Internal Medicine

Antimicrobial stewardship emphasizes selecting the appropriate agent, dose, and duration while minimizing unnecessary broad-spectrum coverage to prevent resistance. Match each of the following common infectious disease presentations with the most appropriate guideline-concordant initial management strategy.

A $62$-year-old woman is brought to the emergency department by her husband due to progressive confusion, profound weakness, and mild shortness of breath over the past $3$ days. She has a history of estrogen receptor-positive breast cancer treated with lumpectomy and radiation $4$ years ago. Two months ago, she developed severe back pain and was diagnosed with widespread osteolytic metastases. For the past week, she has been extremely thirsty, urinating frequently, and has not had a bowel movement in $4$ days. Her husband reports she has become increasingly lethargic today.

Vital signs are: temperature $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), pulse $112$/min, blood pressure $88/55$ mm Hg, and respirations $18$/min.

Physical examination reveals dry mucous membranes and decreased skin turgor. The lungs are clear to auscultation. Heart sounds are rapid but regular. The abdomen is mildly distended with decreased bowel sounds. Neurologic examination shows a lethargic patient who is oriented to name only.

Which of the following is the most appropriate initial step in the management of this patient's current condition?

A 74-year-old man is hospitalized for the management of melena and severe symptomatic anemia. He has a notable medical history of essential hypertension, type 2 diabetes mellitus, and stage 3 chronic kidney disease. Upon admission, his hemoglobin level is $5.8 \text{ g/dL}$, and he is prescribed three units of packed red blood cells. Approximately 30 minutes into the transfusion of the third unit, the patient reports sudden-onset shortness of breath and a dry cough.

Current vital signs include a temperature of $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure of $178/96 \text{ mm Hg}$, heart rate of $115/\text{min}$, and respiratory rate of $26/\text{min}$. Pulse oximetry displays an oxygen saturation of $86\%$ while breathing room air.

Physical examination shows prominent jugular venous distention when the patient is seated at a 45-degree angle. Auscultation of the lungs reveals bilateral basilar crackles without any audible wheezing. Cardiac examination demonstrates a regular tachycardia with a prominent S3 gallop.

An arterial blood gas analysis on room air yields the following results:

pH: $7.28$
PaCO $_2$: $56 \text{ mm Hg}$
PaO $_2$: $52 \text{ mm Hg}$
HCO $_3^-$: $25 \text{ mEq/L}$

A portable chest radiograph displays bilateral pulmonary infiltrates, an enlarged cardiac silhouette, and widening of the vascular pedicle.

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

A 73-year-old man presents to the emergency department with severe, progressively worsening shortness of breath over the past 48 hours. His medical history is significant for ischemic cardiomyopathy with a left ventricular ejection fraction of 35%, severe chronic obstructive pulmonary disease, and stage 3 chronic kidney disease. The patient reports having to sleep upright in a chair to breathe. Temperature is 37.0°C (98.6°F), blood pressure is 168/94 mm Hg, pulse is 112/min, and respirations are 26/min. Pulse oximetry shows 86% on room air. Physical examination reveals use of accessory muscles of respiration. Jugular venous pressure is estimated at 10 cm $H_2O$. Chest auscultation reveals bilateral basilar crackles extending to the mid-lung fields and prolonged expiration with diffuse end-expiratory wheezes. Lower extremities show 2+ pitting edema.

Laboratory results are as follows:
Sodium: 138 mEq/L
Potassium: 4.8 mEq/L
Chloride: 104 mEq/L
Bicarbonate: 16 mEq/L
Blood urea nitrogen: 42 mg/dL
Creatinine: 2.1 mg/dL (baseline 1.8 mg/dL)
Lactic acid: 3.8 mmol/L
Thyroid-stimulating hormone (TSH): 0.9 $\mu$ U/mL (Normal: 0.4-4.0 $\mu$ U/mL)
Free T4: 0.6 ng/dL (Normal: 0.9-1.7 ng/dL)

Arterial blood gas on room air:
pH: 7.30
$PaCO_2$: 31 mm Hg
$PaO_2$: 54 mm Hg

Chest radiograph demonstrates cardiomegaly, bilateral hazy perihilar opacities, and cephalization of the pulmonary vessels without focal consolidation. Which of the following is the most appropriate next step in management?

Match each gastrointestinal disorder to its primary underlying pathophysiological mechanism of malabsorption or characteristic histologic finding.

An ambulatory 29-year-old male construction worker presents to his primary care provider with a 6-month history of progressive fatigue, diminished libido, and a 6-kg (13-lb) weight gain. He states that he feels constantly sluggish and cold, even during warm weather. Fourteen months ago, he sustained a severe traumatic brain injury during a scaffolding collapse at work, which required a 3-week stay in the intensive care unit. His blood pressure is 105/70 mm Hg, and his pulse is 55/min. Physical examination reveals pale skin, sparse axillary and pubic hair, and a delayed relaxation phase of the deep tendon reflexes.

Laboratory studies show:

Which of the following is the most appropriate next step in the diagnostic evaluation of this patient?

A 51-year-old man is currently hospitalized for the management of acute complicated diverticulitis. Four days ago, he presented with severe left lower quadrant abdominal pain, and a computed tomography scan revealed a $4.2\text{-cm}$ pericolic abscess. The abscess was successfully managed with computed tomography-guided percutaneous drainage. Due to a documented history of extended-spectrum beta-lactamase (ESBL) urinary tract infections, he was empirically started on intravenous meropenem upon admission.

Today, the patient reports feeling well and his abdominal pain has completely resolved. He is tolerating a regular diet without nausea. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $122/78\text{ mmHg}$, and pulse is $76/\text{min}$. His leukocyte count has decreased from $17,500/\text{mm}^3$ at admission to $7,200/\text{mm}^3$. The percutaneous drain output has been negligible for the past 24 hours, and the catheter was removed this morning.

The finalized abscess fluid culture demonstrates heavy growth of *Escherichia coli* and *Bacteroides fragilis*. Susceptibility testing of the *E. coli* isolate reveals sensitivity to amoxicillin-clavulanate, ceftriaxone, and ciprofloxacin, with no evidence of ESBL production.

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

Match the following high-resolution esophageal manometry (HRM) profiles based on the Chicago Classification to their most appropriate clinical diagnoses.

A $24$-year-old woman presents to the emergency department with a $2$-day history of severe abdominal cramps and frequent, grossly bloody diarrhea. She recalls eating an undercooked hamburger at a picnic $4$ days prior. Her temperature is $37.2^\circ\mathrm{C}$ ($99.0^\circ\mathrm{F}$), blood pressure is $110/70\text{ mmHg}$, and pulse is $105\text{/min}$. Physical examination reveals diffuse abdominal tenderness without rebound or guarding. Suspecting an infection with enterohemorrhagic \textit{Escherichia coli} (EHEC), arrange the following clinical management steps in the most appropriate chronological order.

A $71$-year-old male is transported to the emergency room by emergency medical services after his family found him writhing in severe abdominal pain. He reports a $3$-day history of colicky abdominal pain, intractable nausea, and bilious vomiting. He has not passed stool or flatus for the past $48$ hours. His medical history includes hypertension, hyperlipidemia, and an open partial colectomy performed $8$ years ago. On arrival, his temperature is $39.4^\circ\text{C}$ ($102.9^\circ\text{F}$), blood pressure is $88/50\text{ mmHg}$, pulse is $128/\text{min}$, and respiratory rate is $26/\text{min}$. Physical examination reveals a tensely distended abdomen. There is diffuse, severe tenderness to palpation with involuntary guarding and positive rebound tenderness. Auscultation reveals a complete absence of bowel sounds.

Laboratory studies show:

An upright abdominal radiograph displays multiple dilated loops of small bowel with prominent air-fluid levels and a complete absence of gas in the colon and rectum.

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

An inpatient oncology service evaluates a 29-year-old man who developed a sudden fever. He is currently on day 12 of induction chemotherapy for acute myeloid leukemia. He reports feeling profoundly fatigued but denies cough, shortness of breath, dysuria, abdominal pain, or diarrhea. Vital signs show a temperature of 38.9°C (102.0°F), blood pressure of 118/74 mm Hg, pulse of 98/min, and respirations of 16/min. Physical examination reveals clear lung fields bilaterally, no cardiac murmurs, and a non-tender abdomen. The insertion site of his right internal jugular central venous catheter is clean, dry, and intact with no surrounding erythema, induration, or purulent discharge. Laboratory studies are significant for a leukocyte count of $300/\text{mm}^3$ with $10\%$ neutrophils (Absolute Neutrophil Count = $30/\text{mm}^3$). Which of the following is the most appropriate next step in the management of this patient?

A 45-year-old man is hospitalized due to severe acute pancreatitis secondary to alcohol use. He is admitted to the intensive care unit and managed with aggressive intravenous fluid resuscitation, analgesia, and enteral nutrition. On day 3 of hospitalization, the patient develops a temperature of $38.8^{\circ}\text{C}$ ($101.8^{\circ}\text{F}$). His blood pressure is $112/70\text{ mmHg}$, pulse is $114\text{/min}$, and respirations are $22\text{/min}$. Physical examination shows a distended abdomen with severe epigastric tenderness but no rebound or guarding.

Laboratory studies show a leukocyte count of $18,500/\text{mm}^3$ and a serum lipase of $1,200\text{ U/L}$. A contrast-enhanced CT scan of the abdomen reveals acute inflammation of the pancreas with a $6\text{-cm}$ area of non-enhancement in the pancreatic body and tail, consistent with $>30\%$ pancreatic necrosis. There is no gas observed within the necrotic collection. The gallbladder is surgically absent, and the biliary tree is not dilated. Blood, urine, and sputum cultures are obtained.

What is the most appropriate next step in management?

A 52-year-old woman presents to the emergency department with a 2-day history of left lower quadrant abdominal pain. The pain is constant and described as a dull ache. She reports mild nausea but no vomiting, diarrhea, or hematochezia. Her medical history is unremarkable, and she takes no daily medications. Temperature is 37.3°C (99.1°F), blood pressure is 128/82 mmHg, pulse is 84/min, and respirations are 14/min. Abdominal examination reveals focal tenderness in the left lower quadrant without guarding, rigidity, or rebound tenderness. Bowel sounds are normal. Laboratory testing shows a leukocyte count of 9,500/mm³ with a normal differential. A CT scan of the abdomen and pelvis with intravenous contrast demonstrates wall thickening and peri-colic fat stranding in the sigmoid colon. There is no evidence of an abscess, stricture, fistula, or free intraperitoneal air. The patient is able to tolerate oral fluids without difficulty. Which of the following is the most appropriate next step in management?

Medical staff are reassessing a $65$-year-old female patient in the critical care ward due to increasing somnolence and tachypnea. The patient was hospitalized $72$ hours prior for septic shock complicating severe community-acquired pneumonia. Initial management included aggressive intravenous fluid resuscitation and empiric antimicrobial therapy with intravenous vancomycin and piperacillin-tazobactam. She has a past medical history of chronic obstructive pulmonary disease and left ventricular hypertrophy. Yesterday, her hemodynamics improved, allowing the discontinuation of vasopressor support. Today, the blood cultures obtained on admission demonstrate heavy growth of Streptococcus pneumoniae, which is reported as susceptible to ceftriaxone and penicillin.

Currently, the patient appears lethargic and is using accessory muscles of respiration. Current vital signs include a temperature of $37.8^\circ C$ ($100.0^\circ F$), blood pressure of $115/75\ mmHg$, heart rate of $105/min$, and a respiratory rate of $30/min$. Pulse oximetry indicates an oxygen saturation of $90\%$ while receiving supplemental oxygen via a high-flow nasal cannula. Physical examination reveals diminished breath sounds bilaterally without jugular venous distention. A bedside point-of-care ultrasound demonstrates a collapsible inferior vena cava and a predominant A-line pattern bilaterally without significant B-lines.

Laboratory evaluation is notable for:
Sodium: $138\ mEq/L$
Chloride: $104\ mEq/L$
Bicarbonate: $15\ mEq/L$
Blood urea nitrogen: $32\ mg/dL$
Creatinine: $1.8\ mg/dL$

An arterial blood gas analysis reveals:
$pH$: $7.22$
$PaCO_2$: $38\ mmHg$
$PaO_2$: $62\ mmHg$
$HCO_3^-$: $15\ mEq/L$

Which of the following are appropriate next steps in the management of this patient? (Select all that apply)

A $29$-year-old woman is brought to the emergency department by her husband due to severe dizziness, lethargy, and confusion that has worsened over the past $48$ hours. She gave birth to a healthy infant $5$ months ago; the delivery was complicated by uterine atony and severe postpartum hemorrhage requiring emergent transfusion of $4$ units of packed red blood cells. Since the delivery, she has been unable to breastfeed and has not resumed menstruation. Her pulse is $115$/min, and blood pressure is $82/50$ mm Hg. Physical examination reveals delayed capillary refill, dry mucous membranes, and loss of axillary and pubic hair. Laboratory studies show:

Serum sodium: $131$ mEq/L
Serum potassium: $4.1$ mEq/L
Serum glucose: $58$ mg/dL
Thyroid-stimulating hormone (TSH): $0.3$ mU/L (Normal: $0.5$ - $5.0$)
Free thyroxine (T4): $0.5$ ng/dL (Normal: $0.9$ - $1.7$)

Which of the following is the most appropriate initial step in the management of this patient?

Match each patient's clinical presentation with the most likely corresponding finding on a peripheral blood smear.

A $24$-year-old woman is brought to the emergency department due to progressive confusion, nausea, vomiting, and severe abdominal pain over the past $24$ hours. She has a history of type 1 diabetes mellitus but reports running out of her medications three days ago. Her temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $90/60\text{ mmHg}$, pulse is $128\text{/min}$, and respirations are $26\text{/min}$ and deep. Mucous membranes are dry. Laboratory studies show:

Blood glucose: $650\text{ mg/dL}$
Serum sodium: $132\text{ mEq/L}$
Serum potassium: $3.1\text{ mEq/L}$
Serum chloride: $98\text{ mEq/L}$
Serum bicarbonate: $11\text{ mEq/L}$
Arterial pH: $7.15$
Serum ketones: Positive

Arrange the following therapeutic interventions in the correct chronological order for the evidence-based management of this patient's condition.

A 54-year-old man is brought to the emergency department by paramedics after being found stuporous in a local park. Beside him, paramedics found several empty bottles of antifreeze. His temperature is $36.5^\circ\text{C}$ ($97.7^\circ\text{F}$), blood pressure is $105/65\text{ mmHg}$, pulse is $98/\text{min}$, and respirations are $14/\text{min}$. Physical examination reveals a lethargic patient who arouses to painful stimuli but is unable to answer questions. Cardiopulmonary examination is unremarkable.

The following laboratory results are obtained:

Arterial blood gas analysis on room air reveals:

Which of the following best describes this patient's primary acid-base disturbance(s)?

A $62$-year-old woman presents to the emergency department with a sudden onset of right-sided chest pain that worsens with deep inspiration, accompanied by severe shortness of breath. Her symptoms started $2$ hours ago. She recently returned from a $12$-hour international flight. Her medical history includes hypertension and osteoarthritis. She takes amlodipine and acetaminophen.

Upon evaluation, her temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $118/76\text{ mmHg}$, pulse is $118/\text{min}$, and respiratory rate is $26/\text{min}$. Oxygen saturation is $89\%$ on room air. Physical examination reveals clear lung fields bilaterally with no wheezing or crackles. Cardiac examination shows a regular, rapid rhythm with no murmurs, rubs, or gallops. The right calf is mildly swollen and tender to palpation compared to the left.

An arterial blood gas analysis on room air reveals:
pH: $7.52$
$\text{PaCO}_2$: $26\text{ mmHg}$
$\text{PaO}_2$: $60\text{ mmHg}$
$\text{HCO}_3^-$: $21\text{ mEq/L}$

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

A 38-year-old man presents to the clinic with a 3-month history of episodic, severe headaches accompanied by profuse sweating and a racing heartbeat. His blood pressure in the clinic is 178/104 mmHg, and his heart rate is 108/min. He has no other significant past medical history and takes no medications. Physical examination is unremarkable. Suspecting a specific catecholamine-secreting neuroendocrine tumor, the physician plans to evaluate and treat the patient. Arrange the following steps in the correct chronological order for the appropriate evidence-based diagnosis and management of this patient's condition.