Internal Medicine

An 81-year-old man is admitted to the medical ward for symptomatic anemia secondary to newly diagnosed myelodysplastic syndrome. He is currently receiving his second unit of packed red blood cells. Approximately two hours after the initiation of the second transfusion, he develops sudden, severe shortness of breath and an upright posture preference.

Vital signs show a temperature of 37.1 °C (98.8 °F), blood pressure of 182/105 mmHg, heart rate of 115/min, and respiratory rate of 28/min. Oxygen saturation is 84% on room air. Physical examination reveals prominent jugular venous distension. Lung auscultation demonstrates bilateral crackles extending to the mid-lung fields. Cardiac auscultation reveals a normal S1 and S2 with a distinct third heart sound (S3).

Which of the following is the most appropriate initial step in the management of this patient's acute symptom onset?

Match each patient's clinical presentation with the most likely histopathologic or defining structural finding associated with their underlying condition.

Match each clinical scenario to the most appropriate first-line antimicrobial therapy.

Match each clinical presentation of a patient experiencing an adverse event during or shortly after a packed red blood cell (pRBC) transfusion to the most likely underlying pathophysiologic mechanism.

A 68-year-old woman seeks medical attention at the emergency department due to a 3-day history of progressively worsening shortness of breath. She also reports a persistent cough and has been sleeping in a recliner chair because she feels a "smothering" sensation when lying flat. Her past medical history is significant for hypertension, hyperlipidemia, and a 40-pack-year smoking history. Her daily medications include amlodipine, atorvastatin, and low-dose aspirin. Her temperature is 36.9°C (98.4°F), blood pressure is 172/96 mm Hg, pulse is 110/min, and respiratory rate is 26/min. Pulse oximetry is 88% on room air. Physical examination shows jugular venous distention when the patient is seated at a 45-degree angle. Pulmonary auscultation reveals diffuse expiratory wheezes and bilateral crackles at the lung bases that do not clear with coughing. Cardiac auscultation demonstrates a regular tachycardia with a prominent S3 gallop. Bilateral 2+ pitting edema is noted in the lower extremities. Which of the following is the most appropriate initial management for this patient's acute symptoms?

On his fourth day in the surgical intensive care unit, a 48-year-old man requires reassessment due to declining urine output and worsening laboratory parameters. He originally underwent an emergent exploratory laparotomy and bowel resection for blunt abdominal trauma. On postoperative day 1, he developed severe alcohol withdrawal delirium, which has been continuously managed with a high-dose intravenous lorazepam infusion.

His temperature is $37.7^\circ\text{C}$ ($99.9^\circ\text{F}$), blood pressure is $118/76\text{ mm Hg}$, pulse is $102/\text{min}$, and respiratory rate is $22/\text{min}$. The abdomen is non-distended and appropriately tender at the incision site, with no rebound or guarding.

Laboratory results are as follows:

Arterial blood gas analysis on room air reveals:
pH: $7.28$
$PaCO_2$: $30 \text{ mm Hg}$
$PaO_2$: $92 \text{ mm Hg}$

Based on the provided information, which of the following is the most appropriate next step in management?

Paramedics are dispatched to the home of a 42-year-old man after he was discovered unresponsive in his garage. According to his husband, the patient has a history of severe depression and recently experienced a job loss. An empty, unlabeled container of sweet-smelling fluid was found nearby. Vital signs upon arrival at the hospital include a temperature of $36.5^\circ\text{C}$ ($97.7^\circ\text{F}$), blood pressure of $110/70 \text{ mm Hg}$, heart rate of $105/\text{min}$, and respiratory rate of $24/\text{min}$. The patient is obtunded, responding only by withdrawing from painful stimuli.

Laboratory studies are obtained:

Serum chemistry:
Sodium: $138 \text{ mEq/L}$
Potassium: $4.5 \text{ mEq/L}$
Chloride: $102 \text{ mEq/L}$
Bicarbonate: $12 \text{ mEq/L}$
Blood urea nitrogen (BUN): $28 \text{ mg/dL}$
Creatinine: $1.2 \text{ mg/dL}$
Glucose: $108 \text{ mg/dL}$

Arterial blood gas (room air):
pH: $7.22$
$\text{pCO}_2$: $26 \text{ mm Hg}$
$\text{pO}_2$: $95 \text{ mm Hg}$

Additional diagnostics:
Measured serum osmolality: $335 \text{ mOsm/kg H}_2\text{O}$

Based on the provided laboratory data, what is this patient's serum osmolar gap? (Enter the numerical value in $\text{mOsm/kg H}_2\text{O}$)

A $45$-year-old man comes to the clinic reporting a $5$-month history of worsening fatigue, generalized weakness, decreased libido, and cold intolerance. He has also experienced an unintentional weight loss of $5 \text{ kg}$ ($11 \text{ lb}$) and frequent morning headaches. Vital signs show a blood pressure of $96/58 \text{ mm Hg}$ and a pulse of $54\text{/min}$. Physical examination reveals pale skin, sparse axillary and pubic hair, and delayed relaxation phase of deep tendon reflexes. No skin hyperpigmentation is noted.

Laboratory results:
Sodium: $133 \text{ mEq/L}$
Potassium: $4.1 \text{ mEq/L}$
Thyroid-stimulating hormone (TSH): $1.5 \text{ mU/L}$ (Reference: $0.4-4.0 \text{ mU/L}$)
Free thyroxine (T4): $0.4 \text{ ng/dL}$ (Reference: $0.9-1.7 \text{ ng/dL}$)

The physician plans to start levothyroxine for the patient's thyroid dysfunction. Which of the following is the most appropriate next step in management to perform prior to initiating this therapy?

A 65-year-old man is evaluated in the intensive care unit for recent fever. He was admitted 10 days ago for severe acute pancreatitis and required aggressive fluid resuscitation via a right internal jugular central venous catheter. Two days ago, he developed a temperature of $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$) and tachycardia. The central catheter was removed, and peripheral blood cultures were drawn. Empiric intravenous vancomycin and cefepime were initiated. Today, the patient is afebrile and hemodynamically stable. Both sets of blood cultures are positive for *Enterococcus faecalis*. Susceptibility testing demonstrates that the isolate is susceptible to ampicillin, vancomycin, and daptomycin, but resistant to cefepime. Which of the following is the most appropriate next step in this patient's antimicrobial therapy?

A 52-year-old man is brought to the emergency department after vomiting a large volume of bright red blood. He has a known history of decompensated liver cirrhosis secondary to chronic hepatitis C infection. On arrival, his blood pressure is 85/50 mm Hg, and his heart rate is 124/min. He is lethargic but protecting his airway, with an oxygen saturation of 96% on room air. Physical examination reveals scleral icterus, spider angiomas, and a distended abdomen with shifting dullness. Arrange the following management steps in the most appropriate chronological sequence for this patient.

A $45$-year-old female teacher is brought to the emergency department by her husband after she was unable to get out of bed this morning due to severe, generalized muscle weakness. Over the past several years, she has experienced a persistent sensation of sand in her eyes and requires frequent sips of water to swallow dry food. She has no other medical conditions and takes no medications. On physical examination, her vital signs are within normal limits. Bilateral parotid gland enlargement is noted. Neuromuscular examination reveals symmetric $\frac{2}{5}$ motor strength in the proximal muscles of the upper and lower extremities. Deep tendon reflexes are diminished globally.

Laboratory results are as follows:

Arterial blood gas (room air):
pH: $7.25$
$\text{pCO}_2$: $26$ mm Hg
$\text{pO}_2$: $95$ mm Hg

Serum chemistry:
Sodium: $140$ mEq/L
Potassium: $2.1$ mEq/L
Chloride: $116$ mEq/L
Bicarbonate: $12$ mEq/L
Creatinine: $0.9$ mg/dL
Blood urea nitrogen: $14$ mg/dL

Urinalysis:
pH: $6.5$
Specific gravity: $1.015$
Glucose: negative
Protein: negative
Ketones: negative

Which of the following is the most likely underlying mechanism for this patient's clinical presentation?

An emergency department physician is evaluating a primigravida at $34$ weeks gestation who presents with a $2$-day history of gingival bleeding while brushing her teeth and a new rash on her legs. The $31$-year-old patient reports feeling otherwise well and has had uncomplicated prenatal care until now. She denies headache, visual changes, right upper quadrant pain, or uterine contractions. Fetal movement is active.

Vital signs are:
* Temperature: $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$)
* Blood pressure: $118/76$ mmHg
* Heart rate: $88/\text{min}$
* Respiratory rate: $16/\text{min}$

Physical examination reveals a gravid, non-tender uterus and scattered petechiae over both lower extremities. Fetal heart rate monitoring is reassuring.

Laboratory results are as follows:

Peripheral blood smear demonstrates profoundly reduced platelet numbers with a few large platelets. No schistocytes or immature leukocytes are observed.

Which of the following is the most appropriate next step in management?

A 73-year-old woman presents to the emergency department reporting a sudden, painless loss of vision in her right eye that began two hours ago. Over the past week, she has experienced a persistent, severe, right-sided headache, fatigue, and pain in her jaw muscles when chewing. Physical examination reveals a tender, non-pulsatile right temporal artery. Laboratory studies show an erythrocyte sedimentation rate of $95$ mm/h. Arrange the following steps in the most appropriate chronological sequence for the standard diagnostic and therapeutic management of this patient's condition.

A $35$-year-old man with a history of advanced HIV (CD4 count of $45 \text{ cells/mm}^3$) is brought to the emergency department by his partner due to $2$ days of fever, severe headache, and progressive confusion. His temperature is $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$), blood pressure is $110/70 \text{ mmHg}$, and pulse is $115/\text{min}$. Physical examination reveals nuchal rigidity and a positive Brudzinski sign. He is lethargic but withdraws all extremities to pain. Fundoscopic examination shows early papilledema. Suspecting acute bacterial meningitis, the physician decides on a management plan. Arrange the following steps in the most appropriate chronological order of execution for this patient.

A 64-year-old man is evaluated on the medical ward on hospital day 3. He was initially admitted for community-acquired pneumonia and was started on empiric therapy with intravenous ceftriaxone and oral azithromycin. Upon admission, he had a temperature of 38.6°C (101.5°F), a respiratory rate of 24/min, and a right lower lobe infiltrate on chest radiography.

Today, the patient reports significant improvement in his cough and shortness of breath. His temperature is 37.1°C (98.8°F), blood pressure is 122/78 mm Hg, pulse is 76/min, and respiratory rate is 16/min. Pulse oximetry shows 97% on room air. He is tolerating an oral diet well. Sputum culture obtained on admission has grown heavy *Streptococcus pneumoniae*. Susceptibility testing results are as follows:

Blood cultures have shown no growth after 72 hours. Which of the following is the most appropriate modification to this patient's pharmacologic management?

A 65-year-old man is brought to the emergency department due to profound weakness and lethargy. He has experienced large-volume, watery diarrhea for the past 5 days following a recent trip abroad. His medical history is significant for severe chronic obstructive pulmonary disease (COPD) requiring 2 L/min of home oxygen, and hypertension. Current medications include inhaled tiotropium, inhaled fluticasone-salmeterol, and lisinopril.

Temperature is 37.2°C (99.0°F), blood pressure is 98/60 mm Hg, pulse is 114/min, and respirations are 26/min. Physical examination shows dry mucous membranes, delayed capillary refill, and diffusely decreased breath sounds with a prolonged expiratory phase.

Laboratory studies show:
Serum sodium: 136 mEq/L
Serum potassium: 3.1 mEq/L
Serum chloride: 114 mEq/L
Serum bicarbonate: 12 mEq/L
Blood urea nitrogen: 48 mg/dL
Serum creatinine: 1.9 mg/dL

Arterial blood gas (on room air):
pH: 7.24
$PaCO_2$: 36 mm Hg
$PaO_2$: 62 mm Hg

Which of the following best characterizes this patient's acid-base disorder?

A 19-year-old female presents to the university clinic reporting two days of persistent nausea, subjective dizziness, and a continuous buzzing sensation in both ears. She also mentions breathing faster than normal over the last few hours. She recently had a severe viral upper respiratory infection and has been taking an over-the-counter medication for muscle aches and fever.

Vital signs are as follows:
Temperature: $37.2^\circ\text{C} (99.0^\circ\text{F})$
Blood pressure: $118/76 \text{ mmHg}$
Heart rate: $112/\text{min}$
Respiratory rate: $26/\text{min}$
Oxygen saturation: $99\%$ on room air

Which of the following best characterizes this patient's acid-base status?

A 52-year-old man is hospitalized for the treatment of newly diagnosed Burkitt lymphoma. Twenty-four hours after receiving his first dose of systemic chemotherapy, he reports weakness, severe muscle cramps, and nausea. His temperature is 37.2°C (99.0°F), blood pressure is 110/70 mm Hg, pulse is 105/min, and respirations are 16/min.

An electrocardiogram reveals peaked T waves and a prolonged PR interval. Which of the following is the most appropriate immediate next step in management?

A $42$-year-old man is diagnosed with a pheochromocytoma following evaluation for episodic headaches, diaphoresis, and severe hypertension. Elevated plasma fractionated metanephrines and an adrenal mass on magnetic resonance imaging (MRI) confirm the diagnosis. The patient is scheduled for surgical resection of the tumor. Arrange the following management steps in the correct mandatory chronological sequence to safely prepare this patient for surgery.

Emergency medical services bring a $21$-year-old male university student to the resuscitation bay after his roommate found him lethargic and vomiting in their dorm. The patient has a history of type 1 diabetes mellitus but ran out of his prescribed insulin three days ago. On initial assessment, he appears severely dehydrated and is taking deep, rapid breaths. Vital signs include a heart rate of $122/\text{min}$, blood pressure of $90/60 \text{ mm Hg}$, and respiratory rate of $28/\text{min}$. A point-of-care capillary glucose reads $520 \text{ mg/dL}$, and a venous blood gas reveals a pH of $7.12$ with a calculated anion gap of $22 \text{ mEq/L}$. The clinical team establishes large-bore peripheral intravenous access. Arrange the following therapeutic steps in the most appropriate chronological order for managing this patient's metabolic decompensation.