Internal Medicine

3151 questions

All types3,151 Multiple choice1,611 Multiple select73 Numeric81 Matching714 Ordering672

A physician is asked to evaluate a hospitalized $72$ -year-old male on postoperative day $4$ following an emergency exploratory laparotomy and small bowel resection for a strangulated hernia. Overnight, he developed an acute fever of $38.4^\circ\text{C}$ ( $101.1^\circ\text{F}$ ) and excruciating pain in his right knee.

The patient has a history of hypertension and chronic kidney disease, with a baseline serum creatinine of $2.1\text{ mg/dL}$ . He is currently receiving continuous intravenous fluids and is transitioning to a clear liquid diet.

On physical examination, his vital signs are stable aside from the fever. The right knee is markedly swollen, uniformly erythematous, warm, and exquisitely tender to light palpation. He refuses to range the joint. The surgical incision site is clean, dry, and intact with no surrounding erythema or induration.

Arthrocentesis of the right knee is performed, yielding $5\text{ mL}$ of cloudy yellow fluid. Synovial fluid analysis reveals:

- Leukocyte count: $45,000/\text{mm}^3$ ( $85\%$ neutrophils)
- Gram stain: No organisms seen
- Crystal analysis: Negatively birefringent, needle-shaped crystals

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

Administer an intra-articular injection of triamcinolone

Initiate empiric intravenous vancomycin and ceftriaxone

Obtain a computed tomography scan of the abdomen and pelvis

Prescribe oral indomethacin

Administer intravenous furosemide

Show answer & explanation

Answer: Administer an intra-articular injection of triamcinolone

Answer

The most appropriate next step in management is to administer an intra-articular injection of triamcinolone.

The correct answer involves administering an intra-articular glucocorticoid injection. This patient has an acute gout flare, definitively diagnosed by the negatively birefringent, needle-shaped crystals. A key principle in rheumatology is tailoring acute flare management to the patient's comorbidities. This patient has advanced chronic kidney disease (precluding the use of NSAIDs like indomethacin) and is recovering from a major intestinal resection (making oral colchicine poorly tolerated and systemic glucocorticoids risky due to potential impairment of anastomotic healing). Intra-articular triamcinolone provides rapid, localized relief without significant systemic side effects.

Step-by-Step Solution

Diagnose the underlying condition based on synovial fluid analysis.

The presence of negatively birefringent, needle-shaped crystals confirms acute monosodium urate crystal arthropathy (gout).

Accurate diagnosis is required to distinguish crystal arthropathy from septic arthritis, as both can present with high synovial leukocyte counts and fever.

Evaluate the safety profile of standard gout therapies against the patient's comorbidities.

NSAIDs are contraindicated due to chronic kidney disease (Cr 2.1 mg/dL). Colchicine is high-risk in CKD and post-bowel resection. Systemic steroids could impair surgical anastomotic healing.

Pharmacotherapy for acute gout must be individualized to prevent severe iatrogenic complications like acute kidney injury or bowel perforation.

Select the optimal targeted therapy.

Intra-articular glucocorticoid injection is selected.

It provides powerful, localized anti-inflammatory effects with minimal systemic absorption, making it the safest choice for this complex postoperative patient.

Key Concept

The management of acute monoarticular gout in patients with significant comorbidities (such as chronic kidney disease or recent gastrointestinal surgery) requires targeted local therapy, such as intra-articular glucocorticoids, to avoid the severe systemic toxicities associated with NSAIDs, colchicine, and systemic steroids.

Estimated Time:1m 30s

Question 922Question →

A 24-year-old man comes to the clinic complaining of lower back pain that has progressively worsened over the past 7 months. He states that the pain is most severe when he wakes up in the morning and is associated with profound stiffness that lasts for about 2 hours. The discomfort noticeably improves after he goes for a jog or stretches, but it does not improve with rest. He has no history of trauma or recent infections. Vital signs are within normal limits. Physical examination reveals reduced forward flexion of the lumbar spine. An anteroposterior radiograph of the pelvis demonstrates bilateral sclerosis and joint space narrowing of the sacroiliac joints. Which of the following is the most appropriate initial pharmacotherapy for this patient's condition?

Nonsteroidal anti-inflammatory drugs

Tumor necrosis factor-alpha inhibitors

Systemic corticosteroids

Acetaminophen

Intravenous broad-spectrum antibiotics

Show answer & explanation

Answer: Nonsteroidal anti-inflammatory drugs

Answer

Nonsteroidal anti-inflammatory drugs are the first-line medical therapy for ankylosing spondylitis.

The patient's clinical presentation of chronic, insidious-onset lower back pain that is worse in the morning, improves with exercise, and is accompanied by radiographic evidence of sacroiliitis is highly characteristic of ankylosing spondylitis. For patients with active ankylosing spondylitis, continuous treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) is the most appropriate first-line pharmacologic therapy. NSAIDs are highly effective in reducing pain, decreasing morning stiffness, and improving overall mobility in these patients.

Step-by-Step Solution

Identify the primary clinical syndrome based on the history.

A young male with chronic lower back pain, severe morning stiffness, and improvement with physical activity but not with rest.

These classic features differentiate inflammatory back pain from mechanical back pain.

Interpret the radiographic findings.

Bilateral sclerosis and joint space narrowing of the sacroiliac joints (sacroiliitis).

Confirms the diagnosis of ankylosing spondylitis when combined with the clinical presentation of inflammatory back pain.

Determine the standard initial pharmacotherapy for this diagnosis.

Nonsteroidal anti-inflammatory drugs (NSAIDs).

Continuous use of NSAIDs is the established first-line treatment to reduce pain and stiffness in axial spondyloarthritis.

Key Concept

Ankylosing spondylitis is characterized by inflammatory back pain and sacroiliitis, and continuous NSAID therapy is the most appropriate initial pharmacologic treatment.

Question 923Question →

Emergency medical services arrive with a $22$ -year-old university student who intentionally ingested a large quantity of analgesic medication following a dispute. According to her roommate, she swallowed approximately $30$ tablets of $500$ -mg acetaminophen exactly $45$ minutes ago. The patient is visibly distressed and reports mild nausea, but denies vomiting, abdominal pain, or other symptoms. Vital signs include a temperature of $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure of $118/75$ mm Hg, pulse of $88$ /min, and respiratory rate of $16$ /min. The physical examination is notable only for a flat, non-tender abdomen and no focal neurologic deficits. Arrange the clinical interventions below in the correct chronological sequence to appropriately evaluate and manage this patient's toxic exposure.

Drag items to arrange them in the correct order

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Answer

The correct chronological sequence is: Administer oral activated charcoal, measure serum acetaminophen concentration at 4 hours post-ingestion, evaluate the level using the Rumack-Matthew nomogram, and finally initiate intravenous N-acetylcysteine therapy if indicated.

The algorithm for acute acetaminophen ingestion emphasizes exact timing. Within

1

2

hours of ingestion, activated charcoal should be administered to decrease gastrointestinal absorption. Serum acetaminophen levels must be checked no earlier than

4

hours post-ingestion to ensure complete drug absorption and to capture the peak level. This

4

-hour level is subsequently plotted on the Rumack-Matthew nomogram to determine the patient's risk of hepatotoxicity. If the plotted level falls on or above the established treatment line, definitive therapy with intravenous N-acetylcysteine is initiated. Because N-acetylcysteine is maximally effective at preventing liver injury when started within

8

hours of ingestion, waiting for the

4

-hour level in this early-presenting patient does not delay necessary care or increase her clinical risk.

Step-by-Step Solution

Determine the time elapsed since ingestion.

The patient presented

45

minutes post-ingestion.

The time elapsed strictly dictates the utility of gastrointestinal decontamination and the appropriate timing for drawing serum drug levels.

Assess indications for immediate gastrointestinal decontamination.

Oral activated charcoal is administered first.

Activated charcoal is highly effective at reducing systemic absorption if administered within

1

2

hours of an acute acetaminophen ingestion in an awake patient.

Determine the optimal timing for laboratory evaluation.

Wait until

4

hours post-ingestion to measure the serum acetaminophen level.

Acetaminophen absorption continues for several hours. Levels measured before the

4

-hour mark are uninterpretable because they do not reflect the true peak concentration.

Analyze the laboratory results to guide definitive therapy.

Plot the

4

-hour level on the Rumack-Matthew nomogram and initiate N-acetylcysteine if the result falls above the treatment line.

The nomogram accurately predicts the risk of liver injury. N-acetylcysteine is nearly

100\%

effective at preventing hepatotoxicity if started within

8

hours of ingestion, allowing ample time to wait for accurate lab results.

Key Concept

The management algorithm for acute acetaminophen toxicity depends strictly on the time since ingestion: immediate activated charcoal for early presenters (

< 2

hours), followed by a

4

-hour serum level plotted on the Rumack-Matthew nomogram to direct subsequent N-acetylcysteine therapy.

Question 924Question →

A $65$ -year-old man comes to the clinic reporting progressive fatigue, weakness, and a "pins and needles" sensation in his feet for the past $4$ months. His past medical history is significant for type $2$ diabetes mellitus, for which he has been taking metformin for $10$ years. Vital signs are within normal limits. Physical examination reveals pale conjunctivae and decreased vibratory sensation in the bilateral toes and ankles.

Laboratory studies show:

Test	Result	Reference Range
Hemoglobin	$10.2$ g/dL	$13.5-17.5$ g/dL
Mean corpuscular volume	$112$ fL	$80-100$ fL
Leukocyte count	$5,500$ /mm³	$4,500-11,000$ /mm³
Platelet count	$180,000$ /mm³	$150,000-400,000$ /mm³

Which of the following is the most appropriate next step in the evaluation of this patient's anemia?

Measurement of serum vitamin B12 and folate levels

Measurement of serum iron, total iron-binding capacity, and ferritin levels

Hemoglobin electrophoresis

Upper gastrointestinal endoscopy

Bone marrow aspiration and biopsy

Show answer & explanation

Answer: Measurement of serum vitamin B12 and folate levels

Answer

Measurement of serum vitamin B12 and folate levels

The correct answer is measurement of serum vitamin B12 and folate levels. This patient presents with a classic picture of macrocytic anemia (MCV >

100

fL) accompanied by peripheral neuropathy (diminished vibratory sensation). Long-term use of metformin is a well-established risk factor for vitamin B12 deficiency due to interference with calcium-dependent absorption of the B12-intrinsic factor complex in the terminal ileum. The next best step in the workup of macrocytic anemia is to check serum B12 and folate levels to distinguish between the two most common megaloblastic causes.

Step-by-Step Solution

Analyze the patient's laboratory findings.

The patient has anemia (hemoglobin

10.2

g/dL) with an elevated MCV (

112

fL), indicating a macrocytic anemia.

Identifying the morphological classification of anemia (microcytic, normocytic, macrocytic) directs the diagnostic algorithm.

Correlate the laboratory findings with the clinical presentation.

The patient presents with progressive fatigue and peripheral neuropathy (decreased vibratory sensation). He also has a history of long-term metformin use.

Macrocytic anemia combined with neurologic deficits strongly suggests vitamin B12 deficiency. Metformin is known to interfere with vitamin B12 absorption in the terminal ileum.

Determine the most appropriate next diagnostic step based on the suspected etiology.

The initial step in confirming suspected megaloblastic macrocytic anemia is measuring serum vitamin B12 and folate levels.

Definitive diagnosis requires biochemical confirmation before initiating therapy or pursuing more invasive investigations.

Key Concept

Evaluation of macrocytic anemia requires initial measurement of serum vitamin B12 and folate levels, particularly in patients with neurologic symptoms or risk factors such as chronic metformin use.

Estimated Time:1m 0s

Question 925Question →

A 52-year-old restaurant manager comes to the clinic due to sudden, excruciating pain and swelling in his left big toe that woke him up from sleep. He reports having two similar episodes over the past twelve months that eventually resolved after taking various over-the-counter pain relievers. His past medical history is notable for hypertension and obesity. Vital signs are stable and within normal limits. Physical examination reveals a markedly erythematous, warm, swollen, and exquisitely tender left first metatarsophalangeal joint. Arrange the following clinical steps in the most appropriate chronological sequence for the optimal evaluation and long-term management of this patient's condition.

Drag items to arrange them in the correct order

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Answer

The correct chronological sequence is: diagnostic arthrocentesis, followed by acute symptom management (NSAIDs/colchicine), then initiation of urate-lowering therapy (allopurinol), and finally long-term titration to a target serum urate level.

The standard sequence for managing a patient presenting with an acute, likely crystal-induced monoarthritis and a history of recurrent flares is to first establish a definitive diagnosis by excluding infection through arthrocentesis. Once confirmed, the immediate goal is suppressing acute inflammation using NSAIDs, colchicine, or systemic glucocorticoids. Because this patient has experienced multiple flares over the past twelve months, he is a candidate for long-term urate-lowering therapy such as allopurinol. Finally, the long-term goal is to titrate this therapy to maintain a serum urate concentration below 6.0 mg/dL in order to dissolve existing crystals and prevent future acute attacks.

Step-by-Step Solution

Identify the suspected diagnosis based on the clinical presentation.

The acute onset of severe pain, warmth, and swelling in the first metatarsophalangeal joint (podagra) is highly suggestive of an acute gout flare.

Recognizing the classic presentation guides the initial diagnostic and therapeutic approach.

Determine the first step in management.

Arthrocentesis with synovial fluid analysis should be performed first.

It is essential to confirm the presence of monosodium urate crystals and definitively rule out septic arthritis, a joint-threatening emergency, before assuming a purely inflammatory etiology.

Select the appropriate acute therapy.

Administer oral naproxen or colchicine.

Acute gout flares are treated with potent anti-inflammatory agents to provide rapid symptom relief and restore patient mobility.

Formulate a long-term preventive strategy.

Initiate allopurinol and subsequently titrate it to a target serum urate level <6.0 mg/dL.

The patient has a history of recurrent attacks, meeting the criteria for long-term urate-lowering therapy to prevent future joint damage and the formation of tophi.

Key Concept

The sequential management of gout involves diagnostic confirmation via arthrocentesis, acute flare treatment with anti-inflammatories, initiation of urate-lowering therapy for recurrent attacks, and long-term dose titration to a specific target serum urate level.

Question 926Question →

A 42-year-old woman is brought to the emergency department by her husband due to sudden-onset, severe weakness in her legs that rapidly progressed over the last 12 hours. She is now unable to stand or bear weight. She also reports feeling intensely "short of breath." Her medical history is significant for a 5-year history of primary Sjögren syndrome, for which she takes artificial tears and cevimeline. Vital signs are temperature $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), pulse 105/min, blood pressure 115/75 mm Hg, and respirations 26/min. Oxygen saturation is 98% on room air.

Physical examination reveals a tachypneic woman taking deep, rapid breaths. Lungs are clear to auscultation bilaterally. Neurologic examination shows 1/5 motor strength in the bilateral lower extremities and 3/5 in the upper extremities. Deep tendon reflexes are absent globally. Sensation is intact.

Laboratory results are as follows:

Laboratory Parameter	Result	Reference Range
Serum chemistry
Sodium	139 mEq/L	136–145 mEq/L
Potassium	1.7 mEq/L	3.5–5.0 mEq/L
Chloride	114 mEq/L	98–106 mEq/L
Bicarbonate	12 mEq/L	22–28 mEq/L
Arterial blood gas (room air)
pH	7.25	7.35–7.45
$pCO_2$	26 mm Hg	35–45 mm Hg
$pO_2$	98 mm Hg	80–100 mm Hg
Urinalysis
pH	7.0	4.5–8.0
Leukocyte esterase	Positive	Negative
Nitrites	Positive	Negative
Thyroid function tests
TSH	0.3 $\mu$ U/mL	0.4–4.0 $\mu$ U/mL
Free $T_4$	1.1 ng/dL	0.9–1.7 ng/dL

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

Intravenous potassium chloride administration

Endotracheal intubation and mechanical ventilation

Intravenous piperacillin-tazobactam administration

Oral levothyroxine administration

Intravenous furosemide and continuous positive airway pressure

Show answer & explanation

Answer: Intravenous potassium chloride administration

Answer

Intravenous potassium chloride administration

The correct intervention is intravenous potassium chloride administration. This patient's acute flaccid paralysis is the result of life-threatening hypokalemia (

1.7

mEq/L). The underlying pathophysiology is Type 1 (distal) renal tubular acidosis (RTA), a known complication of primary Sjögren syndrome caused by autoimmune tubulointerstitial nephritis. Type 1 RTA is characterized by a normal anion gap metabolic acidosis (her AG is 13), severe hypokalemia, and an inability to acidify the urine (urine pH > 5.5; hers is 7.0). The severe hypokalemia alters the resting membrane potential of muscle cells, leading to profound weakness, areflexia, and potentially fatal cardiac arrhythmias or diaphragmatic paralysis. Immediate, aggressive intravenous potassium repletion is the highest priority.

Step-by-Step Solution

Analyze the acid-base disorder using the serum chemistry and arterial blood gas.

The patient has a normal anion gap metabolic acidosis (AG = 139 - [114 + 12] = 13). Winter's formula (

1.5 \times 12 + 8 = 26 \pm 2

) perfectly matches the measured

pCO_2

of 26 mm Hg, indicating appropriate respiratory compensation.

Characterizing the acid-base status distinguishes between respiratory failure and metabolic derangements.

Identify the etiology of the normal anion gap metabolic acidosis.

The combination of severe hypokalemia (

1.7

mEq/L) and an inappropriately alkaline urine pH (

7.0

) in the setting of a normal anion gap acidosis points to distal (Type 1) Renal Tubular Acidosis (RTA).

Type 1 RTA involves a failure of alpha-intercalated cells to secrete hydrogen ions, leading to hypokalemia, metabolic acidosis, and alkaline urine.

Connect the renal pathology to the patient's rheumatologic history.

Primary Sjögren syndrome is a classic cause of Type 1 RTA due to lymphocytic infiltration of the renal interstitium (tubulointerstitial nephritis) damaging the distal tubules.

Recognizing systemic complications of autoimmune diseases is essential for comprehensive rheumatologic care.

Determine the most critical immediate intervention.

The patient's acute flaccid paralysis and absent reflexes are directly caused by profound hypokalemia. Immediate intravenous potassium chloride is required.

Severe hypokalemia (

< 2.0

mEq/L) can rapidly lead to fatal cardiac arrhythmias and diaphragmatic failure.

Key Concept

Patients with primary Sjögren syndrome can develop tubulointerstitial nephritis leading to Type 1 (distal) renal tubular acidosis, which can present acutely with life-threatening hypokalemic flaccid paralysis requiring immediate intravenous potassium replacement.

Question 927Question →

A 72-year-old man is evaluated on postoperative day 2 following a partial colectomy for recurrent diverticulitis. His postoperative course was complicated by surgical site oozing, resulting in a hemoglobin drop to 6.8 g/dL. His past medical history is significant for chronic obstructive pulmonary disease (COPD) and ischemic cardiomyopathy with a left ventricular ejection fraction of 35%. He is currently receiving his second unit of packed red blood cells when he develops sudden-onset severe dyspnea and a dry cough. Temperature is 37.8°C (100.0°F), blood pressure is 175/95 mm Hg, pulse is 115/min, and respirations are 26/min. Pulse oximetry shows 88% on room air. Physical examination reveals an elevated jugular venous pressure of 12 cm H2O. Lung auscultation demonstrates bilateral basilar crackles with scattered expiratory wheezing. Cardiac auscultation reveals a regular tachycardia with a prominent S3 gallop. The transfusion is immediately stopped. Which of the following is the most appropriate next step in management?

Administer inhaled albuterol and systemic corticosteroids

Initiate intravenous broad-spectrum antibiotics

File an incident report regarding the transfusion rate

Administer intravenous furosemide

Obtain a urinalysis and urine culture

Show answer & explanation

Answer: Administer intravenous furosemide

Answer

Administer intravenous furosemide

This patient is experiencing Transfusion-Associated Circulatory Overload (TACO). TACO occurs when a large volume of blood products is administered rapidly, overwhelming the patient's cardiovascular capacity. It is especially common in older patients with underlying left ventricular dysfunction (e.g., ischemic cardiomyopathy with LVEF 35%). The presentation mimics acute decompensated heart failure, characterized by acute dyspnea, hypertension, tachycardia, elevated jugular venous pressure, crackles, and an S3 gallop. The first step in management is to immediately stop the transfusion, provide supplemental oxygen, and administer loop diuretics like intravenous furosemide to reduce preload and clear pulmonary edema.

Step-by-Step Solution

Analyze the onset of symptoms and vital signs.

The patient developed acute hypoxia, dyspnea, and hypertension during a blood transfusion.

Timing strongly suggests a transfusion reaction; hypertension narrows the differential toward volume overload.

Correlate vital signs with physical examination findings.

Elevated JVP, bilateral crackles, and a prominent S3 gallop in a patient with a low ejection fraction confirm cardiogenic pulmonary edema.

These findings reliably distinguish Transfusion-Associated Circulatory Overload (TACO) from Transfusion-Related Acute Lung Injury (TRALI) or other non-cardiogenic causes of hypoxia.

Determine the therapeutic intervention for the diagnosed condition.

The indicated treatment for TACO is intravenous furosemide.

Diuretics rapidly decrease intravascular volume and relieve pulmonary congestion, which is the root cause of the patient's acute respiratory failure.

Key Concept

Diagnosis and management of Transfusion-Associated Circulatory Overload (TACO)

Question 928Question →

A 55-year-old man develops sudden-onset generalized urticaria, wheezing, and a blood pressure of $80/50$ mm Hg shortly after receiving a dose of intravenous ceftriaxone on the medical ward. Arrange the following management steps in the correct chronological sequence, prioritizing immediate life-saving interventions first.

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Answer

The correct sequence is: Administer intramuscular epinephrine, followed by intravenous crystalloid fluids, then adjunctive intravenous glucocorticoids and antihistamines, and finally observe for a biphasic reaction.

The priority in anaphylaxis is the immediate reversal of life-threatening respiratory and cardiovascular collapse. Intramuscular epinephrine is the only medication that achieves this rapidly. This is followed by intravenous fluids to treat distributive shock. Adjunctive therapies like antihistamines and glucocorticoids are given third because they do not treat the acute life-threatening features. Finally, observation is required for a potential biphasic reaction.

Step-by-Step Solution

Identify the condition as anaphylactic shock.

The patient has urticaria, wheezing, and hypotension after antibiotic administration.

Recognizing anaphylaxis triggers immediate life-saving protocols.

Prioritize first-line life-saving therapy.

Administer intramuscular epinephrine.

Epinephrine rapidly reverses vasodilation and bronchoconstriction.

Address persistent hypotension.

Administer rapid intravenous crystalloid fluids.

Anaphylaxis causes severe distributive shock requiring fluid resuscitation.

Administer second-line adjunctive therapies.

Administer intravenous antihistamines and glucocorticoids.

These medications help control cutaneous symptoms and prevent delayed reactions, but act too slowly for acute resuscitation.

Determine post-stabilization care.

Observe the patient for a biphasic reaction.

Anaphylaxis can recur hours after the initial episode resolves.

Key Concept

In anaphylaxis, intramuscular epinephrine is the absolute first-line treatment and must never be delayed. Fluid resuscitation follows to treat distributive shock, followed by adjunctive therapies (antihistamines, glucocorticoids) and observation.

Question 929Question →

Match each clinical presentation of an immunocompromised patient with the most appropriate targeted pharmacotherapy.

Click a left item, then click its matching right item

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Answer

The correct pairings match Toxoplasmosis with pyrimethamine/sulfadiazine/leucovorin, Cryptococcal meningitis with amphotericin B/flucytosine, CMV retinitis with valganciclovir, and severe Pneumocystis pneumonia with TMP-SMX/corticosteroids.

Each targeted pharmacotherapy directly addresses the specific pathogen responsible for the classic opportunistic infection presentations in patients with advanced HIV, adhering to standard induction and primary treatment guidelines.

Step-by-Step Solution

Evaluate the clinical and radiographic presentation in each patient to identify the most likely opportunistic infection.

The pathogens are identified as Toxoplasma gondii, Cryptococcus neoformans, Cytomegalovirus (CMV), and Pneumocystis jirovecii.

Accurate diagnosis of the specific opportunistic infection is required before selecting targeted antimicrobial therapy.

Select the appropriate primary treatment regimen for each identified pathogen based on current clinical guidelines.

Toxoplasmosis requires pyrimethamine-based therapy; Cryptococcus requires amphotericin-based induction; CMV requires a -ganciclovir derivative; PCP requires TMP-SMX.

Different classes of pathogens (protozoan, fungal, viral) require highly specific antimicrobial mechanisms of action.

Assess disease severity for the PCP case to determine if adjunctive therapy is needed.

The patient's PaO2 is 60 mmHg (less than 70 mmHg), indicating severe disease that requires adjunctive corticosteroids.

Steroids prevent the severe inflammatory response that occurs when dying Pneumocystis organisms release inflammatory antigens in the lungs.

Key Concept

Pharmacotherapy for HIV-associated opportunistic infections

Question 930Question →

Match each classic physical examination or imaging finding to its most likely rheumatologic diagnosis.

Click a left item, then click its matching right item

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Answer

Heliotrope rash/Gottron papules matches with Dermatomyositis; Malar rash matches with Systemic lupus erythematosus; Acute first MTP swelling (podagra) matches with Gout; Sacroiliitis matches with Ankylosing spondylitis.

Each provided clinical vignette highlights the most iconic and highly tested physical examination or imaging finding for its respective rheumatologic condition, requiring direct pattern recognition.

Step-by-Step Solution

Evaluate the cutaneous findings of a heliotrope rash and Gottron papules.

Identified as dermatomyositis.

These are highly specific pathognomonic skin signs of this inflammatory myopathy.

Evaluate the malar rash that spares the nasolabial folds.

Identified as systemic lupus erythematosus.

Sparing of the nasolabial folds distinguishes the SLE malar rash from conditions like rosacea or seborrheic dermatitis.

Evaluate the acute swelling of the first metatarsophalangeal joint.

Identified as gout.

This specific joint involvement is called podagra, characteristic of monosodium urate crystal deposition.

Evaluate the progressive lower back pain with sacroiliitis.

Identified as ankylosing spondylitis.

This is a seronegative spondyloarthropathy characterized by inflammation of the axial skeleton, particularly the sacroiliac joints.

Key Concept

Classic clinical presentations in rheumatology

Question 931Question →

A 52-year-old woman undergoing induction chemotherapy for acute myeloid leukemia presents to the emergency department with chills and a temperature of 39.2°C (102.6°F). Laboratory studies reveal an absolute neutrophil count of 250/mm³. Arrange the following steps for the management of this patient in the most appropriate chronological order.

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Answer

The correct sequence is: Assess hemodynamic stability -> Obtain blood cultures -> Administer empiric antibiotics -> Adjust antimicrobial therapy based on results.

The standard protocol for neutropenic fever requires rapid but structured intervention. Hemodynamic assessment is always first to ensure the patient is not in imminent shock. Next, blood cultures must be drawn to identify the pathogen. Immediately following the cultures, empiric broad-spectrum antibiotics (such as cefepime or piperacillin-tazobactam) are administered to cover typical pathogens, including Pseudomonas aeruginosa. Finally, once sensitivities are resulted days later, therapy is narrowed or adjusted.

Step-by-Step Solution

Identify the clinical syndrome presented in the vignette.

The patient has a fever (39.2°C) and profound neutropenia (ANC < 500/mm³), diagnosing her with neutropenic fever, which is an oncologic emergency.

Recognizing neutropenic fever triggers a well-established, time-sensitive clinical pathway to prevent rapid progression to septic shock.

Determine the first priority in emergency management.

Assess hemodynamic stability and perform a focused physical examination.

Regardless of the underlying cause, initial stabilization (ABCs) is always the first step in acute management.

Determine the order of diagnostic versus therapeutic interventions.

Obtain blood cultures before administering empiric antibiotics.

Administering antibiotics prior to drawing cultures can sterilize the blood, severely limiting the ability to identify the offending organism and narrow therapy later.

Identify the final step in the treatment sequence.

Adjust antimicrobial therapy based on microbiological results.

De-escalation and targeted therapy occur days later once speciation and susceptibility testing are finalized.

Key Concept

Management sequence of neutropenic fever

Question 932Question →

A 54-year-old man is hospitalized for fever, chills, and a rapidly expanding area of erythema on his right lower leg. He has a medical history of type 2 diabetes mellitus. On admission, his temperature is $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure is $118/76$ mm Hg, pulse is $102$ /min, and respirations are $18$ /min. Physical examination reveals a warm, tender, sharply demarcated erythematous plaque on the right calf. Blood cultures are drawn, and the patient is empirically started on intravenous vancomycin and piperacillin-tazobactam.

By hospital day 3, the patient's temperature has normalized, and the leg erythema has significantly receded. The blood cultures drawn on admission return positive for *Staphylococcus aureus* in two out of two bottles. Antimicrobial susceptibility testing demonstrates that the isolate is susceptible to oxacillin, cefazolin, and trimethoprim-sulfamethoxazole, but resistant to penicillin G.

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

Discontinue both current antibiotics and initiate intravenous cefazolin

Discontinue piperacillin-tazobactam and continue intravenous vancomycin

Discontinue vancomycin and continue intravenous piperacillin-tazobactam

Continue both intravenous vancomycin and piperacillin-tazobactam

Discontinue both current antibiotics and initiate intravenous linezolid

Show answer & explanation

Answer: Discontinue both current antibiotics and initiate intravenous cefazolin

Answer

Discontinue both current antibiotics and initiate intravenous cefazolin

The correct course of action is to discontinue the broad-spectrum empiric regimen and start a targeted, narrow-spectrum beta-lactam. The patient's blood cultures grew Staphylococcus aureus that is susceptible to oxacillin, which definitively identifies it as methicillin-susceptible S. aureus (MSSA). For systemic MSSA infections, first-generation cephalosporins (such as intravenous cefazolin) or antistaphylococcal penicillins (such as nafcillin or oxacillin) are the drugs of choice. They provide superior bactericidal activity compared to vancomycin and properly narrow the antimicrobial spectrum, adhering to the core principles of antimicrobial stewardship.

Step-by-Step Solution

Interpret the blood culture susceptibility report.

The organism is Staphylococcus aureus susceptible to oxacillin.

Oxacillin susceptibility defines the isolate as methicillin-susceptible Staphylococcus aureus (MSSA).

Determine the optimal treatment for MSSA bacteremia.

Targeted therapy with an antistaphylococcal penicillin (e.g., nafcillin, oxacillin) or a first-generation cephalosporin (e.g., cefazolin) is indicated.

These agents have superior bactericidal activity against MSSA compared to alternative antibiotics.

Apply antimicrobial stewardship principles to the current empiric regimen.

Discontinue the broad-spectrum vancomycin and piperacillin-tazobactam, and start targeted intravenous cefazolin.

De-escalating therapy minimizes collateral damage to the patient's microbiome, limits the development of resistance, and avoids the inferior outcomes associated with treating MSSA with vancomycin.

Key Concept

Targeted antibiotic de-escalation for methicillin-susceptible Staphylococcus aureus (MSSA)

Estimated Time:1m 0s

Question 933Question →

A 58-year-old man is brought to the emergency department by his family due to fever, severe headache, and progressively worsening confusion that started 12 hours ago. He has a history of type 2 diabetes mellitus and hypertension. His temperature is 39.2°C (102.6°F), blood pressure is 142/86 mmHg, pulse is 112/min, and respirations are 18/min. Physical examination reveals marked nuchal rigidity. Neurologic examination shows a lethargic patient who only opens his eyes to painful stimuli. He demonstrates a new-onset left-sided pronator drift. Arrange the following management steps in the most appropriate chronological order for this patient.

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Answer

The correct sequence is to first draw blood cultures, immediately administer empiric antibiotics and dexamethasone, perform a head CT to rule out mass effect, safely perform a lumbar puncture, and finally tailor antibiotic therapy once susceptibilities result.

The gold standard sequence for suspected bacterial meningitis when 'red flag' signs are present (focal neurologic deficit, papilledema, altered mental status, new-onset seizure, or immunocompromise) is to obtain blood cultures, immediately start empiric antibiotics and dexamethasone, and then send the patient for a CT scan. The lumbar puncture is performed only after the CT scan confirms it is safe to do so. Finally, therapy is de-escalated once cultures result.

Step-by-Step Solution

Identify the indications for a CT scan before lumbar puncture (LP).

The patient has a focal neurologic deficit (left-sided pronator drift) and altered mental status, meaning an LP cannot be performed immediately.

Performing an LP in the setting of elevated intracranial pressure from a mass lesion or severe edema risks catastrophic brain herniation.

Prioritize pathogen identification prior to medication administration.

Peripheral blood cultures are drawn as the absolute first step.

Administering bactericidal antibiotics before drawing blood cultures rapidly sterilizes the blood, severely diminishing the ability to identify the organism.

Initiate empiric pharmacotherapy without delay.

Dexamethasone, ceftriaxone, vancomycin, and ampicillin are administered immediately after blood cultures.

Delaying antibiotics for imaging in suspected bacterial meningitis significantly increases mortality. Ampicillin is added for Listeria monocytogenes coverage in patients >50 years old.

Complete the delayed diagnostic workup.

A non-contrast CT head is obtained, followed by an LP.

The CT ensures the LP is safe. The LP provides CSF which can still yield diagnostic information (cell count, protein, glucose, bacterial DNA via PCR) even after antibiotics have been administered.

Optimize ongoing treatment.

Antimicrobial therapy is de-escalated.

Tailoring therapy based on final culture and susceptibility results prevents antibiotic resistance and reduces medication toxicity.

Key Concept

In patients with suspected bacterial meningitis who have indications for a head CT before a lumbar puncture (e.g., focal neurologic deficit, altered mental status, immunocompromise), blood cultures and empiric antibiotics must be administered prior to neuroimaging.

Question 934Question →

Match each diagnostic hematologic profile with its corresponding primary molecular pathogenesis and targeted therapeutic approach.

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Answer

Acute promyelocytic leukemia matches with retinoic acid receptor disruption. Hairy cell leukemia matches with the BRAF V600E mutation. Mantle cell lymphoma matches with Cyclin D1 overexpression. Primary myelofibrosis matches with constitutive non-receptor tyrosine kinase activation. Multiple myeloma matches with monoclonal immunoglobulin overproduction.

Each diagnostic profile presents hallmark cytogenetic, immunophenotypic, or morphological features of a specific hematologic malignancy. Accurate matching requires linking these diagnostic features to their direct pathophysiological consequences and standard-of-care treatments.

Step-by-Step Solution

Analyze the diagnostic profile for the first item.

Identifies acute promyelocytic leukemia (APL) based on greater than 20% blasts, multiple Auer rods, and the t(15;17) translocation.

Recognizing the unique cytogenetic and morphological signature of APL is required to determine the specific molecular mechanism.

Match APL with its pathogenesis and targeted treatment.

Links APL to the disruption of retinoic acid receptor signaling and treatment with a vitamin A derivative (ATRA) and arsenic trioxide.

The PML-RARA fusion protein creates a maturation block that specific targeted therapies can overcome.

Evaluate the immunophenotype of the second item.

Identifies hairy cell leukemia from the specific CD markers (CD11c, CD25, CD103) and marked monocytopenia.

This distinct flow cytometry profile differentiates it from other indolent B-cell neoplasms.

Connect hairy cell leukemia to its genetic driver and therapy.

Links to the BRAF V600E mutation and purine analog therapy, such as cladribine.

The BRAF mutation is nearly universal in this disease and dictates targeted therapeutic approaches.

Assess the cytogenetics of the third item.

Identifies mantle cell lymphoma based on t(11;14) and the proliferation of small-to-medium lymphocytes.

The translocation uniquely identifies this lymphoma subtype among other small B-cell lymphomas.

Associate mantle cell lymphoma with its molecular consequence.

Links t(11;14) to Cyclin D1 overexpression and potential treatment with Bruton tyrosine kinase (BTK) inhibitors.

Cyclin D1 drives the G1-to-S phase transition, characteristic of this aggressive lymphoma.

Analyze the bone marrow findings of the fourth item.

Identifies primary myelofibrosis due to massive splenomegaly, marked fibrosis, megakaryocytic atypia, and the JAK2 mutation.

Clinical and molecular features precisely define this myeloproliferative neoplasm.

Connect primary myelofibrosis to its pathophysiology and symptomatic treatment.

Links to constitutive activation of a non-receptor tyrosine kinase (JAK2) and ruxolitinib therapy.

Targeted JAK inhibition effectively controls massive splenomegaly and constitutional symptoms.

Evaluate the diagnostic findings in the fifth item.

Identifies multiple myeloma based on greater than 10% clonal plasma cells, CD38/CD138 positivity, and rouleaux formation.

These are the classic diagnostic criteria for this plasma cell dyscrasia.

Match multiple myeloma to its disease mechanisms and core therapy.

Links to monoclonal protein overproduction causing end-organ damage and treatment with proteasome inhibitors.

Proteasome inhibitors are uniquely effective due to the heavy protein synthesis burden in malignant plasma cells.

Key Concept

Molecular pathogenesis, diagnostic criteria, and targeted therapies for specific hematologic malignancies.

Question 935Question →

An oncology clinic evaluates a patient undergoing induction chemotherapy for acute myeloid leukemia who developed chills and a high temperature earlier today. The patient reports generalized weakness but denies cough, dysuria, abdominal pain, or skin changes. Vital signs show a temperature of $38.7^\circ\text{C}$ ( $101.7^\circ\text{F}$ ), blood pressure of $118/76\text{ mmHg}$ , heart rate of $105/\text{min}$ , and respiratory rate of $16/\text{min}$ . Physical examination is unremarkable, with clear lung fields and no induration or erythema at the central venous catheter site. Laboratory studies reveal a total leukocyte count of $800/\text{mm}^3$ with $10\%$ neutrophils and $5\%$ bands. After obtaining appropriate blood and urine cultures, which of the following is the most appropriate empiric pharmacotherapy?

Intravenous cefepime

Intravenous cefepime and vancomycin

Intravenous ceftriaxone and azithromycin

Oral ciprofloxacin and amoxicillin-clavulanate

Intravenous fluconazole

Show answer & explanation

Answer: Intravenous cefepime

Answer

Intravenous cefepime

The correct answer provides monotherapy with an antipseudomonal beta-lactam. Neutropenic fever is an oncologic emergency defined by an Absolute Neutrophil Count (ANC) <

500/\text{mm}^3

and a single temperature equivalent to

\geq 38.3^\circ\text{C}

(

101.0^\circ\text{F}

) or

\geq 38.0^\circ\text{C}

(

100.4^\circ\text{F}

) sustained for over 1 hour. This patient's ANC is

120/\text{mm}^3

. In high-risk patients (such as those with profound neutropenia from hematologic malignancies), prompt initiation of empiric bactericidal intravenous therapy covering Pseudomonas aeruginosa is mandated. Cefepime, piperacillin-tazobactam, and meropenem are the drugs of choice.

Step-by-Step Solution

Calculate the Absolute Neutrophil Count (ANC).

ANC = Total WBC x (% neutrophils + % bands). ANC =

800 \times (0.10 + 0.05) = 120/\text{mm}^3

An ANC <

500/\text{mm}^3

(or expected to decrease to <

500/\text{mm}^3

in 48 hours) combined with a fever defines febrile neutropenia.

Stratify the patient's risk to determine the treatment setting and route.

The patient is undergoing induction chemotherapy for AML and has profound neutropenia, making her a high-risk patient.

High-risk febrile neutropenia requires admission and intravenous broad-spectrum antibiotics, whereas selected low-risk patients may be treated orally as outpatients.

Select the appropriate empiric antibiotic regimen.

Intravenous antipseudomonal beta-lactam monotherapy (e.g., cefepime, meropenem, or piperacillin-tazobactam) is selected.

The patient is hemodynamically stable without signs of catheter infection or pneumonia, so MRSA coverage (vancomycin) is not empirically required.

Key Concept

The initial management of high-risk febrile neutropenia requires prompt initiation of an intravenous antipseudomonal beta-lactam antibiotic.

Estimated Time:1m 15s

Question 936Question →

A $42$ -year-old man with a history of advanced HIV infection (CD4 count $85/\text{mm}^3$ ) is brought to the emergency department by his partner due to $3$ days of high fever, severe generalized headache, and progressive lethargy. His temperature is $39.1^\circ\text{C}$ ( $102.4^\circ\text{F}$ ), blood pressure is $115/75 \text{ mmHg}$ , pulse is $110/\text{min}$ , and respirations are $18/\text{min}$ . Physical examination reveals a lethargic man who is oriented only to person. He has pronounced resistance to passive neck flexion. Cranial nerve examination is notable for an inability to abduct the right eye. The remainder of the examination is unremarkable. Arrange the following steps in the most appropriate sequential order for the management of this patient.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence is: Draw blood cultures, administer empiric dexamethasone and antibiotics, obtain a head CT scan, perform a lumbar puncture, and finally de-escalate the antimicrobial regimen.

The standard sequence for suspected bacterial meningitis is obtaining blood cultures, followed immediately by a lumbar puncture, and then administering empiric antibiotics. However, if the patient has indications for a CT scan prior to the lumbar puncture (such as an immunocompromised state, history of CNS disease, new-onset seizure, papilledema, altered mental status, or a focal neurologic deficit), this sequence must be altered. In such cases, blood cultures should be drawn first, followed immediately by the administration of empiric antibiotics and dexamethasone. Only then should the CT scan be performed, followed by the lumbar puncture if the CT is negative for mass effect. Finally, once cultures and susceptibilities result, the antibiotic regimen is de-escalated to targeted therapy.

Step-by-Step Solution

Draw blood cultures

Blood is collected for diagnostic testing prior to any interference from medications.

Administering antibiotics before drawing blood cultures significantly decreases the chance of isolating the offending pathogen.

Administer empiric dexamethasone and antibiotics

The patient receives life-saving broad-spectrum coverage (vancomycin, ceftriaxone, ampicillin) and inflammation reduction (dexamethasone).

Because this patient requires a CT scan before a lumbar puncture, antibiotics must be given immediately. Any delay in treatment increases mortality in bacterial meningitis.

Obtain a noncontrast CT scan of the head

Neuroimaging is performed to evaluate for mass effect or space-occupying lesions.

The patient has 'red flags' for mass effect (HIV infection and a right cranial nerve VI palsy). Performing a lumbar puncture without prior CT imaging in this setting carries a high risk of brain herniation.

Perform a lumbar puncture

Cerebrospinal fluid is obtained for Gram stain, culture, and cell count.

Once the CT scan confirms the absence of mass effect, a lumbar puncture is safely performed. Cerebrospinal fluid analysis remains crucial for definitive diagnosis even if antibiotics have already been administered.

De-escalate the antimicrobial regimen

Targeted antibiotic therapy replaces broad-spectrum empiric coverage.

Antibiotic stewardship dictates that once the pathogen and its susceptibilities are known, therapy should be narrowed to reduce toxicity and prevent resistance.

Key Concept

Management sequence for suspected bacterial meningitis with indications for head CT prior to lumbar puncture.

Estimated Time:1m 30s

Question 937Question →

Paramedics bring a 35-year-old previously healthy male to the emergency department after he was found lethargic at home. His wife reports he has been complaining of an excruciating diffuse headache and photophobia since yesterday. Vital signs show a temperature of 39.2°C (102.6°F), pulse of 118/min, and blood pressure of 105/65 mmHg. Neurologic examination demonstrates a depressed level of consciousness and clear bilateral papilledema. The care team suspects acute bacterial meningitis and prepares to manage the patient. Arrange the following interventions in the correct procedural sequence.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence is: Draw peripheral blood cultures, followed by administration of empiric intravenous antibiotics and dexamethasone, then a noncontrast CT scan of the head, and finally a lumbar puncture.

The correct sequence prioritizes pathogen isolation and immediate life-saving therapy before neuroimaging and invasive procedures. Blood cultures are drawn first, followed immediately by empiric antibiotics and dexamethasone. Because the patient has papilledema and altered mental status, a CT scan is required to rule out a mass lesion before safely proceeding with a lumbar puncture.

Step-by-Step Solution

Identify the clinical presentation and risks.

The patient presents with signs of acute bacterial meningitis complicated by features of increased intracranial pressure (papilledema and altered mental status).

Recognizing these high-risk features determines the need for neuroimaging prior to lumbar puncture.

Determine the first intervention.

Draw peripheral blood cultures.

Cultures must be obtained before administering antibiotics to prevent sterilization of the sample, ensuring the pathogen can be identified.

Determine the second intervention.

Administer empiric intravenous antibiotics and dexamethasone.

Delaying antibiotics increases mortality. They must be administered immediately after cultures are drawn and before the patient leaves for imaging.

Sequence the diagnostic imaging and procedure.

Obtain a noncontrast CT scan of the head, followed by a lumbar puncture.

A CT scan is mandatory before an LP in patients with papilledema to rule out mass effect and prevent fatal brain herniation.

Key Concept

In patients with suspected bacterial meningitis and indications for cranial imaging (e.g., papilledema, altered mental status), blood cultures should be drawn and empiric antibiotics administered prior to obtaining a head CT and performing a lumbar puncture.

Question 938Question →

A general internist is conducting preoperative evaluations for several patients scheduled for elective surgeries next week. Match each patient's chronic medication scenario to the most appropriate perioperative management recommendation.

Click a left item, then click its matching right item

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Answer

Lisinopril is withheld the morning of surgery; Warfarin is stopped 5 days prior without bridging; Empagliflozin is stopped 3-4 days prior; Buprenorphine is continued throughout; and Raloxifene is stopped 4 weeks prior.

Correct matching requires identifying the specific physiological risks posed by each medication during surgery and anesthesia. ACE inhibitors risk severe vasoplegia; SGLT2 inhibitors risk euglycemic DKA; SERMs risk VTE. Conversely, stopping buprenorphine risks severe withdrawal, and low-risk warfarin patients do not require bridging.

Step-by-Step Solution

Analyze the ACE inhibitor scenario.

Lisinopril matches with withholding on the morning of surgery.

Prevents refractory hypotension during anesthesia induction.

Analyze the Warfarin scenario.

Warfarin matches with stopping 5 days prior without bridging.

Low thromboembolic risk (CHA2DS2-VASc = 1) does not warrant bridging, but INR must normalize.

Analyze the SGLT2 inhibitor scenario.

Empagliflozin matches with stopping 3-4 days prior.

Mitigates the risk of perioperative euglycemic diabetic ketoacidosis.

Analyze the Buprenorphine scenario.

Buprenorphine matches with continuing the current maintenance dose.

Prevents opioid withdrawal and maintains baseline tolerance for multimodal pain management.

Analyze the SERM scenario.

Raloxifene matches with stopping 4 weeks prior.

Reduces the elevated risk of venous thromboembolism associated with major orthopedic surgery.

Key Concept

Perioperative medication management requires balancing the risks of disease exacerbation upon discontinuation against the physiological stresses and drug interactions associated with anesthesia and surgery.

Question 939Question →

Emergency medical services bring a 68-year-old male to the resuscitation bay due to progressive unresponsiveness and profound weakness over the last two days. According to his family, he recently recovered from a mild viral upper respiratory infection. His past medical history is significant for severe chronic obstructive pulmonary disease, ischemic cardiomyopathy with an ejection fraction of 35%, and a nonfunctioning pituitary macroadenoma for which he underwent transsphenoidal surgical resection six months ago. He was prescribed multiple replacement therapies postoperatively but abruptly discontinued all medications three weeks ago due to loss of insurance.

Vital signs show a temperature of 35.4 °C (95.7 °F), pulse of 46/min, blood pressure of 74/40 mm Hg, respirations of 24/min, and oxygen saturation of 89% on room air. Physical examination reveals a somnolent, difficult-to-arouse patient. Jugular venous distension is absent. Chest auscultation demonstrates distant breath sounds with prolonged expiration and faint diffuse wheezing, but no crackles. Cardiac examination shows a regular, bradycardic rhythm with muffled heart sounds. The extremities are cool with delayed capillary refill, and there is notable non-pitting periorbital and lower extremity edema.

Laboratory studies reveal:

Test	Result
Sodium	120 mEq/L
Potassium	4.2 mEq/L
Chloride	90 mEq/L
Bicarbonate	14 mEq/L
Blood urea nitrogen	48 mg/dL
Creatinine	2.1 mg/dL
Glucose	52 mg/dL
Thyroid-stimulating hormone (TSH)	0.2 µU/mL (Normal: 0.4-4.0 µU/mL)
Free T4	0.3 ng/dL (Normal: 0.9-1.7 ng/dL)

An arterial blood gas on room air shows:

Test	Result
pH	7.28
PaCO2	30 mm Hg
PaO2	55 mm Hg

Electrocardiogram demonstrates sinus bradycardia with low-voltage QRS complexes.

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

Administration of loop diuretics and noninvasive positive pressure ventilation

Empiric therapy with a broad-spectrum beta-lactam/beta-lactamase inhibitor

Infusion of hypertonic sodium bicarbonate solution

Initiation of high-dose thyroid hormone replacement

Immediate administration of stress-dose glucocorticoids

Show answer & explanation

Answer: Immediate administration of stress-dose glucocorticoids

Answer

Immediate administration of stress-dose glucocorticoids

The patient's presentation of severe hypotension, hypoglycemia, hyponatremia, hypothermia, and bradycardia following abrupt cessation of medications after a transsphenoidal resection is classic for panhypopituitarism, resulting in simultaneous adrenal crisis and myxedema coma. The most critical, life-saving intervention is the immediate administration of stress-dose glucocorticoids. Crucially, in any patient with suspected concomitant adrenal insufficiency and hypothyroidism, glucocorticoids MUST be given before thyroid hormone replacement. Giving thyroid hormone first increases the metabolic rate and cortisol clearance, which can precipitate a fatal adrenal crisis.

Step-by-Step Solution

Analyze the patient's history and vital signs.

The patient has a history of transsphenoidal pituitary resection and recently stopped all medications, placing him at high risk for panhypopituitarism. He presents in shock (blood pressure 74/40 mm Hg) with hypothermia and bradycardia.

Establishing the underlying vulnerability is crucial to identifying the specific etiology of the shock.

Interpret the laboratory and physical exam findings.

Labs show hypoglycemia, hyponatremia, and central hypothyroidism (low TSH, low free T4). The arterial blood gas shows a metabolic acidosis with appropriate respiratory compensation (

PaCO_2

of 30 mm Hg matches the Winter's formula calculation).

These findings confirm central adrenal insufficiency (causing hyponatremia, hypoglycemia, and shock) and central hypothyroidism (causing bradycardia, hypothermia, and non-pitting edema).

Determine the necessary sequence of pharmacological interventions.

Both adrenal crisis and myxedema coma require emergent treatment, but glucocorticoids must be administered before thyroid hormone.

Administering thyroid hormone increases the basal metabolic rate and hepatic clearance of cortisol. In a cortisol-deficient state, this will precipitate a potentially fatal adrenal crisis.

Key Concept

In patients with suspected panhypopituitarism presenting with combined adrenal crisis and myxedema coma, stress-dose glucocorticoids must be administered before thyroid hormone replacement to prevent precipitating a fatal adrenal crisis.

Question 940Question →

A 56-year-old woman is evaluated in the hospital on the third day of her admission for acute complicated pyelonephritis. On presentation to the emergency department, she had severe right flank pain, a temperature of 39.2°C (102.6°F), and a blood pressure of 90/60 mm Hg. After initial intravenous fluid resuscitation, her hemodynamics normalized, and she was admitted to the medical ward. She was empirically started on intravenous cefepime and vancomycin. Today, the patient reports that her flank pain has nearly resolved. She has been afebrile for the past 24 hours and is tolerating a regular diet without nausea or vomiting. Her current blood pressure is 122/78 mm Hg and pulse is 76/min. Blood and urine cultures obtained on admission both grow Escherichia coli. Susceptibility testing indicates the isolate is resistant to ampicillin but susceptible to ceftriaxone, piperacillin-tazobactam, ciprofloxacin, and trimethoprim-sulfamethoxazole. Which of the following is the most appropriate next step in the management of this patient's infection?

Switch to oral ciprofloxacin

Switch to intravenous ceftriaxone

Switch to oral amoxicillin

Discontinue vancomycin and continue intravenous cefepime

Continue intravenous cefepime and vancomycin

Show answer & explanation

Answer: Switch to oral ciprofloxacin

Answer

The most appropriate next step is to switch to oral ciprofloxacin.

The patient has acute complicated pyelonephritis with associated Gram-negative bacteremia. She has achieved clinical stability (afebrile for 24 hours, hemodynamically normal) and can tolerate an oral diet. The standard of care in this scenario is antimicrobial stewardship: transitioning from empiric, broad-spectrum intravenous antibiotics to a targeted, narrow-spectrum, highly bioavailable oral antibiotic based on susceptibility results. Fluoroquinolones (like ciprofloxacin) and trimethoprim-sulfamethoxazole have excellent oral bioavailability, achieving systemic levels nearly equivalent to intravenous dosing. This 'step-down' therapy facilitates prompt hospital discharge, minimizes the risk of nosocomial complications (such as central line infections or DVT from prolonged bed rest), and reduces healthcare costs without compromising clinical outcomes.

Step-by-Step Solution

Evaluate the patient's current clinical trajectory.

The patient is hemodynamically stable, has been afebrile for 24 hours, and is tolerating oral intake.

Clinical stability dictates the safety and timing of transitioning a patient from intravenous to oral antimicrobial therapy.

Review culture and susceptibility data.

The infection is caused by E. coli that is susceptible to ciprofloxacin, trimethoprim-sulfamethoxazole, and several intravenous cephalosporins, but resistant to ampicillin.

Therapy must be targeted to the specific organism to ensure efficacy while avoiding excessively broad-spectrum agents.

Select the optimal targeted regimen.

Switching to an oral highly bioavailable agent, such as ciprofloxacin, is indicated.

Ciprofloxacin achieves serum and tissue concentrations comparable to intravenous administration, making it ideal for step-down therapy to facilitate hospital discharge.

Key Concept

In patients with acute complicated pyelonephritis and Gram-negative bacteremia who achieve clinical stability and tolerate an oral diet, empiric intravenous antibiotics should be de-escalated to targeted, highly bioavailable oral antibiotics.

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