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Infection, Pharmacology & VTE MCQs

Practice Set 52 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 1021

Topic: Infection, Pharmacology & VTE

During a TKA for a severe varus deformity, the surgeon proceeds with a sequential medial release. After releasing the deep medial collateral ligament (MCL) and posteromedial capsule, the knee remains tight medially in flexion. Which structure, serving as the primary restraint to valgus stress at 90 degrees of flexion, must be addressed next?

. Semimembranosus tendon
. Pes anserinus
. Superficial medial collateral ligament
. Posterior cruciate ligament
. Medial head of the gastrocnemius

Correct Answer & Explanation

. Superficial medial collateral ligament

Explanation

The superficial MCL is the primary restraint to valgus stress at both full extension and 90 degrees of flexion. In severe varus deformities, it often requires subperiosteal elevation or partial release to balance the flexion gap.

Question 1022

Topic: Infection, Pharmacology & VTE

A 72-year-old male with a history of Parkinson's disease sustains a comminuted, displaced intertrochanteric hip fracture. What is the most critical consideration for his post-operative management?

. Early full weight-bearing.
. Aggressive range of motion exercises.
. Prevention of pneumonia and pressure ulcers.
. Pain control with narcotics.
. Referral to long-term rehabilitation facility.

Correct Answer & Explanation

. Prevention of pneumonia and pressure ulcers.

Explanation

For an elderly patient with significant comorbidities like Parkinson's disease and an intertrochanteric hip fracture, preventing complications of immobility is paramount. These patients are at high risk for pneumonia, pressure ulcers, DVT/PE, and delirium due to prolonged bed rest and anesthesia. Therefore, aggressive mobilization, despite the fracture, and vigilant nursing care focusing on respiratory hygiene, skin integrity, and early ambulation (within the limits of fixation) are critical (C). Early full weight-bearing (A) may not be possible depending on fracture stability and fixation. Aggressive range of motion (B) is not the immediate priority for hip fractures. Pain control (D) is important but is a means to allow mobilization. Referral to rehab (E) is a later step.

Question 1023

Topic: Infection, Pharmacology & VTE

A 6-year-old child presents with a swollen, painful knee following a fall. She is febrile (39°C) and unable to bear weight. Physical exam reveals warmth, erythema, and exquisite tenderness to palpation of the knee. What is the most appropriate immediate diagnostic and therapeutic step?

. Administer oral antibiotics and observe.
. Order an MRI of the knee.
. Perform an urgent aspiration of the knee joint.
. Apply a knee immobilizer and crutches.
. Obtain blood cultures and start broad-spectrum IV antibiotics empirically.

Correct Answer & Explanation

. Perform an urgent aspiration of the knee joint.

Explanation

The clinical picture (fever, warmth, erythema, pain, inability to bear weight) strongly suggests septic arthritis of the knee. This is a surgical emergency. The most appropriate immediate step is urgent aspiration of the knee joint to obtain synovial fluid for cell count, culture, and gram stain. This is both diagnostic and therapeutic (decompression). While blood cultures and empirical IV antibiotics should follow, the aspiration is critical for diagnosis and to guide antibiotic therapy. MRI can confirm inflammation but is not as urgent as aspiration. Oral antibiotics are insufficient, and immobilization is supportive but not definitive treatment.

Question 1024

Topic: Infection, Pharmacology & VTE

A 75-year-old male with a comminuted intertrochanteric hip fracture is medically optimized for surgery. Which of the following is the most appropriate strategy for venous thromboembolism (VTE) prophylaxis in this patient?

. No prophylaxis, as early mobilization is sufficient.
. Sequential compression devices (SCDs) alone.
. Low-molecular-weight heparin (LMWH) starting post-operatively.
. Aspirin pre-operatively and post-operatively.
. Warfarin for 6 weeks post-operatively.

Correct Answer & Explanation

. Low-molecular-weight heparin (LMWH) starting post-operatively.

Explanation

Hip fracture patients are at high risk for VTE. LMWH (e.g., enoxaparin) is the preferred pharmacological agent, typically initiated post-operatively once bleeding risks have diminished. Mechanical prophylaxis (SCDs) should be used in conjunction with LMWH or if LMWH is contraindicated. Aspirin is a less potent agent and might be considered in some lower-risk trauma patients but is generally insufficient for high-risk hip fracture patients. Warfarin requires close INR monitoring and is less commonly used than LMWH for VTE prophylaxis in this setting due to increased bleeding risk and slow onset. Early mobilization is important but not sufficient as sole prophylaxis.

Question 1025

Topic: Infection, Pharmacology & VTE

A 60-year-old diabetic male with peripheral neuropathy presents with a traumatic ulcer on the sole of his foot that extends to bone. X-rays show adjacent osteolysis and periosteal reaction. He is afebrile. What is the most appropriate initial management step?

. Aggressive debridement of the ulcer and bone, followed by culture-directed antibiotics.
. Broad-spectrum oral antibiotics and offloading.
. Urgent MRI to assess the extent of osteomyelitis.
. Non-weight bearing and observation for 2 weeks.
. Transcutaneous oxygen measurement.

Correct Answer & Explanation

. Aggressive debridement of the ulcer and bone, followed by culture-directed antibiotics.

Explanation

A diabetic foot ulcer extending to bone with radiographic signs of osteolysis and periosteal reaction is highly suspicious for osteomyelitis. This requires aggressive management to prevent limb loss. The most appropriate initial step is surgical debridement of the ulcer and necrotic bone, along with obtaining bone biopsies and tissue cultures to guide antibiotic therapy. While MRI can assess the extent, surgical debridement and culture are more critical for treatment. Broad-spectrum oral antibiotics alone are often insufficient for osteomyelitis. Offloading is crucial but not definitive treatment for infection. Transcutaneous oxygen measurements are for assessing healing potential, not for diagnosing or treating osteomyelitis.

Question 1026

Topic: Infection, Pharmacology & VTE

A 60-year-old female with diabetes and peripheral neuropathy sustains a comminuted fracture of the cuboid bone in her midfoot. The fracture is displaced, but she has palpable pulses and intact motor function. What is the most critical concern regarding wound healing and infection in her management?

. Avascular necrosis of the cuboid.
. Compartment syndrome.
. Deep vein thrombosis (DVT).
. Diabetic foot ulcers and osteomyelitis.
. Complex regional pain syndrome (CRPS).

Correct Answer & Explanation

. Diabetic foot ulcers and osteomyelitis.

Explanation

Patients with diabetes, especially those with peripheral neuropathy, are at significantly increased risk for developing diabetic foot ulcers, delayed wound healing, and subsequent osteomyelitis following any foot trauma or surgery. Impaired sensation, poor circulation, and compromised immune function create a high-risk environment. Therefore, careful wound management, diligent glycemic control, and vigilance for signs of infection are paramount. While AVN, compartment syndrome, DVT, and CRPS are potential complications, the combination of diabetes and foot trauma makes ulcers and osteomyelitis a very pressing and common concern. This requires a multidisciplinary approach.

Question 1027

Topic: Infection, Pharmacology & VTE

A 68-year-old male undergoes open reduction and internal fixation of a distal femur fracture. Postoperatively, he develops sudden onset dyspnea, pleuritic chest pain, and hypoxemia. What is the most important initial diagnostic test to confirm the suspected diagnosis?

. Electrocardiogram (ECG).
. Chest X-ray.
. D-dimer assay.
. Computed tomography pulmonary angiogram (CTPA).
. Lower extremity venous duplex ultrasound.

Correct Answer & Explanation

. Computed tomography pulmonary angiogram (CTPA).

Explanation

The patient's symptoms (sudden dyspnea, pleuritic chest pain, hypoxemia) following a major lower limb orthopedic surgery are highly suggestive of a pulmonary embolism (PE). The most important initial diagnostic test to confirm a PE is a computed tomography pulmonary angiogram (CTPA). This imaging modality directly visualizes emboli in the pulmonary arteries. While D-dimer assay is a good screening test, a positive result requires further imaging for confirmation, especially in high-risk patients. ECG and chest X-ray might show non-specific changes but are not diagnostic for PE. Lower extremity venous duplex ultrasound can identify the source DVT but does not confirm the PE itself.

Question 1028

Topic: Infection, Pharmacology & VTE

A 50-year-old obese male suffers a low-energy fall, sustaining an unstable intertrochanteric hip fracture. He has multiple medical comorbidities. What is the primary benefit of early surgical fixation (within 24-48 hours) for this patient?

. Reduced risk of avascular necrosis of the femoral head.
. Reduced incidence of nonunion.
. Decreased time to ambulation and reduced medical complications.
. Elimination of the need for DVT prophylaxis.
. Improved cosmetic outcome.

Correct Answer & Explanation

. Decreased time to ambulation and reduced medical complications.

Explanation

For elderly patients with hip fractures, early surgical fixation (ideally within 24-48 hours, 'hip fracture in 24-48') is crucial. The primary benefit is a significantly decreased time to ambulation and reduced incidence of medical complications such as pneumonia, pressure ulcers, DVT/PE, and overall mortality. Prolonged bed rest in this population leads to increased morbidity and mortality. While surgical fixation does improve union rates, the immediate benefit for an unstable intertrochanteric fracture is the ability to mobilize the patient. AVN is not a primary concern with intertrochanteric fractures, unlike femoral neck fractures. DVT prophylaxis is still needed. Cosmetic outcome is not a primary driver for urgency.

Question 1029

Topic: Infection, Pharmacology & VTE

What is the most common immediate post-operative complication following endoprosthetic reconstruction for distal femoral osteosarcoma?

. Deep vein thrombosis
. Periprosthetic fracture
. Infection
. Nerve injury
. Pulmonary embolism

Correct Answer & Explanation

. Infection

Explanation

Infection is the most common and devastating complication following endoprosthetic reconstruction for tumor resection, particularly in osteosarcoma patients who are often immunocompromised from chemotherapy. The incidence can range from 5-20%. While DVT, PE, periprosthetic fracture, and nerve injury can occur, infection remains the most frequent major complication. Mechanical loosening and aseptic failure are also long-term issues.

Question 1030

Topic: Infection, Pharmacology & VTE

A 60-year-old male with multiple comorbidities sustains a stable, non-displaced minimally comminuted subtrochanteric fracture. He is deemed a very poor surgical candidate. What non-operative management strategy could be considered?

. Immediate weight-bearing as tolerated in a brace
. Short leg cast immobilization
. Bed rest and skeletal traction for 12 weeks
. Dynamic hip screw (DHS) in traction
. Spica cast

Correct Answer & Explanation

. Spica cast

Explanation

For extremely frail or medically unstable patients who cannot tolerate surgery for even stable subtrochanteric fractures, prolonged bed rest with skeletal traction can be a salvage non-operative option. This aims to maintain alignment and reduce pain, though it carries significant risks of complications associated with prolonged recumbency (e.g., pressure sores, DVT/PE, pneumonia). It is a measure of last resort. Immediate weight-bearing, short leg casts, or spica casts are inappropriate for subtrochanteric fractures. DHS is a surgical option.

Question 1031

Topic: Infection, Pharmacology & VTE

A 14-year-old active boy with a previously managed Non-Ossifying Fibroma in the distal tibia presents with new pain at the site. Radiographs show a healed pathological fracture but also a mild increase in lucency at the periphery of the former lesion. What is the most appropriate next step?

. Immediately schedule for repeat curettage and bone grafting.
. Recommend strict non-weight-bearing for 6 months.
. Obtain an MRI to further characterize the lesion and rule out recurrence or other pathology.
. Initiate systemic NSAID treatment for chronic pain.
. Reassure the patient that this is normal healing and no further action is needed.

Correct Answer & Explanation

. Obtain an MRI to further characterize the lesion and rule out recurrence or other pathology.

Explanation

While NOFs have a low recurrence rate after curettage, new pain combined with a change in radiographic appearance (increased lucency) warrants further investigation. An MRI would be the most appropriate next step to assess for any residual or recurrent fibrous tissue, subtle soft tissue changes, or to differentiate from other potential causes of pain. Immediate repeat surgery is premature without further imaging, non-weight-bearing is not diagnostic, and simple reassurance is insufficient given the new symptoms and radiographic changes.

Question 1032

Topic: Infection, Pharmacology & VTE

Which of the following factors is most strongly associated with an increased risk of DVT/PE in a patient with a lower extremity fracture?

. Younger age (<30 years).
. Early ambulation.
. Presence of an epidural catheter for pain control.
. Traumatic brain injury.
. Prolonged immobilization.

Correct Answer & Explanation

. Prolonged immobilization.

Explanation

Prolonged immobilization, especially of the lower extremity, is a well-established major risk factor for deep vein thrombosis (DVT) and pulmonary embolism (PE) due to venous stasis. Other risk factors include advanced age, malignancy, obesity, history of DVT/PE, and specific fracture types (pelvis, hip). While traumatic brain injury can be associated with hypercoagulability, prolonged immobilization is a more direct and significant factor for DVT/PE in lower extremity trauma. Early ambulation is protective. Epidural catheters do not directly increase DVT/PE risk. Younger age is generally protective.

Question 1033

Topic: Infection, Pharmacology & VTE

What is the most sensitive imaging modality for diagnosing osteomyelitis following an open fracture?

. Plain radiographs.
. CT scan.
. MRI with contrast.
. Bone scan (Technetium-99m).
. Indium-111 labeled leukocyte scan.

Correct Answer & Explanation

. Indium-111 labeled leukocyte scan.

Explanation

While MRI with contrast is highly sensitive for soft tissue and bone marrow edema, making it excellent for early osteomyelitis, an Indium-111 labeled leukocyte scan (or combined WBC/bone scan) is often considered the most specific and sensitive imaging modality for diagnosing active infection (osteomyelitis), especially in the presence of hardware or previous surgery, as it specifically targets actively inflamed leukocytes. Plain radiographs are insensitive in early stages. CT is good for bony detail but less for early infection. Bone scans are sensitive but not very specific for infection in the presence of other bone pathology like fractures or hardware.

Question 1034

Topic: Infection, Pharmacology & VTE

A patient with a suspected L3-L4 discitis and adjacent vertebral osteomyelitis has negative blood cultures. What is the most appropriate next step for definitive diagnosis?

. Empiric broad-spectrum antibiotic therapy
. Repeat blood cultures weekly
. CT-guided biopsy of the L3-L4 disc space
. Fluoroscopy-guided lumbar puncture
. Positron Emission Tomography (PET) scan

Correct Answer & Explanation

. CT-guided biopsy of the L3-L4 disc space

Explanation

When blood cultures are negative in suspected spinal infection (discitis/osteomyelitis), obtaining tissue for culture and histology is paramount for definitive diagnosis and targeted antibiotic therapy. A CT-guided biopsy of the affected disc space and/or vertebral body is the most appropriate and minimally invasive method to achieve this. Empiric antibiotics without pathogen identification can delay effective treatment and obscure future culture results. Lumbar puncture is for CSF analysis. PET scan helps localize infection but does not provide microbial diagnosis.

Question 1035

Topic: Infection, Pharmacology & VTE

Which feature is more characteristic of pyogenic spinal osteomyelitis/abscess compared to tuberculous spondylitis (Pott's disease)?

. Involvement of multiple contiguous vertebral bodies
. Large paraspinal cold abscesses
. More rapid onset and progression of symptoms
. Prominent kyphotic deformity
. Preservation of disc space in early stages

Correct Answer & Explanation

. More rapid onset and progression of symptoms

Explanation

Pyogenic spinal osteomyelitis and abscesses typically have a more acute or subacute onset with rapid progression of symptoms (days to weeks), including fever, severe pain, and rapid neurological decline. Tuberculous spondylitis (Pott's disease) is characterized by a more indolent, chronic course (months to years), often with gradual onset of pain, constitutional symptoms (weight loss, night sweats), and slow development of kyphosis or neurological deficit. The other options are more characteristic of tuberculous spondylitis.

Question 1036

Topic: Infection, Pharmacology & VTE

A patient's blood cultures come back positive for Methicillin-resistant Staphylococcus aureus (MRSA) from a confirmed spinal epidural abscess. The patient has no known allergies. Which antibiotic would be the most appropriate first-line targeted therapy?

. Ceftriaxone
. Piperacillin-tazobactam
. Vancomycin
. Ciprofloxacin
. Daptomycin

Correct Answer & Explanation

. Vancomycin

Explanation

Vancomycin is the cornerstone of treatment for MRSA infections, including spinal epidural abscesses, due to its reliable activity against methicillin-resistant strains. Ceftriaxone and Piperacillin-tazobactam lack MRSA coverage. Ciprofloxacin has some activity against S. aureus but is generally not preferred as first-line monotherapy for serious MRSA infections. Daptomycin is an alternative for MRSA, particularly in cases of vancomycin failure, intolerance, or in specific clinical scenarios, but vancomycin is typically first-line due to its established efficacy and cost-effectiveness.

Question 1037

Topic: Infection, Pharmacology & VTE

A patient with a prior lumbar fusion 6 months ago presents with worsening back pain, fever, and elevated inflammatory markers. Imaging suggests a deep surgical site infection involving the fusion hardware. What is the most appropriate initial management approach?

. Long-term suppressive oral antibiotics
. Urgent hardware removal, debridement, and IV antibiotics
. Percutaneous aspiration and antibiotic cement injection
. Continued observation and repeat imaging in 2 weeks
. High-dose steroids to reduce inflammation

Correct Answer & Explanation

. Urgent hardware removal, debridement, and IV antibiotics

Explanation

In the context of chronic or subacute deep surgical site infection involving spinal instrumentation, hardware removal, thorough debridement, and prolonged intravenous antibiotic therapy are often necessary to eradicate the infection. The biofilm formed on hardware makes antibiotic penetration difficult and typically prevents eradication without removal. Long-term suppressive antibiotics are rarely curative and typically reserved for patients who cannot undergo definitive surgery. Percutaneous aspiration may not be sufficient for extensive hardware-related infection. Observation is inappropriate. Steroids are contraindicated in active bacterial infection.

Question 1038

Topic: Infection, Pharmacology & VTE

Which class of antibiotics generally has poor penetration into the central nervous system and epidural space, making it less ideal as a primary monotherapy treatment for spinal epidural abscess?

. Fluoroquinolones
. Glycopeptides (e.g., Vancomycin)
. Beta-lactams (e.g., Ceftriaxone)
. Aminoglycosides
. Rifamycins

Correct Answer & Explanation

. Aminoglycosides

Explanation

Aminoglycosides (e.g., Gentamicin) generally have poor penetration into the central nervous system and epidural space. While they might be used in combination therapy for specific gram-negative organisms, they are not ideal as primary monotherapy agents for SEA due to this limited penetration and potential for nephrotoxicity and ototoxicity. Fluoroquinolones, beta-lactams, and rifamycins typically have better CNS penetration. Vancomycin's penetration is variable but it is still the primary choice for MRSA due to its efficacy and lack of superior alternatives for MRSA.

Question 1039

Topic: Infection, Pharmacology & VTE

Which of the following describes the typical MRI appearance of discitis?

. T1 hyperintense, T2 hypointense disc with no endplate changes
. T1 hypointense, T2 hyperintense disc with indistinct endplates and enhancement
. Normal disc signal with only mild vertebral body edema
. T1 hyperintense, T2 hyperintense disc with sharp endplate margins
. Diffuse vertebral body enhancement without disc involvement

Correct Answer & Explanation

. T1 hypointense, T2 hyperintense disc with indistinct endplates and enhancement

Explanation

Discitis typically presents on MRI with T1 hypointense and T2 hyperintense signal within the disc space, indicating increased fluid and inflammation. This is often accompanied by indistinct or irregular vertebral endplates and enhancement of both the disc and adjacent vertebral bodies after gadolinium administration, reflecting active infection and inflammation. Normal disc signal or sharp endplate margins would argue against active discitis. Diffuse vertebral body enhancement without disc involvement would be more typical of osteomyelitis without discitis, or other conditions.

Question 1040

Topic: Infection, Pharmacology & VTE

A 55-year-old male with a history of chronic alcoholism and liver cirrhosis presents with several weeks of progressive back pain and fever. MRI shows diffuse L2 vertebral osteomyelitis. What organism should be particularly considered in this patient population?

. Staphylococcus aureus
. Streptococcus pneumoniae
. Klebsiella pneumoniae
. Mycobacterium avium complex
. Coagulase-negative Staphylococcus

Correct Answer & Explanation

. Klebsiella pneumoniae

Explanation

Patients with chronic alcoholism and liver cirrhosis are often immunocompromised and are at increased risk for infections with Gram-negative organisms, particularly Klebsiella pneumoniae, which can cause severe infections including vertebral osteomyelitis. While S. aureus is the most common cause overall, specific host factors broaden the differential for causative organisms. M. avium complex is seen in advanced HIV. S. pneumoniae is less common in vertebral osteomyelitis. Coagulase-negative Staph is usually associated with hardware or indolent infections.

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