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First Aid USMLE Step 3 Questions with Detailed Verified
Answers (100% Correct Answers) /Already Graded A+
A 42 year old woman presents with HA, nausea, vomiting, and a red eye
that has progressively worsened since this morning. She also notes vision
changes. Exam reveals conjunctival injection: a mid-range fixed, dilated
pupil: and no focal weakness in the extremities. What should you do next?
Ans: Use tonometry to check IOP. A pressure of over 30 mmHg confirms
the diagnosis of acute closed angle glaucome. Emergent referral to
ophthamology and possible hospitalization to reduce IOP. Treatment
includes topical BB (timolol), IV acetazolamide, and topical steroids.
A 71 year old man with a history of well controlled asthma presents in
November for his annual checkup. He has no complaints, and his PE
findings are unremarkable. He received the pneumococcal vaccine 3 years
ago. What should be given before the completion of his visit?
Ans: Annual influenza vaccination is recommended for all patients over 6
months of age who lack contraindications (severe allergy/ anaphylaxis to
egg protein). The live attenuated vaccine should not be used in populations
who are pregnant, immunosuppressed, or have taken influenza antiviral
medication within 48 hours.
A 68 year old woman is brought to your office because her son is concerned
that she is losing her memory. He describes several instances in which she
forgot what he has just told her, adding that she was recently unaware that
he was calling to her at a crowded park. She spends most of her time at
home watching television. What is the diagnosis?
Ans: Presbycusis, or age related hearing loss. Hearing loss in elderly
persons must be evaluated. Patients may have difficulty distinguishing
voices in a crowd, which is often misinterpreted as memory loss. Patients
may become socially isolated.
A 24 year old medical student develops a rash when he puts on a pair of
latex examination gloves. What is the mechanism leading to this rash?
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Ans: Allergic contact dermatitis is a result of delayed contact (type IV)
hypersensitivity caused by allergen-primed memory T lymphocytes (vs
irritant contact dermatitis, which results from cytokines released following
irritant contact).
A 26 year old man presents with targetoid papules that appeared on his
palms 2 days ago. He states that he was recently prescribed a new
antiseizure medication for his epilepsy. He denies any other symptoms, and
exam reveals no other lesions. What is the diagnosis?
Ans: Erythema multiforme secondary to the new antiseizure medication.
EM differs from Steven-Johnson syndrome/ toxic epidermal necrolysis in
that lesions are genrally localized to the extremities (vs spreading from the
face and trunk), and the disease course is usually less severe.
A 71 year old man complains of a lesion on his right flank that was
preceeded by tingling in the same area 1 day ago. Exam reveals a 4 inch
band of painful vesicles with secondary crusting and a clear midline border.
What test do you send to confirm your clinical diagnosis?
Ans: Although a clinical exam is typically sufficient for the diagnosis of
herpes zoster, a PCR of fluid from the lesion can be confirmatory. NSAIDs
may be useful for pain control, and antiviral therapy may speed resolution
and decrease the likelihood of postherpetic neuralgia.
A patient presents for evaluation of a pigmented skin lesions. Biopsy reveals
melanocytes with marked atypia characteristic of melanoma. What feature
is the most important prognostic factor?
Ans: Depth of invasion of the melanoma
A 74 year old man presents with inability to maintain an erection. Although
the problem started several years ago, he states that he ignored it because he
thought it was a normal part of aging. How should the patient be counseled?
Ans: Although erectile dysfunction is associated with age, it is still
considered abnormal, and patients with erection difficulties should be
adequately evaluated for all potential causes.
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A 70 year old man is prescribed terazosin for his benign prostatic
hyperplasia. How does the drug treat his condition, and what other medical
condition does its mechanism of action address?
Ans: Alpha blockers such as terazosin act on smooth muscle in the
prostate, bladder neck, and urethra. They also act on vascular smooth
muscle, causing vasodilation; therefore, they can work to lower HTN as
well.
A 41 year old woman with woman with no significant medical history
comes to your clinic for her first checkup. Her mother has type 2 DM. Her
PE findings, including BMI, are normal. Which screening tests might you
recommend?
Ans: A Pap smear and HTN screening. A diabetes workup (fasting glucose
test, HbA1c) is not needed as the patient is under 45 years of age with a
normal BMI. Given the patient’s age, a screening mammogram is
controversial. It is important to discuss the risks, benefits, and alternatives of
screening before proceeding.
A 58 year old woman with long standing HTN is admitted to the hospital
with dyspnea on exertion and bibasilar crackles, and you suspect heart
failure. Which imaging modality would confirm your diagnosis?
Ans: Transthoracis echocardiography (TTE). TTE provides specific
information, such as left ventricular ejection factor (LVEF) and diastolic
compliance and relaxation, which can confirm the diagnosis of systolic and
diastolic heart failure. It also yields information about specific etiologies or
precipitants such as valvular or wall motion abnormalities.
A 54 year old business executive develops chest pain while at work. His
vital signs remain stable. The chest pain is partially relieved by nitroglycerin
but worsens with cough and deep inspiration. He is brought to the ED,
where his ECG reveals diffuse ST-T elevations. His cardiac biomarkers are
normal. What is the appropriate treatment?
Ans: NSAIDs. The patient most likely has pericarditis, which is a clinical
diagnosis.
A 64 year old woman suddenly develops hypotension and SOB 1 day after
CABG surgery. Exam reveals JVD and muffled heart sounds, and bedside
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pulsus paradoxus is present. Besides ordering an urgent echocardiogram,
what are your next therapeutic steps?
Ans: Administer IV fluids pursue emergent therapeutic pericardiocentesis
or pericardial window.
A 65 year old Caucasian man who has a history of diabetes and is currently
on meformin has BP readings of 150/90 and 140/95 on multiple office
visits. You start him on an ACEI, but he returns for follow-up complaining
of a dry cough with a measured BP of 145/92. What is your BP goal for this
patient, and what are additional options for treating his hypertension?
Ans: Thiazide diuretics, CCBs, ACEIs, and ARBs are all therapeutic
options. The BP goal for this patient would be under 130/80. In light of his
cough (a potential adverse effect of ACEIs), you could switch the patient to
an ARB and add a second medication to achieve goal BP.
A 69 year old hospital administrator presents to the ED with severe, tearing
chest pain that radiates to his back. CXR is unrevealing. Given your
concern for potential aortic dissection, what is the next diagnostic step?
Ans: Chest CT with IV contrast. TEE is appropriate for patients with a
history of allergic reaction to IV contrast.
A 73 year old man with a history of diabetes mellitus, but with no history of
clinical CAD, comes to your office for the result of his recent bloodwork.
His fasting lipid panel is significant for an LDL of 130 mg/dL, and his 10
year risk of atherosclerotic cardiovascular disease is 7%. In addition to
educating him on diet and lifestyle changes, what action should you take?
Ans: Start moderate intensity statin therapy with a goal LDL reduction of
30-50%.
A 26 year old IV drug user is admitted to the hospital with fevers and chills.
Despite broad antibiotic therapy, blood cultures remain persistently (+), but
TTE is normal. Given your suspicion of infective endocarditis, what is your
next step?
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Ans: Order a TEE, which is more sensitive than TTE for visualizing
vegetations and diagnosing endocarditis. When endocarditis is suspected
clinically but TTE is normal, a TEE is indicated to better confirm or rule
our infection.
A 73 year old woman who has had palpitations for 4 days presents with AF
with rapid ventricular response. Other than mild shortness of breath, she is
hemodynamically stable. What is the best management approach?
Ans: Rate control. Paroxysmal AF may also lead to atrial clot formation.
Cardioversion should be attempted only is a mural thrombus has been ruled
out.
A 25 year old man becomes involved in a bar fight and sustains a “fight
bite” (closed fist injury) to his hand. The wound culture grows gram (-) rods.
What is the most likely pathogen, and how should it be treated?
Ans: Eikenella corrodens, the most likely pathogen, is common in human
bit infections that are sustained in closed-fist injuries. Treat with
amoxicillin/ clavulanate.
A 37 year old known IV drug user is brought to the ED with trismus and
facial grimacing 30 minutes after using heroin. What is the most likely
diagnosis?
Ans: Strychnine poisoning, which can look just like tetanus. When heroin
is “cut” drug dealers use white, bitter chemicals so that the drug still tastes
pure. Strychnine antagonized glycine (an inhibitory neurotransmitter) in the
spinal cord. Give benzodiazepines.
A 20 year old woman is pulled unconscious from a cold lake 5 minutes after
her sailboat capsized. Despite the problems associated with hypothermia,
her near drowning is likely to have a outcome than other causes of hypoxia.
Why is this the case?
Ans: Activation of the diving reflex (reflex bradycardia and breath
holding), which reduces metabolic demands and the effects of hypoxemia,
shunts blood to the vital organs and limits aspiration of water.
A 35 year old migrant worker with no past medical history has a syncopal
episode while harvesting tobacco. Exam reveals diminished mentation,
