Internal Medicine

A 24-year-old man with type 1 diabetes mellitus is brought to the emergency department due to altered mental status, generalized weakness, and abdominal pain for the past 24 hours. He recently had an upper respiratory infection and stopped taking his insulin due to poor oral intake. His blood pressure is 90/60 mm Hg, heart rate is 118/min, and respiratory rate is 24/min with deep, rapid breaths. Laboratory results show a blood glucose of 580 mg/dL, arterial pH of 7.12, serum bicarbonate of 10 mEq/L, and strongly positive serum ketones. Arrange the following management steps in the most appropriate chronological order for the optimal acute management of this patient's condition.

A $74$-year-old man is evaluated on postoperative day $3$ following an uncomplicated laparoscopic cholecystectomy. Over the past $12$ hours, he has developed a fever and severe pain in his right knee. He states the pain is so intense that he cannot bear weight or tolerate the bedsheets touching his leg. His medical history is significant for essential hypertension, diet-controlled type 2 diabetes mellitus, and hypothyroidism. Current medications include lisinopril and levothyroxine. His temperature is $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), blood pressure is $138/86\text{ mmHg}$, and pulse is $98/\text{min}$. Cardiopulmonary examination is unremarkable. His abdomen is soft and non-tender, and the surgical incisions are clean and intact. Examination of the right knee reveals marked erythema, warmth, and a large effusion. The joint is exquisitely tender to palpation and passive range of motion. Laboratory studies show a leukocyte count of $13,500/\text{mm}^3$ and a thyroid-stimulating hormone (TSH) level of $5.5\text{ mIU/L}$. Arthrocentesis of the right knee yields $3\text{ mL}$ of cloudy synovial fluid. Analysis of the fluid reveals a leukocyte count of $28,000/\text{mm}^3$ with $80\%$ neutrophils. Polarized light microscopy demonstrates rhomboid-shaped crystals with weak positive birefringence. Gram stain of the synovial fluid reveals no organisms. Which of the following is the most appropriate next step in the management of this patient?

A 22-year-old man with type 1 diabetes mellitus is brought to the emergency department with abdominal pain, vomiting, and deep, rapid breathing. Laboratory studies confirm severe diabetic ketoacidosis (DKA) with a blood glucose of 540 mg/dL and a serum potassium of 4.8 mEq/L. Arrange the following management steps in the most appropriate chronological sequence.

A 61-year-old man is evaluated in the intensive care unit to optimize his medication regimen. He was admitted a week ago after sustaining multiple severe injuries in a high-speed motorcycle collision. He required immediate intubation and has remained mechanically ventilated. Three days ago, he developed a temperature of $39.0^\circ\text{C}$ ($102.2^\circ\text{F}$), a heart rate of $112/\text{min}$, thick purulent airway secretions, and a leukocytosis of $18,500/\mu\text{L}$. A portable chest radiograph demonstrated a new dense consolidation in the right lower lobe. He was promptly started on a broad-spectrum empiric antimicrobial regimen consisting of intravenous vancomycin, cefepime, and tobramycin.

Today, his clinical trajectory has improved; his temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), his heart rate is $85/\text{min}$, and his fraction of inspired oxygen ($\text{FiO}_2$) has been successfully titrated down. Blood cultures drawn three days ago show no growth. A quantitative culture of an endotracheal aspirate obtained at the onset of his fever grew $>10^5\text{ colony-forming units/mL}$ of *Pseudomonas aeruginosa*. The isolate's susceptibility profile is as follows:

Amikacin: Susceptible
Cefepime: Susceptible
Ciprofloxacin: Susceptible
Meropenem: Susceptible
Tobramycin: Susceptible

Routine morning laboratory results reveal a serum creatinine level of $2.2 \text{ mg/dL}$, which has climbed from a baseline of $1.0 \text{ mg/dL}$ on admission.

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

Match each clinical scenario with its most likely primary acid-base disorder.

Match each commonly prescribed medication with its primary mechanism of inducing acute kidney injury (AKI).

Match each patient's clinical presentation with the most accurate underlying pathophysiologic description.

A 61-year-old man comes to the emergency department due to severe right knee pain and swelling that began abruptly overnight. He reports that the pain is excruciating, and he is unable to bear weight on the right leg. His medical history includes type 2 diabetes mellitus, chronic kidney disease (stage 3a), and a recent hospitalization two weeks ago for a chronic obstructive pulmonary disease exacerbation. His temperature is 38.2°C (100.8°F), blood pressure is 142/88 mm Hg, and pulse is 98/min. Physical examination reveals a markedly swollen, erythematous, and warm right knee. Range of motion is severely limited by pain. There are no skin breaks or ulcerations around the joint. Which of the following is the most appropriate next step in management?

A 65-year-old man is evaluated during a routine follow-up appointment. He reports feeling unusually tired over the past few months, along with new-onset constipation and dry skin. His medical history is notable for the transsphenoidal resection of a nonfunctioning pituitary macroadenoma two years ago. He currently takes no medications. Vital signs are normal except for a heart rate of 58/min. Physical examination reveals delayed relaxation of the deep tendon reflexes. Laboratory studies show a thyroid-stimulating hormone (TSH) level of $1.8 \text{ \mu U/mL}$ (normal: $0.5\text{-}5.0 \text{ \mu U/mL}$) and a free T4 level of $0.5 \text{ ng/dL}$ (normal: $0.9\text{-}1.7 \text{ ng/dL}$). Which of the following is the most likely diagnosis?

A $62$-year-old man with a history of osteoarthritis and type $2$ diabetes mellitus presents to the emergency department with acute onset of severe right knee pain, swelling, and a fever of $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$). He is unable to bear weight on the right leg. Physical examination reveals a warm, erythematous, and markedly swollen right knee with a severely restricted range of motion due to pain. Arrange the following steps in the most appropriate chronological sequence for the management of this patient's condition.

A 25-year-old man presents to the clinic for a routine health maintenance examination. He has no past medical history and takes no medications. The patient reports having unprotected receptive anal intercourse with a new male partner 4 weeks ago. He is currently asymptomatic. Physical examination reveals normal vital signs and no lymphadenopathy, rash, or mucosal lesions. The patient requests screening for sexually transmitted infections, including HIV.

Arrange the following steps in the most appropriate chronological order for the diagnosis and initial management of this patient's suspected HIV infection, in accordance with current guidelines.

A $68$-year-old woman is evaluated in the hospital on postoperative day $7$ following an elective right total hip arthroplasty. Since the surgery, she has been receiving subcutaneous enoxaparin for deep venous thrombosis prophylaxis. She now reports new-onset right leg pain and swelling that began this morning. Temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $132/82\text{ mm Hg}$, pulse is $92/\text{min}$, and respirations are $16/\text{min}$. Physical examination shows a swollen, erythematous right lower extremity with tenderness to palpation over the calf and thigh.

Laboratory studies:
Hemoglobin: $11.2\text{ g/dL}$
Leukocyte count: $7,800/\text{mm}^3$
Platelet count: $52,000/\text{mm}^3$ (Preoperative platelet count was $260,000/\text{mm}^3$)

A lower extremity venous duplex ultrasound reveals a noncompressible segment in the right femoral vein consistent with an acute deep venous thrombosis. Which of the following is the most appropriate next step in management?

Paramedics arrive at the emergency room with a 52-year-old man who was discovered unresponsive in a public park. The patient has a documented medical history of severe alcohol use disorder. Upon initial evaluation, his body temperature is $36.2^\circ\text{C}$ ($97.2^\circ\text{F}$), pulse is $102/\text{min}$, blood pressure is $110/70\text{ mm Hg}$, and respirations are $24/\text{min}$. He is unarousable to painful stimuli. Cardiopulmonary examination is unremarkable. Initial laboratory studies show the following:

Arterial blood gas (room air) shows a pH of $7.22$ and a $\text{PaCO}_2$ of $26\text{ mm Hg}$.

Based on the provided laboratory results, what is the patient's serum osmolar gap in $\text{mOsm/kg}$?

Match each patient's clinical and histopathologic presentation with the corresponding defining cytogenetic abnormality and characteristic therapeutic approach.

A 41-year-old woman is evaluated in the clinic for progressive fatigue, cold intolerance, and a 6-kg (13-lb) weight gain over the past eight months. She has also experienced diffuse muscle aches and secondary amenorrhea during this time. A urine pregnancy test is negative. She takes no medications and has no significant past medical history. Vital signs show a blood pressure of $102/64$ mmHg and a pulse of $54$/min. Physical examination reveals dry skin, a pale appearance, and delayed relaxation of the Achilles tendon reflexes. Palpation of the anterior neck reveals no thyromegaly or nodules.

Laboratory results are as follows:

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

An electrocardiogram previously documented ventricular tachycardia in a $68$-year-old man. He now visits the physician complaining of severe palpitations, unintended weight loss, and profound fatigue persisting for the last $3$ weeks. His medical history includes ischemic cardiomyopathy and placement on a rhythm-control medication approximately $14$ months ago. Current medications include lisinopril, carvedilol, and aspirin. The patient's temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $142/86$ mm Hg, and pulse is $115$/min and irregularly irregular. Physical examination demonstrates brisk deep tendon reflexes and a prominent bilateral hand tremor. Palpation of the neck reveals a diffusely firm, slightly enlarged thyroid gland with no distinct nodules.

Laboratory studies reveal:
Thyroid-stimulating hormone (TSH): $<0.01 \ \mu\text{U/mL}$
Free thyroxine (T4): $4.1 \text{ ng/dL}$
Total triiodothyronine (T3): $195 \text{ ng/dL}$

A $24$-hour radioactive iodine uptake scan demonstrates $1\%$ uptake. Subsequent color Doppler ultrasonography of the thyroid shows a diffusely enlarged gland with markedly diminished internal vascularity. Which of the following is the most appropriate next step in the management of this patient's current condition?

A 19-year-old college student presents to the student health clinic complaining of severe, watery diarrhea for the past 3 days after returning from a camping trip. He reports feeling profoundly weak and lightheaded when standing. His temperature is 37.2°C (99.0°F), blood pressure is 98/60 mm Hg while supine and 82/50 mm Hg while standing, and pulse is 115/min. Physical examination shows dry mucous membranes and delayed capillary refill. Laboratory results reveal:

Serum sodium: $138 \text{ mEq/L}$
Serum potassium: $3.1 \text{ mEq/L}$
Serum chloride: $112 \text{ mEq/L}$
Serum bicarbonate: $14 \text{ mEq/L}$

Arterial blood gas on room air:
pH: 7.28
$pCO_2$: 29 mm Hg
$pO_2$: 95 mm Hg

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

A 31-year-old woman is evaluated in the outpatient clinic for progressive fatigue, cold intolerance, and generalized weakness over the past 5 months. She also reports a complete cessation of menses since the birth of her son 6 months ago. The patient's pregnancy was complicated by placental abruption, which resulted in significant blood loss requiring emergency cesarean delivery and transfusion of packed red blood cells. She was unable to breastfeed despite multiple attempts. Vital signs show a blood pressure of 90/60 mmHg and a pulse of 58/min. Physical examination reveals pale, dry skin and a delay in the relaxation phase of the deep tendon reflexes.

Laboratory results are as follows:
Sodium: 134 mEq/L
Potassium: 4.1 mEq/L
Thyroid-stimulating hormone (TSH): 2.1 $\mu$ U/mL (normal: 0.5-5.0 $\mu$ U/mL)
Free thyroxine (T4): 0.3 ng/dL (normal: 0.9-1.7 ng/dL)

Which of the following best describes the underlying pathogenesis of this patient's current condition?

A 42-year-old woman is evaluated in the rheumatology clinic for worsening episodes of painful blanching and cyanosis in her fingers upon exposure to cold air. She has a known history of diffuse cutaneous systemic sclerosis and currently takes no medications for her vascular symptoms. Arrange the following therapeutic interventions for secondary Raynaud phenomenon in the correct sequential order of escalation, from initial management to salvage therapy for critical ischemia.

A physician is evaluating four different patients in the outpatient clinic who present with varying signs of adrenal dysfunction. Match each patient's clinical presentation and characteristic laboratory profile to the most likely underlying adrenal disorder.