USMLE STEP 3 2026 STUDY GUIDE SCRIPT
FULL QUESTIONS AND CORRECT
ANSWERS
◉Which of the following conditions is a/w increased susceptibility
to heat stroke in the elderly?
A: heat wave
B: antiparkinsonian therapy
C: bedridden status
D: diuretics
E: all of the above Answer: E
the elderly and very young are at a higher risk of non-exertional heat
stroke. Environmental stress (heat wave) is the MC precipitating
factor, particularly in the bedridden or those living in poorly
ventilated or non air-conditioned conditions. Meds such as
antiparkinsonian treatment, diuretics, or anticholinergics increase
the risk of heat stroke.
,◉68 YO alcoholic male arrives in the ED after being found in the
snow on a cold winter night in Chicago. His core temperature based
on rectal and esophageal probe is 27C. HR 30 and BP 75/40. He is
immobile and lacks corneal, oculocephalic, and peripheral reflexes.
He is immediately intubated and placed on a cardiac monitor. He
then converts to ventricular fibrillation: a defibrillator attempt at
2J/kg is not successful. What should be the next step in
management?
A: active rewarming with forced-air heating blankets, heated
humidified oxygen, heated crystalloid infusion
B: amiodarone infusion
C: insertion of a trans venous pacemaker
D: passive rewarming with numerous blankets for insulation
E: repeat defibrillation Answer: A
initial focus should be aggressive rewarming. Further attempts at
defibrillation are unlikely to work until core temperature is
normalized. Pharm strategies are also ineffective in the setting of
hypothermia, though the possibility of toxicity based on
accumulation of drug does exist once successful rewarming is
achieved. If initial active rewarming techniques are ineffective,
cardiopulmonary bypass, warmed HD, peritoneal lavage with
warmed fluid, or pleural lavage with warmed fluid should be
considered on an emergent basis. A pacemaker will not be effective
for Vfib and may provoke arrhythmias due to ventricular irritation
,◉in the evaluation of malnutrition, which protein has the shortest
half life and thus is most predictive of recent nutritional status?
Answer: Fibronectin
Albumin has a half life of 2-3 weeks and is sensitive, but not specific
measure of protein-calorie malnutrition. Other situations in which
albumin is low include sepsis, surgery, over hydration, and increased
plasma volume, including CHF, renal failure, and chronic liver
disease. Among the other markers, transferrin has a half life of 1
week. Prealbumin and retinol-binding protein complex have a half
life of 2 days. Fibronectin has the shortest half life: 1 day.
◉45 YO M is stranded overnight in the cold after an avalanche. He is
airlifted to your medical center and found to have anesthesia and a
clumsy sensation in the distal extent of the fingers on the LE. What is
the best initial management of his hand?
A: IV nitroglycerine
B: oral nifedipine
C: rapid rewarming
D: surgical debridement
E: topical nitroglycerine paste Answer: C
, the patient has severe frostbite vesiculations implying deep tissue
injury, including the microvasculature. Medical therapy with IV or
topical vasodilators is not effective. Decisions regarding surgical
debridement and amputation are best made in the chronic stage of
management rather than acutely in the absence of infection. Initially,
rewarming and aggressive analgesia with opiates are the mainstay
of therapy
◉FOBT was shown to decrease CRC mortality from 8.8/1000
persons to 5.9/1000 persons over a 13-year period. What is the
approx ARR of this intervention in the studied population? Answer:
0.3%
It is important to contrast the RRR of an intervention versus the
ARR. The ARR is 0.88% - 0.59% = 0.29%. The RRR in this case is
~30%. It might be predicted, therefore, that this intervention might
result in a 30% decrease in CRC if widely implemented in a target
population. However, the ARR is much smaller; 1 divided by the ARR
(1/0.29), equals the NNT to prevent 1 colon cancer death. In this
case that number is ~330. Therefore, while the impact on a
population level might be large, it takes a large number of patients to
prevent one event with the FOBT intervention.
◉Which preventative intervention leads to the largest average
increase in life expectancy for a target population?
A: a regular exercise program for a 40 YO M
FULL QUESTIONS AND CORRECT
ANSWERS
◉Which of the following conditions is a/w increased susceptibility
to heat stroke in the elderly?
A: heat wave
B: antiparkinsonian therapy
C: bedridden status
D: diuretics
E: all of the above Answer: E
the elderly and very young are at a higher risk of non-exertional heat
stroke. Environmental stress (heat wave) is the MC precipitating
factor, particularly in the bedridden or those living in poorly
ventilated or non air-conditioned conditions. Meds such as
antiparkinsonian treatment, diuretics, or anticholinergics increase
the risk of heat stroke.
,◉68 YO alcoholic male arrives in the ED after being found in the
snow on a cold winter night in Chicago. His core temperature based
on rectal and esophageal probe is 27C. HR 30 and BP 75/40. He is
immobile and lacks corneal, oculocephalic, and peripheral reflexes.
He is immediately intubated and placed on a cardiac monitor. He
then converts to ventricular fibrillation: a defibrillator attempt at
2J/kg is not successful. What should be the next step in
management?
A: active rewarming with forced-air heating blankets, heated
humidified oxygen, heated crystalloid infusion
B: amiodarone infusion
C: insertion of a trans venous pacemaker
D: passive rewarming with numerous blankets for insulation
E: repeat defibrillation Answer: A
initial focus should be aggressive rewarming. Further attempts at
defibrillation are unlikely to work until core temperature is
normalized. Pharm strategies are also ineffective in the setting of
hypothermia, though the possibility of toxicity based on
accumulation of drug does exist once successful rewarming is
achieved. If initial active rewarming techniques are ineffective,
cardiopulmonary bypass, warmed HD, peritoneal lavage with
warmed fluid, or pleural lavage with warmed fluid should be
considered on an emergent basis. A pacemaker will not be effective
for Vfib and may provoke arrhythmias due to ventricular irritation
,◉in the evaluation of malnutrition, which protein has the shortest
half life and thus is most predictive of recent nutritional status?
Answer: Fibronectin
Albumin has a half life of 2-3 weeks and is sensitive, but not specific
measure of protein-calorie malnutrition. Other situations in which
albumin is low include sepsis, surgery, over hydration, and increased
plasma volume, including CHF, renal failure, and chronic liver
disease. Among the other markers, transferrin has a half life of 1
week. Prealbumin and retinol-binding protein complex have a half
life of 2 days. Fibronectin has the shortest half life: 1 day.
◉45 YO M is stranded overnight in the cold after an avalanche. He is
airlifted to your medical center and found to have anesthesia and a
clumsy sensation in the distal extent of the fingers on the LE. What is
the best initial management of his hand?
A: IV nitroglycerine
B: oral nifedipine
C: rapid rewarming
D: surgical debridement
E: topical nitroglycerine paste Answer: C
, the patient has severe frostbite vesiculations implying deep tissue
injury, including the microvasculature. Medical therapy with IV or
topical vasodilators is not effective. Decisions regarding surgical
debridement and amputation are best made in the chronic stage of
management rather than acutely in the absence of infection. Initially,
rewarming and aggressive analgesia with opiates are the mainstay
of therapy
◉FOBT was shown to decrease CRC mortality from 8.8/1000
persons to 5.9/1000 persons over a 13-year period. What is the
approx ARR of this intervention in the studied population? Answer:
0.3%
It is important to contrast the RRR of an intervention versus the
ARR. The ARR is 0.88% - 0.59% = 0.29%. The RRR in this case is
~30%. It might be predicted, therefore, that this intervention might
result in a 30% decrease in CRC if widely implemented in a target
population. However, the ARR is much smaller; 1 divided by the ARR
(1/0.29), equals the NNT to prevent 1 colon cancer death. In this
case that number is ~330. Therefore, while the impact on a
population level might be large, it takes a large number of patients to
prevent one event with the FOBT intervention.
◉Which preventative intervention leads to the largest average
increase in life expectancy for a target population?
A: a regular exercise program for a 40 YO M
