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Infection, Pharmacology & VTE MCQs

Practice Set 54 of 68

This practice set contains high-yield board review questions covering key concepts in Infection, Pharmacology & VTE. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1061

Topic: Infection, Pharmacology & VTE

When discussing the importance of post-operative pain management for an orthopedic patient, what key benefit should be highlighted to an examiner, beyond patient comfort?

. It makes the patient like the surgeon more.
. It's a low priority compared to wound care.
. Effective pain management facilitates early mobilization, reduces the risk of complications (e.g., DVT, pneumonia), improves patient satisfaction, and optimizes rehabilitation outcomes.
. It allows the patient to return to work immediately.
. Only strong opioids are effective.

Correct Answer & Explanation

. Effective pain management facilitates early mobilization, reduces the risk of complications (e.g., DVT, pneumonia), improves patient satisfaction, and optimizes rehabilitation outcomes.

Explanation

Effective post-operative pain management is crucial not just for patient comfort but for achieving optimal functional outcomes. A high-scoring answer will articulate how good pain control facilitates early mobilization, which in turn reduces major complications like DVT, pulmonary embolism, and pneumonia, and significantly enhances rehabilitation success. It demonstrates an understanding of the systemic implications of pain and its management.

Question 1062

Topic: Infection, Pharmacology & VTE

A candidate is discussing surgical consent for an elective total knee arthroplasty. The examiner asks, 'How do you ensure truly informed consent, especially regarding less common but significant risks, without unduly alarming the patient?' Which approach is most ethically sound and practically effective?

. List every conceivable complication from a comprehensive checklist, irrespective of individual patient relevance.
. Focus primarily on the most common risks, briefly mentioning others only if the patient specifically asks.
. Discuss common and relevant patient-specific risks in detail, then group less common but serious risks (e.g., DVT/PE, infection, nerve injury) and explain their potential impact, ensuring the patient understands they are rare but possible.
. Have the patient sign a generic consent form and assume they have read and understood the small print.
. Delegate the discussion of all surgical risks to a junior resident to save time.

Correct Answer & Explanation

. Discuss common and relevant patient-specific risks in detail, then group less common but serious risks (e.g., DVT/PE, infection, nerve injury) and explain their potential impact, ensuring the patient understands they are rare but possible.

Explanation

Truly informed consent involves more than just a checklist. It requires a tailored discussion focusing on risks relevant to the specific patient and procedure. Grouping less common but serious risks allows for efficient communication without overwhelming the patient, while still fulfilling ethical and legal obligations. Option A can cause undue anxiety. Option B is inadequate for informed consent. Option D is legally and ethically unsound. Option E is a delegation of a core responsibility and inappropriate.

Question 1063

Topic: Infection, Pharmacology & VTE

In a discussion about the management of osteomyelitis, the examiner asks, 'When considering surgical debridement for chronic osteomyelitis, what is the 'surgical goal' and why is it so critical?'

. The surgical goal is primarily to achieve perfect anatomical reduction of any associated fracture to optimize healing.
. The surgical goal is to remove all devitalized, infected, and foreign material, creating a viable, well-vascularized bed for subsequent bone healing and antibiotic penetration. This is critical because antibiotics alone cannot sterilize necrotic tissue.
. The surgical goal is to simply drain any obvious abscess and apply a local antibiotic bead pouch.
. The surgical goal is to stabilize the bone with external fixation to prevent pathological fracture.
. The surgical goal is to obtain cultures for targeted antibiotic therapy, making extensive debridement unnecessary until results are known.

Correct Answer & Explanation

. The surgical goal is to remove all devitalized, infected, and foreign material, creating a viable, well-vascularized bed for subsequent bone healing and antibiotic penetration. This is critical because antibiotics alone cannot sterilize necrotic tissue.

Explanation

The cornerstone of chronic osteomyelitis management is aggressive surgical debridement. The goal is to remove all non-viable, infected bone and soft tissue, foreign bodies (implants if infected), and any sequestra or involucrum, creating a clean, well-vascularized environment. This is critical because necrotic bone acts as a sanctuary for bacteria, impenetrable to systemic antibiotics and host immune defenses. Antibiotic penetration and immune cell access are only effective in viable tissue. Options A, C, D, and E represent incomplete or incorrect surgical goals for chronic osteomyelitis.

Question 1064

Topic: Infection, Pharmacology & VTE

In a discussion about post-operative rehabilitation following knee surgery, the examiner asks, 'What is the primary rationale for early weight-bearing and mobilization protocols after many lower extremity orthopedic procedures, especially those involving articular cartilage?'

. To prevent deep vein thrombosis (DVT) and pulmonary embolism (PE).
. To accelerate bone healing and consolidate fixation.
. To promote synovial fluid circulation, enhance cartilage nutrition, and prevent joint stiffness and adhesions.
. To reduce patient dependence on caregivers and facilitate early discharge.
. To minimize post-operative pain and reliance on analgesics.

Correct Answer & Explanation

. To promote synovial fluid circulation, enhance cartilage nutrition, and prevent joint stiffness and adhesions.

Explanation

The primary rationale for early weight-bearing and mobilization, particularly after procedures involving articular cartilage (e.g., microfracture, cartilage repair, meniscal repair, even arthroplasty), is to promote chondrocyte health through cyclical loading, enhance synovial fluid circulation for cartilage nutrition, and prevent deleterious effects like joint stiffness, adhesions, and disuse atrophy. While DVT prevention (A) is a benefit, it's not the primary rationale forarticular cartilagehealth. Accelerating bone healing (B) is true for some fractures but not the universal primary reason across all lower extremity procedures involving cartilage. Reducing dependence (D) and pain (E) are secondary benefits.

Question 1065

Topic: Infection, Pharmacology & VTE

You are asked to describe the initial management of a suspected acute deep vein thrombosis (DVT) in a post-operative orthopedic patient. The examiner focuses on diagnostics. What is the MOST appropriate first-line diagnostic investigation?

. MRI venography of the affected limb.
. Computed tomography pulmonary angiogram (CTPA) to rule out pulmonary embolism.
. Doppler ultrasound of the affected limb.
. D-dimer blood test, followed by ultrasound only if D-dimer is elevated.
. Ascending venography as the gold standard.

Correct Answer & Explanation

. Doppler ultrasound of the affected limb.

Explanation

The most appropriate first-line diagnostic investigation for suspected acute DVT is a Doppler ultrasound of the affected limb. It is non-invasive, widely available, and highly sensitive and specific for proximal DVT. While a D-dimer test (D) can be used torule outDVT in low-probability patients, it is not sufficiently specific in post-operative orthopedic patients (who often have elevated D-dimer due to surgery itself) to be themost appropriate first-line diagnosticwhen DVT is suspected. CTPA (B) is for suspected PE. MRI venography (A) and ascending venography (E) are more invasive or costly and typically reserved for complex cases or when ultrasound is inconclusive.

Question 1066

Topic: Infection, Pharmacology & VTE

You are discussing the non-operative management of a stable intertrochanteric hip fracture in a very frail, non-ambulatory patient. The examiner asks, 'What is the MOST critical aspect of their management plan to prevent significant morbidity and mortality?'

. Strict bed rest to prevent any weight-bearing on the affected hip.
. Aggressive pain management, early mobilization out of bed to a chair, pressure ulcer prevention, and nutritional support.
. Immediate placement in a spica cast to immobilize the fracture.
. Long-term antibiotic prophylaxis to prevent infection.
. Minimizing all movement to promote fracture healing.

Correct Answer & Explanation

. Aggressive pain management, early mobilization out of bed to a chair, pressure ulcer prevention, and nutritional support.

Explanation

For a very frail, non-ambulatory patient with a stable intertrochanteric hip fracture managed non-operatively, the MOST critical aspect is to focus on comfort and preventing the devastating complications of immobility. This includes aggressive pain management to facilitate movement, early mobilization out of bed to a chair (even if not weight-bearing on the limb), meticulous skin care for pressure ulcer prevention, and adequate nutritional support. Strict bed rest (A, E) significantly increases the risk of pneumonia, DVT/PE, pressure ulcers, and functional decline. Spica cast (C) is inappropriate for intertrochanteric fractures in this demographic. Antibiotic prophylaxis (D) is not indicated.

Question 1067

Topic: Infection, Pharmacology & VTE

A candidate is preparing for a structured viva examining musculoskeletal pathology. Which of the following pre-exam activities is least effective for improving performance in this specific domain?

. Reviewing classical macroscopic and microscopic slides of common bone tumors.
. Practicing differential diagnoses for various arthropathies with an examiner mindset.
. Memorizing the detailed surgical steps of a highly specialized pediatric orthopedic procedure.
. Understanding the etiologies and pathogenesis of osteomyelitis variants.
. Familiarizing oneself with common staining techniques and their clinical significance in bone biopsies.

Correct Answer & Explanation

. Memorizing the detailed surgical steps of a highly specialized pediatric orthopedic procedure.

Explanation

While knowing surgical steps is crucial for orthopedics, it is not directly related to a viva specifically examining musculoskeletal pathology. Pathology vivas focus on disease processes, diagnostic features, and interpretations, not surgical technique details.

Question 1068

Topic: Infection, Pharmacology & VTE

In a viva, if an examiner asks you to differentiate between two similar conditions (e.g., septic arthritis vs. transient synovitis), what structured approach is best?

. Focus only on the single most obvious difference.
. Provide a comprehensive, head-to-head comparison covering epidemiology, clinical features, investigations, and management implications.
. State only the treatment for each condition.
. Admit that they are very similar and difficult to differentiate.
. List all symptoms of one, then all symptoms of the other.

Correct Answer & Explanation

. Provide a comprehensive, head-to-head comparison covering epidemiology, clinical features, investigations, and management implications.

Explanation

A head-to-head comparison, systematically covering relevant aspects, demonstrates a nuanced understanding of both conditions and the critical distinguishing factors. This shows a holistic and comparative understanding.

Question 1069

Topic: Infection, Pharmacology & VTE

When discussing surgical risks with an examiner, what level of detail is MOST appropriate?

. Listing only the most catastrophic, life-threatening complications.
. Stating general risks like 'infection' and 'bleeding' without further elaboration.
. Detailing common risks (e.g., DVT, PE, infection, neurovascular injury, malunion/nonunion, implant failure, need for re-operation), their approximate incidence, and relevant preventative/mitigation strategies, tailored to the specific procedure and patient.
. Focusing on extremely rare risks to demonstrate comprehensive knowledge.
. Avoiding discussion of risks unless specifically prompted by the examiner.

Correct Answer & Explanation

. Detailing common risks (e.g., DVT, PE, infection, neurovascular injury, malunion/nonunion, implant failure, need for re-operation), their approximate incidence, and relevant preventative/mitigation strategies, tailored to the specific procedure and patient.

Explanation

A comprehensive discussion of surgical risks includes common and clinically significant complications relevant to the specific procedure and patient. Discussing their approximate incidence, prevention, and mitigation strategies demonstrates a practical and safe approach to surgery. Focusing only on extremes or being overly vague is insufficient for a board-level examination. It shows understanding of proactive patient care.

Question 1070

Topic: Infection, Pharmacology & VTE

Which of the following is NOT typically part of the initial non-operative management for a Rockwood Type I or II AC joint injury?

. Ice application
. Sling immobilization for comfort
. Early range of motion exercises (within pain limits)
. Oral analgesics and anti-inflammatory medications
. Sustained overhead activities

Correct Answer & Explanation

. Sustained overhead activities

Explanation

Sustained overhead activities would typically be avoided during the initial healing phase for a Rockwood Type I or II AC joint injury, as they can exacerbate pain and potentially hinder healing of the sprained ligaments. Initial management focuses on rest, pain control (ice, NSAIDs), temporary immobilization for comfort (sling), and early, pain-free range of motion to prevent stiffness.

Question 1071

Topic: Infection, Pharmacology & VTE

What is the appropriate management for a Rockwood Type I AC joint injury?

. Surgical repair of the AC ligaments.
. Coracoclavicular ligament reconstruction.
. Sling immobilization for 4-6 weeks with no active motion.
. Symptomatic treatment including ice, analgesics, and early protected range of motion.
. Distal clavicle excision (Mumford procedure).

Correct Answer & Explanation

. Symptomatic treatment including ice, analgesics, and early protected range of motion.

Explanation

Rockwood Type I AC joint injuries are managed conservatively with symptomatic treatment. This typically includes rest, ice, oral analgesics (NSAIDs), and a short period of sling immobilization for comfort, followed by early initiation of protected range of motion exercises as pain allows. Surgical intervention or prolonged immobilization is not indicated for Type I injuries.

Question 1072

Topic: Infection, Pharmacology & VTE
A 4-year-old child presents with a painful limp and refusal to bear weight on the right leg. Vitals show a temperature of 38.6°C (101.5°F). Laboratory analysis reveals a WBC count of 13,000/mm³ and an ESR of 45 mm/hr. According to the Kocher criteria, what is the approximate probability that this child has septic arthritis of the hip?
. 3%
. 40%
. 71%
. 93%
. 99%

Correct Answer & Explanation

. 93%

Explanation

The Kocher criteria for septic arthritis of the hip in pediatrics include four parameters: 1) Non-weight-bearing on the affected side, 2) ESR > 40 mm/hr, 3) Fever > 38.5°C, and 4) WBC > 12,000/mm³. This patient meets all 4 criteria. The probability of septic arthritis is approximately 3% for 1 criterion, 40% for 2, 93% for 3, and 99% for 4 criteria.

Question 1073

Topic: Infection, Pharmacology & VTE

Periprosthetic joint infections caused by Staphylococcus epidermidis are notoriously difficult to eradicate due to biofilm formation. During the accumulation/proliferation phase of biofilm development, which of the following molecules mediates the critical cell-to-cell adhesion and structural integrity of the extracellular polymeric substance?

. Fibronectin-binding proteins (FnBPs)
. Polysaccharide intercellular adhesin (PIA)
. Protein A
. Panton-Valentine leukocidin (PVL)
. Hyaluronidase

Correct Answer & Explanation

. Polysaccharide intercellular adhesin (PIA)

Explanation

Biofilm formation occurs in stages: attachment, proliferation/accumulation, maturation, and dispersion. While initial attachment relies on autolysins and surface-binding proteins like fibronectin-binding proteins, the critical component for intercellular adhesion and forming the protective slime layer (extracellular polymeric substance) during the proliferation phase is Polysaccharide Intercellular Adhesin (PIA), mediated by the icaADBC operon in Staphylococcus epidermidis.

Question 1074

Topic: Infection, Pharmacology & VTE

In the pathogenesis of orthopedic implant infections, bacteria form a mature biofilm that makes them highly resistant to systemic antibiotics and host immune defenses. The structural integrity and protective barrier of this biofilm are primarily provided by which of the following?

. Peptidoglycan cell wall
. Extracellular polymeric substance (glycocalyx)
. Bacterial flagella
. Lipopolysaccharide (LPS) layer
. Planktonic dissemination factors

Correct Answer & Explanation

. Extracellular polymeric substance (glycocalyx)

Explanation

Once bacteria adhere to an implant, they secrete an extracellular polymeric substance (glycocalyx) to form a mature biofilm. This matrix acts as a physical barrier and alters the metabolic state of the bacteria (sessile state), making them highly resistant to antibiotics.

Question 1075

Topic: Infection, Pharmacology & VTE

In the pathogenesis of periprosthetic joint infection, biofilm formation is a critical factor in antibiotic resistance. Which of the following best describes the function of "quorum sensing" in this process?

. Initial adherence of planktonic bacteria to the host proteins on the implant
. Irreversible bacterial attachment mediated by fibronectin-binding proteins
. Intercellular bacterial communication regulating gene expression and biofilm maturation
. Active dispersion of individual bacteria from a mature biofilm into the bloodstream
. Evasion of host phagocytosis strictly through capsular polysaccharide production

Correct Answer & Explanation

. Intercellular bacterial communication regulating gene expression and biofilm maturation

Explanation

Quorum sensing is a chemical communication system used by bacteria to monitor population density, allowing them to coordinate gene expression essential for mature biofilm formation and virulence.

Question 1076

Topic: Infection, Pharmacology & VTE
A 65-year-old patient is prescribed rivaroxaban for deep vein thrombosis prophylaxis following a primary total knee arthroplasty. What is the precise mechanism of action of this pharmacological agent?
. Direct inhibition of thrombin (Factor IIa)
. Indirect inhibition of Factor Xa via antithrombin III
. Direct, competitive inhibition of Factor Xa
. Antagonism of Vitamin K-dependent clotting factors
. Irreversible inhibition of ADP-induced platelet aggregation

Correct Answer & Explanation

. Direct, competitive inhibition of Factor Xa

Explanation

Rivaroxaban is an oral anticoagulant that works by directly and reversibly binding to and inhibiting Factor Xa, interrupting both the intrinsic and extrinsic coagulation pathways.

Question 1077

Topic: Infection, Pharmacology & VTE

During the pathogenesis of a periprosthetic joint infection, Staphylococcus aureus utilizes surface proteins to adhere to host proteins that have coated an orthopedic implant. What is the initial, prerequisite step in biofilm formation before irreversible attachment occurs?

. Quorum sensing to coordinate gene expression
. Planktonic cell dispersal from mature matrix
. Exopolysaccharide (glycocalyx) matrix production
. Reversible attachment to the conditioned surface via van der Waals forces
. Irreversible attachment via MSCRAMMs

Correct Answer & Explanation

. Reversible attachment to the conditioned surface via van der Waals forces

Explanation

The primary initial step of biofilm formation is the reversible, non-specific attachment of planktonic bacteria to the host-conditioned surface of the implant, mediated by electrostatic and van der Waals forces. This is rapidly followed by irreversible attachment mediated by specific bacterial adhesins known as MSCRAMMs.

Question 1078

Topic: Infection, Pharmacology & VTE
A 5-year-old boy is evaluated for an acute onset of right hip pain and a limp. He is afebrile but refuses to bear any weight on the right leg. Laboratory tests show a WBC count of 11,000/mm³, an ESR of 25 mm/hr, and a CRP of 0.8 mg/dL. Radiographs of the pelvis are unremarkable. According to the Kocher criteria, what is the approximate statistical probability that this patient has septic arthritis of the hip?
. < 5% (approximately 3%)
. ~ 40%
. ~ 71%
. ~ 93%
. 100%

Correct Answer & Explanation

. < 5% (approximately 3%)

Explanation

The Kocher criteria differentiate septic arthritis from transient synovitis in children. The four criteria are: non-weight-bearing on the affected side, fever > 38.5°C (101.3°F), ESR > 40 mm/hr, and WBC > 12,000/mm³. This patient meets only one criterion (non-weight-bearing). The probability of septic arthritis based on the number of criteria met is: 0 criteria = <1%, 1 criterion = 3%, 2 criteria = 40%, 3 criteria = 71%, and 4 criteria = 93%.

Question 1079

Topic: Infection, Pharmacology & VTE
A 4-year-old boy presents with an acute onset limp, severe right hip pain, and a temperature of 38.6°C. He refuses to bear weight on the right leg. Laboratory evaluation reveals an ESR of 45 mm/hr and a WBC count of 13,500/mm³. According to the Kocher criteria, what is the approximate probability that this child has septic arthritis of the hip?
. 3%
. 40%
. 73%
. 93%
. 99%

Correct Answer & Explanation

. 99%

Explanation

The Kocher criteria for differentiating septic arthritis from transient synovitis include non-weight-bearing, temperature >38.5°C, ESR >40 mm/hr, and WBC >12,000/mm³. This patient meets all four criteria, which yields a 93% predicted probability of septic arthritis.

Question 1080

Topic: Infection, Pharmacology & VTE
A 4-year-old boy presents with a 3-day history of right hip pain and refusal to bear weight. His temperature is 38.6°C (101.5°F). Labs reveal a WBC count of 14,000/mm³, ESR of 45 mm/hr, and a CRP of 3.5 mg/dL. According to the Kocher criteria, what is the probability that this child has septic arthritis?
. 3%
. 40%
. 71%
. 93%
. 99%

Correct Answer & Explanation

. 93%

Explanation

The child has 3 of the 4 classic Kocher criteria (fever, inability to bear weight, ESR >40). The probability of septic arthritis with 3 criteria is approximately 93%.

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