First Aid USMLE Step 2 CS - Mini-Cases
complete Questions with correct
Answers
26 yo M presents after falling and losing consciousness at work. He had rhythmic movements of the
limbs, bit his tongue, and lost control of his bladder. He was subsequently confused after regaining
consciousness (as witnessed by his colleagues) - correct answer-Differential:
*Generalized tonic-clonic seizure*
Convulsive syncope
Substance abuse/overdose
Malingering
Hypoglycemia
Workup:
CBC
Electrolytes, glucose
Urine toxicology
EEG
MRI—brain
CT—head
LP—CSF analysis
ECG
34 yo F nurse presents with worsening cough of 6 weeks' duration accompanied by weight loss, fatigue,
night sweats, and fever. She has a history of contact with tuberculosis at work. - correct answer-
Differential:
*Tuberculosis*
Pneumonia
Lung abscess
Vasculitis
Lymphoma
Metastatic cancer
HIV/AIDS
Sarcoidosis
Workup:
CBC
PPD/QuantiFERON-TB Gold
Sputum Gram stain, acid-fast stain, and culture
CXR
CT-chest
Bronchoscopy
HIV antibody
Lymph node biopsy
55 yo F c/o dizziness for the past day. She feels faint and has severe diarrhea that started 2 days ago. She
takes furosemide for hypertension. On examination, she feels dizzy upon standing. - correct answer-
Differential:
,*Orthostatic hypotension due to dehydration* (diarrhea, diuretic use)
Vertebrobasilar insufficiency
Cardiac arrhythmias
Vestibular neuronitis
Labyrinthitis
Benign positional vertigo
Workup:
Orthostatic vital signs
Rectal exam
CBC
Urea, electrolytes
Stool for occult blood
Stool leukocytes
65 yo M presents after falling and losing consciousness for a few seconds. He had no warning before
passing out but recently had palpitations. His history includes a coronary artery bypass graft. - correct
answer-Differential:
*Cardiac arrhythmia (causing syncope)*
Severe aortic stenosis
Syncope (other causes)
Seizure
Pulmonary embolism
Workup:
ECG
Holter monitoring
CBC
Electrolytes, glucose
Echocardiography
CT—head
12 yo F presents with a 2-month history of fighting in school, truancy, and breaking curfew. Her parents
recently divorced, and she just started school in a new district. Before her parents divorced, she was an
average student with no behavioral problems. - correct answer-Differential:
*Adjustment disorder*
Substance intoxication, abuse, or dependence
Oppositional defiant disorder
Conduct disorder
Manic episode
Workup:
Physical exam
Mental status exam
Urine toxicology
1-month-old F is brought in because she has been spitting up her milk for the last 10 days. The vomiting
episodes have increased in frequency and forcefulness. Emesis is nonbloody and nonbilious. The
episodes usually occur immediately after breastfeeding. She has stopped gaining weight. - correct
answer-Differential:
*Pyloric stenosis*
,Partial duodenal atresia
GERD
Gastroenteritis
Hepatitis
UTI
Workup:
CBC
Electrolytes
U/S—abdomen
Barium swallow
Esophageal pH probe
Endoscopy
LFTs, alkaline phosphatase
UA, urine culture
12-month-old M presents with fever for the past 2 days accompanied by a maculopapular rash on his
face and body. He has not yet received the MMR vaccine. - correct answer-Differential:
*Measles (or other viral exanthem)*
Rubella
Roseola
Fifth disease
Varicella
Scarlet fever
Meningitis
Workup:
CBC
Viral antibodies/titers
Throat swab for culture
LP—CSF analysis
14 yo M presents with short stature and lack of sexual development. His birth weight and length were
normal, but he is the shortest child in his class. His father and uncles had the same problem when they
were young, but they are now of normal stature. - correct answer-Differential:
*Constitutional short stature*
Growth hormone (GH) deficiency
Hypothyroidism
Chronic renal insufficiency
Genetic causes
Workup:
CBC with differentials
Electrolytes
GH stimulation test
IGF-1, IGFBP-3 levels
TSH, FT4
XR—hand
U/S—renal and cardiac
BUN/Cr
, 15 yo M presents with a 1-year history of failing grades, school absenteeism, and legal problems,
including shoplifting. His parents report that he spends most of his time alone in his room, adding that
when he does go out, it is with a new set of friends. - correct answer-Differential:
*Substance abuse*
Conduct disorder
Oppositional defiant disorder
Adjustment disorder
Workup:
Urine toxicology
Physical exam
Mental status exam
17 yo F presents with prolonged, excessive menstrual bleeding occurring irregularly within the past 6
months. - correct answer-Differential:
*Dysfunctional uterine bleeding*
Coagulation disorder (eg, von Willebrand's disease, hemophilia)
Cervical cancer
Molar pregnancy
Hypothyroidism
Workup:
Pelvic exam
Pap smear
CBC
PT/PTT
Urine hCG
Cervical culture
ESR
LH/FSH, TSH, prolactin
U/S—pelvis
17 yo M presents with low back pain that radiates to the left leg and began after he fell on his knee
during gym class. He also describes areas of loss of sensation in his left foot. The pain and sensory loss
do not match any known distribution. He insists on requesting a week off from school because of his
injury. - correct answer-Differential:
*Malingering*
Lumbar muscle strain
Disk herniation
Knee or leg fracture
Ankylosing spondylitis
Workup:
XR—L-spine/knee
MRI—L-spine
ESR, CRP
18 yo F presents with amenorrhea for the past 4 months. BMI is 14.5kg/m2. She attends vigorous
exercises classes frequently and has a history of heat intolerance. - correct answer-Differential:
*Anorexia nervosa*
Pregnancy
complete Questions with correct
Answers
26 yo M presents after falling and losing consciousness at work. He had rhythmic movements of the
limbs, bit his tongue, and lost control of his bladder. He was subsequently confused after regaining
consciousness (as witnessed by his colleagues) - correct answer-Differential:
*Generalized tonic-clonic seizure*
Convulsive syncope
Substance abuse/overdose
Malingering
Hypoglycemia
Workup:
CBC
Electrolytes, glucose
Urine toxicology
EEG
MRI—brain
CT—head
LP—CSF analysis
ECG
34 yo F nurse presents with worsening cough of 6 weeks' duration accompanied by weight loss, fatigue,
night sweats, and fever. She has a history of contact with tuberculosis at work. - correct answer-
Differential:
*Tuberculosis*
Pneumonia
Lung abscess
Vasculitis
Lymphoma
Metastatic cancer
HIV/AIDS
Sarcoidosis
Workup:
CBC
PPD/QuantiFERON-TB Gold
Sputum Gram stain, acid-fast stain, and culture
CXR
CT-chest
Bronchoscopy
HIV antibody
Lymph node biopsy
55 yo F c/o dizziness for the past day. She feels faint and has severe diarrhea that started 2 days ago. She
takes furosemide for hypertension. On examination, she feels dizzy upon standing. - correct answer-
Differential:
,*Orthostatic hypotension due to dehydration* (diarrhea, diuretic use)
Vertebrobasilar insufficiency
Cardiac arrhythmias
Vestibular neuronitis
Labyrinthitis
Benign positional vertigo
Workup:
Orthostatic vital signs
Rectal exam
CBC
Urea, electrolytes
Stool for occult blood
Stool leukocytes
65 yo M presents after falling and losing consciousness for a few seconds. He had no warning before
passing out but recently had palpitations. His history includes a coronary artery bypass graft. - correct
answer-Differential:
*Cardiac arrhythmia (causing syncope)*
Severe aortic stenosis
Syncope (other causes)
Seizure
Pulmonary embolism
Workup:
ECG
Holter monitoring
CBC
Electrolytes, glucose
Echocardiography
CT—head
12 yo F presents with a 2-month history of fighting in school, truancy, and breaking curfew. Her parents
recently divorced, and she just started school in a new district. Before her parents divorced, she was an
average student with no behavioral problems. - correct answer-Differential:
*Adjustment disorder*
Substance intoxication, abuse, or dependence
Oppositional defiant disorder
Conduct disorder
Manic episode
Workup:
Physical exam
Mental status exam
Urine toxicology
1-month-old F is brought in because she has been spitting up her milk for the last 10 days. The vomiting
episodes have increased in frequency and forcefulness. Emesis is nonbloody and nonbilious. The
episodes usually occur immediately after breastfeeding. She has stopped gaining weight. - correct
answer-Differential:
*Pyloric stenosis*
,Partial duodenal atresia
GERD
Gastroenteritis
Hepatitis
UTI
Workup:
CBC
Electrolytes
U/S—abdomen
Barium swallow
Esophageal pH probe
Endoscopy
LFTs, alkaline phosphatase
UA, urine culture
12-month-old M presents with fever for the past 2 days accompanied by a maculopapular rash on his
face and body. He has not yet received the MMR vaccine. - correct answer-Differential:
*Measles (or other viral exanthem)*
Rubella
Roseola
Fifth disease
Varicella
Scarlet fever
Meningitis
Workup:
CBC
Viral antibodies/titers
Throat swab for culture
LP—CSF analysis
14 yo M presents with short stature and lack of sexual development. His birth weight and length were
normal, but he is the shortest child in his class. His father and uncles had the same problem when they
were young, but they are now of normal stature. - correct answer-Differential:
*Constitutional short stature*
Growth hormone (GH) deficiency
Hypothyroidism
Chronic renal insufficiency
Genetic causes
Workup:
CBC with differentials
Electrolytes
GH stimulation test
IGF-1, IGFBP-3 levels
TSH, FT4
XR—hand
U/S—renal and cardiac
BUN/Cr
, 15 yo M presents with a 1-year history of failing grades, school absenteeism, and legal problems,
including shoplifting. His parents report that he spends most of his time alone in his room, adding that
when he does go out, it is with a new set of friends. - correct answer-Differential:
*Substance abuse*
Conduct disorder
Oppositional defiant disorder
Adjustment disorder
Workup:
Urine toxicology
Physical exam
Mental status exam
17 yo F presents with prolonged, excessive menstrual bleeding occurring irregularly within the past 6
months. - correct answer-Differential:
*Dysfunctional uterine bleeding*
Coagulation disorder (eg, von Willebrand's disease, hemophilia)
Cervical cancer
Molar pregnancy
Hypothyroidism
Workup:
Pelvic exam
Pap smear
CBC
PT/PTT
Urine hCG
Cervical culture
ESR
LH/FSH, TSH, prolactin
U/S—pelvis
17 yo M presents with low back pain that radiates to the left leg and began after he fell on his knee
during gym class. He also describes areas of loss of sensation in his left foot. The pain and sensory loss
do not match any known distribution. He insists on requesting a week off from school because of his
injury. - correct answer-Differential:
*Malingering*
Lumbar muscle strain
Disk herniation
Knee or leg fracture
Ankylosing spondylitis
Workup:
XR—L-spine/knee
MRI—L-spine
ESR, CRP
18 yo F presents with amenorrhea for the past 4 months. BMI is 14.5kg/m2. She attends vigorous
exercises classes frequently and has a history of heat intolerance. - correct answer-Differential:
*Anorexia nervosa*
Pregnancy
