Internal Medicine

A $58$-year-old man comes to the physician complaining of profound fatigue, cold intolerance, and decreased libido for the past $6$ months. He also reports recent onset of intermittent headaches and frequently bumping his shoulders into doorframes. Vital signs are within normal limits. Physical examination reveals bitemporal hemianopsia and delayed relaxation phase of deep tendon reflexes. Laboratory studies show the following:

Magnetic resonance imaging of the brain reveals a $2.6 \text{ cm}$ mass in the sella turcica with suprasellar extension compressing the optic chiasm. The physician determines that the patient requires thyroid hormone replacement therapy for symptomatic relief prior to planned transsphenoidal surgery. Which of the following is the most appropriate next step in management before initiating this therapy?

Match each of the following patient clinical vignettes with the arterial blood gas and basic metabolic panel profile that most accurately reflects their expected mixed acid-base disorder.

A $19$-year-old college student is brought to the emergency department by his friends due to intractable vomiting, diffuse abdominal pain, and profound lethargy for the past two days. His friends note that he has been extremely thirsty and has been urinating frequently for the past three weeks. He has no known past medical history and takes no medications.

Vital signs are temperature $37.0^\circ$ C ($98.6^\circ$ F), blood pressure $95/60$ mm Hg, pulse $125$/min, and respiratory rate $28$/min. Physical examination shows dry mucous membranes, decreased skin turgor, and deep, rapid respirations. The abdomen is diffusely tender without guarding or rebound.

Laboratory values are as follows:
Sodium: $136$ mEq/L
Potassium: $5.1$ mEq/L
Chloride: $98$ mEq/L
Bicarbonate: $10$ mEq/L
Blood glucose: $520$ mg/dL
Blood urea nitrogen: $32$ mg/dL
Creatinine: $1.4$ mg/dL
Leukocyte count: $16,500$/mm $^3$

Arterial blood gas (room air):
$pH$: $7.24$
$PaCO_2$: $23$ mm Hg
$PaO_2$: $96$ mm Hg

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

Match each clinical presentation of hyponatremia to the most appropriate initial management step.

A 68-year-old man is brought to the emergency department by his wife due to a 24-hour history of severe headache, high fever, and progressive confusion. His temperature is 39.2°C (102.6°F), blood pressure is 145/85 mmHg, heart rate is 112/min, and respiratory rate is 18/min. Neurologic examination reveals a lethargic patient who only opens his eyes to painful stimuli. He demonstrates marked nuchal rigidity and profound weakness of the right upper and lower extremities.

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

A $42$-year-old woman is evaluated in the emergency department after her roommate found her confused and breathing rapidly. The roommate reports that the patient has a history of chronic lower back pain and has recently been complaining of a continuous ringing in her ears. Her temperature is $38.2^\circ C$ ($100.8^\circ F$), blood pressure is $112/72$ mm Hg, pulse is $115$/min, and respirations are $28$/min. Physical examination shows a diaphoretic and agitated woman. Cardiopulmonary examination is unremarkable except for tachycardia and tachypnea. The lungs are clear to auscultation bilaterally.

Laboratory results are as follows:

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

Match each acute clinical presentation to the most appropriate initial management step or targeted therapeutic intervention.

A $55$-year-old man is evaluated in the step-down unit due to progressively worsening lethargy and tachypnea over the last $4$ hours. He was admitted two days ago for a severe intra-abdominal infection following a perforated appendix and is receiving intravenous broad-spectrum antibiotics. His past medical history is significant for severe chronic obstructive pulmonary disease. Vital signs show a temperature of $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$), blood pressure of $86/50$ mm Hg, pulse of $118$/min, and respiratory rate of $28$/min.

Laboratory and arterial blood gas results on room air are as follows:

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

A 65-year-old woman is evaluated in the emergency department for three days of worsening right-sided flank pain, subjective fever, and profound weakness. Her past medical history is significant for hypertension and type 2 diabetes mellitus. On physical examination, her temperature is $38.9^\circ C$ ($102.0^\circ F$), blood pressure is $88/55$ mmHg, pulse is $118$/min, and respiratory rate is $26$/min. The patient appears lethargic but is arousable. Mucous membranes are dry, and there is marked tenderness to percussion over the right costovertebral angle.

Laboratory studies reveal the following:

Arterial blood gas analysis on room air shows:

Based on the provided laboratory data, which of the following combinations best characterizes this patient's current acid-base status?

A 28-year-old man presents to the clinic complaining of a painless, enlarging lump in his right neck that he noticed two months ago. He also reports drenching night sweats and a 5-kg (11-lb) weight loss over the past six weeks. On physical examination, a 3.5-cm, firm, rubbery, mobile lymph node is palpated in the right anterior cervical chain. The remainder of the examination is unremarkable. Basic laboratory studies reveal a normocytic anemia and an elevated erythrocyte sedimentation rate. The physician suspects a hematologic malignancy.

Arrange the following steps in the most appropriate clinical sequence for the definitive diagnosis, staging, and initial management of this patient.

An intensive care unit team is conducting morning rounds. The patient is a 68-year-old female who was admitted one week ago following an out-of-hospital cardiac arrest. She was successfully resuscitated and placed on mechanical ventilation. Three days ago, her condition became complicated with a new fever of 39.2°C (102.6°F), worsening hypoxemia, and purulent endotracheal secretions. A chest radiograph demonstrated a new right lower lobe consolidation. Empiric intravenous vancomycin and cefepime were initiated for a presumed ventilator-associated pneumonia.

Today, she exhibits significant clinical improvement. She is afebrile with a temperature of 37.1°C (98.8°F), blood pressure of 128/78 mm Hg, and heart rate of 82/min. Her ventilator settings have been successfully weaned. An endotracheal aspirate culture obtained at the onset of fever demonstrates heavy growth of Pseudomonas aeruginosa. Susceptibility testing shows the organism is susceptible to cefepime, piperacillin-tazobactam, and meropenem, but resistant to levofloxacin. No other organisms are isolated. A nasal swab polymerase chain reaction (PCR) screen for methicillin-resistant Staphylococcus aureus (MRSA) obtained three days ago is negative.

Based on the culture and susceptibility results, which of the following is the most appropriate next step in the pharmacologic management of this patient?

A hospitalised 68-year-old female is evaluated on postoperative day 6 following an elective right total knee arthroplasty. She reports new-onset pain and tightness in her right calf. She has been receiving subcutaneous unfractionated heparin for chemical thromboprophylaxis since her surgery. Vital signs are within normal limits. Physical examination reveals an erythematous, swollen right lower extremity with tenderness to palpation over the popliteal fossa. A venous duplex ultrasonography confirms an acute occlusive thrombus in the right popliteal vein. Laboratory studies show a current platelet count of $55,000/\text{mm}^3$. Her preoperative baseline platelet count was $250,000/\text{mm}^3$. The patient has no history of liver disease or other bleeding disorders. Based on the calculated clinical probability score, arrange the following management steps in the correct chronological sequence for this patient.

An endocrinology consultation is requested for a 48-year-old male who has been experiencing progressive sluggishness, unexplained weight gain, and persistent chilliness for the past six months. Upon further questioning, he reports bothersome headaches and difficulty maintaining an erection. He has no significant past medical history and takes no medications. Vital signs are within normal limits, except for a pulse of $54/\text{min}$. Physical examination reveals dry, coarse skin and a notable delay in the relaxation phase of the Achilles tendon reflex. A confrontation visual field test detects bilateral peripheral vision deficits.

Laboratory evaluation reveals:
Serum thyroid-stimulating hormone (TSH): $1.4 \text{ mIU/L}$ (normal: $0.5-5.0 \text{ mIU/L}$)
Serum free thyroxine (T4): $0.4 \text{ ng/dL}$ (normal: $0.9-1.7 \text{ ng/dL}$)

Which of the following is the most likely etiology of this patient's thyroid laboratory abnormalities?

A 29-year-old female graduate student presents to the university health clinic complaining of burning with urination and increased urinary frequency for the past $48$ hours. She denies any back pain, nausea, vomiting, or vaginal discharge. Her temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure is $110/70\text{ mm Hg}$, and pulse is $78\text{/min}$. Physical examination demonstrates mild suprapubic discomfort on deep palpation but no costovertebral angle tenderness. A urine sample collected at an outside urgent care facility three days ago has just returned positive for *Klebsiella pneumoniae*. The microbiology report flags the isolate as an extended-spectrum beta-lactamase (ESBL) producer. Susceptibility testing reveals resistance to ceftriaxone, cefepime, and ciprofloxacin, but confirms susceptibility to nitrofurantoin, fosfomycin, and meropenem. Which of the following is the most appropriate next step in management?

A 42-year-old woman arrives at the emergency department reporting a severe, throbbing headache and blurred vision that began this morning. She also notes new-onset shortness of breath over the past two days. Her medical history includes diffuse cutaneous systemic sclerosis, which was diagnosed four years ago. She currently takes mycophenolate mofetil. Vital signs show a blood pressure of 230/125 mmHg, a heart rate of 110/min, and a respiratory rate of 22/min. Physical examination reveals thickened, tight skin over the face and proximal extremities, as well as bilateral basilar crackles on lung auscultation. Laboratory studies show:

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

Match each patient's presenting clinical and laboratory profile with the most likely underlying pathophysiologic condition.

A 62-year-old man with a history of end-stage renal disease comes to the emergency department due to severe muscle weakness and palpitations. He reports missing his last two scheduled hemodialysis sessions because of transportation issues. His temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure is $112/68\text{ mmHg}$, pulse is $52\text{/min}$, and respiratory rate is $16\text{/min}$. Physical examination reveals diminished deep tendon reflexes in both lower extremities. An electrocardiogram demonstrates widened QRS complexes and tall, peaked T waves. A point-of-care basic metabolic panel reveals a serum potassium level of $7.9\text{ mEq/L}$. Arrange the following therapeutic interventions in the most appropriate sequential order of execution, from the most immediate priority to the definitive management step.

Correlate the following clinical presentations of central nervous system and disseminated infections in immunocompromised hosts with their most appropriate primary targeted management.

A 26-year-old woman is brought to the emergency department by her roommate due to severe anxiety, shortness of breath, and tingling around her mouth and hands. Her symptoms began 30 minutes ago following an argument. Her past medical history is significant for migraine headaches and a seizure disorder, which are managed with a daily medication she started 6 months ago. On physical examination, she appears anxious and is hyperventilating. Her lungs are clear to auscultation bilaterally. Inflation of a blood pressure cuff above her systolic pressure for 3 minutes elicits carpopedal spasm.

Vital signs are:
Temperature: 37.0°C (98.6°F)
Blood pressure: 115/75 mm Hg
Heart rate: 112/min
Respiratory rate: 32/min
Oxygen saturation: 99% on room air

Arterial blood gas (room air):
pH: 7.53
$pCO_2$: 18 mm Hg
$pO_2$: 102 mm Hg

Serum chemistries:
Sodium: 139 mEq/L
Potassium: 3.7 mEq/L
Chloride: 114 mEq/L
Bicarbonate: 14 mEq/L

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

A $28$-year-old woman comes to the clinic complaining of palpitations, excessive sweating, and a $5\text{ kg}$ ($11\text{ lb}$) weight loss over the past $6$ weeks despite an increased appetite. She has a history of major depressive disorder, for which she takes fluoxetine. She is a competitive bodybuilder and reports feeling immense pressure for an upcoming competition. Vital signs show a temperature of $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure of $145/75\ \text{mmHg}$, and a pulse of $112\text{/min}$. Physical examination reveals a fine resting tremor, brisk deep tendon reflexes, and warm, moist skin. The thyroid gland is nonpalpable, and there is no exophthalmos.

Laboratory results are as follows:

* Thyroid-stimulating hormone (TSH): $<0.01 \ \mu\text{U/mL}$ (Normal: $0.4-4.0 \ \mu\text{U/mL}$)
* Free T4: $0.3 \ \text{ng/dL}$ (Normal: $0.9-2.4 \ \text{ng/dL}$)
* Free T3: $8.5 \ \text{pg/mL}$ (Normal: $2.0-4.4 \ \text{pg/mL}$)
* Radioactive iodine uptake ($24$-hour): $1\%$ (Normal: $10\%-30\%$)

Which of the following additional findings is most likely present in this patient?