A 36-year-old man presents
to his physician complaining of right scrotal swelling. He states that the
swelling has been present for 1 week. He
initially noticed the
swelling shortly after moving furniture for his new living room. He denies any
nausea, vomiting, change in bowel habits,
abdominal pain, or urinary
tract symptoms. He has no other significant medical or surgical history. On
examination, he has an enlarged right
hemi-scrotum with a mass
that appears to be originating at the level of the external inguinal ring. With
the patient completely relaxed, the
physician is able to
reduce the mass by pushing it back through the external inguinal ring. With the
mass reduced, the physician instructs the
patient to perform a
Valsalva maneuver, upon which a protrusion is felt at the external inguinal
ring. Once the mass is reduced, the testicle
appears normal in size and
consistency.
Question
1 of 4
Which of the following is
the most likely diagnosis?
/ A. Hydrocele
/ B. Femoral hernia
/ C. Inguinal hernia
/ D. Testicular cancer
/ E. Varicocele
|
Explanation - Q: 1.1
|
|
The correct answer is C. This patient has a
reducible inguinal hernia. A hernia is a protrusion of a structure, usually
intestine, through tissue that normally contains it. Inguinal hernias are
either direct or indirect. Indirect inguinal hernias occur through the
internal inguinal ring in a protrusion of peritoneum along the spermatic cord
in the internal spermatic fascia. Direct inguinal hernias occur through the
floor of the inguinal canal, separate from the spermatic cord as a result of
breakdown of the transversus abdominis aponeurosis and transversalis fascia.
If the mass, i.e., hernia, is easily returned back to its normal position,
then it is called reducible. If the mass is not reducible, then this is
called incarcerated. And, if the mass becomes incarcerated and develops
compromised blood supply, it is termed strangulated. Strangulated hernias
require emergent repair because the intestinal contents will necrose and
cause the patient to become sick. As long as the mass is reducible, surgical
repair can be performed on an outpatient basis.
A hydrocele (choice A) is a fluid collection
contained within the tunica vaginalis that surrounds the testicle. It
presents as a painless swelling of the scrotum, which transilluminates light
when it is placed against the mass. A hydrocele cannot be reduced.
Femoral hernias (choice B) are more common in
women, presenting as swellings in the upper part of the thigh. The neck of
the hernia sac lies at the femoral ring, below and lateral to the pubic
tubercle, distinguishing these from inguinal hernias, which are above and
medial to the tubercle.
A mass caused by testicular cancer (choice D)
cannot be reduced either. Patients will complain of a dull, heavy, aching
feeling within the testicle. The testicle itself is usually enlarged, hard,
irregular, and nontender.
A varicocele(choice E) is caused by dilatation of
the pampiniform venous plexus of the spermatic cord. It is typically
described as feeling like "a bag of worms" on physical examination.
The dilatation is more easily appreciated with the patient standing or during
the Valsalva maneuver.
|
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of klepting technologies ***
A 36-year-old man presents
to his physician complaining of right scrotal swelling. He states that the
swelling has been present for 1 week. He
initially noticed the
swelling shortly after moving furniture for his new living room. He denies any
nausea, vomiting, change in bowel habits,
abdominal pain, or urinary
tract symptoms. He has no other significant medical or surgical history. On
examination, he has an enlarged right
hemi-scrotum with a mass
that appears to be originating at the level of the external inguinal ring. With
the patient completely relaxed, the
physician is able to
reduce the mass by pushing it back through the external inguinal ring. With the
mass reduced, the physician instructs the
patient to perform a
Valsalva maneuver, upon which a protrusion is felt at the external inguinal
ring. Once the mass is reduced, the testicle
appears normal in size and
consistency.
Question
2 of 4
Which of the following
nerves travels along the spermatic cord within the inguinal canal and may be
damaged during a surgical procedure to
correct this patient's
condition?
/ A. IIiohypogastric
/ B. IIioinguinal
/ C. Lateral femoral cutaneous
/ D. Obturator
/ E. Pudendal
|
Explanation - Q: 1.2
|
|
The correct answer is B. Although it is now
possible to perform inguinal hernia repairs laparoscopically, the traditional
approach is through an incision over the inguinal canal. At the time of
surgery, the inguinal canal is opened via sharp dissection through the
external oblique aponeurosis (the anterior wall of the inguinal canal). The
ilioinguinal nerve is then encountered as it runs on the anterior aspect of
the spermatic cord. If not properly identified at time of surgery it is
possible to transect the ilioinguinal nerve or to "trap" it during
closure. If the ilioinguinal nerve is transected or entrapped in closure, the
patient will complain of numbness over the nerve's distribution, i.e., the
upper medial aspect of the thigh and the anterior portion of the scrotum on
the affected side.
The iliohypogastric, lateral femoral cutaneous,
obturator, and pudendal nerves are not encountered during traditional
inguinal hernia repair.
The iliohypogastric nerve(choice A) is derived
from L1 (as is the ilioinguinal nerve) and runs with the ilioinguinal nerve
as they both pierce the transversus abdominis muscle near the anterior
superior iliac spine. They then pass through the internal and external
oblique muscles to supply the skin of the suprapubic and inguinal regions and
the abdominal musculature. The iliohypogastric sends a lateral branch to the
skin of the gluteal region and then continues on, to pass through the
superficial inguinal ring.
The lateral femoral cutaneous nerve (choice C)
originates from L2 and L3 and is a direct branch of the lumbar plexus. It
enters the thigh deep to the lateral end of the inguinal ligament near the
anterior superior iliac spine and supplies the skin on the anterior and
lateral aspects of the thigh.
The obturator nerve(choice D) is the nerve of
the adductor muscles of the thigh. It arises from the lumbar plexus (L2, L3,
L4), enters the pelvis minor, and then leaves the pelvis via the obturator
foramen. The obturator nerve also sends a small cutaneous branch to the
medial aspect of the mid thigh.
The pudendal nerve (choice E) arises from the
sacral plexus (S2, S3, S4), accompanies the internal pudendal artery, and
leaves the pelvis between the piriformis and coccygeus muscles. The nerve
hooks around the sacrospinous ligament to enter the perineum through the
lesser sciatic foramen to supply the muscles of the perineum, including the
external anal sphincter, and then ends as the dorsal nerve of the penis or
clitoris. It also supplies some sensation to the external genitalia
|
A 36-year-old man presents
to his physician complaining of right scrotal swelling. He states that the
swelling has been present for 1 week. He
initially noticed the
swelling shortly after moving furniture for his new living room. He denies any
nausea, vomiting, change in bowel habits,
abdominal pain, or urinary
tract symptoms. He has no other significant medical or surgical history. On
examination, he has an enlarged right
hemi-scrotum with a mass
that appears to be originating at the level of the external inguinal ring. With
the patient completely relaxed, the
physician is able to
reduce the mass by pushing it back through the external inguinal ring. With the
mass reduced, the physician instructs the
patient to perform a
Valsalva maneuver, upon which a protrusion is felt at the external inguinal
ring. Once the mass is reduced, the testicle
appears normal in size and
consistency.
Question
3 of 4
If a segment of terminal
ileum becomes strangulated as a consequence of his condition, it may become
infarcted and necrotic due to
occlusion of a branch of
which of the following vessels?
/ A. Celiac trunk
/ B. Inferior mesenteric artery
/ C. Middle colic artery
/ D. Right colic artery
/ E. Superior mesenteric artery
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|
Explanation - Q: 1.3
|
|
The correct answer is E. The small bowel is a
derivative of the midgut and therefore receives its blood supply from the
superior mesenteric artery. This artery emerges from the aorta 1 cm below the
celiac trunk and passes ventral to the left renal vein to give off 12 to 15
jejunal and ileal arteries. As these arteries divide, they join with an adjacent
branch to form arches. These arches may then communicate to form an arcade.
Straight arteries also emerge from these arches to supply the bowel. Although
there are variants, the ileal artery is usually a branch of the superior
mesenteric artery, which supplies a branch to the terminal ileum.
The celiac trunk (choice A) provides branches to
supply the stomach, liver, pancreas, and duodenum. It is not responsible for
supplying blood to the terminal ileum.
The inferior mesenteric artery (choice B)
provides branches that supply a limited part of the transverse colon near the
splenic flexure and the descending and sigmoid colon.
The middle colic artery (choice C) is a branch
of the superior mesenteric artery. There are two branches, right and left.
The right branch supplies the right half of the transverse colon and the left
branch supplies the left half of the transverse colon.
The right colic artery (choice D) is also a
branch of the superior mesenteric artery. It is responsible for supplying the
hepatic flexure as well as that part of the ascending colon not supplied by
the ileocolic artery.
|
A 36-year-old man presents
to his physician complaining of right scrotal swelling. He states that the
swelling has been present for 1 week. He
initially noticed the
swelling shortly after moving furniture for his new living room. He denies any
nausea, vomiting, change in bowel habits,
abdominal pain, or urinary
tract symptoms. He has no other significant medical or surgical history. On
examination, he has an enlarged right
hemi-scrotum with a mass
that appears to be originating at the level of the external inguinal ring. With
the patient completely relaxed, the
physician is able to
reduce the mass by pushing it back through the external inguinal ring. With the
mass reduced, the physician instructs the
patient to perform a
Valsalva maneuver, upon which a protrusion is felt at the external inguinal
ring. Once the mass is reduced, the testicle
appears normal in size and
consistency.
Question
4 of 4
Which of the following pathological
processes might cause the patient's underlying condition to occur in an infant?
/ A. Defect in the floor of the inguinal canal
/ B. Defect in the internal inguinal ring
/ C. Defect in the linea semilunaris
/ D. Patent processus vaginalis
/ E. Persistent lumen of the tunica vaginalis
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our users? ***
|
Explanation - Q: 1.4
|
|
The correct answer is D. The pathologic process
that causes hernias is different in neonates and infants than in an adult.
Embryologically, in the seventh week, the testes begin descending from their
location at the 10th thoracic level into the scrotum. After the eighth week,
a peritoneal evagination called the processus vaginalis forms just anterior
to the gubernaculum. The gubernaculum is a condensation of peritoneum that
attaches superiorly to the gonad and inferiorly to the fascia that is
developing between the external and internal oblique muscles in the region of
the labioscrotal swellings. The processus vaginalis pushes out as a
"sock-like" extension into the transversalis fascia, the internal
oblique muscle, and the external oblique muscle, thus forming the inguinal
canal. After the processus vaginalis has evaginated into the scrotum, the gubernacula
shorten and simply pull the gonads through the canal. Within the first year
after birth, the superior portion of the processus vaginalis is usually
obliterated, leaving only a distal remnant sac, the tunica vaginalis, which
lies anterior to the testis. During infancy, this sac wraps around most of
the testis. Its lumen is normally collapsed, but under pathologic conditions
it may fill with serous secretions, forming a testicular hydrocele (choice
E). If the processus vaginalis remains patent, a connection between the
abdominal cavity and scrotal sac will occur. Loops of intestine may herniate
into this processus, resulting in an indirect inguinal hernia.
In adults, hernias are caused by a protrusion of a
structure, usually intestine, through a tissue that normally contains it.
Direct inguinal hernias occur through the floor of the inguinal canal
separate from the spermatic cord (choice A). Direct inguinal hernias
occur because of a breakdown of the transversus abdominis aponeurosis and
transversalis fascia.
An indirect inguinal hernia occurs through the internal
inguinal ring in a protrusion of peritoneum along the spermatic cord in the
internal spermatic fascia. Therefore, a large indirect inguinal hernia will
descend into the scrotum along the spermatic cord (choice B).
Spigelian hernias are rare and occur due to a weakness
in the linea semilunaris (choice C), which is located at the lateral
margin of the rectus sheath.
|
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A 2-year-old child is seen
for a welI-child visit in a pediatric clinic. Abdominal examination
demonstrates a palpable, non-tender mass on the
Ieft side of the abdomen.
The mother had no idea the mass was present and the pediatrician did not note
the presence of the mass at the
child's 18-month
welI-child visit. Physical examination is otherwise unremarkable.
Question
1 of 5
CT examination
demonstrates an 8-cm diameter, roughly round, mass involving the lower pole of
the kidney. Which of the following is the
most likely cause of this
mass?
/ A. Ewing sarcoma
/ B. Neuroblastoma
/ C. Renal cell carcinoma
/ D. Transitional cell carcinoma
/ E. Wilms tumor
|
Explanation - Q: 2.1
|
|
The correct answer is E. Wilms tumor is an embryonal
malignancy of the kidney that most commonly affects children from birth to
age 4, but can affect children up to about age 15. This tumor is the second
most common extracranial solid tumor in children and tends to form large,
round, solitary masses of the kidney, although bilaterality and
multicentricity may also occur. Wilms tumors usually present with a palpable
abdominal mass, with less common presentations including abdominal pain,
hematuria (indicating invasion of the collecting system), hypertension,
fever, nausea, and vomiting.
Neuroblastoma (choice B) may also effect very
young children, and typically arises in the adrenal gland. Extensions into
the kidney can occur, but usually involve the upper pole first.
Renal cell carcinoma (choice C) and transitional
cell carcinoma (choice D) would be much more likely to involve the
kidney of an adult.
|
A 2-year-old child is seen
for a welI-child visit in a pediatric clinic. Abdominal examination
demonstrates a palpable, non-tender mass on the
Ieft side of the abdomen.
The mother had no idea the mass was present and the pediatrician did not note
the presence of the mass at the
child's 18-month welI-child
visit. Physical examination is otherwise unremarkable.
Question
2 of 5
If a CT guided biopsy of
the mass were performed, which of the following histological patterns would be
most suggestive of the likely
diagnosis?
/ A. Cords of clear cells with rounded or polygonal shape and
abundant clear cytoplasm
/ B. Invasive papillary lesions with delicate connective tissue
stalk covered with epithelium resembling that lining the bladder
/ C. Small dark cells embedded in a finely fibrillar matrix with
formation of numerous rosettes
/ D. Triphasic pattern with tubule formation, spindle cells, and
blastemal elements
/ E. Uniform sheets of small round cells with scanty cytoplasm
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Kleptomania, send trial ***
|
Explanation - Q: 2.2
|
|
The correct answer is D. Adequate sampling of
most Wilms tumors will detect the three distinct growth patterns that are
most characteristic of this tumor: less cellular tumor areas containing
spindle cells; densely cellular (blastemal) areas with closely packed small
cells with scanty cytoplasm and darkly blue nuclei; and areas with production
of more mature-appearing epithelium that may form occasional tubules. The
tissues present are similar to those present in the developing kidney, and
may also include primitive glomeruli. Wilms tumors may additionally contain
heterologous elements, such as skeletal muscle, smooth muscle, squamous or
mucinous epithelium, adipose tissue, cartilage, bone, or neural tissue.
Choice A suggests renal cell carcinoma.
Choice B suggests transitional cell carcinoma.
Choice C suggests neuroblastoma.
Choice E suggests
|
*** Copy messages from the dialog boxes ***
A 2-year-old child is seen
for a welI-child visit in a pediatric clinic. Abdominal examination
demonstrates a palpable, non-tender mass on the
Ieft side of the abdomen.
The mother had no idea the mass was present and the pediatrician did not note
the presence of the mass at the
child's 18-month
welI-child visit. Physical examination is otherwise unremarkable.
Question
4 of 5
Sometimes this child's
disease occurs in association with certain congenital anomalies. Children with
which of the following abnormalities at
birth should be monitored
for the development of this disease?
/ A. Aniridia
/ B. Coarctation of the aorta
/ C. Cystic hygroma
/ D. Parathyroid hyperplasia
/ E. Simian crease
|
Explanation - Q: 2.4
|
|
The correct answer is A. The WAGR syndrome
includes Wilms tumor, aniridia (lack or defect of the iris), genital
anomalies (gonadal dysgenesis, hypospadias, cryptorchidism, or other
genitourinary anomalies), and mental retardation. Wilms tumor can also occur
as part of the Beckwith-Wiedemann syndrome with hemihypertrophy, and the
Drash syndrome with nephropathy and ambiguous genitalia.
Coarctation of the aorta (choice B) and cystic
hygroma (choice C) are associated with Turner syndrome, which may
predispose for later development of ovarian cancer.
Parathyroid hyperplasia (choice D) can be a
component of multiple endocrine neoplasia (MEN).
Simian crease (choice E) suggests Down syndrome,
which is associated with an increased incidence of leukemia.
|
A 2-year-old child is seen
for a welI-child visit in a pediatric clinic. Abdominal examination
demonstrates a palpable, non-tender mass on the
Ieft side of the abdomen.
The mother had no idea the mass was present and the pediatrician did not note
the presence of the mass at the
child's 18-month
welI-child visit. Physical examination is otherwise unremarkable.
Question
5 of 5
Abnormalities of which of
the following chromosomes have been linked to this disease?
/ A. 3
/ B. 5
/ C. 11
/ D. 15
/ E. 21
|
Explanation - Q: 2.5
|
|
The correct answer is C. Inactivation of the
WT-1 Wilms tumor gene (located at 11p13, and thought to encode a DNA-binding
protein important in fetal kidney development) has been reported in the tumor
cells from many Wilms tumor cases. Also, the WAGR syndrome involves a
deletion of chromosome 11p13 and the Beckwith-Wiedemann syndrome involves a
rearrangement of chromosome 11p15. The genetic basis of the Drash syndrome
has not been established. The other choices are distracters.
|
A 67-year-old man with an
18-year history of type 2 diabetes mellitus presents for a routine physical
examination. His temperature is 36.9 C
(98.5 F), his blood
pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On
examination, the physician notes a nontender,
pulsatile, mass in the
mid-abdomen. A plain abdominal x-ray film with the patient in the lateral
position reveals spotty calcification of a
markedly dilated abdominal
aortic walI.
Question
1 of 5
Which of the following is
most likely pathogenetically related to this patient's aortic disease?
/ A. Atherosclerosis
/ B. Cystic medial necrosis
/ C. Kawasaki disease
/ D. Mönckeberg arteriosclerosis
/ E. Syphilis
|
Explanation - Q: 3.1
|
|
The correct answer is A. This patient has an
abdominal aortic aneurysm (AAA); these are most commonly the result of
atherosclerosis. Hypertension and cigarette smoking are also risk factors.
AAA may be asymptomatic, or may be associated with pain. Some aortic
aneurysms are palpable as pulsating masses in the abdomen. Abdominal aortic
aneurysms typically begin below the renal arteries and may extend well into
the iliac system bilaterally. Calcified atherosclerotic plaques on plain
films of the abdomen can be seen in the majority of cases. Rupture of an
aortic aneurysm is usually preceded by excruciating pain in the lower abdomen
and back. The mortality rate for abdominal aortic aneurysm repair performed
electively is about 2-5%, while that performed emergently after rupture of
the aneurysm has begun is 50%. Many patients with atherosclerotic aneurysms
also have severe coronary artery disease, and repair of the coronary arteries
may be needed before the patient is subjected to the risk of aortic aneurysm
repair.
Cystic medial necrosis (choice B) is a risk
factor for dissecting aneurysms that typically do not widen the lumen of the
aorta.
Mönckeberg's arteriosclerosis (choice D) can
cause focal calcification of (usually medium-sized) arteries, but is not associated
with aneurysm formation.
Syphilis (choice E) is a now rare cause of
aortic aneurysms that typically involve the aortic root and ascending aorta.
|
A 67-year-old man with an
18-year history of type 2 diabetes mellitus presents for a routine physical
examination. His temperature is 36.9 C
(98.5 F), his blood
pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On
examination, the physician notes a nontender,
pulsatile, mass in the
mid-abdomen. A plain abdominal x-ray film with the patient in the lateral
position reveals spotty calcification of a
markedly dilated abdominal
aortic walI.
Question
2 of 5
Which of the following
physiologic observations helps to account for the fact that 75% of the
aneurysms of this patient's type are found in the
abdomen and only 25%
principally involve the thorax?
/ A. Diastolic pressure is greater in the abdominal aorta in the
supine position
/ B. Negative intrathoracic pressure reduces aortic wall tension in
the thorax
/ C. The average blood flow in the abdominal aorta is greater than
that in the thoracic aorta
/ D. The average blood pressure in the abdominal aorta is higher
than that in the thoracic aorta
/ E. The average degree of turbulence in the thoracic aorta is
higher than that in the abdominal aorta
|
Explanation - Q: 3.2
|
|
The correct answer is D. Increased blood
pressure is a strong risk factor for atherosclerosis, and humans pay a price
for their erect sitting and standing postures. In these postures, the
abdominal aorta experiences the weight of a column of blood added to the
pressure produced by the heart. In the supine posture, the pressures in the
thoracic and abdominal aorta are similar. So, if an average daily pressure is
taken, the abdominal aorta tends to have a significantly higher pressure than
does the thoracic aorta.
Diastolic pressure (choice A) is actually
greater in the thoracic aorta compared to the abdominal aorta in the supine
position. However, the systolic blood pressure is greater in the abdominal
aorta.
A negative intrathoracic pressure (choice B)
would tend to increase transmural pressure across the wall of the thoracic
aorta, and thereby increase wall tension and promote the development of
aneurysms.
Blood flow (choice C) in the abdominal aorta is
less than that in the thoracic aorta, because some blood leaves the aorta
through its thoracic branches.
Higher turbulence (choice E) tends to predispose
for atherosclerosis, and the flow in the abdominal aorta, with its many
branches, tends to be more turbulent than that in the thoracic aorta; this
problem is exacerbated as atherosclerotic disease advances.
|
*** If your relatives ever use the Kleptomania... ***
A 67-year-old man with an
18-year history of type 2 diabetes mellitus presents for a routine physical
examination. His temperature is 36.9 C
(98.5 F), his blood
pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On
examination, the physician notes a nontender,
pulsatile, mass in the
mid-abdomen. A plain abdominal x-ray film with the patient in the lateral
position reveals spotty calcification of a
markedly dilated abdominal
aortic walI.
Question
3 of 5
The patient is taken to
surgery and the abdominal aorta and proximal common iliac arteries are replaced
with a graft. Which of the following
aneurysm diameters is
usually considered the threshold above which elective surgery is recommended,
unless contraindicated by other
disease?
/ A. 1 cm
/ B. 2 cm
/ C. 6 cm
/ D. 10 cm
/ E. 15 cm
|
Explanation - Q: 3.3
|
|
The correct answer is C. This recommendation is
made because larger aneurysms have a much greater chance of rupture, and
emergency repair carries a high mortality rate. For aneurysms larger than 5
cm, the risk of rupture is 5-10% per year
|
A 67-year-old man with an
18-year history of type 2 diabetes mellitus presents for a routine physical
examination. His temperature is 36.9 C
(98.5 F), his blood
pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On
examination, the physician notes a nontender,
pulsatile, mass in the
mid-abdomen. A plain abdominal x-ray film with the patient in the lateral
position reveals spotty calcification of a
markedly dilated abdominal
aortic walI.
Question
4 of 5
Following surgery, the
patient is placed on a low-fat diet to reduce the risk of continued progression
of his atherosclerotic disease. A bile
acid sequestrant is added
to interrupt enterohepatic circulation of bile acids. Which of the following
agents was most likely prescribed?
/ A. Atorvastatin
/ B. Cholestyramine
/ C. CIofibrate
/ D. Gemfibrozil
/ E. Lovastatin
*** Send Kleptomania trial anywhere
***
|
Explanation - Q: 3.4
|
|
The correct answer is B. Cholestyramine and
colestipol are bile acid sequestrants that bind bile acids in the intestine,
thereby interrupting enterohepatic circulation of bile acids. This has an
indirect effect to enhance LDL clearance and lower lipids in the blood.
Atorvastatin (choice A) and lovastatin (choice
E) are lipid-lowering drugs that competitively inhibit HMG-CoA reductase,
an early step in cholesterol biosynthesis.
Clofibrate (choice C) and gemfibrozil (choice
D) are fibric acid derivatives that may increase the activity of
lipoprotein lipase.
|
*** Wanna buy some Kleptomania? ***
A 67-year-old man with an
18-year history of type 2 diabetes mellitus presents for a routine physical
examination. His temperature is 36.9 C
(98.5 F), his blood
pressure is 158/98 mm Hg and his pulse is 82/minute and regular. On
examination, the physician notes a nontender,
pulsatile, mass in the
mid-abdomen. A plain abdominal x-ray film with the patient in the lateral
position reveals spotty calcification of a
markedly dilated abdominal
aortic walI.
Question
5 of 5
The
table shows values of vessel radius (r), intraluminal pressure (P), and wall
thickness (w) for both the normal aorta and an aortic aneurysm.
*** Any other useful examples for our users? ***
What effect does the
aneurysm have on wall stress?
/ A. Wall stress decreases 10 fold
/ B. Wall stress decreases 2.5 fold
/ C. Wall stress decreases 5 fold
/ D. Wall stress increases 10 fold
/ E. Wall stress increases 2.5 fold
/ F. Wall stress increases 5 fold
|
Explanation - Q: 3.5
|
|
The correct answer is E. According to the Law of
LaPlace for a cylindrical structure such as the aorta: wall stress (s) = (P x
r)/w. Because P and w are shown in the table to be unaffected by the aneurysm
and because radius is increased by 2.5 fold at the site of the aneurysm, it
is clear that wall stress has increased by 2.5 fold at the site of the
aneurysm. This relationship between vessel radius and wall tension can
explain why the probability of rupture increases as the aneurysm becomes
larger.
|
A 3-year-old girl is seen
in the emergency department with acute abdominal pain. She has a 5-day history
of vomiting and abdominal
distension. She has not
passed stool during this time, and during the past day, has been vomiting
bilious materiaI. On physical examination,
she is lethargic, with a
firm and tender abdomen, and peritoneal signs are present. She is immediately
referred for laparotomy for suspected
diagnoses of
intussusception vs. volvulus. At surgery, approximately 20 cm of small
intestine is found to be markedly distended, and is
resected. The section
contains a tightly knotted ball of nematodes that are about 15 to 35 cm in
length. The worms have tapered ends without
hooks.
Question
1 of 5
The worms are most likely
which of the following?
|
Explanation - Q: 4.1
|
|
The
correct answer is B. Ascaris lumbricoides is the only parasitic
worm that is likely to cause intestinal obstruction, and then only if the
worm burden is high. The description given of the worms in the case
presentation is typical. All of the other worms listed in the choices are
also nematodes or roundworms.
Ankylostoma
duodenale(choice A) is a small (approximately 1 cm) hookworm that
inhabits the small intestine and clings to the mucosa.
Enterobius
vermicularis(choice C) is the pinworm. This is an approximately 1
cm long worm that inhabits the large bowel (and appendix); the female
deposits eggs on the perianal skin.
Strongyloides
stercoralis(choice D), or threadworm, is a 2.5 mm worm that lives
in the crypts of the small bowel and may cause chronic infection due to
autoinfection. It is the only nematode capable of increasing its numbers in a
host. In immunocompromised hosts, it can cause life-threatening disseminated
infection.
Trichuris
trichiura(choice E), or whipworm, is a 3-5 cm worm that lives on
the colorectal mucosa.
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*** Microsoft beyond the screen, Kleptomania above the
screen ***
A 3-year-old girl is seen
in the emergency department with acute abdominal pain. She has a 5-day history
of vomiting and abdominal
distension. She has not
passed stool during this time, and during the past day, has been vomiting
bilious materiaI. On physical examination,
she is lethargic, with a
firm and tender abdomen, and peritoneal signs are present. She is immediately
referred for laparotomy for suspected
diagnoses of
intussusception vs. volvulus. At surgery, approximately 20 cm of small
intestine is found to be markedly distended, and is
resected. The section
contains a tightly knotted ball of nematodes that are about 15 to 35 cm in
length. The worms have tapered ends without
hooks.
Question
2 of 5
Which of the following
best describes what would have been seen under the microscope if the patient's
stool had been analyzed for ova and
parasites?
/ A. Large oval eggs with a lateral spine
/ B. Large round to oval eggs, with a thick mammillated shells
/ C. Lemon-shaped eggs, with bipolar plugs,
/ D. Round eggs and proglottids filled with eggs
/ E. Small larvae
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Explanation - Q: 4.2
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The correct answer is B. This is the correct
description of fertilized Ascaris eggs. Both fertilized and somewhat
more elongated unfertilized eggs may be seen; fertilized eggs may contain
multiple cells under the thick wavy shell.
Choice A describes the eggs of the trematode
(fluke) Schistosoma mansoni.
Choice C describes the eggs of Trichuris
trichiura.
Choice D describes the eggs of the cestodes
(tapeworms) Taenia saginata and Taenia solium.
Choice E describes the larvae of Strongyloides
stercoralis. Strongyloides stercoralis has a rapid life cycle in
its host. It is the only nematode whose diagnostic form is a larva, not an
egg.
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A 3-year-old girl is seen
in the emergency department with acute abdominal pain. She has a 5-day history
of vomiting and abdominal
distension. She has not
passed stool during this time, and during the past day, has been vomiting
bilious materiaI. On physical examination,
she is lethargic, with a
firm and tender abdomen, and peritoneal signs are present. She is immediately
referred for laparotomy for suspected
diagnoses of
intussusception vs. volvulus. At surgery, approximately 20 cm of small
intestine is found to be markedly distended, and is
resected. The section
contains a tightly knotted ball of nematodes that are about 15 to 35 cm in
length. The worms have tapered ends without
hooks.
Question
3 of 5
If this child acquired her
infection in the United
States
/ A. Desert Southwest
/ B. Midwest
/ C. Northeast
/ D. Pacific Northwest
/ E. Southeast
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clipboard ***
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Explanation - Q: 4.3
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The correct answer is E. It is easy for medical
students, residents, and physicians to neglect parasitic diseases because
they assume that the American population is not likely to have them. However,
it is thought that more than 4 million individuals in the Untied States, most
of whom are immigrants from developing countries, are infected with Ascaris
species, predominately Ascaris lumbricoides. Most of these people have
asymptomatic infections. Ascaris can also be acquired in rural areas
of the
|
A 3-year-old girl is seen
in the emergency department with acute abdominal pain. She has a 5-day history
of vomiting and abdominal
distension. She has not
passed stool during this time, and during the past day, has been vomiting
bilious materiaI. On physical examination,
she is lethargic, with a
firm and tender abdomen, and peritoneal signs are present. She is immediately
referred for laparotomy for suspected
diagnoses of
intussusception vs. volvulus. At surgery, approximately 20 cm of small
intestine is found to be markedly distended, and is
resected. The section
contains a tightly knotted ball of nematodes that are about 15 to 35 cm in
length. The worms have tapered ends without
hooks.
Question
4 of 5
Which of the following
medications would be the most appropriate pharmacotherapy for this patient?
/ A. Bithionol
/ B. Mebendazole
/ C. Metronidazole
/ D. Niclosamide
/ E. Praziquantel
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screen ***
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Explanation - Q: 4.4
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The correct answer is B. Mebendazole is a
systemically absorbed broad-spectrum anthelminthic agent effective against Ascaris
species, hookworm, tapeworm, liver fluke, and pinworms.
Bithionol (choice A) is used to treat infections
caused by Fasciola hepatica, a tissue fluke.
Metronidazole (choice C) is used to treat
infections caused by anaerobic organisms, including the intestinal protozoa, Giardia
lamblia, and Entamoeba histolytica.
Niclosamide (choice D) is not available in the
Praziquantel (choice E) has broad-spectrum
activity against most trematodes and cestodes, with the exception of F.
hepatica.
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screen! ***
A 3-year-old girl is seen
in the emergency department with acute abdominal pain. She has a 5-day history
of vomiting and abdominal
distension. She has not
passed stool during this time, and during the past day, has been vomiting
bilious materiaI. On physical examination,
she is lethargic, with a
firm and tender abdomen, and peritoneal signs are present. She is immediately
referred for laparotomy for suspected
diagnoses of intussusception
vs. volvulus. At surgery, approximately 20 cm of small intestine is found to be
markedly distended, and is
resected. The section
contains a tightly knotted ball of nematodes that are about 15 to 35 cm in
length. The worms have tapered ends without
hooks.
Question
5 of 5
Part of the life cycle of
this patient's parasite is a filarial stage in which larva, hatched in the
duodenum, penetrate the wall of the small
intestine. The passage of
migrating larvae most commonly produces symptomatic disease in which of the
following organs?
/ A. Heart
/ B. Liver
/ C. Lungs
/ D. Pancreas
/ E. Stomach
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Explanation - Q: 4.5
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The correct answer is C. Ascaris
infection is acquired by ingestion of the eggs, usually from contaminated
soil. The ingested eggs hatch in the duodenum to produce larvae, which cross
the small intestinal wall to enter the blood stream. They then pass through
the heart to lodge in the lungs. They leave the lung capillary bed to enter
the airspaces. They then ascend the bronchial tree into the oropharynx, where
they are again swallowed. This time, they return to the small intestine where
they develop into mature worms that can live in the host for up to two years.
A gravid female worm may produce up to 250,000 eggs daily, which are shed in
stool. The passage of the larvae through the lungs often produces cough
and/or wheezing, and may, in severe cases, produce fever, dyspnea, fleeting
patchy pulmonary infiltrates (Loeffler pneumonitis with prominent eosinophilia),
and rarely hemoptysis.
Passage through the heart (choice A) is usually
asymptomatic, as the larvae are small.
A single adult worm, but not usually larval forms, can
migrate into the biliary tree (choice B), leading to biliary colic,
cholangitis, or gallstone formation; obstructive jaundice uncommonly occurs.
The pancreas (choice D) and stomach (choice
E) are not common sites for complications of ascariasis.
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