D is warrante
B. Hepatocytes have a low 25-hydroxylase activity
C. Intestinal cells are underexpressing calcium transporter genes
D. Isolated cells from the kidney have high 1-hydroxylase activity
E. The levels of 1,25-dihydroxy vitamin D are normal
Answer
<31>A 48-year-old man presents to his physician with complaints of
dizziness
and fatigue. Physical examination reveals a blood pressure of 130/50 mm Hg
and a heart rate of 100 beats per minute. On examination, the physician
notes a large scar on the patient's abdomen. The man states that he was
severely injured in an automobile accident several years ago, and required
abdominal surgery at that time. Which of the following is the most likely
diagnosis?
A. Arteriovenous fistula
B. Cardiac tamponade
C. Heart failure
D. Hypovolemia
E. Shock
Answer
<32>A renal pathologist examining the day's kidney biopsies notes that
one
biopsy shows amorphous red nodules within the glomerular mesangium in
hematoxylin and eosin stained material. Congo red stain of the biopsy
demonstrates apple-green birefringence of these nodules. These nodules
are most likely to be related to which of the following?
A. Acute urinary tract infection
B. Diabetes mellitus
C. Sarcoidosis
D. Systemic lupus erythematosus
E. Tuberculosis
Answer
<33>A patient goes to his family doctor complaining of persistent and
severe headaches. His physician diagnoses migraine headaches and prescribes
sumatriptan. What is the mechanism of action of this drug?
A. Dopamine1 agonist
B. GABAB antagonist
C. Muscarinic3 antagonist
D. Non-selective beta antagonist
E. Serotonin1D agonist
Answer
<34>A 60-year-old man presents to his physician after a routine screening
test indicates hyperlipidemia. Physical examination reveals raised,
irregular, yellow papules in the skin of the soft tissues below the eyes.
Biopsy of these lesions would most likely show which of the following?
A. Benign nevus cells
B. Malignant nevus cells
C. Microscopic blisters
D. Munro microabscesses
E. Multinucleated giant cells
Answer
<35> Trisomy 21 Normal karyotype
Positive test 100 50
Negative test 100 250
An experimental diagnostic test is developed to noninvasively detect the
presence of trisomy 21, Down's syndrome. The test is administered to a
group of 500 women considered to be at risk for a Down's fetus based on
blood tests. The results of this test are shown above. What is the
sensitivity of this new test?
A. 40%
B. 50%
C. 67%
D. 71%
E. 83%
Answer
<36>An autopsy is performed on a 60-year-old man who developed
progressive
dementia, parkinsonism, and visual hallucinations beginning 5 years prior
to death. Histopathologic examination reveals numerous eosinophilic
intracytoplasmic inclusions within neurons of substantia nigra, limbic
cortex, and basal nucleus of Meynert. These inclusions are immunoreactive
for ubiquitin. Which of the following is the most likely postmortem
diagnosis?
A. Alzheimer disease
B. Amyotrophic lateral sclerosis (ALS)
C. Diffuse Lewy body disease (dementia with Lewy bodies)
D. Parkinson disease
E. Pick disease
Answer
<37>A 60-year-old factory worker reports to his physician that he can no
longer push heavy boxes across the floor. Upon examination it is noted
that the patient elevates the right shoulder when attempting shoulder
flexion, but shoulder abduction is not impaired. The medial border of
the right scapula is very prominent. Which of the following nerves
innervates the affected muscle?
A. Long thoracic nerve
B. Lower subscapular nerve
C. Musculocutaneous nerve
D. Suprascapular nerve
E. Upper subscapular nerve
Answer
<38>The American Diabetes Association (ADA) recently lowered the cutoff
value for fasting glucose used in diagnosing diabetes mellitus from
140 mg/dL to 126 mg/dL. This reference interval change would be expected
to produce which of the following alterations?
A. Decrease the test's sensitivity
B. Increase the test's false negative rate
C. Increase the test's negative predictive value
D. Increase the test's positive predictive value
E. Increase the test's specificity
Answer
<39>An emergency room physician examines a patient who has fallen from a
motorcycle and injured his shoulder. The clinician notices a loss of the
normal contour of the shoulder and a abnormal-appearing depression below
the acromion. Which of the following injuries did the patient most likely
sustain?
A. Avulsion of the coronoid process
B. Dislocated shoulder joint
C. Fracture of the mid shaft of the humerus
D. Fracture of the surgical neck of the humerus
E. Laceration of the axillary branch of the posterior cord
Answer
<40>A 7-month-old child with failure to thrive is found to have a
hemoglobin
of 4.4 g/dL. The peripheral smear shows very small red cells with marked
pallor. It is determined that the child has very low levels of
hemoglobin A, with elevated fractions of hemoglobin A2 and hemoglobin F.
Which of the following underlying mechanisms is most likely related to
the observed findings?
A. Amino acid substitution on b globin
B. Antibody against fetal blood cells
C. Cytoskeletal protein defect
D. Insufficient production of b globin
E. Iron deficiency
Answer
<41>During a routine pelvic examination, a 20-year-old woman is found to
have an enlarged uterus. Ultrasound studies demonstrate a multiloculated
cystic structure within the uterine cavity, but no baby is identified.
This mass is removed with dilation and curettage of the uterus, and
placental-like tissue is observed during pathologic examination.
Which of the following tumor markers would be most useful in
establishing that residual tumor does not remain in the uterus?
A. b-hCG
B. Bombesin
C. CEA
D. PSA
E. S-100
Answer
<42>On physical examination of a 7-year-old boy, the child's upper body
appears much more developed than his lower body. Blood pressure in the
upper extremities exceeds that of the lower extremities. On cardiac
examination, there is a midsystolic murmur over the anterior chest
and back. The child's lower extremities are cold, and femoral pulses
are absent. The part of the vascular system that is affected in this
disorder is derived from which of the following embryologic
structures?
A. Bulbus cordis
B. Ductus arteriosus
C. Left horn of sinus venosus
D. Right common cardinal vein
E. Right horn of sinus venosus
F. Third, fourth, and sixth aortic arches
Answer
<43>A 42-year-old obese woman experiences episodic abdominal pain.
She notes that the pain increases after the ingestion of a fatty meal.
The action of which of the following hormones is responsible for the
postprandial intensification of her symptoms?
A. Cholecystokinin
B. Gastrin
C. Pepsin
D. Secretin
E. Somatostatin
Answer
<44>A 42-year-old man was in an automobile accident and suffered severe
pelvic trauma. The bulb of the penis and the urethra were torn from the
inferior surface of the urogenital diaphragm. This has allowed urine to
extravasate from the urethra. Into which of the following regions will
the urine flow?
A. Deep perineal space
B. Ischioanal space
C. Rectovesical pouch
D. Retroperitoneal space
E. Superficial perineal space
Answer
<45>Karyotypic analysis of a spontaneously aborted fetus demonstrates
trisomy of one of the chromosomes. Which chromosome is most likely to
be affected?
A. 8
B. 13
C. 16
D. 18
E. 21
Answer
<46>At which of the following locations might a penetrating wound to the
heart damage the AV node?
A. Apex of the heart
B. Interatrial septum
C. Interventricular septum
D. Wall of the right atrium
E. Wall of the left atrium
Answer
<47>A 9-month-old infant is brought to the Health Department to receive
the second dose of OPV (oral polio vaccine) 2 weeks after the first
vaccination. The child has mild diarrhea, so the decision is made to
defer further immunizations. Bacteriologic examination of a stool culture
is unremarkable; however, a small, single-stranded, positive RNA virus is
isolated from the specimen. This same agent was isolated from sewage
effluent the preceding week. The viral isolate was not inactivated by
ether. Which of the following viruses was most likely isolated?
A. Adenovirus
B. Hepatitis C
C. Parvovirus B19
D. Poliovirus
E. Rotavirus
Answer
<48> The photomicrograph shows a section of synovium from the knee joint
of a patient with rheumatoid arthritis (RA). Which of the following are
the most abundant cells in the inflammatory infiltrate?
A. Eosinophils
B. Langhans type giant cells
C. Lymphocytes and plasma cells
D. Neutrophils
E. Type A and B synovial cells
Answer
<49>A 54-year-old African-American female patient undergoes a routine
insurance physical examination. Chest x-ray reveals bilateral hilar
masses. Biopsy of the masses shows granulomata, but acid-fast and
fungal stains are negative for organisms. Which of the following
diseases should be suspected?
A. Caroli's disease
B. Raynaud's disease
C. Sarcoidosis
D. Scleroderma
E. Systemic lupus erythematosus
Answer
<50>A neuroscientist discovers a way to selectively label neural crest
cells in a developing laboratory animal. After birth, he sacrifices the
animal and examines the tissue to search for labeled cells. Which of
the following cell types will contain the label?
A. Astrocytes
B. Ependymal cells
C. Microglia
D. Oligodendroglia
E. Pseudounipolar cells
Answer
Answers
1The correct answer is B. The most specific clue in the description is the
presence of erythematous patches with central clearing, known clinically as
"target lesions," which are associated with erythema multiforme. Both
erythema multiforme and its severe, life-threatening version, known as Stevens-Johnson
syndrome, are produced by immune complex deposition in dermal blood vessels. In
approximately 50% of patients, no specific precipitating cause is identified.
In the remainder of patients, however, a variety of causes have been
implicated, including certain infections (herpes simplex, enteroviruses,
Mycoplasma pneumoniae, Chlamydia, histoplasmosis), drugs (penicillin,
sulfonamides, phenytoin, aspirin, corticosteroids, cimetidine, allopurinol,
oral contraceptives), neoplasia (leukemia, lymphoma, multiple myeloma, internal
malignancy), sarcoidosis, and foods (notably emulsifiers in margarine).
Erythema migrans chronicum (choice A) also produces an annular erythematous
rash with central clearing, but usually affects the thigh, groin, and axilla;
it is associated with Lyme disease.
Kaposi's sarcoma (choice C) causes purple lesions with no target lesions.
Psoriasis (choice D) causes erythematous plaques with silvery scale but does
not produce target lesions.
Urticaria (choice E) causes wheals that are intensely pruritic, but does not
produce target lesions.
--------------------------------------------------------------------------------2The
correct answer is C. Raloxifene is a selective estrogen receptor modulator that
helps prevent osteoporosis by lessening bone resorption and reducing bone
turnover. It lowers risk for vertebral fractures by 40% to 50%. It is a
bone-preserving alternative for women who prefer to avoid estrogen. Raloxifene
does not cause breast pain and may lessen the risk for breast cancer in
menopausal women. There is also a favorable effect on LDL and cholesterol.
Calcitonin nasal spray (choice A) is an osteoclastic bone resorption inhibitor
that modestly increases bone mineral density and reduces the incidence of
vertebral fracture. Although it is an estrogen alternative for bone
preservation, its impact on hip fracture is not known. It is also lacks the
anti-breast cancer properties of raloxifene.
Oral conjugated estrogen (choice B) and transdermal estradiol (choice E) are
not the best choices, as this patient wants to avoid estrogen because of a
strong family history of breast cancer. The route of administration of estrogen
has been shown to have similar effects on bone preservation, even though the
transdermal dosage is generally half that of the oral dosage. Breast cancer
risk, however, is slightly increased with the unopposed higher dosage oral
estrogen replacement.
Tamoxifen (choice D), while indicated in the long-term care of breast cancer
patients, is not alone useful for treatment or prevention of osteoporosis.
Tamoxifen is an anti-estrogen agent that competes with estrogen for binding
sites.
--------------------------------------------------------------------------------3The
correct answer is B. The nerve is the axillary branch of the posterior cord
(also called the axillary nerve), which can be damaged by either fracture or
dislocations of the humeral neck. The muscle is the deltoid muscle, which is
supplied by this nerve. The deltoid arises from the lateral portions of the
clavicle and the acromion and inserts into the deltoid tuberosity of the
humerus.
The deltoid arises from both the acromion (choice A) and the clavicle.
The deltoid does not arise from the coracoid process (choices C, D, and E).
--------------------------------------------------------------------------------4The
correct answer is B. The patient has neurosyphilis, specifically general
paresis, a term that means "general paralysis of the insane." In this
late sequela of syphilitic infection which occurs 5 to 20 years after
infection, patients develop mental deterioration, which precedes motor system
deterioration, leading eventually to "general paralysis" with mutism
and incontinence. The abnormalities may be conveniently recalled using paresis
as a mnemonic for personality, affect, hyperactive reflexes, Argyll Robertson
pupils in the eyes, defects in the sensorium, intellectual decline and
deficient speech. Specific anti-treponemal tests such as FTA-ABS are usually
positive on both serum and cerebrospinal fluid.
The cerebrospinal (CSF) glucose (choice A) in neurosyphilis is usually normal.
Gram's stain (choice C) of CSF will not demonstrate spirochetes in
neurosyphilis.
The CSF lymphocyte count (choice D) is typically elevated in neurosyphilis, but
this is a non-specific finding.
The CSF neutrophil count (choice E) is usually normal in neurosyphilis.
5>The correct answer is A. The man described is probably suffering from
avoidant personality disorder, characterized by feelings of inadequacy and
extreme sensitivity to criticism, leading to social inhibition and withdrawal.
These individuals often avoid interpersonal relationships entirely rather than
subject themselves to the potential risk of criticism or rejection, although
they may yearn for a more satisfying personal life.
Borderline personality disorder (choice B) is characterized by unstable
interpersonal relationships, instability of affect, impulsivity, feelings of
emptiness or anger and, in some cases, paranoid or dissociative symptoms.
Dependent personality disorder (choice C) is characterized by the need for
constant support and reassurance, with unrealistic anxieties over being forced
to fend for oneself.
Narcissistic personality disorder (choice D) is characterized by excessive
grandiosity and an exaggerated sense of self-importance, accompanied by a
feeling of entitlement and a need for attention or admiration.
Schizotypal personality disorder (choice E) is characterized by eccentricities
of behavior, odd beliefs or magical thinking, and difficulties with social and
interpersonal relationships.
--------------------------------------------------------------------------------6The
correct answer is D. Respiratory syncytial virus is the most common cause of
bronchiolitis and pneumonia in children younger than 1 year. Outbreaks occur
seasonally in winter and early spring. Infection does not result in lasting
immunity, and reinfection can occur.
Coronavirus (choice A) causes the common cold (nasal obstruction and discharge,
sneezing, no fever or mild fever, occasional sore throat, and/or cough) and
acute pharyngitis (sore throat, with or without cervical adenopathy,
ulceration, and conjunctivitis).
Influenza type A (choice B) is the leading cause of influenza. Influenza is a
systemic illness characterized by the sudden onset of fever, headache,
myalgias, malaise, and prostration, followed by cough, nasal obstruction, and
sore throat. The lower respiratory tract may also be involved.
Parainfluenza viruses (choice C) are the leading cause of croup, or acute
laryngotracheobronchitis, in children. This infection involves both the upper
and lower respiratory tracts. Inflammation in the subglottal area leads to
hoarseness, dyspnea, a barking cough, and inspiratory stridor.
Rhinovirus (choice E) is the most common cause of the common cold.
--------------------------------------------------------------------------------7The
correct answer is D. Maturation of germ cells (spermatogenesis) within the
seminiferous tubules occurs in a concentric pattern with the less mature
spermatogonia near the basal lamina and the mature forms near the tubule
center. Spermatogonia are 2N cells and mature into larger primary spermatocytes
(4N) (choice A). These mature into secondary spermatocytes (2N) (choice B), and
finally into spermatids (1N) (choice C). Spermatids undergo spermiogenesis to
become mature spermatozoa (choice E). Acrosomes form from the Golgi apparatus
and a flagellum forms from microtubules. Unneeded organelles are shed. The
seminiferous tubules of a reproductive-age male should exhibit all stages of
maturation, with mature flagellated sperm in their centers.
8The correct answer is C. The presentation described is classic for pulmonary
hypertension, and, more specifically, the primary idiopathic form of pulmonary
hypertension. This rare condition is suspected of being related to the collagen
vascular diseases, since up to 50% of patients have antinuclear antibodies
(despite the absence of frank presentation of other autoimmune disease). Also,
a similar, known secondary form of pulmonary hypertension is sometimes seen in
patients with a wide variety of collagen vascular diseases, including systemic
lupus erythematosus, polymyositis, dermatomyositis, systemic sclerosis, and
adult and juvenile forms of rheumatoid arthritis. A wide variety of other
conditions have also been associated with secondary pulmonary hypertension,
including shunts, left atrial hypertension, chronic hypoxia, pulmonary
embolism, drug reaction, hepatic cirrhosis, and sickle cell disease. Both
primary and secondary forms of pulmonary hypertension are associated with
prominent changes in the pulmonary vasculature, which can include
muscularization of smaller arterioles, concentric hypertrophy of the intima
("onion skinning"), and a distinctive plexiform lesion (plexogenic
pulmonary vasculopathy) in which the smallest arterioles become markedly
dilated with lumens partially occluded by endothelial (or possibly mesenchymal)
cells and sometimes, thrombus. The prognosis of untreated pulmonary
hypertension is poor. However, the use of the vasodilator hydralazine with
anticoagulation can slow the course (fatal in about 3 years in untreated
patients). If the pulmonary hypertension is secondary, therapy of the primary
disease can be helpful.
Unlike cor pulmonale, atrial fibrillation with mural thrombus (choice A)
formation is uncommon in primary pulmonary hypertension.
The absence of left ventricular findings on echocardiography tends to exclude
myocardial infarction as the source of the patient's findings (choice B).
The presence of enlargement of the main pulmonary artery excludes pulmonary
artery stenosis (choice D).
The clear lung fields exclude severe pulmonary fibrosis (choice E).
--------------------------------------------------------------------------------9The
correct answer is B. The ureter leaves the renal pelvis and lies on the
posterior abdominal wall as it descends to the pelvis. It crosses the pelvic
brim at the level of the bifurcation of the common iliac artery. At this point
it crosses anterior to the origin of the external iliac artery to enter the
pelvis.
The origin of the common iliac artery (choice A) is at the bifurcation of the
abdominal aorta, which occurs at the level of the fourth lumbar vertebra in the
midline of the abdomen. Both ureters are lateral to the aortic bifurcation.
The origin of the internal iliac artery (choice C) is at the bifurcation of the
common iliac artery, which occurs at about the level of the first sacral
vertebra. The ureter and the internal iliac artery both enter the pelvis with
the ureter on the lateral side of the artery.
The origin of the gonadal artery (choice D) (either the testicular artery or
the ovarian artery) is from the abdominal aorta at a variable level, usually
between the renal artery and the inferior mesenteric artery. The ureters are
lateral to the origin of this artery.
The origin of the renal artery (choice E) is from the abdominal aorta at about
the level of the second lumbar vertebra. The renal arteries pass laterally to
enter the renal pelvis. At this site, the ureter is posterior to the artery.
--------------------------------------------------------------------------------10The
correct answer is D. This is an example of relative polycythemia, in which
there is an increased hematocrit or RBC count without a true increase in the
total number of body RBCs. What usually happens in these cases is a significant
reduction in plasma volume due to processes such as dehydration, vomiting,
diarrhea, or diuresis.
Cyanotic heart disease (choice A), via appropriate erythropoietin secretion,
can cause secondary absolute polycythemia.
Increased erythropoietin (choice B), whether appropriately or inappropriately
secreted, can cause secondary absolute polycythemia.
Polycythemia vera (choice C) causes primary absolute polycythemia with usually
low erythropoietin levels.
Renal cell carcinoma (choice E), via inappropriate erythropoietin secretion,
can cause secondary absolute polycythemia.
--------------------------------------------------------------------------------11The
correct answer is E. Hypospadias, which is congenital displacement of the
urethral opening onto the ventral surface (underside) of the penis, is due to
malformation of the urethral groove and canal. Hypospadias frequently
accompanies other genitourinary anomalies, especially cryptorchidism. Isolated
hypospadias is repaired because the abnormal opening is often constricted,
leading to urinary retention and ascending urinary tract infections. Another
important consequence of hypospadias is sterility, which occurs if the opening
is too close to the base of the penis to permit normal ejaculation. Although
hypospadias can occur in isolation, it is strongly associated with other
urogenital anomalies.
Bladder exstrophy (choice A) is a completely unrelated congenital malformation
in which the abdominal wall and anterior bladder wall form incompletely, and
the bladder mucosa is exposed to the environment.
Hydrocele (choice B) is a serous accumulation in the tunica vaginalis, often
producing a readily apparent scrotal mass. Hydrocele usually arises without any
obvious cause.
Phimosis (choice C) is the condition in which the foreskin cannot be retracted
over the head of the penis. It is usually either a congenital malformation or a
consequence of scarring.
Urachal cysts (choice D) are produced by areas of persistent urachal
epithelium, which may be present anywhere between the bladder and the
umbilicus.
--------------------------------------------------------------------------------12The
correct answer is E. Von Willebrand factor (vWF) is a self-polymerizing
clotting protein present in the serum and the subendothelial basal lamina,
which has binding sites for collagen, platelets, and fibrin. At a site of
injury, vWF forms the bridge between the exposed collagen fibers and platelets
in circulation, stimulating platelet degranulation and initiating the cellular
component of the clotting cascade. An equally important role for vWF is binding
platelets to the newly formed fibrin strands in a blood clot.
Factor VIII (choice A) and Factor IX (choice B) are clotting proteins of the
intrinsic pathway. Factor VIII acts in concert with activated Factor IX (IXa)
to cleave Factor X to Xa. Xa is the prothrombin activator central to both the
intrinsic and extrinsic pathways.
Fibronectin (choice C) is a serum protein that acts as an opsonin for
phagocytic cells in clots. Fibronectin binds non-specifically to bacteria and
other materials in the newly forming clots, and draws the cell membrane of
phagocytes into contact with these substances.
Tissue factor (choice D) is a protein released from injured tissues that works
in concert with Factor VII to initiate the extrinsic pathway of coagulation.
Like Factors VIII and IX, tissue factor and Factor VII cleave Factor X to Xa.
--------------------------------------------------------------------------------13The
correct answer is D. The patient is most likely experiencing a potentiation of
the effects of warfarin by norfloxacin, which decreases the metabolism of the
warfarin. The increased warfarin effect produces an increase in the INR. (The
target INR for patients with prosthetic heart valves is usually 1.5-4,
depending on the type of valve.) Although norfloxacin is the most likely drug
among the choices given to cause this effect in this patient, the antibiotics
most commonly associated with this type of interaction are the macrolides, such
as erythromycin, metronidazole, and the sulfonamide antibiotics.
Oral doses of penicillins, such as ampicillin (choice A), are generally not
associated with a potentiation of warfarin's effect, although large IV doses of
penicillin may be.
Cephalexin (choice B) is a first-generation cephalosporin that can be used in
the treatment of acute cystitis. Although this agent is generally not
associated with an increased hypoprothrombinemic effect when given with
warfarin, the cephalosporins with a methyltetrazolethiol side chain, such as
cefazolin, cefmetazole, and cefoperazone, are known to increase warfarin's
therapeutic effect.
Nitrofurantoin (choice C) is a urinary anti-infective agent that does not
interact with warfarin.
Phenazopyridine (choice E) is a urinary tract analgesic that does not interact
with warfarin, although it commonly changes the color of urine to a bright
orange/red color, which the patient may mistake as blood in the urine.
--------------------------------------------------------------------------------14The
correct answer is D. Propylthiouracil works primarily by inhibiting the
peripheral conversion of T4 to T3. The thyroid extracts iodide from the plasma
and, in an oxidative process, iodinates tyrosine residues in thyroglobulin
molecules. Monoiodotyrosines and diiodotyrosines are formed and then coupled to
produce either thyroxine (tetraiodothyronine, T4) or triiodothyronine (T3).
Proteolytic cleavage of thyroglobulin molecules leads to free T3 or T4, which
is then released into the circulation; T3 is several times more potent than T4.
Peripheral deiodination of T4 at the 5' position leads to T3 formation (mainly
in the liver); this step is inhibited by propylthiouracil.
Decreasing the efficacy of TSH binding (choice A), decreasing the rate of
thyroglobulin proteolysis (choice B), increasing the amount of rT3 formation
(choice C), and inhibiting the uptake of iodide into the thyroid (choice E),
would all tend to decrease the formation of thyroid hormones in the thyroid
itself.
--------------------------------------------------------------------------------15The
correct answer is A. Acetylcholine is the neurotransmitter of primary
importance for the induction of REM sleep. Some of the other neurotransmitters
do function in sleep, but REM sleep can occur in their absence.
Dopamine (choice B) is a neurotransmitter with a role in voluntary movement,
mood, cognition, and regulation of prolactin release.
Epinephrine (choice C) is important in sympathetic nervous system responses. It
is also a CNS neurotransmitter.
Norepinephrine (choice D) is important in sympathetic nervous system responses.
It is also a CNS neurotransmitter involved in attention, arousal, and mood.
Serotonin (choice E) is a CNS neurotransmitter that plays an important role in
mood and sensation. In the periphery, it is involved in vascular regulation and
digestive function.
--------------------------------------------------------------------------------16The
correct answer is E. This is a case of Neisseria gonorrhoeae arthritis.
Patients are continuously susceptible to reinfection because of antigenic
variation and phase variation of the pili.
N. gonorrhoeae is not an intracellular pathogen (choice A), although it may be
found intracellularly in neutrophils after it has been phagocytized.
Ceftriaxone (choice B) is the drug of choice for N. gonorrhoeae.
Gonococci are especially susceptible to complement-mediated lysis, not
resistant to it (choice C).
N. gonorrhoeae has an insignificant capsule that does not play a major role in
the pathogenesis, but its capsule is immunogenic (compare with choice D).
Streptococcus pyogenes is the best known example of a nonimmunogenic capsule,
made of hyaluronic acid, but virtually all other capsules are immunogenic.
--------------------------------------------------------------------------------17The
correct answer is E. Specificity is the proportion of persons without the
disease who are correctly identified by the test as being disease-free. It is
given by TN/(FP + TN), where TN stands for true negatives (people who do not
have the disease and test negative on the test) and FP stands for false
positives (people who do not have the disease but test positive on the test).
In this case, 95/(5 + 95) = 95/100 = 0.95.
--------------------------------------------------------------------------------18The
correct answer is B. 2,3-diphosphoglycerate (2,3-DPG) is produced in red cells
by a variation on the glycolytic pathway, and levels diminish when glycolysis
by the red cells slows. The depletion of 2,3-DPG in stored blood causes the
hemoglobin dissociation curve to shift to the left, leading to an increase in
oxygen affinity. This increase is helpful in the picking up of oxygen by
hemoglobin in the lungs, but can be very problematic in the release of oxygen
from the blood in tissues. This is not just a theoretical point: considerable
effort has been expended in developing improved solutions for storing packed
red cells and methods for "restoring" older stored cells so that the
2,3-DPG levels are adequate. In practice, in otherwise reasonably healthy
patients, older transfused blood will quickly regenerate 2,3-DPG when placed in
the glucose-containing environment of the serum, but even transiently decreased
2,3-DPG levels in a severely compromised patient can be dangerous.
--------------------------------------------------------------------------------19The
correct answer is C. Entamoeba are relatively common enteric pathogens that can
produce asymptomatic infection or more severe disease characterized by mucosal
ulcerations and submucosal spread causing abdominal distress and liquid stools.
Stools may show either trophozoite forms or the typical spherical cysts.
Several species of Entamoeba are seen, including Entamoeba coli and E.
hartmanni. E. histolytica cysts characteristically are spherical in shape,
10-20 mm in diameter, and have granular cytoplasm containing 1, 2, or 4 nuclei.
Cryptosporidium parvum (choice A) infections occur in the immunocompromised
population and may cause severe diarrhea. The organism presents as minute (2-5
mm) intracellular spheres or arc-shaped merozoites under normal mucosa, and can
be difficult to appreciate by light microscopy. Cysts in the stool are too
small (4-5 mm) to be confused with Entamoeba.
Dientamoeba fragilis (choice B) is an intestinal amoeba that also may produce
an infectious diarrhea. It does not have a cyst form, and only the trophozoite
forms are seen in stools.
Giardia lamblia (choice D) is a flagellate protozoan that infects the stomach
and small intestine when contaminated water is ingested. Diagnosis is usually
made by examining duodenal contents; however, the stools may contain the oval
or elliptical cysts, which are thick-walled and measure 8-14 mm in diameter.
Spherical cysts are not seen in Giardia infection.
Isospora belli (choice E) produces self-limited intestinal infections mostly in
the tropics, where fever and diarrhea may last weeks to months. The stool-borne
cysts are much larger than Entamoeba (30 x 15 mm), are asymetrical, and are
typically almond-shaped.
--------------------------------------------------------------------------------20The
correct answer is A. The concrete operational stage (age 7-11 years) is defined
by the child's awareness of the conservation of volume, which demonstrates that
the child is able to reason in a logical way in terms of the physical world.
Note that the child does not develop understanding of abstract concepts until
he or she has reached the formal operational stage (choice B), at age 11 to
adulthood.
The preoperational stage (choice C), ages 2 to 7 years, is associated with
significant language development. However, the child has not yet developed the
ability to take the perspective of others, and thus the child's thinking tends
to remain egocentric.
The sensorimotor stage (choice D) corresponds to ages 0 to 2 years and is
characterized by the infant developing increasingly sophisticated sensorimotor
skills and behavior patterns.
--------------------------------------------------------------------------------21The
correct answer is B. The reference intervals for serum alkaline phosphatase
(ALP) and serum phosphate are higher in children than in adults. Growing bone
in children requires alkaline phosphatase secreted by osteoblasts and an
increase in serum phosphate to provide a proper solubility product ([calcium] x
[phosphorus]) for mineralization of bone. However, the normal serum ALP in
children is no greater than 5-times the upper limit of normal for adults, hence
this patient's ALP is abnormally elevated. The most likely scenario is that the
child is a victim of abuse and has suffered a femoral fracture that is healing.
Bone repair further increases the serum ALP owing to the increase in
osteoblastic activity.
Aseptic necrosis of bone in the leg (choice A) is more likely to occur in the
femoral head (Legg-Calve-Perthes disease). This disease is more common in boys
than girls and occurs in the 3- to 10-year-old age bracket. Although aseptic
necrosis is associated with dense bone formation, it does not extend out into
the soft tissue nor would it produce skin discoloration directly over the
lesion (due to trauma in this case).
Since the elevation in serum ALP is increased for age and related to the bone
lesion, choice C is incorrect.
Since the serum ALP is not normal for the age of this patient, choices D and E
are incorrect. Furthermore, osteogenic sarcoma (choice D) does not normally
occur in the first decade and favors the metaphysis of the distal femur or
proximal tibia
--------------------------------------------------------------------------------22The
correct answer is C. Norepinephrine (NE) is an agonist at alpha1-, alpha2- and
beta1-receptors. NE exerts its vascular actions via alpha (predominantly
alpha1) receptors and its cardiac actions via beta1-receptors. Labetalol is a
nonselective antagonist at alpha- and beta-receptors, and therefore, could
prevent all actions of NE.
Atenolol (choice A) is a selective beta1 antagonist, and therefore would block
only norepinephrine's cardiac effects.
Esmolol (choice B) is a selective beta1 antagonist, and therefore would block
only norepinephrine's cardiac effects. Metaproterenol (choice D) is a selective
beta2 agonist and so would not block NE's effects.
Prazosin (choice E) is a selective alpha1 antagonist and would therefore block
most of norepinephrine's actions in the vasculature, but would not antagonize
other effects.
--------------------------------------------------------------------------------23The
correct answer is C. The pudendal nerve is a branch of the sacral plexus that
exits from the greater sciatic foramen and then enters the lesser sciatic
foramen to lie in the pudendal canal on the lateral wall of the ischioanal
fossa. The inferior rectal nerve is a branch of the pudendal nerve, which
crosses the ischioanal fossa to reach the anal canal where it innervates the
external anal sphincter and provides sensory innervation to the area.
The inferior gluteal nerve (choice A), a branch of the sacral plexus, exits
through the greater sciatic foramen and innervates the gluteus maximus muscle.
The pelvic splanchnic nerves (choice B) are branches of the second, third, and
fourth sacral nerves that carry preganglionic parasympathetic nerves to several
pelvic organs.
The sciatic nerve (choice D) is a branch of the lumbosacral plexus that exits
through the greater sciatic foramen, then enters the lower limb to innervate
muscles of the posterior thigh, the leg, and the foot, and provides sensory
innervation to the area as well.
The superior gluteal nerve (choice E) is a branch of the sacral plexus that
exits through the greater sciatic foramen and innervates the gluteus medius,
gluteus minimus, and tensor fascia latae muscles.
--------------------------------------------------------------------------------24The
correct answer is A. The girl has Turner syndrome, which is specifically
associated with coarctation of the aorta. Even when coarctation has not been
diagnosed in early childhood and the patient appears to be doing well, surgical
correction of any significant degree of coarctation is recommended. Uncorrected
coarctation can cause death after about age 40 due to a variety of causes,
including congestive heart failure, infective aortitis (analogous to infective
endocarditis), and hypertension-induced intracranial hemorrhage or rupture of
the damaged (pre-coarctation) aorta.
Associate dextrocardia (choice B) with Kartagener syndrome.
Associate ostium primum septal defect (choice C) with Down syndrome.
Pulmonary stenosis (choice D) and tetralogy of Fallot (choice E) are not
specifically associated with Turner syndrome.
--------------------------------------------------------------------------------25The
correct answer is A. The malignant tumor is a yolk sac tumor, also known as
infantile embryonal carcinoma and endodermal sinus tumor. The biggest tip-off
in the question stem is the presence of endodermal sinuses that resemble
primitive glomeruli. The cytoplasmic globules described contain alpha-fetoprotein,
indicating yolk cell differentiation, and alpha-1-antitrypsin.
Alpha-fetoprotein can also be used as a serum marker for recurrent disease.
Yolk sac tumors occur in pure form in infants and children and may be part of
mixed tumors in adults.
Estrogen receptors (choice B) are important markers in breast cancer because
they predict tumor response to hormonal manipulation.
Human chorionic gonadotropin (choice C) is found in the syncytial cells of
embryonal carcinoma.
Human papilloma virus (choice D) can be found in condylomas, cervical cancer,
penile cancer, laryngeal polyps, and warts.
Melanin (choice E) can be found in melanomas.
--------------------------------------------------------------------------------26The
correct answer is D. The splenorenal ligament is the portion of the dorsal
mesentery between the posterior abdominal wall and the spleen. This mesentery
transmits the splenic artery and vein from their retroperitoneal position in
the proximal portion of their course to the peritoneal spleen.
The gastrocolic ligament (choice A) is the portion of the greater omentum
between the greater curvature of the stomach and the transverse colon. This
portion of mesentery is not related to the spleen.
The gastrosplenic ligament (choice B) is the portion of the dorsal mesogastrium
between the greater curvature of the stomach and the spleen. There are no
splenic vessels in this mesentery.
The lesser omentum (choice C) is derived from the ventral mesentery. It is the
mesentery between the lesser curvature of the stomach and the liver and between
the first portion of the duodenum and the liver. It is not related to the
spleen.
--------------------------------------------------------------------------------27The
correct answer is D. This is one of those questions for which having a good
idea of what you are looking for before exploring the answer choices will
certainly save you valuable time. The answers all look alike and you could have
been easily confused if you were not confident of the answer before approaching
the choices.
This patient has long-standing hyperparathyroidism (elevated PTH), which
predisposes to the development of osteitis fibrosa, her bone disease. PTH acts
initially on osteocytes of bone tissue (osteocytic osteolysis) and subsequently
on osteoclasts (osteoclastic resorption) to resorb calcium from bone matrix and
make it available to the circulation. This increases plasma calcium levels. PTH
also causes decreased phosphate reabsorption in the proximal renal tubule,
yielding hypophosphatemia. Hypercalciuria is another sequela of excess PTH
production, which predisposes the patient to the formation of calcium oxalate
stones.
Choices A and E correspond to neither hyper- nor hypoparathyroid states.
Choice B is the profile of hypoparathyroidism. You should have quickly
eliminated this choice since the PTH was decreased and you were looking for a
profile consistent with HYPERparathyroidism.
Choice C is the profile of secondary hyperparathyroidism. This occurs when
there is parathyroid overproduction due to a nonparathyroid cause. By far, the
most common cause is chronic renal failure. In such cases, there is decreased
calcium absorption since the kidneys are involved in the conversion of 25(OH)D3
to the active form 1,25(OH)D3. The decreased calcium ion level stimulates the
parathyroid, leading to elevated PTH levels. Hyperphosphatemia results from
diminished renal synthesis of 1,25 dihydroxyvitamin D3, creating further
calcium-phosphate imbalance and enhanced PTH production.
--------------------------------------------------------------------------------28The
correct answer is D. The processus vaginalis is an evagination of the parietal
peritoneum of the abdomen that descends through the inguinal canal before the
descent of the testis. Normally, the distal end of this evagination remains
patent as the tunica vaginalis and the remainder of the processus vaginalis
fuses and becomes fibrous. If a part of the processus vaginalis does not fuse
(incomplete fusion), the resulting cystic structure is a hydrocele of the
spermatic cord.
A communication between the epididymis and the tunica vaginalis (choice A) will
result in the passage of sperm into the epididymis. This is a spermatocele.
Failure of the processus vaginalis to form (choice B) would result in an
absence of the tunica vaginalis.
Total failure of the proc