Pathophysiology Case Studies
A 54 year old female patient arrived to the ER after becoming confused and incoherent to family and
having a syncopal episode. Upon arrival to the ER the patient was hypotensive at 75/45, tachycardic at
123, temperature of 100.3 and RR of 20. Blood glucose was 56. CBC was within normal limits. BMP
results showed K+ 6.0 mM and Na+ 127 mM. Further lab tests showed cortisol was decreased and ACTH
was increased, compared with normal. Which of the following is most likely? ANS: Addison's disease
Two weeks after orthopedic surgery, a 62 year-old female presented with uncontrolled pain and
purulent drainage from the surgical incision. She was admitted and taken to the OR for irrigation and
debridement of the infection site. Additionally, she was started on antibiotics to control the infection.
Later that week she started having 3-4 foul smelling watery stools a day, became febrile, and
complained of N/V. Which of the following pathogens is most likely causing her abdominal problems?
ANS: C. diff
A 56 year-old male presents with no specific complaint. He works as a truck driver and has been in 2
accidents recently and his boss insists that he gets "checked out" by a medical professional before he
can drive again. He claims that objects suddenly appear from out of nowhere. He admits to recent loss
of libido and erectile dysfunction. Which of the following is most likely? ANS: prolactinoma
A 63 year-old male presents with depression, confusion, vague pains in his bones, and ulcers. He was
recently diagnosed with kidney stones. Blood tests reveal that PTH is decreased, while both serum Ca++
and phosphate are increased. Which of the following is most likely? ANS: metastatic bone cancer
The mother of a 2-year old girl brings her daughter to the pediatrician's office. The mother states that
the patient has had frequent watery, foul smelling and sometimes greasy stools on and off for the past 3
months. At other times she seems to be constipated. She is noticeably small for her age - in the 50th
percentile for height and 25th percentile for weight. The mother also reports that after the patient's last
cold, the cough did not subside for several weeks and each cough was producing thick, grayish mucus.
Her medical record shows 3 hospitalizations in the past 2 years from respiratory tract infections, all of
which were treated with antibiotics. Today, she appears to be in good health with no apparent cough,
but she looks malnourished and pale. Abdominal ultrasound showed no obstructions or mechanical
blockages, and stool culture revealed normal bacterial growth, without viral infection. Stool sample was
po ANS: cystic fibrosis
,A 2 month-old female presents for evaluation of poor feeding. She is in no apparent acute distress, but
mom reports that she has difficulty with feeding and get short of breath at times. Mom is concerned
that the baby seems to be losing weight and is excessively tired. The baby's weight is below average for
age and length. She is alert at this time and does not appear to be in any acute distress. Respiratory rate
is 41, and auscultation reveals crackles in bilateral bases. Patient is afebrile and has strong peripheral
pulses in upper and lower extremities. Auscultation reveals a HR of 140 with a continuous murmur.
Which scenario is most likely in this patient? ANS: patent ductus ateriosus
A 72 year old male presents to the ED comatose. Vitals are HR 132 (Sinus Tachycardia), BP 87/45. CMP
shows blood glucose 2250 (mg/dl), pH 7.41, Na+ 133, K+ 4.6, Cl- 97, HCO3- 23, and serum osmolarity
356 mOsm. Which scenario is most likely in this patient? ANS: hyperosmolar hyperglycemic non-ketotic
syndrome
One week after a severe strep throat, a 6 year old female patient presents with oliguria. Which type of
glomerular nephritis is most likely in this patient? ANS: acute proliferative (postinfectious)
glomerulonephritis
A 34 y/o female presents to the ED with anxiety, palpitations, and chest pain. She is currently receiving
radiation to the chest as a result of breast cancer. She denies fever, chills, SOB, cough, abdominal pain,
or N/V/D. Vital signs are: T 98.9, BP 90/60, HR 100, RR 26, SpO2 98% RA. Lungs are clear to auscultation
bilaterally. Heart shows regular rhythm with weak S1, S2, and faint rub. Jugular venous distension is
present. Peripheral pulses are weak bilaterally. EKG shows normal sinus rhythm with decreased voltage.
Chest x-ray shows increased cardiac silhouette. Echocardiogram is positive for effusion. Which scenario
is most likely in this patient? ANS: cardiac tamponade
A 23 year-old male presented to the ED with complaints of chest pain of 19 months duration. Chest pain
was aggravated by strenuous activities and moderately relieved with rest. Patient stated a history of
dyspnea on exertion and effort intolerance since childhood. Patient remembered frequent squatting to
relieve episodes of breathlessness following exertion. Patient denies history of cough, change in urine or
bowels, leg swelling, nocturia or oliguria. General examination showed central cyanosis with digital
clubbing. Pulse was regular with a rate of 80 BPM, and BP was 120/70 mmHg. Cardiac examination
found a systolic murmur. The lungs were clear and abdomen was non-tender. Chest radiograph showed
enlarged heart with pulmonary oligemia with right ventricular hypertrophy. There was no aortic or
mitral regurgitation. Patient Hct was 72%. Which scenario is most likely in this patient? ANS: Tetralogy
of Fallot
, A 3 year old presents to the ER with acute left sided facial palsy. Patient's mother states her son has
been irritable over the last few weeks. His current VS include: 36.6 degrees C, HR 80 bpm in sinus
rhythm, BP 180/110, RR 22, and oxygen saturation of 99% on RA. On assessment, patient has a normal
neurologic exam except for his left sided facial palsy. He has no cardiac murmur and has 2+ pulses on
both upper and lower extremities. His lungs are clear to auscultation. Patient is placed on a cardiac
monitor, which continues to show a normal HR and rhythm. A CT scan is negative for a cranial bleed. The
following labs are all normal: CBC, serum electrolytes, BUN, creatinine, urinalysis and urine culture.
Patient undergoes an ultrasound of the kidneys and abdomen followed by a magnetic resonance
angiography (MRA) of the kidneys. These results indicate a unilateral stenosis of the right renal artery.
Which scenario is m ANS: only the right kidney is producing excessive renin
A 14 year old previously healthy female presents to the ED. She has a 2 day history of increased fatigue,
thirst, and frequent urination. She has "fruity" breath odor, and her blood glucose is > 600 mg/dl. Which
of the following is expected? ANS: she has elevated anion gap acidosis, urinalysis will show ketones, she
has decreased PaCO2, she has dehydration due to polyuria
A 73-year-old male, presents to the ED with a primary complaint of chest pain. He has past medical
history of type II diabetes, hypertension, hyperlipidemia, stroke, dementia, complete heart block with
permanent pacemaker placement, and bladder cancer. Upon admission to the ED, he is alert but
confused, and complains of severe pain/heaviness to his chest. Patient is diaphoretic and short of
breath. EKG reveals ST segment elevation. Cardiac enzymes are elevated, and serial cardiac enzymes
demonstrate a peak in Troponin. Which scenario is most likely in this patient? ANS: myocardial
infarction
A 23 y/o female presents to the ED with general weakness and vomiting. Her PMH includes IDDM. ROS is
positive for polyuria, and polydipsia. Pt also reports dysuria that started 3 days prior. Pt denies SOB or
cough, chest pain, abdominal pain, bloating, and change in bowel habits. Vitals include: Temp: 101.2, BP:
120/80, HR: 120, RR: 24, SpO2: 98% on RA. She is AAOx3, but drowsy, lungs are CTAB, and heart sounds
are normal with tachycardia. Lab tests reveal: Na+: 149 mEq/L; K+: 3.2 mEq/L; HCO3-: 16 mEq/L; pH: 7.2;
Anion gap: 18; plasma glucose: 455 mg/dL. Urinalysis was positive for ketones, leukocyte esterase,
nitrites, and WBCs. Which of the following best explains the patient's symptoms? ANS: diabetic
ketoacidosis
An 82 year old male was brought to the ED after a syncopal (fainting) episode at his nursing facility.
Assessment includes a hematoma above the left eye and the patient reports decreased urine output and
blurry vision at times. Vitals include: BP 113/68, HR 118, RR 18, Temp 36.9, and SpO2 96% on room air.
A 54 year old female patient arrived to the ER after becoming confused and incoherent to family and
having a syncopal episode. Upon arrival to the ER the patient was hypotensive at 75/45, tachycardic at
123, temperature of 100.3 and RR of 20. Blood glucose was 56. CBC was within normal limits. BMP
results showed K+ 6.0 mM and Na+ 127 mM. Further lab tests showed cortisol was decreased and ACTH
was increased, compared with normal. Which of the following is most likely? ANS: Addison's disease
Two weeks after orthopedic surgery, a 62 year-old female presented with uncontrolled pain and
purulent drainage from the surgical incision. She was admitted and taken to the OR for irrigation and
debridement of the infection site. Additionally, she was started on antibiotics to control the infection.
Later that week she started having 3-4 foul smelling watery stools a day, became febrile, and
complained of N/V. Which of the following pathogens is most likely causing her abdominal problems?
ANS: C. diff
A 56 year-old male presents with no specific complaint. He works as a truck driver and has been in 2
accidents recently and his boss insists that he gets "checked out" by a medical professional before he
can drive again. He claims that objects suddenly appear from out of nowhere. He admits to recent loss
of libido and erectile dysfunction. Which of the following is most likely? ANS: prolactinoma
A 63 year-old male presents with depression, confusion, vague pains in his bones, and ulcers. He was
recently diagnosed with kidney stones. Blood tests reveal that PTH is decreased, while both serum Ca++
and phosphate are increased. Which of the following is most likely? ANS: metastatic bone cancer
The mother of a 2-year old girl brings her daughter to the pediatrician's office. The mother states that
the patient has had frequent watery, foul smelling and sometimes greasy stools on and off for the past 3
months. At other times she seems to be constipated. She is noticeably small for her age - in the 50th
percentile for height and 25th percentile for weight. The mother also reports that after the patient's last
cold, the cough did not subside for several weeks and each cough was producing thick, grayish mucus.
Her medical record shows 3 hospitalizations in the past 2 years from respiratory tract infections, all of
which were treated with antibiotics. Today, she appears to be in good health with no apparent cough,
but she looks malnourished and pale. Abdominal ultrasound showed no obstructions or mechanical
blockages, and stool culture revealed normal bacterial growth, without viral infection. Stool sample was
po ANS: cystic fibrosis
,A 2 month-old female presents for evaluation of poor feeding. She is in no apparent acute distress, but
mom reports that she has difficulty with feeding and get short of breath at times. Mom is concerned
that the baby seems to be losing weight and is excessively tired. The baby's weight is below average for
age and length. She is alert at this time and does not appear to be in any acute distress. Respiratory rate
is 41, and auscultation reveals crackles in bilateral bases. Patient is afebrile and has strong peripheral
pulses in upper and lower extremities. Auscultation reveals a HR of 140 with a continuous murmur.
Which scenario is most likely in this patient? ANS: patent ductus ateriosus
A 72 year old male presents to the ED comatose. Vitals are HR 132 (Sinus Tachycardia), BP 87/45. CMP
shows blood glucose 2250 (mg/dl), pH 7.41, Na+ 133, K+ 4.6, Cl- 97, HCO3- 23, and serum osmolarity
356 mOsm. Which scenario is most likely in this patient? ANS: hyperosmolar hyperglycemic non-ketotic
syndrome
One week after a severe strep throat, a 6 year old female patient presents with oliguria. Which type of
glomerular nephritis is most likely in this patient? ANS: acute proliferative (postinfectious)
glomerulonephritis
A 34 y/o female presents to the ED with anxiety, palpitations, and chest pain. She is currently receiving
radiation to the chest as a result of breast cancer. She denies fever, chills, SOB, cough, abdominal pain,
or N/V/D. Vital signs are: T 98.9, BP 90/60, HR 100, RR 26, SpO2 98% RA. Lungs are clear to auscultation
bilaterally. Heart shows regular rhythm with weak S1, S2, and faint rub. Jugular venous distension is
present. Peripheral pulses are weak bilaterally. EKG shows normal sinus rhythm with decreased voltage.
Chest x-ray shows increased cardiac silhouette. Echocardiogram is positive for effusion. Which scenario
is most likely in this patient? ANS: cardiac tamponade
A 23 year-old male presented to the ED with complaints of chest pain of 19 months duration. Chest pain
was aggravated by strenuous activities and moderately relieved with rest. Patient stated a history of
dyspnea on exertion and effort intolerance since childhood. Patient remembered frequent squatting to
relieve episodes of breathlessness following exertion. Patient denies history of cough, change in urine or
bowels, leg swelling, nocturia or oliguria. General examination showed central cyanosis with digital
clubbing. Pulse was regular with a rate of 80 BPM, and BP was 120/70 mmHg. Cardiac examination
found a systolic murmur. The lungs were clear and abdomen was non-tender. Chest radiograph showed
enlarged heart with pulmonary oligemia with right ventricular hypertrophy. There was no aortic or
mitral regurgitation. Patient Hct was 72%. Which scenario is most likely in this patient? ANS: Tetralogy
of Fallot
, A 3 year old presents to the ER with acute left sided facial palsy. Patient's mother states her son has
been irritable over the last few weeks. His current VS include: 36.6 degrees C, HR 80 bpm in sinus
rhythm, BP 180/110, RR 22, and oxygen saturation of 99% on RA. On assessment, patient has a normal
neurologic exam except for his left sided facial palsy. He has no cardiac murmur and has 2+ pulses on
both upper and lower extremities. His lungs are clear to auscultation. Patient is placed on a cardiac
monitor, which continues to show a normal HR and rhythm. A CT scan is negative for a cranial bleed. The
following labs are all normal: CBC, serum electrolytes, BUN, creatinine, urinalysis and urine culture.
Patient undergoes an ultrasound of the kidneys and abdomen followed by a magnetic resonance
angiography (MRA) of the kidneys. These results indicate a unilateral stenosis of the right renal artery.
Which scenario is m ANS: only the right kidney is producing excessive renin
A 14 year old previously healthy female presents to the ED. She has a 2 day history of increased fatigue,
thirst, and frequent urination. She has "fruity" breath odor, and her blood glucose is > 600 mg/dl. Which
of the following is expected? ANS: she has elevated anion gap acidosis, urinalysis will show ketones, she
has decreased PaCO2, she has dehydration due to polyuria
A 73-year-old male, presents to the ED with a primary complaint of chest pain. He has past medical
history of type II diabetes, hypertension, hyperlipidemia, stroke, dementia, complete heart block with
permanent pacemaker placement, and bladder cancer. Upon admission to the ED, he is alert but
confused, and complains of severe pain/heaviness to his chest. Patient is diaphoretic and short of
breath. EKG reveals ST segment elevation. Cardiac enzymes are elevated, and serial cardiac enzymes
demonstrate a peak in Troponin. Which scenario is most likely in this patient? ANS: myocardial
infarction
A 23 y/o female presents to the ED with general weakness and vomiting. Her PMH includes IDDM. ROS is
positive for polyuria, and polydipsia. Pt also reports dysuria that started 3 days prior. Pt denies SOB or
cough, chest pain, abdominal pain, bloating, and change in bowel habits. Vitals include: Temp: 101.2, BP:
120/80, HR: 120, RR: 24, SpO2: 98% on RA. She is AAOx3, but drowsy, lungs are CTAB, and heart sounds
are normal with tachycardia. Lab tests reveal: Na+: 149 mEq/L; K+: 3.2 mEq/L; HCO3-: 16 mEq/L; pH: 7.2;
Anion gap: 18; plasma glucose: 455 mg/dL. Urinalysis was positive for ketones, leukocyte esterase,
nitrites, and WBCs. Which of the following best explains the patient's symptoms? ANS: diabetic
ketoacidosis
An 82 year old male was brought to the ED after a syncopal (fainting) episode at his nursing facility.
Assessment includes a hematoma above the left eye and the patient reports decreased urine output and
blurry vision at times. Vitals include: BP 113/68, HR 118, RR 18, Temp 36.9, and SpO2 96% on room air.
