Internal Medicine

A 62-year-old man is brought to the emergency department by emergency medical services due to severe confusion and lethargy. His family reports that he has been increasingly difficult to arouse since yesterday morning. The patient has end-stage renal disease secondary to hypertensive nephrosclerosis and normally receives hemodialysis three days a week. However, he missed his last two scheduled treatments due to transportation issues. His past medical history is also significant for severe chronic obstructive pulmonary disease, for which he requires continuous home oxygen therapy.

Upon arrival, his temperature is $36.8^\circ C$ ($98.2^\circ F$), blood pressure is $158/92$ mm Hg, heart rate is $105$/min, and respiratory rate is $12$/min and shallow. He is somnolent and oriented only to person. Pulmonary examination reveals a prolonged expiratory phase with diffuse expiratory wheezing.

Arterial blood gas and serum laboratory analysis reveal the following:

Based on these laboratory findings, which of the following best describes this patient's primary acid-base abnormalities?

Match each clinical presentation and coagulation laboratory profile to the most likely underlying hematologic diagnosis.

A 29-year-old woman is brought to the emergency department by her husband due to severe left-sided back pain, nausea, and shaking chills that began $48$ hours ago. Her temperature is $39.2^{\circ}C$ ($102.6^{\circ}F$), blood pressure is $86/50$ mmHg, pulse is $128$/min, and respiratory rate is $28$/min. Physical examination reveals flushed skin, dry mucous membranes, and marked left costovertebral angle tenderness. Laboratory testing reveals the following:

Based on the laboratory results, which of the following best characterizes this patient's acid-base status?

Match each clinical presentation of infective endocarditis with the most likely causative microorganism.

A 52-year-old man comes to the primary care clinic reporting a 7-month history of progressive fatigue, feeling constantly cold, and worsening constipation. He also mentions a reduced libido and difficulty achieving erections over the same period. His only significant medical history is essential hypertension treated with amlodipine. His vital signs show a temperature of $36.2^\circ\text{C}$ ($97.2^\circ\text{F}$), blood pressure of 108/68 mm Hg, and heart rate of 50/min. Physical examination reveals dry skin, thinning of the lateral eyebrows, and delayed relaxation of the ankle reflexes. His testes are soft and bilaterally decreased in volume.

Initial laboratory studies reveal:

Which of the following is the most likely pathophysiologic mechanism for this patient's thyroid laboratory profile?

A 31-year-old man is diagnosed with active ankylosing spondylitis. His symptoms are currently confined to the axial skeleton, presenting as severe inflammatory back pain and profound morning stiffness. Arrange the following pharmacologic management steps in the correct chronological sequence for escalating his therapy, assuming he experiences inadequate clinical responses at each preceding stage.

A 24-year-old woman comes to the clinic for a routine follow-up evaluation. Three months ago, she was prescribed a combined oral contraceptive pill for primary dysmenorrhea and mild facial acne. She reports that her menstrual cramps have significantly improved and she is satisfied with the medication. She has no other medical conditions and takes no other medications. She denies any fatigue, weight changes, palpitations, heat or cold intolerance, or changes in bowel habits.

Her blood pressure is 112/72 mm Hg, and pulse is 70/min. Physical examination reveals a normal-sized, non-tender thyroid gland with no palpable nodules. Her skin is warm and dry, and there is mild residual acne on her chin.

Laboratory studies are obtained as part of a routine health screening:
Thyroid-stimulating hormone (TSH): $1.7 \text{ \mu U/mL}$ (Normal: $0.4-4.0 \text{ \mu U/mL}$)
Free thyroxine (Free T4): $1.3 \text{ ng/dL}$ (Normal: $0.8-1.8 \text{ ng/dL}$)
Total thyroxine (Total T4): $14.2 \text{ \mu g/dL}$ (Normal: $4.5-10.9 \text{ \mu g/dL}$)

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

A 64-year-old man is evaluated in the intensive care unit on hospital day 3. He was admitted with septic shock secondary to an obstructing right ureteral calculus. A percutaneous nephrostomy tube was placed shortly after admission. Empiric therapy with intravenous vancomycin and meropenem was initiated. Today, his temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $118/74\text{ mmHg}$, and pulse is $82/\text{min}$. Vasopressors were weaned off yesterday. Blood and urine cultures obtained at admission both grow *Enterobacter cloacae*. Susceptibility testing results for both isolates are as follows:

Based on these results and the patient's clinical improvement, which of the following is the most appropriate next step in pharmacotherapy?

A 58-year-old man is hospitalized for acute ascending cholangitis. On admission, he presented with fever, jaundice, and right upper quadrant abdominal pain. He was started on empiric intravenous piperacillin-tazobactam, and an endoscopic retrograde cholangiopancreatography (ERCP) was performed, successfully removing a common bile duct stone and establishing biliary drainage. Forty-eight hours later, the patient is afebrile, his vital signs are stable, and his abdominal pain has significantly improved. Both blood and bile cultures grow Escherichia coli. Susceptibility testing indicates the organism is susceptible to ceftriaxone, ciprofloxacin, and piperacillin-tazobactam. Which of the following is the most appropriate next step in antibiotic management?

Match each of the following clinical vignettes and laboratory profiles to the most accurate underlying pathophysiologic mechanism.

A $58$-year-old man comes to the clinic reporting a $4$-month history of difficulty swallowing. He initially noticed a sensation of food "getting stuck" in his lower chest when eating solid foods such as meat and bread. Over the past few weeks, this sensation has progressed to involve softer foods. The patient also reports an unintentional $6\text{-kg}$ ($13.2\text{-lb}$) weight loss during this period. His past medical history is significant for frequent episodes of burning substernal chest pain over the last $15$ years, which he has managed intermittently with over-the-counter calcium carbonate antacids. He has a $30$-pack-year smoking history. Vital signs are within normal limits. Physical examination reveals a thin, well-appearing man with an unremarkable abdominal exam. Laboratory studies show a hemoglobin of $11.2\text{ g/dL}$ and a mean corpuscular volume of $78\text{ fL}$. Which of the following is the most appropriate next step in management?

A 45-year-old man is evaluated during hospital rounds. He was admitted 3 days ago for fever, productive cough, and pleuritic chest pain. A chest radiograph on admission showed a right lower lobe consolidation, and he was diagnosed with community-acquired pneumonia. Empiric therapy with intravenous ceftriaxone and oral azithromycin was initiated. He has no significant past medical history and takes no daily medications. He has no known drug allergies. Today, the patient reports feeling significantly better. His temperature is 37.1°C (98.8°F), blood pressure is 120/80 mmHg, pulse is 78/min, and respiratory rate is 16/min. Oxygen saturation is 98% on room air. Blood cultures obtained on admission are now growing *Streptococcus pneumoniae*. Susceptibility testing indicates the isolate is highly susceptible to penicillin, ceftriaxone, and levofloxacin, but resistant to macrolides. The patient is tolerating a regular diet without difficulty. Which of the following is the most appropriate next step in pharmacotherapy?

A $42$-year-old man is brought to the emergency department due to severe, generalized abdominal pain and recurrent, bilious vomiting for the past $24$ hours. He has a $10$-year history of stricturing Crohn's disease, for which he takes adalimumab. The patient reports that he has not passed flatus or had a bowel movement for the last two days. Two days prior to symptom onset, he sustained a blunt abdominal trauma after tripping and falling against a low wall, but he did not seek medical care at that time.

His temperature is $39.2^\circ \text{C}$ ($102.6^\circ \text{F}$), heart rate is $128$/min, blood pressure is $82/50$ mm Hg, and respiratory rate is $24$/min. Physical examination reveals a distended, rigid abdomen with diffuse rebound tenderness and involuntary guarding. Bowel sounds are absent.

Laboratory studies show:
Leukocyte count: $22,000/\mu \text{L}$
Hemoglobin: $11.2 \text{ g/dL}$
Platelet count: $350,000/\mu \text{L}$
Serum lactate: $5.8 \text{ mmol/L}$

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

A 58-year-old male is evaluated in the urgent care clinic for a three-week history of progressive facial swelling, hoarseness, and difficulty breathing. He reports that his symptoms worsen significantly when he bends forward to tie his shoes or lies flat in bed. His medical history is notable for hypertension and a 45-pack-year history of smoking. Vital signs show a blood pressure of 138/88 mm Hg, a pulse of 94/min, and an oxygen saturation of 95% on room air. Physical examination reveals pronounced plethora and edema of the face and neck. The jugular veins are distended and fail to collapse during inspiration. Prominent, dilated superficial veins are visible across his anterior chest. Heart sounds are normal with no murmurs, and lung auscultation reveals mild expiratory wheezing. Which of the following is the most appropriate initial diagnostic step for this patient?

Management is ongoing for a $78$-year-old man admitted $4$ days ago with worsening dyspnea, orthopnea, and severe lower extremity swelling. He has a medical history significant for chronic obstructive pulmonary disease, hypertension, and ischemic cardiomyopathy with a left ventricular ejection fraction of $30\%$. On admission, physical examination revealed elevated jugular venous pressure and bilateral crackles. Initial chest radiography demonstrated cardiomegaly and moderate bilateral pleural effusions.

He was immediately started on a continuous intravenous infusion of furosemide. Over the past $96$ hours, his weight has decreased by $7$ kg ($15.4$ lb), and his oxygen requirements have normalized on room air. A follow-up chest radiograph obtained today demonstrates complete resolution of the left-sided effusion, but a persistent moderate right-sided pleural effusion. A diagnostic thoracentesis of the right pleural cavity yields $500$ mL of clear, yellow fluid. Concurrent laboratory studies are as follows:

(Reference range for serum LDH is $100-250$ U/L).

Pleural fluid analysis also shows a glucose level of $105$ mg/dL, a pH of $7.48$, and a leukocyte count of $280$/mm³ ($85\%$ mononuclear cells, $15\%$ neutrophils).

Which of the following is the most appropriate next step in the management of this patient's pleural fluid collection?

A 58-year-old woman is brought to the emergency department by her husband due to a 24-hour history of severe headache, confusion, and high fever. Her temperature is 39.2°C (102.6°F), blood pressure is 110/70 mm Hg, pulse is 115/min, and respirations are 18/min. Physical examination reveals marked nuchal rigidity. Funduscopic examination shows bilateral optic disc swelling (papilledema). She is somnolent but localizes to painful stimuli. There are no focal motor deficits. The physician suspects acute bacterial meningitis. Arrange the following interventions in the most appropriate chronological order of execution.

A $72$-year-old man with a history of severe chronic obstructive pulmonary disease and a prior appendectomy is evaluated in the hospital for sudden-onset, severe, diffuse abdominal pain and bilious vomiting. He was admitted $4$ days ago for community-acquired pneumonia. A sputum culture collected on admission grew *Streptococcus pneumoniae* that is susceptible to penicillin and ceftriaxone; however, he has been maintained on the empiric intravenous piperacillin-tazobactam started in the emergency department. He has not passed flatus for $24$ hours. Temperature is $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$), blood pressure is $88/54\text{ mm Hg}$, pulse is $122/\text{min}$, and respirations are $26/\text{min}$. Physical examination reveals a markedly distended, tympanitic abdomen with diffuse rebound tenderness and involuntary guarding. Bowel sounds are absent. Lung auscultation reveals decreased crackles at the right base compared to admission.

Laboratory results are as follows:

Arterial blood gas analysis on room air shows:
pH: $7.27$
pCO $_2$: $26\text{ mm Hg}$
pO $_2$: $85\text{ mm Hg}$

An upright abdominal radiograph demonstrates multiple dilated loops of small bowel with prominent air-fluid levels and a paucity of gas in the colon. No free air is visible under the diaphragm.

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

A 42-year-old man comes to the clinic reporting sudden, severe episodes of a pounding headache, profuse sweating, and a rapid heartbeat that last for 15 to 20 minutes. His blood pressure in the clinic is 178/105 mm Hg, and his heart rate is 102/min. He is otherwise healthy and takes no medications. You suspect a specific adrenal medullary tumor. Arrange the following steps in the most appropriate chronological sequence for the diagnosis and comprehensive management of this patient's likely condition.

Evaluate the following patient presentations involving esophageal symptoms. Match each specific clinical vignette to the highly characteristic diagnostic finding associated with the underlying pathology.

Match each clinical presentation of systemic vasculitis with its most likely corresponding diagnosis.