Internal Medicine

A $54$-year-old man comes to the emergency department due to a $3$-day history of high fevers, chills, drenching sweats, and extreme fatigue. He resides in coastal Massachusetts and frequently hikes in wooded areas. His past medical history is notable for hereditary spherocytosis, for which he underwent a splenectomy at age $20$. His temperature is $39.2^\circ\text{C}$ ($102.6^\circ\text{F}$), blood pressure is $110/70\text{ mmHg}$, pulse is $115/\text{min}$, and respirations are $18/\text{min}$. Physical examination reveals scleral icterus and pale conjunctivae. There is no rash or lymphadenopathy. Laboratory studies show:

- Hemoglobin: $8.2\text{ g/dL}$
- Platelet count: $95,000/\text{mm}^3$
- Leukocyte count: $9,400/\text{mm}^3$
- Total bilirubin: $4.1\text{ mg/dL}$ (direct: $0.6\text{ mg/dL}$)
- Lactate dehydrogenase: $850\text{ U/L}$

A peripheral blood smear demonstrates intraerythrocytic pleomorphic ring forms and occasional tetrad structures. Which of the following is the most appropriate pharmacotherapy for this patient's condition?

Match each hereditary gastrointestinal polyposis or colorectal cancer syndrome with its characteristic genetic mechanism and associated clinical manifestations.

A $27$-year-old woman comes to the clinic for evaluation of profound fatigue, proximal muscle weakness, and progressive facial hair growth over the past $14$ months. Her menstrual periods occur only once every $3$ to $4$ months. She also reports severe mood swings. Three months ago, a different physician started her on fluoxetine monotherapy for depression; shortly after, she experienced a $10$-day period of rapid speech, grandiosity, and a decreased need for sleep before returning to a depressed state.

She brings laboratory results from an outside wellness clinic. They performed a novel serum biomarker test for 'adrenal malignancies.' The test has a sensitivity of $90\%$ and a specificity of $90\%$. The prevalence of adrenal malignancy in her age group is $1\%$. The test result was positive, and she is terrified that she has cancer.

Vital signs are temperature $36.8^\circ\text{C}$ ($98.2^\circ\text{F}$), blood pressure $155/96$ mmHg, pulse $82$/min, and BMI $34 \text{ kg/m}^2$. Physical examination reveals a plethoric face, prominent coarse hair on the chin, and multiple $2$-cm wide violaceous striae on the lower abdomen.

Laboratory results:
TSH: $2.1 \text{ \mu U/mL}$ (Normal: $0.5 - 5.0 \text{ \mu U/mL}$)
Free T4: $0.5 \text{ ng/dL}$ (Normal: $0.9 - 1.7 \text{ ng/dL}$)
Testosterone, total: $95 \text{ ng/dL}$ (Normal: $15 - 70 \text{ ng/dL}$)

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

An unconscious adult patient in the intensive care unit is currently receiving mechanical ventilation following a complicated abdominal surgery performed a week ago. The nursing staff reports a sudden increase in the volume of thick, purulent pulmonary secretions. The patient's core body temperature has risen to 39.1°C (102.4°F), and ventilator settings have been adjusted due to worsening hypoxia. A bedside chest radiograph demonstrates a dense, new consolidation in the right middle lobe, leading to a presumptive diagnosis of ventilator-associated pneumonia (VAP).

What is the correct chronological order of the following clinical actions to optimize both patient outcomes and antimicrobial stewardship?

During clinical rounds on the internal medicine service, an attending physician is reviewing guideline-directed therapies for Clostridioides difficile with the medical team. Based on current consensus guidelines, correctly pair each patient presentation with the most appropriate therapeutic management strategy.

A $42$-year-old man who recently emigrated from a region with highly endemic tuberculosis is admitted to the hospital due to a $6$-week history of worsening productive cough, drenching night sweats, and a $5$-kg weight loss. His vital signs show a temperature of $38.2^\circ C$ ($100.8^\circ F$). A chest radiograph reveals a distinct cavitary lesion in the apical segment of the right upper lobe.

Arrange the following steps in the most appropriate chronological order for the management of this patient.

A 64-year-old man is evaluated in the hospital on day 3 of admission. He was initially admitted with fever, confusion, and abdominal pain. His medical history includes hepatitis C virus-related cirrhosis complicated by ascites. Three weeks ago, he was hospitalized for an acute variceal hemorrhage treated with endoscopic band ligation. Upon this admission, a diagnostic paracentesis revealed cloudy fluid with a leukocyte count of $1,200/\text{mm}^3$ and a neutrophil count of $950/\text{mm}^3$. Due to his recent hospitalization, he was empirically started on intravenous piperacillin-tazobactam. Intravenous albumin was also administered.

Today, the patient is alert and oriented. His abdominal pain has resolved. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $112/68\text{ mm Hg}$, and pulse is $78/\text{min}$. Ascitic fluid cultures from admission grow *Klebsiella pneumoniae*. The isolate's antimicrobial susceptibility profile is as follows:

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

During a routine wellness examination, a 55-year-old male executive reports a six-month history of unusual lethargy, a persistent feeling of being cold, and significant constipation. He also mentions a gradual decline in libido and experiencing occasional dull morning headaches. He takes no medications and has no prior medical conditions. Vital signs show a blood pressure of $108/68$ mmHg and a pulse of $54$/min. Physical examination reveals dry, cool skin and delayed relaxation of the deep tendon reflexes. Confrontation visual field testing demonstrates a loss of peripheral vision bilaterally. Laboratory evaluation is obtained, showing a serum thyroid-stimulating hormone (TSH) level of $1.8$ $\mu$ U/mL (normal: $0.5$-$5.0$ $\mu$ U/mL) and a free thyroxine (T4) level of $0.4$ ng/dL (normal: $0.9$-$1.7$ ng/dL). Which of the following is the most likely underlying mechanism for this patient's clinical presentation?

A $62$-year-old man presents to the clinic with a $3$-month history of progressive muscle weakness and fatigue. He reports increasing difficulty getting up from a seated position, climbing stairs, and brushing his hair. Over the past month, he has also noticed a mildly pruritic, violaceous eruption on his upper eyelids and an erythematous, scaly rash over the dorsal aspects of his metacarpophalangeal and interphalangeal joints. His medical history includes hypertension and hyperlipidemia, for which he has taken lisinopril and atorvastatin for the past $5$ years. Vital signs are within normal limits. Neurologic examination demonstrates $4/5$ motor strength in the bilateral deltoid, hip flexor, and quadriceps muscles, with normal distal strength. Sensation and deep tendon reflexes are intact. Laboratory evaluation reveals a serum creatine kinase level of $2,400 \text{ U/L}$ and an aldolase level of $15 \text{ U/L}$ (normal: $1.0 - 7.5 \text{ U/L}$). A screening thyroid-stimulating hormone (TSH) level is $2.5 \text{ \mu U/mL}$ (normal: $0.4 - 4.0 \text{ \mu U/mL}$). Based on the most likely diagnosis, which of the following is the most appropriate additional evaluation for this patient?

A $45$-year-old man presents to the clinic for follow-up of resistant hypertension. He currently takes amlodipine, lisinopril, and chlorthalidone at maximal doses, but his office blood pressure remains $168/98$ mm Hg. He has recently experienced episodes of severe muscle cramps and generalized weakness. Laboratory studies show a serum potassium level of $2.8$ mEq/L and a serum sodium level of $144$ mEq/L. Suspecting a secondary endocrine etiology, the physician plans a comprehensive diagnostic workup. Assume the patient is a surgical candidate and that each consecutive diagnostic test in the algorithm yields abnormal results consistent with a unilateral adrenal source. Arrange the following diagnostic steps in the correct chronological sequence for the evaluation of this patient.

A 60-year-old man with a history of peptic ulcer disease is brought to the emergency department due to 5 days of severe, intractable nausea and nonbilious vomiting. He reports being unable to tolerate any oral intake and feels profoundly weak. On physical examination, the patient appears lethargic. His mucous membranes are markedly dry, and capillary refill is prolonged. Temperature is 37.1 C (98.8 F), blood pressure is 88/55 mm Hg, pulse is 118/min, and respirations are 16/min. Laboratory studies are as follows:

Which of the following is the most accurate interpretation of this patient's acid-base status?

An $82$-year-old man is evaluated on postoperative day $3$ following an open reduction and internal fixation of a right femoral neck fracture. The nursing staff reports that he has developed severe abdominal distension and worsening nausea over the last $24$ hours. His medical history includes hypertension, benign prostatic hyperplasia, and osteoarthritis. He is currently receiving intravenous morphine for pain control.

Vital signs are temperature $37.2^\circ\text{C}$, blood pressure $110/70\text{ mmHg}$, pulse $105/\text{min}$, and respirations $18/\text{min}$. Physical examination reveals a massively distended, tympanitic abdomen with markedly decreased bowel sounds. There is diffuse mild tenderness to palpation but no guarding, rigidity, or rebound tenderness.

Laboratory studies reveal:
- Leukocytes: $8,500/\text{mm}^3$
- Sodium: $138\text{ mEq/L}$
- Potassium: $3.1\text{ mEq/L}$
- Calcium: $8.4\text{ mg/dL}$

An abdominal radiograph demonstrates marked gaseous distension of the cecum to $10.5\text{ cm}$, as well as dilation of the ascending and transverse colon. There is no distinct transition point and no free intraperitoneal air.

Based on the diagnosis of acute colonic pseudo-obstruction (Ogilvie syndrome), arrange the following therapeutic interventions in the correct chronological sequence, from initial management to the definitive treatment of last resort, assuming each preceding step fails to achieve clinical resolution.

Match each of the following clinical conditions with its characteristic laboratory profile involving plasma renin activity, serum aldosterone, and potassium levels.

A 48-year-old woman is hospitalized in the hematology-oncology unit undergoing induction chemotherapy for acute myeloid leukemia. On hospital day 12, she develops chills and a new-onset fever. Her temperature is 38.7°C (101.7°F), blood pressure is 110/68 mm Hg, and pulse is 112/min. Physical examination reveals a clean central venous catheter insertion site and no focal signs of infection. Her absolute neutrophil count is 100/mm³. Two sets of blood cultures are obtained, and empiric therapy with intravenous cefepime is initiated. Forty-eight hours later, the patient is alert and her temperature has normalized to 37.2°C (99.0°F). Her vital signs are stable, and her absolute neutrophil count is now 150/mm³. The initial blood cultures are finalized, showing growth of Klebsiella pneumoniae in both sets. Susceptibility testing demonstrates that the isolate is sensitive to ceftriaxone, cefepime, piperacillin-tazobactam, and meropenem, but resistant to ampicillin.

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

Match each clinical patient presentation to the most likely vasculitic syndrome.

A $55$-year-old woman is evaluated on the surgical ward for nausea, bilious vomiting, and diffuse abdominal cramping. She is currently on postoperative day $6$ following an open abdominal hysterectomy for uterine fibroids. The patient reports she has not passed flatus or stool since the operation. Her temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $128/78\text{ mmHg}$, pulse is $86/\text{min}$, and respiratory rate is $14/\text{min}$. Physical examination reveals a significantly distended and tympanic abdomen. Auscultation demonstrates high-pitched, hyperactive bowel sounds. There is mild diffuse tenderness to palpation, but no guarding, rigidity, or rebound tenderness. The surgical incision is healing well with no erythema or discharge. Laboratory results show a leukocyte count of $7,500/\text{mm}^3$ and normal serum lactate levels. Upright abdominal radiography reveals multiple dilated loops of small bowel with prominent air-fluid levels and no free intraperitoneal air. Which of the following is the most appropriate next step in management?

Emergency medical services bring a 47-year-old mechanic to the hospital after he was found deeply lethargic in his workshop. His coworkers report that he had been working alone on a vehicle's cooling system and seemed disoriented before collapsing. On presentation, his temperature is $36.8^\circ C$ ($98.2^\circ F$), blood pressure is $105/65$ mmHg, pulse is $112$/min, and respiratory rate is $24$/min. Physical examination reveals an unarousable patient with deep, rapid breathing. Arterial blood gas analysis on room air shows a pH of 7.21, $PaCO_2$ of 24 mmHg, and $PaO_2$ of 95 mmHg.

Based on the provided laboratory results, what is the patient's calculated serum osmolar gap in mOsm/kg $H_2O$?

A 68-year-old man is evaluated in the hospital for decreased urine output. He was admitted 3 days ago for severe community-acquired pneumonia and has been receiving intravenous antibiotics. His blood pressure is 98/60 mm Hg and heart rate is 102/min. Physical examination shows dry mucous membranes and flat jugular veins. Laboratory studies are obtained to evaluate his acute kidney injury:

What is the patient's fractional excretion of sodium (FeNa) expressed as a percentage?

Match each clinical exposure or presentation with the most appropriate empiric antimicrobial therapy or post-exposure prophylaxis.

A 21-year-old woman is brought to the emergency department by her family due to progressively worsening confusion, jaundice, and abdominal swelling over the past 5 days. She has no significant past medical history, takes no medications, and does not consume alcohol. Her temperature is $37.2^\circ\text{C}$ ($99^\circ\text{F}$), blood pressure is $105/60\text{ mmHg}$, pulse is $112/\text{min}$, and respiratory rate is $22/\text{min}$. Physical examination reveals severe scleral icterus, palmar erythema, and a distended abdomen with shifting dullness. She is lethargic and oriented only to person. Asterixis is elicited upon wrist extension.

Laboratory results are as follows:

Direct antiglobulin (Coombs) test is negative. Blood and urine cultures are drawn.

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