Internal Medicine

An asymptomatic $65$-year-old woman visits her primary care physician for an annual checkup. She mentions feeling slightly more fatigued recently, though she attributes this to a busy daily routine. Her medical history includes well-controlled essential hypertension. Her temperature is $37.0^\circ$ C, blood pressure is $125/80$ mm Hg, and pulse is $72$/min. Physical examination reveals a normal-sized thyroid gland with no palpable nodules. A screening laboratory evaluation demonstrates the following results:

Thyroid-stimulating hormone (TSH): $7.8$ mU/L (normal: $0.4$-$4.2$ mU/L)
Free thyroxine (T4): $1.3$ ng/dL (normal: $0.8$-$2.7$ ng/dL)

Which of the following is the most likely diagnosis?

A $72$-year-old man is brought to the emergency department from a long-term care facility due to altered mental status. Facility staff report that the patient has experienced intractable vomiting and an inability to tolerate oral intake for the past $48$ hours. His past medical history includes hypertension, benign prostatic hyperplasia, and mild cognitive impairment. Upon arrival, his temperature is $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$), blood pressure is $88/54\text{ mm Hg}$, pulse is $118\text{/min}$, and respirations are $28\text{/min}$. Physical examination reveals dry mucous membranes, delayed capillary refill, and diffuse abdominal rigidity with severe rebound tenderness.

Based on the laboratory data provided, which of the following combinations of primary pathophysiologic processes best explains this patient's complete acid-base status?

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

During a routine health maintenance visit, a $48$-year-old male construction worker describes a gradual decline in his energy levels and libido over the past $14$ months. He has also developed a pervasive feeling of being cold, even during summer months, alongside chronic, dull pain in the joints of his hands. He has no significant past medical history and takes no medications.

Vital signs include a blood pressure of $112/74$ mmHg and a heart rate of $58$/min. Physical examination reveals a slate-gray to bronze discoloration of the skin, which is most prominent in sun-exposed areas and old scars. Palpation of the abdomen reveals a firm, non-tender liver edge $3$ cm below the right costal margin. Testicular volume is reduced bilaterally. The relaxation phase of the deep tendon reflexes is noticeably delayed.

Laboratory evaluation demonstrates:

Based on the patient's presentation and laboratory findings, which of the following is the most appropriate next step in diagnostic evaluation?

A 32-year-old man comes to the clinic due to 5 days of severe, watery diarrhea. He recently returned from a trip to Southeast Asia. The patient reports having 8 to 10 loose bowel movements daily. He has been drinking plain water but has not consumed any food or electrolyte solutions. His temperature is 37.1°C (98.8°F), blood pressure is 108/64 mm Hg, and pulse is 104/min. Physical examination shows dry mucous membranes and decreased skin turgor. Laboratory studies show the following:

Based on these findings, which of the following acid-base disturbances is most likely present in this patient?

A 28-year-old woman presents to the emergency department with a 2-day history of sharp right-sided chest pain that worsens with deep inspiration. She also reports shortness of breath and generalized fatigue. She was diagnosed with systemic lupus erythematosus (SLE) three years ago and is currently prescribed hydroxychloroquine, though she admits to missing several doses recently. Her temperature is $38.1^\circ\text{C}$ ($100.6^\circ\text{F}$), blood pressure is $122/78\text{ mm Hg}$, pulse is $102/\text{min}$, and respirations are $22/\text{min}$. Physical examination reveals a pleural friction rub over the right lower lung field. Her wrists and metacarpophalangeal joints are tender and swollen bilaterally.

Laboratory studies are as follows:

Arterial blood gas analysis on room air:

Chest radiography shows a small right pleural effusion with no pulmonary infiltrates. Electrocardiography shows normal sinus rhythm.

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

Match each of the following fasting laboratory profiles, obtained during a symptomatic hypoglycemic episode, to the most likely underlying etiology. Assume normal renal and hepatic function.

A 42-year-old woman is brought to the emergency department by ambulance due to severe confusion, agitation, and high fever. Her husband reports she has a history of Graves' disease but stopped taking her medications three months ago. Temperature is 40.2°C (104.4°F), blood pressure is 158/68 mm Hg, and pulse is 152/min and irregularly irregular. Physical examination shows profound diaphoresis, a fine resting tremor, bilateral exophthalmos, and an enlarged, non-tender thyroid gland. An ECG confirms atrial fibrillation with rapid ventricular response. After securing the airway and initiating intravenous fluid resuscitation, the care team prepares a targeted pharmacologic regimen for her acute hypermetabolic state. Arrange the following management steps in the most appropriate chronological sequence for this patient.

A $74$-year-old woman is brought to the emergency department from a skilled nursing facility due to sudden-onset, severe abdominal pain and altered mental status. Staff report that she had several episodes of bloody diarrhea earlier in the day. Her medical history includes hypertension, type 2 diabetes mellitus, and paroxysmal atrial fibrillation for which she frequently misses her doses of apixaban. Her temperature is $38.4^\circ\text{C}$ ($101.1^\circ\text{F}$), blood pressure is $82/50\text{ mmHg}$, heart rate is $128/\text{min}$ and irregular, and respiratory rate is $24/\text{min}$. On physical examination, she appears lethargic. The abdomen is rigid with diffuse involuntary guarding and severe rebound tenderness. Bowel sounds are absent.

Laboratory results:
Leukocytes: $22,500/\mu\text{L}$
Hemoglobin: $11.2\text{ g/dL}$
Platelets: $210,000/\mu\text{L}$
Lactic acid: $8.4\text{ mmol/L}$
Bicarbonate: $12\text{ mEq/L}$

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

A 24-year-old woman presents to the emergency department with a 2-day history of progressively worsening shortness of breath, chest tightness, and a nonproductive cough. She has a history of asthma and normally uses an albuterol inhaler as needed, but she ran out of medication two weeks ago. Her temperature is 37.1 C (98.8 F), blood pressure is 128/82 mm Hg, pulse is 118/min, and respiratory rate is 28/min. Oxygen saturation is 93% on room air. Physical examination reveals diffuse bilateral expiratory wheezing with a prolonged expiratory phase. She is speaking in short phrases, using accessory muscles of respiration, and appears anxious. Which of the following are appropriate initial pharmacological interventions for this patient? (Select all that apply)

During rounds in the intensive care unit, the telemetry alarm sounds for a 55-year-old female patient who was admitted for atypical chest pain. Upon entering the room, the medical team finds her unresponsive, apneic, and without a palpable pulse. The bedside monitor reveals chaotic, highly irregular waveform deflections of varying amplitudes with no discernible P waves, QRS complexes, or T waves. A manual defibrillator is immediately available at the bedside. Assuming her rhythm remains refractory to all interventions, arrange the following management steps in the correct chronological sequence according to the standard adult Advanced Cardiac Life Support (ACLS) algorithm.

Accompanied by her husband, a $62$-year-old woman arrives at the emergency department experiencing acute-onset breathlessness and a persistent cough. Her symptoms began rapidly over the past $4$ hours. She has a medical history notable for type $2$ diabetes mellitus and refractory major depressive disorder. Her daily medications include metformin and phenelzine. Three days ago, she developed a mild upper respiratory tract infection and began taking an over-the-counter oral decongestant containing pseudoephedrine.

On arrival, the patient is visibly distressed, diaphoretic, and speaking in short phrases. Her temperature is $37.0^{\circ}\mathrm{C}$ ($98.6^{\circ}\mathrm{F}$), blood pressure is $218/116$ mmHg, pulse is $114$/min, and respiratory rate is $26$/min. Pulse oximetry demonstrates an oxygen saturation of $89\%$ on room air. Physical examination reveals prominent jugular venous distention. Cardiac auscultation shows a regular tachycardia with a loud $S_4$ gallop and no discernible murmurs. Pulmonary auscultation reveals diffuse, fine inspiratory crackles bilaterally, extending up to the mid-lung fields. Bilateral trace pedal edema is present.

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

A 62-year-old male patient with a body mass index of 32 kg/m² is evaluated in the outpatient setting for an 8-month history of progressive bilateral knee discomfort. He reports that the pain exacerbates at the end of the day and after prolonged ambulation. Radiographs of the knees demonstrate asymmetric joint space narrowing, subchondral sclerosis, and marginal osteophytes. Arrange the following therapeutic interventions in the standard chronological order of escalation for the management of this patient's condition, assuming inadequate symptomatic relief is achieved at each preceding step.

A 68-year-old man with a history of type 2 diabetes mellitus and chronic obstructive pulmonary disease (COPD) is brought to the emergency department by his daughter due to lethargy and confusion. The daughter reports that he has had severe nausea and vomiting for the past 3 days and has been unable to eat or take his usual medications, including insulin. On physical examination, the patient is lethargic and oriented to person only. His temperature is 37.2°C (99.0°F), blood pressure is 90/60 mm Hg, pulse is 115/min, and respiratory rate is 24/min with shallow breaths. Mucous membranes are extremely dry, and skin turgor is decreased. Pulmonary examination reveals prolonged expiration with bilateral wheezes and decreased breath sounds.

Laboratory results are as follows:

Arterial blood gas (room air):
$pH$: 7.25
$PaCO_2$: 50 mm Hg
$PaO_2$: 55 mm Hg
$HCO_3^-$: 21 mEq/L

Serum chemistry:
$Na^+$: 140 mEq/L
$K^+$: 4.8 mEq/L
$Cl^-$: 90 mEq/L
$HCO_3^-$: 21 mEq/L
Blood urea nitrogen: 45 mg/dL
Creatinine: 2.2 mg/dL
Glucose: 450 mg/dL
Albumin: 4.0 g/dL

Urinalysis is strongly positive for ketones.

Which of the following best describes this patient's primary acid-base disturbances?

A 62-year-old woman is evaluated in the emergency department for severe abdominal pain, nausea, and vomiting that began 24 hours ago. She has not passed flatus or had a bowel movement since the symptoms started. Her past medical history includes an open hysterectomy 5 years ago. Her temperature is 38.8°C (101.8°F), blood pressure is 90/60 mmHg, and pulse is 120/min. Physical examination reveals a markedly distended abdomen. Bowel sounds are absent. There is diffuse abdominal tenderness with marked rigidity and rebound tenderness. Laboratory studies demonstrate a leukocyte count of 19,000/mm³. Upright abdominal radiography shows multiple dilated loops of small bowel, prominent air-fluid levels, and no gas in the rectum. Which of the following is the most appropriate next step in the management of this patient?

A 68-year-old man presents to the emergency department with acute onset of severe shortness of breath that awoke him from sleep. He has a history of hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. His temperature is 37.1°C, blood pressure is 165/95 mmHg, pulse is 110/min, and respirations are 24/min. Pulse oximetry shows 88% on room air. Physical examination reveals jugular venous distention and bilateral pitting edema to the knees. The physician is evaluating the patient for acute decompensated heart failure versus an exacerbation of chronic obstructive pulmonary disease (COPD). Which of the following additional findings would most specifically confirm acute decompensated heart failure in this patient?

A 72-year-old man is brought to the emergency department due to severe, worsening shortness of breath for the past 24 hours. He reports waking up in the middle of the night gasping for air and can only sleep propped up on three pillows. His medical history includes a 40-pack-year smoking history, type 2 diabetes mellitus, and hypertension. He was evaluated at an urgent care clinic three days ago for a mild cough; a sputum culture from that visit has finalized, growing normal respiratory flora with *Streptococcus pneumoniae* that is susceptible to penicillin and amoxicillin.

In the emergency department, his temperature is 37.1°C (98.8°F), blood pressure is 165/95 mmHg, heart rate is 112/min, and respiratory rate is 26/min. Pulse oximetry shows 88% on room air. Physical examination reveals elevated jugular venous pressure, bilateral basilar lung crackles, and diffuse expiratory wheezes. Cardiac auscultation demonstrates a normal $S_1$ and $S_2$ with an $S_3$ gallop.

Laboratory and diagnostic evaluation shows:

Arterial blood gas on room air:

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

Match each classic urinalysis sediment finding with its most likely underlying renal pathology.

A $70$-year-old man comes to the emergency department at $2:00$ AM due to acute-onset, severe shortness of breath that awoke him from sleep. He has a history of severe chronic obstructive pulmonary disease (COPD) and coronary artery disease. He reports a dry cough but denies fever, chills, or increased sputum production. His current medications include an umeclidinium-vilanterol inhaler, aspirin, and atorvastatin. His temperature is $37.1^\circ$ C ($98.8^\circ$ F), blood pressure is $165/95$ mm Hg, pulse is $115$/min, and respirations are $28$/min. Pulse oximetry shows $85\%$ on room air. The patient is diaphoretic, speaks in short sentences, and is using accessory muscles of respiration. Jugular venous pressure is $10$ cm $H_2O$. Pulmonary examination reveals a prolonged expiratory phase with diffuse bilateral wheezing. Cardiac examination shows tachycardia with a regular rhythm and an $S_3$ gallop.

Arterial blood gas analysis on room air reveals:

pH: $7.25$
$PaCO_2$: $60$ mm Hg
$PaO_2$: $52$ mm Hg
$HCO_3^-$: $26$ mEq/L

Chest radiography reveals prominent pulmonary vasculature, Kerley B lines, and a slightly enlarged cardiac silhouette.

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

A 42-year-old woman comes to the clinic due to a 6-month history of worsening fatigue, generalized weakness, and cold intolerance. She also reports that she has not had a menstrual period for the past 8 months. She has no significant past medical history and takes no medications. Her temperature is 36.1°C (97.0°F), blood pressure is 95/60 mm Hg, and pulse is 56/min. Physical examination reveals dry skin and a delayed relaxation phase of the deep tendon reflexes. Laboratory studies show:

Which of the following is the most likely diagnosis?