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Infection, Pharmacology & VTE MCQs

Practice Set 43 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 841

Topic: Infection, Pharmacology & VTE

A 30-year-old male sustains a traumatic complete T4 spinal cord injury. Which of the following is the most significant long-term cardiovascular risk related to his level of injury?

. Peripheral vascular disease.
. Hypertension secondary to renal dysfunction.
. Autonomic dysreflexia.
. Deep vein thrombosis (DVT) and pulmonary embolism (PE).
. Coronary artery disease.

Correct Answer & Explanation

. Autonomic dysreflexia.

Explanation

For spinal cord injuries at or above T6, autonomic dysreflexia is a significant and life-threatening long-term cardiovascular risk. It is a sudden, uncontrolled sympathetic response to noxious stimuli below the level of injury, leading to severe hypertension, bradycardia, headache, and sweating above the injury. While DVT/PE risk is high initially and can persist, and other cardiovascular issues can occur, autonomic dysreflexia is a unique and acute life-threatening phenomenon specific to high-level SCI. Hypertension secondary to renal dysfunction is possible but not the most significant or direct cardiovascular risk stemming from the SCI level itself. Peripheral vascular disease and coronary artery disease are general risks, not specific to this level of SCI.

Question 842

Topic: Infection, Pharmacology & VTE

A patient with a T8 spinal cord injury has developed a chronic non-healing sacral pressure ulcer. What specific orthopedic complication might be present underneath the ulcer that requires surgical debridement and long-term antibiotic therapy?

. Heterotopic ossification.
. Deep vein thrombosis.
. Osteomyelitis.
. Septic arthritis.
. Neuropathic joint (Charcot arthropathy).

Correct Answer & Explanation

. Osteomyelitis.

Explanation

Chronic, non-healing deep pressure ulcers, especially over bony prominences like the sacrum in a patient with spinal cord injury, frequently lead to osteomyelitis of the underlying bone (sacrum or ischium). This infection is a serious complication that mandates surgical debridement of necrotic and infected bone along with long-term systemic antibiotic therapy for eradication. Heterotopic ossification is bone formation in soft tissues, DVT is a vascular complication, septic arthritis is infection of a joint, and Charcot arthropathy is neurogenic joint destruction; while these can occur in SCI, osteomyelitis directly beneath a chronic pressure ulcer is the most common and relevant orthopedic complication in this specific scenario.

Question 843

Topic: Infection, Pharmacology & VTE

A 6-year-old child presents with a painful swollen left knee and fever. Labs show elevated ESR and CRP, and a white blood cell count of 18,000/uL. Aspiration of the knee joint yields cloudy fluid with a WBC count of 75,000/uL, 90% neutrophils, and positive Gram stain for Staphylococcus aureus. What is the immediate next step in management?

. Start oral antibiotics and observe
. Apply a splint and continue observation
. Perform emergent surgical irrigation and debridement of the joint, followed by intravenous antibiotics
. Administer anti-inflammatory drugs
. Order an MRI of the knee

Correct Answer & Explanation

. Perform emergent surgical irrigation and debridement of the joint, followed by intravenous antibiotics

Explanation

This clinical scenario, lab findings, and joint fluid analysis are diagnostic of septic arthritis. Septic arthritis is an orthopedic emergency, especially in children, due to the rapid destruction of articular cartilage. The immediate next step is emergent surgical irrigation and debridement of the joint (often arthroscopic in larger joints like the knee), followed by appropriate intravenous antibiotics. Delay can lead to irreversible joint damage. Oral antibiotics are insufficient, and MRI, while helpful, is not the immediate therapeutic intervention.

Question 844

Topic: Infection, Pharmacology & VTE

A 50-year-old female presents with severe pain and swelling in the first metatarsophalangeal (MTP) joint, which started suddenly last night. Examination reveals a red, hot, swollen, and exquisitely tender joint. Labs show elevated serum uric acid. What is the most appropriate initial management?

. Initiate allopurinol immediately
. Administer intra-articular steroid injection
. Start a course of colchicine or NSAIDs
. Advise rest and elevation only
. Perform surgical debridement of the joint

Correct Answer & Explanation

. Start a course of colchicine or NSAIDs

Explanation

The clinical presentation (acute monoarticular arthritis, severe inflammation, elevated uric acid) is highly suggestive of acute gout. The most appropriate initial management for an acute gout attack is to rapidly reduce inflammation and pain. This is typically achieved with colchicine, NSAIDs (e.g., indomethacin), or oral corticosteroids. Allopurinol is a uric acid-lowering therapy used for long-term management to prevent future attacks, but it should not be started during an acute attack as it can worsen symptoms. Intra-articular steroid injection can be considered for isolated joint involvement but is often used if oral medications are contraindicated. Surgical debridement is not indicated.

Question 845

Topic: Infection, Pharmacology & VTE

What is the most common organism causing osteomyelitis in healthy children?

. Escherichia coli
. Streptococcus pyogenes
. Pseudomonas aeruginosa
. Staphylococcus aureus
. Haemophilus influenzae

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common causative organism for acute hematogenous osteomyelitis in healthy children and adults across all age groups. E. coli and Pseudomonas are more common in specific scenarios (e.g., genitourinary infections, IV drug users, puncture wounds through shoes). S. pyogenes is less common, and H. influenzae was more common before widespread vaccination.

Question 846

Topic: Infection, Pharmacology & VTE

A patient presents with a painful snapping sensation on the medial side of the knee during flexion and extension. Palpation reveals tenderness over the medial tibial condyle just distal to the joint line. What is the most likely diagnosis?

. Medial meniscus tear
. MCL injury
. Pes anserine bursitis
. Patellofemoral pain syndrome
. Osteoarthritis of the medial compartment

Correct Answer & Explanation

. Pes anserine bursitis

Explanation

The symptoms (painful snapping, tenderness on the medial tibial condyle just distal to the joint line) are characteristic of pes anserine bursitis. This condition involves inflammation of the bursa located deep to the conjoined tendons of the sartorius, gracilis, and semitendinosus muscles (the pes anserinus). Medial meniscus tears usually cause pain directly at the joint line. MCL injury involves tenderness over the ligament. Patellofemoral pain is anterior knee pain. OA would have broader symptoms.

Question 847

Topic: Infection, Pharmacology & VTE

A 5-year-old child presents with a high fever, refusal to bear weight on the right leg, and exquisite tenderness over the distal femur metaphysis. Blood cultures grow methicillin-sensitive Staphylococcus aureus. Radiographs are normal. What is the most appropriate next step?

. MRI of the right femur
. Bone scan
. Start intravenous antibiotics immediately
. Surgical drainage of the femur
. Repeat radiographs in 1 week

Correct Answer & Explanation

. Start intravenous antibiotics immediately

Explanation

This is a classic presentation of acute osteomyelitis in a child (fever, localized bone pain, refusal to bear weight, positive blood cultures, normal initial radiographs). Given the high suspicion and positive blood cultures, immediate initiation of appropriate intravenous antibiotics is crucial to treat the infection and prevent bone destruction. Radiographs may be normal early in the course (before 7-10 days). MRI or bone scan can help localize the lesion but starting antibiotics should not be delayed. Surgical drainage is indicated if there is an abscess or no response to antibiotics, but not as the initial step after positive blood cultures.

Question 848

Topic: Infection, Pharmacology & VTE

A patient with a history of intravenous drug use presents with acute onset fever and severe back pain localized to the lumbar spine. MRI shows signal changes consistent with discitis and osteomyelitis at L3-L4. What is the most appropriate initial management?

. Physical therapy and pain management
. Immediate surgical debridement
. Biopsy for culture and histology, followed by empiric intravenous antibiotics
. Oral NSAIDs and observation
. Spinal bracing alone

Correct Answer & Explanation

. Biopsy for culture and histology, followed by empiric intravenous antibiotics

Explanation

Given the history of IV drug use and MRI findings consistent with discitis and osteomyelitis, an infection is highly probable. The most appropriate initial management is to obtain a biopsy (either CT-guided percutaneous or open) for culture and histology to identify the causative organism, followed by empiric intravenous antibiotics. Surgical debridement may be necessary later if conservative measures fail or neurological compromise develops, but direct identification of the pathogen is crucial for targeted therapy. Physical therapy, NSAIDs, observation, or bracing alone are insufficient for an active spinal infection.

Question 849

Topic: Infection, Pharmacology & VTE

In a patient with a displaced femoral neck fracture, what is the most significant risk associated with delaying definitive surgical fixation?

. Increased pain
. Increased risk of deep vein thrombosis (DVT)
. Increased risk of non-union and avascular necrosis (AVN) of the femoral head
. Increased blood loss
. Increased risk of infection

Correct Answer & Explanation

. Increased risk of non-union and avascular necrosis (AVN) of the femoral head

Explanation

Delayed definitive surgical fixation of a displaced femoral neck fracture significantly increases the risk of complications, particularly non-union and avascular necrosis (AVN) of the femoral head. This is because the blood supply to the femoral head, which is already tenuous, is further compromised by the fracture and prolonged displacement. While other complications like pain and DVT are also concerns, the risk to the femoral head's viability is paramount and time-sensitive.

Question 850

Topic: Infection, Pharmacology & VTE

While Staphylococcus aureus is the most common overall cause of acute hematogenous osteomyelitis, patients with sickle cell disease have a uniquely higher incidence of infection caused by which of the following organisms compared to the general population?

. Staphylococcus epidermidis
. Salmonella species
. Haemophilus influenzae
. Streptococcus pneumoniae
. Pseudomonas aeruginosa

Correct Answer & Explanation

. Salmonella species

Explanation

In patients with sickle cell disease, functional asplenia and bone infarcts (which can serve as a nidus for infection) predispose them to osteomyelitis. While S. aureus is still extremely common, Salmonella species are uniquely associated with osteomyelitis in sickle cell patients and account for a significantly higher percentage of cases than in healthy individuals.

Question 851

Topic: Infection, Pharmacology & VTE

A 55-year-old male with chronic osteomyelitis of the tibia develops SIRS criteria. Blood cultures are pending. What is the most critical initial step in his management, specifically related to the orthopedic source?

. Start broad-spectrum antibiotics immediately after cultures are drawn
. Perform a CT scan to identify abscess formation
. Prepare for surgical debridement and removal of infected hardware if present
. Initiate aggressive fluid resuscitation to optimize hemodynamics
. Consult infectious disease for antibiotic guidance

Correct Answer & Explanation

. Prepare for surgical debridement and removal of infected hardware if present

Explanation

While all options are important, source control is paramount in the management of sepsis originating from an orthopedic infection like osteomyelitis, especially when there's an infected hardware or devitalized tissue. Delay in source control is associated with increased mortality. Therefore, preparing for surgical debridement and removal of infected hardware is the most critical initial orthopedic step, often performed concurrently with resuscitation and antibiotic initiation. Antibiotics are crucial but often ineffective without source control in established osteomyelitis. Imaging helps but surgery is the definitive step. Resuscitation and ID consult are part of general sepsis management.

Question 852

Topic: Infection, Pharmacology & VTE

A 62-year-old male develops septic arthritis of his knee following an arthroscopic procedure. He is hypotensive and tachycardic. Blood cultures are positive for methicillin-resistant Staphylococcus aureus (MRSA). Which antibiotic regimen would be most appropriate for empiric coverage of MRSA in severe sepsis, pending sensitivities?

. Ceftriaxone
. Piperacillin-tazobactam
. Vancomycin
. Ciprofloxacin
. Ampicillin-sulbactam

Correct Answer & Explanation

. Vancomycin

Explanation

Vancomycin is the drug of choice for empiric coverage of MRSA in severe infections, including septic arthritis leading to sepsis. The other options either lack MRSA coverage (Ceftriaxone, Piperacillin-tazobactam, Ciprofloxacin, Ampicillin-sulbactam) or are not the primary choice for confirmed or highly suspected MRSA.

Question 853

Topic: Infection, Pharmacology & VTE

What is the leading cause of mortality in patients with severe sepsis and septic shock, particularly in those with orthopedic origins?

. Cardiac arrhythmias
. Uncontrolled bleeding
. Multiple Organ Dysfunction Syndrome (MODS)
. Anaphylaxis to antibiotics
. Deep vein thrombosis (DVT) with pulmonary embolism (PE)

Correct Answer & Explanation

. Multiple Organ Dysfunction Syndrome (MODS)

Explanation

Multiple Organ Dysfunction Syndrome (MODS) is the leading cause of mortality in patients with severe sepsis and septic shock. Sepsis is characterized by a dysregulated host response to infection, leading to widespread inflammation, microvascular dysfunction, and subsequent failure of two or more organ systems (e.g., respiratory, renal, cardiovascular, hepatic, neurologic, hematologic). While other complications can occur, MODS is the ultimate pathway to death in the majority of these cases.

Question 854

Topic: Infection, Pharmacology & VTE

Which component of the systemic inflammatory response in sepsis is responsible for the widespread vasodilation and increased vascular permeability leading to distributive shock?

. Increased erythrocyte production
. Overproduction of anti-inflammatory cytokines (e.g., IL-10)
. Release of nitric oxide (NO) and other vasodilatory mediators from activated endothelial cells
. Decreased systemic vascular resistance due to direct bacterial cytotoxicity
. Increased cardiac output leading to relative hypovolemia

Correct Answer & Explanation

. Release of nitric oxide (NO) and other vasodilatory mediators from activated endothelial cells

Explanation

The widespread vasodilation and increased vascular permeability characteristic of distributive shock in sepsis are primarily mediated by the release of potent vasodilatory substances. Nitric oxide (NO), prostaglandins, and other inflammatory mediators (like bradykinin, histamine, C3a, C5a) released from activated endothelial cells, macrophages, and other immune cells play a central role. This leads to a profound drop in systemic vascular resistance and leakage of fluid from the intravascular space, contributing to hypoperfusion.

Question 855

Topic: Infection, Pharmacology & VTE

Regarding DVT prophylaxis in an orthopedic patient with severe sepsis, which statement is most appropriate?

. DVT prophylaxis should be withheld due to the risk of bleeding in DIC.
. Mechanical prophylaxis (e.g., intermittent pneumatic compression devices) is contraindicated in septic patients.
. Pharmacological prophylaxis (e.g., LMWH) should be initiated unless contraindications exist.
. All septic patients require placement of an inferior vena cava (IVC) filter.
. Only patients undergoing major orthopedic surgery require DVT prophylaxis in sepsis.

Correct Answer & Explanation

. Pharmacological prophylaxis (e.g., LMWH) should be initiated unless contraindications exist.

Explanation

Patients with severe sepsis are at high risk for venous thromboembolism (VTE). Pharmacological prophylaxis with low molecular weight heparin (LMWH) or unfractionated heparin (UFH) is recommended unless contraindications (e.g., active bleeding, severe thrombocytopenia) exist. If pharmacological agents are contraindicated, mechanical prophylaxis (intermittent pneumatic compression devices) should be used. Withholding prophylaxis due to DIC is not universal; careful risk-benefit assessment is needed. IVC filters are reserved for specific situations. All critically ill septic patients require DVT prophylaxis, not just those with major orthopedic surgery.

Question 856

Topic: Infection, Pharmacology & VTE

What is the primary role of echocardiography in the management of septic shock?

. To diagnose the source of infection (e.g., endocarditis).
. To assess cardiac function, fluid responsiveness, and differentiate shock types.
. To evaluate for pulmonary embolism.
. To guide placement of central venous catheters.
. To measure central venous pressure (CVP) non-invasively.

Correct Answer & Explanation

. To assess cardiac function, fluid responsiveness, and differentiate shock types.

Explanation

Echocardiography (transthoracic or transesophageal) is an invaluable tool in the management of septic shock. It allows for rapid, non-invasive assessment of cardiac function (contractility, ejection fraction), volume status, and fluid responsiveness. It can help differentiate between different types of shock (e.g., distributive, cardiogenic, obstructive) when the cause is unclear, and can guide fluid and vasopressor therapy. While it can sometimes identify endocarditis (a source), its primary role in general shock management is hemodynamic assessment. It's not the primary tool for PE, CVC guidance, or CVP measurement.

Question 857

Topic: Infection, Pharmacology & VTE

A 58-year-old male with a history of recurrent osteomyelitis in his left foot develops sepsis. Blood cultures grow Pseudomonas aeruginosa. What is the most appropriate initial empiric antibiotic regimen, knowing the high prevalence of resistant strains and potential for sepsis?

. Oral Ciprofloxacin monotherapy
. Intravenous Ceftriaxone
. Intravenous Piperacillin-tazobactam or a Carbapenem (e.g., Meropenem)
. Intravenous Vancomycin
. Oral Amoxicillin-Clavulanate

Correct Answer & Explanation

. Intravenous Piperacillin-tazobactam or a Carbapenem (e.g., Meropenem)

Explanation

Pseudomonas aeruginosa is a common pathogen in osteomyelitis, especially in patients with a history of recurrent infections or diabetes. It is often resistant to many common antibiotics. For severe infections and sepsis involving Pseudomonas, antipseudomonal beta-lactams like Piperacillin-tazobactam or Carbapenems (e.g., Meropenem, Imipenem) are typically first-line, often in combination with an aminoglycoside or fluoroquinolone if severe. Oral ciprofloxacin monotherapy is insufficient for severe sepsis. Ceftriaxone lacks robust antipseudomonal activity. Vancomycin covers Gram-positives, not Pseudomonas. Amoxicillin-Clavulanate is not active against Pseudomonas.

Question 858

Topic: Infection, Pharmacology & VTE

A 72-year-old patient with well-controlled type 2 diabetes and a history of penicillin allergy (rash) is scheduled for an elective total knee arthroplasty. According to prophylactic antibiotic guidelines and general principles, which of the following antibiotic regimens is the most appropriate prophylactic choice to prevent periprosthetic joint infection?

. Vancomycin alone, given penicillin allergy.
. Cefazolin, as the rash is not a severe allergy and provides excellent coverage.
. Clindamycin alone, providing good gram-positive coverage and safe for penicillin allergy.
. Vancomycin plus Gentamicin, for broad-spectrum coverage.
. Daptomycin, due to its efficacy against resistant organisms.

Correct Answer & Explanation

. Vancomycin alone, given penicillin allergy.

Explanation

For patients with a history of penicillin allergy, especially non-severe reactions like a rash, a cephalosporin such as cefazolin might still be considered due to its excellent efficacy and narrow spectrum. However, for a board-level question and especially in the context of prophylaxis for arthroplasty where the consequence of infection is severe, Vancomycin is the safest and most commonly recommended alternative in patients with a stated penicillin allergy, particularly for a 'rash' which could still represent a Type I hypersensitivity. Cefazolin carries a low but present cross-reactivity risk. Clindamycin is an alternative but often preferred for patients with severe beta-lactam allergies (anaphylaxis) or if methicillin-resistant S. aureus (MRSA) coverage is specifically desired and Vancomycin cannot be used; it has less robust data than cefazolin or vancomycin. Daptomycin is generally reserved for treating established infections rather than prophylaxis. Gentamicin is not typically used for routine prophylaxis in TKA due to potential nephrotoxicity and narrow spectrum for skin flora.

Question 859

Topic: Infection, Pharmacology & VTE

A 60-year-old patient with poorly controlled diabetes and a history of chronic osteomyelitis of the distal tibia is scheduled for a debridement and external fixation. According to the general principles for prophylactic antibiotic use, which of the following is an additional significant indication for administering prophylactic antibiotics in this patient, beyond the surgical procedure itself?

. His history of chronic osteomyelitis, requiring long-term suppression.
. Anticipated duration of external fixation exceeding 6 weeks.
. Poorly controlled diabetes, categorizing him as a high-risk patient.
. Age exceeding 60 years, increasing general surgical risk.
. The specific location of the infection (distal tibia) being prone to recurrence.

Correct Answer & Explanation

. Poorly controlled diabetes, categorizing him as a high-risk patient.

Explanation

The general principles for prophylactic antibiotic use specifically state: '(4) Patients with high-risk factors for infection, such as advanced age, malnutrition, diabetes, granulocytopenia; or those undergoing steroid, immunosuppressant, or anticancer drug therapy, and those with immune dysfunction requiring surgery.' Poorly controlled diabetes significantly impairs immune function and microvascular circulation, placing the patient at a much higher risk for surgical site infection. While chronic osteomyelitis is a concern, the question asks for anadditionalindication forprophylacticuse, distinct from the treatment of his existing infection. His diabetes is a direct 'high-risk factor' for infection prophylaxis.

Question 860

Topic: Infection, Pharmacology & VTE

A 3-year-old child presents with a high fever, refusal to bear weight on the right leg, and extreme pain with passive range of motion of the right hip. Inflammatory markers (ESR, CRP) are significantly elevated. Which of the following is the most appropriate immediate diagnostic and therapeutic step?

. Order a plain radiograph of the hip and femur.
. Start oral antibiotics and observe for improvement.
. Perform an MRI of the hip to identify synovitis.
. Aspirate the hip joint immediately and initiate empiric intravenous antibiotics.
. Refer to physical therapy for range of motion exercises.

Correct Answer & Explanation

. Aspirate the hip joint immediately and initiate empiric intravenous antibiotics.

Explanation

The presentation (high fever, refusal to bear weight, severe pain with passive ROM, elevated inflammatory markers) in a child is highly suspicious for septic arthritis of the hip, which is an orthopedic emergency. Delayed diagnosis and treatment can lead to rapid articular cartilage destruction, avascular necrosis, and growth disturbances. Therefore,immediatehip joint aspiration (to obtain fluid for culture and cell count) and initiation of empiric intravenous antibiotics are crucial. Radiographs are often normal early on. MRI can be helpful but should not delay aspiration and antibiotics. Oral antibiotics are insufficient. Physical therapy is contraindicated in acute septic arthritis.

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