USMLE STEP 3 EXAM EXAM READINESS
ASSESSMENT WITH COMPLETE SOLUTIONS
2026
◉ norovirus. Answer: -causes viral gastroenteritis
-*cruise-ship* outbreaks
-BRIEF duration: resolves within days
-*VOMITING more common*rota
◉ rotavirus. Answer: *watery diarrhea* in kids age 2 and under
-within 1-2 DAYS of exposure
-also emesis, abd pain
This child with fever, emesis, profuse watery diarrhea, and
hyperactive bowel sounds likely has viral gastroenteritis. Rotavirus
is one of the most common causes of viral gastroenteritis in children
worldwide, particularly at age <2. It usually occurs during winter
and can spread rapidly in schools or day care facilities.
Since the introduction of widespread rotavirus vaccination, the
incidence of rotavirus-related hospitalization has decreased
drastically. Therefore, this oral, live-attenuated vaccine is
recommended for all healthy infants. The vaccine is generally well
,tolerated and any side effects (eg, fussiness, low fever) are usually
mild. The vaccine is associated with a slightly increased risk of
intussusception; however, this potential effect is rare and much less
likely than the risk of severe rotavirus gastroenteritis in
unvaccinated children.
◉ meta-analysis. Answer: -combines results of *several studies* to
*increase statistical power* thru an *increased sample size*
-ideally, the results are the same as produced by single study
w/larger sample size
-BUT *increase in statistical power may lead to *statistically
SIGNIFICANT* effect sizes that maybe *CLINICALLY
IRRELEVANT*=detects a very small effect(eg risk ratio)--not
practical
---also, *validity depends on the design*-metanalysis isn't always
more valid than other study designs
◉ cephalohematoma vs caput succedaneum. Answer:
cephalohematoma: DOESN'T cross suture lines & resolves within
WEEKS, *can lead to jaundice* b/c RBC breakdown&Calcification
after resolution-located UNDER periosteum
Caput succedaneum: like a CAP crosses suture lines&resolves DAYS
after birth-serosanuineous fluid collection above
periosteum/beneath scalp
,◉ subgaleal hemorrhage. Answer: -bleeding under galea
aponeurotica
-fatal complication of vacuum-assisted deliveries
-rapidly expanding swelling leading to hypovolemic shock from
blood loss
◉ 2 week old girl has *asymmetric gluteal skinfolds&increased #
thigh creases on right>left*. what else would be found?. Answer:
*Apparent leg-length discrepancy* when pt lies supine w/knees
flexed: affected leg looks shorter(Galeazzi test)
DX: developmental dysplasia of hip
-abnormal development of hip joint tht prevents femoral head from
sitting properly in acetabulum
-RF: *females, breech position, FH DDH, excessively tight swaddling*
-instability during attempted dislocation&reduction if palpable
clunk heard (Barlow and Ortolani maneuvers)
◉ who has asymmetric moro reflex?. Answer: erb palsy (seen in
large for gestational age infants)
◉ who has sacral dimple?. Answer: neural tube defect
(myelomeningocele)
, ◉ what's the next step after u/s shows dislocated right hip w/flat
acetabulum and positive barlow and ortolani tests?. Answer:
*Consult orthopedic surgeon*
--when ID within first 6 months of life, treat by maintaining hip in
*flexed&abducted position in Pavlik harness for 3 months*
-when hip extension & adduction are limited, the dislocated hip is
reduced and/or stabilized and normal acetabular development is
promoted
--monitor pavlik harness closely by orthopedic surgeon b/c
associated risks( avascular necrosis, femoral nerve palsy)
w/excessive hip flexion & abduction
>hip radiograph if >4 months old
◉ prognosis for development dysplasia of hip. Answer: *most
infants who are treated early have no long-term sequelae*
-the need for surgical correction for DDH correlates w/increased age
at diagnosis: <5% of pts dx & treated w/pavlik harness in early
infancy require surgery
◉ vestibular neuritis(labyrinthitis). Answer: -*single episode* of
severe vertigo that can last for days & is self-limited
-*labyrinthitis when associated w/unilateral hearing loss*
-normal MRI
-after viral infection
-feeling of imabalnce and unsteady gait
ASSESSMENT WITH COMPLETE SOLUTIONS
2026
◉ norovirus. Answer: -causes viral gastroenteritis
-*cruise-ship* outbreaks
-BRIEF duration: resolves within days
-*VOMITING more common*rota
◉ rotavirus. Answer: *watery diarrhea* in kids age 2 and under
-within 1-2 DAYS of exposure
-also emesis, abd pain
This child with fever, emesis, profuse watery diarrhea, and
hyperactive bowel sounds likely has viral gastroenteritis. Rotavirus
is one of the most common causes of viral gastroenteritis in children
worldwide, particularly at age <2. It usually occurs during winter
and can spread rapidly in schools or day care facilities.
Since the introduction of widespread rotavirus vaccination, the
incidence of rotavirus-related hospitalization has decreased
drastically. Therefore, this oral, live-attenuated vaccine is
recommended for all healthy infants. The vaccine is generally well
,tolerated and any side effects (eg, fussiness, low fever) are usually
mild. The vaccine is associated with a slightly increased risk of
intussusception; however, this potential effect is rare and much less
likely than the risk of severe rotavirus gastroenteritis in
unvaccinated children.
◉ meta-analysis. Answer: -combines results of *several studies* to
*increase statistical power* thru an *increased sample size*
-ideally, the results are the same as produced by single study
w/larger sample size
-BUT *increase in statistical power may lead to *statistically
SIGNIFICANT* effect sizes that maybe *CLINICALLY
IRRELEVANT*=detects a very small effect(eg risk ratio)--not
practical
---also, *validity depends on the design*-metanalysis isn't always
more valid than other study designs
◉ cephalohematoma vs caput succedaneum. Answer:
cephalohematoma: DOESN'T cross suture lines & resolves within
WEEKS, *can lead to jaundice* b/c RBC breakdown&Calcification
after resolution-located UNDER periosteum
Caput succedaneum: like a CAP crosses suture lines&resolves DAYS
after birth-serosanuineous fluid collection above
periosteum/beneath scalp
,◉ subgaleal hemorrhage. Answer: -bleeding under galea
aponeurotica
-fatal complication of vacuum-assisted deliveries
-rapidly expanding swelling leading to hypovolemic shock from
blood loss
◉ 2 week old girl has *asymmetric gluteal skinfolds&increased #
thigh creases on right>left*. what else would be found?. Answer:
*Apparent leg-length discrepancy* when pt lies supine w/knees
flexed: affected leg looks shorter(Galeazzi test)
DX: developmental dysplasia of hip
-abnormal development of hip joint tht prevents femoral head from
sitting properly in acetabulum
-RF: *females, breech position, FH DDH, excessively tight swaddling*
-instability during attempted dislocation&reduction if palpable
clunk heard (Barlow and Ortolani maneuvers)
◉ who has asymmetric moro reflex?. Answer: erb palsy (seen in
large for gestational age infants)
◉ who has sacral dimple?. Answer: neural tube defect
(myelomeningocele)
, ◉ what's the next step after u/s shows dislocated right hip w/flat
acetabulum and positive barlow and ortolani tests?. Answer:
*Consult orthopedic surgeon*
--when ID within first 6 months of life, treat by maintaining hip in
*flexed&abducted position in Pavlik harness for 3 months*
-when hip extension & adduction are limited, the dislocated hip is
reduced and/or stabilized and normal acetabular development is
promoted
--monitor pavlik harness closely by orthopedic surgeon b/c
associated risks( avascular necrosis, femoral nerve palsy)
w/excessive hip flexion & abduction
>hip radiograph if >4 months old
◉ prognosis for development dysplasia of hip. Answer: *most
infants who are treated early have no long-term sequelae*
-the need for surgical correction for DDH correlates w/increased age
at diagnosis: <5% of pts dx & treated w/pavlik harness in early
infancy require surgery
◉ vestibular neuritis(labyrinthitis). Answer: -*single episode* of
severe vertigo that can last for days & is self-limited
-*labyrinthitis when associated w/unilateral hearing loss*
-normal MRI
-after viral infection
-feeling of imabalnce and unsteady gait
