All practice questions

A 32-year-old woman is evaluated in the outpatient clinic for progressive fatigue and severe muscle weakness that has worsened over the last month. She reports that her weakness is most pronounced in her thighs and shoulders, making it difficult to climb stairs or comb her hair. She has no chronic medical conditions and does not take any prescription or over-the-counter medications. Her blood pressure is 112/74 mm Hg, pulse is 84/min, and respiratory rate is 16/min. Physical examination reveals normal muscle bulk but 3/5 motor strength in the proximal upper and lower extremities bilaterally. Sensation is intact.

Laboratory analysis reveals the following:

Serum chemistry:
$Na^+$: 140 mEq/L
$K^+$: 2.6 mEq/L
$Cl^-$: 114 mEq/L
$HCO_3^-$: 14 mEq/L
Blood urea nitrogen: 14 mg/dL
Creatinine: 0.8 mg/dL

Arterial blood gas (room air):
$pH$: 7.29
$pCO_2$: 29 mm Hg
$pO_2$: 96 mm Hg

Urinalysis:
$pH$: 6.5
Specific gravity: 1.012
Ketones: Negative
Protein: Negative

Urine electrolytes:
$Na^+$: 45 mEq/L
$K^+$: 15 mEq/L
$Cl^-$: 25 mEq/L

Which of the following best describes this patient's acid-base disturbance and underlying etiology?

A $64$-year-old man is brought to the emergency department by his family due to severe shortness of breath, generalized weakness, and newly developed confusion over the past $12$ hours. He has a history of severe chronic obstructive pulmonary disease (COPD) and type 2 diabetes mellitus. For the past three days, he has had a worsening cough productive of thick, yellow sputum and a fever. His temperature is $38.8^\circ\text{C}$ ($101.8^\circ\text{F}$), blood pressure is $88/54\text{ mmHg}$, pulse is $122/\text{min}$, and respirations are $34/\text{min}$. On physical examination, the patient is lethargic and oriented only to person. He is using accessory muscles of respiration. Lung auscultation demonstrates diffuse rhonchi bilaterally and localized crackles in the right lower lung field. Jugular venous pressure is $6\text{ cm H}_2\text{O}$. Heart sounds are normal with no murmurs or gallops. There is no lower extremity edema. A chest radiograph reveals a right lower lobe consolidation. Arterial blood gas analysis on room air shows:

pH: $7.24$
$\text{pCO}_2$: $35\text{ mmHg}$
$\text{pO}_2$: $58\text{ mmHg}$
$\text{HCO}_3^-$: $15\text{ mEq/L}$

Serum lactate is $5.4\text{ mmol/L}$. The patient receives a $30\text{ mL/kg}$ intravenous fluid bolus, and empiric intravenous ceftriaxone and azithromycin are initiated. What is the most appropriate next step in management?

A $71$-year-old man is brought to the emergency department due to progressively worsening shortness of breath and an increased volume of thick, purulent sputum over the past $48$ hours. His medical history is significant for severe chronic obstructive pulmonary disease (COPD), ischemic heart disease, and stage 3 chronic kidney disease. Vital signs show a temperature of $37.6^\circ\text{C}$ ($99.7^\circ\text{F}$), heart rate of $112$/min, respiratory rate of $26$/min, and blood pressure of $155/88$ mm Hg. Oxygen saturation is $86\%$ on room air.

On physical examination, the patient appears somnolent but arouses to verbal stimuli. Jugular venous pressure is estimated at $7$ cm H $_2$ O. Chest auscultation reveals a markedly prolonged expiratory phase with diffuse bilateral wheezes and coarse rhonchi. No S3 gallop is appreciated. Bilateral 1+ pitting edema is present in the lower extremities.

An arterial blood gas analysis on room air reveals:

A chest radiograph shows hyperlucent lung fields and flattened hemidiaphragms without focal consolidations or pleural effusions. A sputum Gram stain shows abundant polymorphonuclear leukocytes and Gram-negative coccobacilli.

Based on the clinical presentation and laboratory findings, which of the following are appropriate initial management steps for this patient? (Select all that apply)

A $19$-year-old university student is evaluated in the emergency department for severe generalized weakness, abdominal cramping, and frequent vomiting over the past $24$ hours. She has a known history of type 1 diabetes mellitus and reports that her insulin pump malfunctioned yesterday. Vital signs show a temperature of $37.1^\circ$ C ($98.8^\circ$ F), blood pressure of $105/65$ mm Hg, pulse of $115$/min, and respiratory rate of $28$/min with deep, sighing breaths.

Laboratory results are as follows:

An arterial blood gas analysis on room air reveals:

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

For each of the following acute gastrointestinal scenarios evaluated in the emergency department, identify the most appropriate next step in diagnosis or management.

A $65$-year-old man is evaluated in the intensive care unit for worsening altered mental status and respiratory distress. He was admitted $2$ days ago for community-acquired pneumonia and was started on appropriate intravenous antibiotics. His medical history includes chronic obstructive pulmonary disease (COPD) and hypertension. Temperature is $38.6^\circ\text{C}$ ($101.5^\circ\text{F}$), blood pressure is $88/54\text{ mmHg}$, pulse is $112/\text{min}$, and respirations are $28/\text{min}$. Pulse oximetry shows $92\%$ on a $50\%$ Venturi mask. Physical examination reveals bilateral crackles and scattered wheezes. Laboratory results are as follows:

Arterial blood gas analysis on $50\%$ oxygen:

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

A $64$-year-old man is admitted to the hospital with a $2$-week history of progressively worsening mid-back pain and low-grade fevers. He has a history of poorly controlled type 2 diabetes mellitus. His temperature is $38.2^\circ\text{C}$ ($100.8^\circ\text{F}$), blood pressure is $128/78\text{ mmHg}$, and pulse is $92\text{/min}$. Physical examination reveals point tenderness over the $T10-T11$ spinous processes. Neurologic examination of the lower extremities is completely normal. Laboratory studies show an erythrocyte sedimentation rate (ESR) of $85\text{ mm/h}$ and a C-reactive protein (CRP) level of $112\text{ mg/L}$. Magnetic resonance imaging (MRI) of the thoracic spine demonstrates abnormal marrow signal and enhancement of the $T10$ and $T11$ vertebral bodies with a small adjacent fluid collection, diagnostic of vertebral osteomyelitis. Two sets of blood cultures are obtained, and the patient is started on empiric intravenous vancomycin and piperacillin-tazobactam. On hospital day $3$, the patient's temperature is $37.4^\circ\text{C}$ ($99.3^\circ\text{F}$). Both sets of blood cultures are positive for Staphylococcus aureus that is susceptible to oxacillin, cefazolin, and vancomycin, but resistant to penicillin. Which of the following is the most appropriate next step in the pharmacologic management of this patient?

A 58-year-old man with a history of cavitary pulmonary tuberculosis presents to the emergency department after coughing up approximately 600 mL of bright red blood over the last 2 hours. He appears anxious and is in visible respiratory distress. His blood pressure is 88/55 mmHg, pulse is 122/min, and respiratory rate is 28/min. Auscultation reveals prominent coarse crackles over the right upper and middle lung fields, with clear breath sounds on the left. Arrange the following steps in the most appropriate sequential order for the management of this patient's condition.

A $55$-year-old man comes to the clinic reporting a $6$-month history of worsening fatigue, generalized weakness, and constipation. He also notes experiencing frequent dull headaches and has recently been bumping into doorframes while walking. His medical history is unremarkable, and he takes no medications. Vital signs are within normal limits. Physical examination reveals dry, cool skin and delayed relaxation of the deep tendon reflexes. Confrontation visual field testing demonstrates decreased peripheral vision bilaterally. Laboratory results are as follows:

Thyroid-stimulating hormone (TSH): $2.1$ $\mu$ U/mL (Normal: $0.5$–$5.0$ $\mu$ U/mL)
Free thyroxine (T4): $0.5$ ng/dL (Normal: $0.9$–$2.4$ ng/dL)

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

A 45-year-old woman is receiving a transfusion of packed red blood cells for severe anemia secondary to abnormal uterine bleeding. Thirty minutes into the transfusion, she develops sudden-onset chills, severe flank pain, and dyspnea. Her temperature is 39.2°C (102.6°F), blood pressure is 85/50 mm Hg, and heart rate is 120/min. Arrange the following management steps in the most appropriate chronological sequence.

Review the following serum and urine laboratory profiles for four different adult patients. Reference ranges: Calcium 8.4-10.2 mg/dL, Intact PTH 10-65 pg/mL, Phosphorus 2.7-4.5 mg/dL, Creatinine 0.6-1.2 mg/dL; normal 24-hour urine calcium is typically 100-300 mg/day. Match each laboratory profile with the most likely clinical diagnosis.

Match the following arterial blood gas and serum electrolyte profiles with their most likely underlying clinical etiology.

An emergency department physician evaluates a 69-year-old female resident of an assisted living facility who presents with a 4-day history of profuse, watery diarrhea and progressively worsening shortness of breath. She has a medical history of chronic obstructive pulmonary disease (COPD) and heart failure with reduced ejection fraction. She reports an increase in cough and purulent sputum production that began one week ago. Three days ago, her primary care physician obtained a sputum culture that subsequently grew *Moraxella catarrhalis* sensitive to amoxicillin, azithromycin, and cefuroxime.

Physical examination reveals dry oral mucosa and flat neck veins when supine. Lung auscultation demonstrates scattered expiratory wheezes and a prolonged expiratory phase, without crackles. Cardiac examination shows a regular tachycardia with no S3 gallop.

Which of the following are appropriate next steps in the management of this patient? (Select all that apply)

A 29-year-old woman is evaluated in the clinic for a 4-month history of rapidly progressive facial hair growth, severe acne, and absent menses. Prior to this, she had regular 28-day menstrual cycles. The patient also reports recent deepening of her voice. She takes no medications and has no chronic medical conditions. Her BMI is $24 \text{ kg/m}^2$, and her blood pressure is $115/75 \text{ mmHg}$. Physical examination reveals coarse, dark terminal hair on her chin, chest, and lower abdomen. Temporal hair thinning is noted. Pelvic examination is remarkable for clitoromegaly. A urine pregnancy test is negative.

Laboratory studies show:
- Serum total testosterone: $155 \text{ ng/dL}$ (normal: $15-70 \text{ ng/dL}$)
- Dehydroepiandrosterone sulfate (DHEAS): $8,200 \text{ \mu g/dL}$ (normal: $35-430 \text{ \mu g/dL}$)
- Thyroid-stimulating hormone (TSH): $2.2 \text{ \mu U/mL}$ (normal: $0.5-5.0 \text{ \mu U/mL}$)
- Prolactin: $12 \text{ ng/mL}$ (normal: $4-24 \text{ ng/mL}$)

Which of the following is the most likely diagnosis?

A 67-year-old man is brought to the emergency department from his home by his daughter due to progressive confusion, a productive cough with rust-colored sputum, and subjective fever for the past 3 days. He has a history of severe obesity hypoventilation syndrome, untreated obstructive sleep apnea, and chronic lower extremity edema.

Vital signs include a temperature of $38.8^\circ C$ ($101.8^\circ F$), heart rate of $115$/min, blood pressure of $105/65$ mmHg, respiratory rate of $24$/min, and oxygen saturation of $82\%$ on room air.

Physical examination reveals a body mass index of $42$ kg/m $^2$. The patient is lethargic but rousable. Jugular venous distention is present to the angle of the jaw. Chest auscultation reveals bronchial breath sounds and egophony in the right lower lobe, along with trace bilateral expiratory wheezing; no fine crackles are heard. Cardiac examination reveals a prominent $P_2$ and a right-sided $S_3$. There is $3+$ pitting edema bilaterally up to the knees.

Laboratory results:
Leukocyte count: $16,500/\mu L$ (with $12\%$ bands)
Serum sodium: $138$ mEq/L
Serum potassium: $4.1$ mEq/L
Serum chloride: $92$ mEq/L
Serum bicarbonate: $16$ mEq/L
Blood urea nitrogen: $32$ mg/dL
Serum creatinine: $1.4$ mg/dL
Serum lactate: $4.2$ mmol/L

Arterial blood gas (on room air):
pH: $7.13$
PaO $_2$: $50$ mm Hg
PaCO $_2$: $50$ mm Hg

Chest radiograph shows a dense right lower lobe consolidation. There is prominent central pulmonary vasculature and right ventricular enlargement, but no pulmonary venous congestion or pleural effusion.

A rapid lower respiratory tract multiplex PCR panel is positive for *Streptococcus pneumoniae* and negative for all other bacterial and viral targets.

Based on the patient's presentation and diagnostic findings, which of the following statements are correct regarding his diagnosis and management? (Select all that apply)

Surgical team rounds are being conducted on a 71-year-old male patient who is currently recovering six days after an elective open abdominal aortic aneurysm repair. His past medical history is notable for diet-controlled type 2 diabetes and mild chronic obstructive pulmonary disease.

Seventy-two hours after his surgery, he experienced acute tachypnea, a productive cough, and a temperature spike to 38.7°C (101.7°F). Portable chest imaging confirmed a right lower lobe consolidation. The patient was promptly started on an empiric antimicrobial regimen of intravenous piperacillin-tazobactam and vancomycin for suspected hospital-acquired pneumonia.

Today, the patient feels much better, is breathing comfortably on ambient air, and his temperature has normalized to 37.1°C (98.8°F). Leukocyte counts have trended down from a peak of 16,500/mm³ to 8,500/mm³. The microbiology laboratory reports that respiratory cultures from the initial febrile episode have finalized, revealing a heavy growth of Haemophilus influenzae. The isolate demonstrates susceptibility to ceftriaxone, levofloxacin, and amoxicillin-clavulanate.

Which of the following represent the most appropriate management decisions at this time? (Select exactly 2 answers)

A 71-year-old man is transported to the hospital by emergency medical services due to the abrupt onset of severe difficulty breathing. Three days ago, the patient experienced a prolonged episode of substernal discomfort and diaphoresis but declined to seek medical care, assuming it was severe heartburn. His medical history includes hypertension, hyperlipidemia, and a 45-pack-year history of smoking.

On arrival, his blood pressure is 88/54 mm Hg, heart rate is 118/min, and respiratory rate is 26/min. Oxygen saturation is 86% on room air. The patient is diaphoretic and unable to speak in full sentences. Neck veins are distended. Lung auscultation reveals diffuse bilateral crackles and prominent expiratory wheezing. Cardiac examination demonstrates a rapid regular rhythm with a loud, blowing holosystolic murmur that is most prominent at the cardiac apex and radiates to the left axilla.

An electrocardiogram displays normal sinus rhythm with prominent Q waves and inverted T waves in leads II, III, and aVF.

Based on the clinical presentation, which of the following is the most likely etiology of this patient's acute respiratory distress?

Match each HIV-positive patient's clinical presentation and neuroimaging or cerebrospinal fluid (CSF) finding with the most likely causative pathogen or etiology.

An inpatient surgical consult is requested for a 62-year-old male on the medical ward who was admitted two days ago for a small bowel obstruction. He has a history of an open appendectomy in childhood. Initially, his symptoms improved with bowel rest and nasogastric decompression. Over the past 4 hours, however, his clinical status has rapidly declined. Current vital signs show a temperature of 38.6°C (101.5°F), heart rate of 118/min, and blood pressure of 98/60 mm Hg. Physical examination reveals a distended abdomen with marked tenderness, guarding, and rebound in the right lower quadrant. Laboratory studies demonstrate a leukocyte count of 18,500/mm³ and a serum lactate of 4.2 mmol/L. Intravenous fluid resuscitation is immediately initiated. Which of the following is the most appropriate next step in management?

Evaluate the following distinct patient encounters involving recent exposures to infectious agents. Match each patient scenario to the most appropriate, guideline-based post-exposure prophylaxis (PEP) or vaccine intervention.