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Infection, Pharmacology & VTE MCQs

Practice Set 1 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 1

Topic: Infection, Pharmacology & VTE

What is the gold standard for diagnosing osteomyelitis?

. Bone biopsy with culture
. MRI
. X-ray
. Blood test (ESR/CRP)
. CT scan

Correct Answer & Explanation

. Bone biopsy with culture

Explanation

Bone biopsy with subsequent histopathological examination and culture is considered the gold standard for confirming the diagnosis of osteomyelitis.

Question 2

Topic: Infection, Pharmacology & VTE

What is the most common cause of septic arthritis in adults?

. E. coli
. Streptococcus pneumoniae
. Pseudomonas aeruginosa
. Staphylococcus aureus
. Neisseria gonorrhoeae

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common causative organism for septic arthritis across all age groups, including adults.

Question 3

Topic: Infection, Pharmacology & VTE
While femoral-sided Grade III MCL tears are typically managed nonoperatively when combined with an ACL tear, a tibial-sided Grade III MCL avulsion requires surgical repair. Why is operative intervention specifically indicated for this variant?
. It lacks blood supply compared to the femoral origin.
. The distal end of the superficial MCL can flip superficial to the pes anserinus.
. It invariably includes a medial meniscus root tear.
. It leads to rapid chondrolysis of the medial compartment.
. Tibial-sided tears cause isolated rotational instability.

Correct Answer & Explanation

. The distal end of the superficial MCL can flip superficial to the pes anserinus.

Explanation

In a tibial-sided Grade III MCL tear, the distal end of the superficial MCL can become entrapped outside the pes anserinus tendons, preventing healing. This creates a Stener-like lesion of the knee that requires surgical repair.

Question 4

Topic: Infection, Pharmacology & VTE

The superficial medial collateral ligament (sMCL) has distinct femoral and tibial attachments. Where is its primary distal (tibial) attachment located?

. 1 cm distal to the joint line deep to the pes anserinus
. 4 to 5 cm distal to the joint line deep to the pes anserinus
. On the medial meniscus
. On the adductor tubercle
. 2 cm proximal to the joint line

Correct Answer & Explanation

. 4 to 5 cm distal to the joint line deep to the pes anserinus

Explanation

The superficial MCL attaches 4 to 5 cm distal to the joint line on the anteromedial surface of the tibia, deep to the pes anserinus tendons. The deep MCL attaches much closer to the articular margins of the joint line.

Question 5

Topic: Infection, Pharmacology & VTE

A patient sustains a high-energy knee dislocation. On examination, there is a transverse skin furrow (dimple sign) over the medial joint line, and the knee cannot be closed-reduced. What structure is most likely interposing and preventing reduction?

. Medial meniscus
. Medial head of the gastrocnemius
. Medial collateral ligament and medial capsule
. Pes anserinus tendons
. Posterior cruciate ligament stump

Correct Answer & Explanation

. Medial collateral ligament and medial capsule

Explanation

The 'dimple sign' or 'pucker sign' occurs in an irreducible posterolateral knee dislocation when the medial joint capsule and medial collateral ligament buttonhole through the joint. An open reduction via a medial approach is urgently required to extricate these structures and achieve reduction.

Question 6

Topic: Infection, Pharmacology & VTE

A 20-year-old soccer player developed myositis ossificans in the vastus intermedius following a contusion 6 weeks ago. Radiographs show immature, fluffy ossification. What is the most appropriate management?

. Immediate surgical excision of the mass
. Radiation therapy to halt progression
. Rest, NSAIDs, and gentle active range of motion until the lesion matures
. Aggressive passive stretching under anesthesia
. Local injection of corticosteroids directly into the mass

Correct Answer & Explanation

. Rest, NSAIDs, and gentle active range of motion until the lesion matures

Explanation

Early surgical excision of myositis ossificans is contraindicated due to a high risk of recurrence. The mass should be allowed to mature over 6 to 12 months with conservative management before considering excision.

Question 7

Topic: Infection, Pharmacology & VTE

A 22-year-old football player sustains a severe thigh contusion. Three weeks later, he presents with worsening pain and decreased knee flexion. Radiographs show calcification in the anterior thigh. What is the most appropriate initial management?

. Immediate surgical excision of the calcification
. Indomethacin and gentle active range of motion
. Aggressive passive stretching under anesthesia
. Extracorporeal shockwave therapy
. Corticosteroid injection into the calcified mass

Correct Answer & Explanation

. Indomethacin and gentle active range of motion

Explanation

Myositis ossificans traumatica is best managed non-operatively initially with NSAIDs (such as indomethacin) and gentle active range of motion. Early surgical excision is contraindicated as it exacerbates the inflammatory process and leads to high rates of recurrence.

Question 8

Topic: Infection, Pharmacology & VTE

The medial collateral ligament (MCL) of the knee consists of superficial and deep layers. The superficial MCL is the primary restraint to valgus stress. Where is its primary tibial insertion?

. Immediately distal to the joint line, deep to the pes anserinus
. Approximately 4-5 cm distal to the joint line, deep to the pes anserinus
. Approximately 4-5 cm distal to the joint line, superficial to the pes anserinus
. On the anterior medial tibial crest
. Directly on the medial meniscus

Correct Answer & Explanation

. Immediately distal to the joint line, deep to the pes anserinus

Explanation

The superficial MCL has a broad tibial insertion located approximately 4.5 cm distal to the joint line. It sits deep to the pes anserinus tendons, separated from them by a bursa.

Question 9

Topic: Infection, Pharmacology & VTE

A 22-year-old football player sustains a valgus knee injury. MRI demonstrates a complete rupture of the medial collateral ligament (MCL) with the distal end flipped superficial to the pes anserinus tendons. What is the most appropriate management?

. Hinged knee brace locked in extension for 4 weeks
. Early active range of motion and weight-bearing as tolerated
. Surgical repair of the MCL
. Injection of platelet-rich plasma (PRP)
. Cast immobilization for 6 weeks

Correct Answer & Explanation

. Surgical repair of the MCL

Explanation

While most MCL tears are managed non-operatively, a distal avulsion where the MCL retracts superficial to the pes anserinus (a "Stener-like" lesion of the knee) prevents anatomic healing. This specific injury pattern typically requires surgical repair.

Question 10

Topic: Infection, Pharmacology & VTE
A 19-year-old collegiate football player sustains an acute grade III medial collateral ligament (MCL) injury. MRI demonstrates a distal avulsion of the superficial MCL from the tibia. The distal end of the ligament is retracted and rests superficial to the pes anserinus. What is the most appropriate management for this specific injury pattern?
. Hinged knee brace locked in extension for 4 weeks
. Acute surgical repair of the MCL
. Early functional rehabilitation with weight-bearing as tolerated
. Late reconstruction of the MCL using an allograft
. Casting in 30 degrees of flexion for 6 weeks

Correct Answer & Explanation

. Acute surgical repair of the MCL

Explanation

This describes a Stener-like lesion of the medial knee, where the distal superficial MCL avulses and flips over the pes anserinus tendons. Because the interposed pes anserinus prevents spontaneous healing, acute surgical repair is indicated.

Question 11

Topic: Infection, Pharmacology & VTE

Which of the following medial collateral ligament (MCL) injury patterns has the poorest healing potential and is most likely to require surgical repair rather than non-operative management?

. Proximal femoral avulsion
. Midsubstance tear
. Distal tibial avulsion with the superficial MCL flipped superficial to the pes anserinus
. Partial articular-sided tear
. Tear isolated to the deep MCL

Correct Answer & Explanation

. Distal tibial avulsion with the superficial MCL flipped superficial to the pes anserinus

Explanation

A distal avulsion of the superficial MCL where the ligament flips superficial to the pes anserinus tendons creates a 'Stener-like' lesion of the knee. This prevents apposition of the torn ends, necessitating surgical repair.

Question 12

Topic: Infection, Pharmacology & VTE

Which of the following is a contraindication to kyphoplasty:

. Local osteomyelitis
. Osteoblastic lesions
. Sepsis
. Bleeding diathesis
. All of the above

Correct Answer & Explanation

. All of the above

Explanation

It is important to properly evaluate a patient prior to any surgical procedure. If a patient presents with osteomyelitis, osteoblastic lesions, sepsis, or bleeding diathesis, then surgery should be postponed until the underlying condition is corrected.

Question 13

Topic: Infection, Pharmacology & VTE

Which of the following is the most common organism identified in cases of vertebral osteomyelitis:

. Staphylococcus aureus
. Streptococcus pneumoniae
. Haemophilus influenzae
. Escherichia coli
. Anaerobic gram-negative rods

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus remains the most common causative organism, but an increasing proportion of cases are due to gramnegative and anaerobic organisms such as Proteus, Escherichia coli and Pseudomonas.

Question 14

Topic: Infection, Pharmacology & VTE
Which of the following is the most common presentation of vertebral osteomyelitis?
. Fever of unknown origin
. Lower extremity pain and weakness
. Unrelenting back pain not relieved by rest
. Urinary incontinence
. None of the above. It is usually an incidental finding during an unrelated work-up.

Correct Answer & Explanation

. Unrelenting back pain not relieved by rest

Explanation

The most common presenting sign of vertebral osteomyelitis is back pain and malaise, often of 3 months' duration or greater. It is often well localized to the affected level and the nature is not unlike most degenerative spinal conditions. A high index of suspicion is essential to make a timely diagnosis. Back pain that awakens a patient at night is a hallmark of infection or tumor. Pain associated with infection tends to be relentless and not related to activity level. Most patients have percussion tenderness over the involved segments. Fevers are noted in fewer than half of patients.

Question 15

Topic: Infection, Pharmacology & VTE

Which of the following is the hallmark distinguishing feature of vertebral osteomyelitis when compared to a neoplastic process on imaging:

. Uniform enhancement after administration of gadolinium in the neoplasia
. Destruction of disk space and encroachment of adjacent vertebral body in vertebral osteomyelitis
. Lack of endplate involvement in the neoplastic process
. Evidence of a compression fracture in vertebral osteomyelitis
. There are no distinguishing radiographic features between vertebral osteomyelitis and a tumor.

Correct Answer & Explanation

. Destruction of disk space and encroachment of adjacent vertebral body in vertebral osteomyelitis

Explanation

The crossing of the infectious process along the disk space to involve adjacent vertebrae is a hallmark feature of osteomyelitis used to differentiate it from a neoplastic process.

Question 16

Topic: Infection, Pharmacology & VTE

A 55-year-old poorly controlled diabetic male presents with fevers, severe localized back pain, and an elevated CRP. MRI reveals fluid in the L3-L4 disc space and adjacent vertebral body edema. What is the most common causative organism for this condition?

. Pseudomonas aeruginosa
. Staphylococcus aureus
. Escherichia coli
. Mycobacterium tuberculosis
. Streptococcus pneumoniae

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common organism responsible for pyogenic vertebral osteomyelitis and discitis. While Pseudomonas is a notable risk in IV drug users, S. aureus remains the most common overall.

Question 17

Topic: Infection, Pharmacology & VTE

Which of the following represents an absolute contraindication to performing a percutaneous vertebroplasty for a painful osteoporotic compression fracture?

. Asymptomatic adjacent level fracture
. Presence of an intravertebral vacuum cleft
. Active osteomyelitis or discitis at the target level
. Failure of conservative management after 6 weeks
. Patient age greater than 85 years

Correct Answer & Explanation

. Active osteomyelitis or discitis at the target level

Explanation

Active infection such as osteomyelitis, discitis, or systemic bacteremia is an absolute contraindication to percutaneous cement augmentation due to the high risk of abscess formation and failure of eradication.

Question 18

Topic: Infection, Pharmacology & VTE

A 75-year-old female presents with severe, unremitting back pain after a fall from standing height. MRI shows an acute L1 compression fracture. She has failed 6 weeks of conservative management. What is an absolute contraindication to performing a vertebroplasty?

. Involvement of the posterior vertebral body wall
. Retropulsion of bone into the spinal canal without neurologic deficit
. Active osteomyelitis at the affected level
. Patient age greater than 80 years
. Cortical disruption of the superior endplate

Correct Answer & Explanation

. Active osteomyelitis at the affected level

Explanation

Active infection (osteomyelitis or discitis) and uncorrectable coagulopathy are absolute contraindications to vertebroplasty and kyphoplasty. Asymptomatic retropulsion and posterior wall involvement are relative contraindications.

Question 19

Topic: Infection, Pharmacology & VTE

A patient with a T4 complete spinal cord injury suddenly develops a severe, pounding headache, profound diaphoresis above the level of injury, and severe hypertension. What is the most common precipitating cause of this condition?

. Bladder distension
. Deep vein thrombosis
. Pulmonary embolism
. Acute myocardial infarction

Correct Answer & Explanation

. Bladder distension

Explanation

This presentation describes autonomic dysreflexia, which occurs in patients with spinal cord injuries above T6. The most common trigger is a noxious stimulus below the level of injury, typically a distended bladder or bowel impaction.

Question 20

Topic: Infection, Pharmacology & VTE

A 60-year-old poorly controlled diabetic male undergoes an L4-L5 posterior spinal fusion. Three weeks postoperatively, he presents with increasing back pain, incisional erythema, and purulent wound drainage. The most commonly isolated organism in this clinical scenario is:

. Staphylococcus epidermidis
. Staphylococcus aureus
. Pseudomonas aeruginosa
. Escherichia coli
. Cutibacterium acnes

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common causative organism in both spontaneous pyogenic vertebral osteomyelitis and acute postoperative spinal surgical site infections.

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