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6. Spine MCQs

Practice Set 335 of 379

This practice set contains high-yield board review questions covering key concepts in 6. Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 6681

Topic: 6. Spine

A 45-year-old male presents to the emergency department with severe, new-onset back pain, subjective fevers, and a history of recent staphylococcal bacteremia. Physical exam is unremarkable for neurological deficit. What is the most appropriate next step?

. Discharge with oral analgesics and follow-up
. Admit for IV antibiotics and observation
. Obtain an urgent MRI of the spine with contrast
. Obtain plain radiographs of the spine
. Perform a lumbar puncture

Correct Answer & Explanation

. Obtain an urgent MRI of the spine with contrast

Explanation

The combination of severe back pain, fevers, and recent staphylococcal bacteremia is highly suggestive of spinal infection (e.g., discitis, osteomyelitis, or epidural abscess) even in the absence of neurological deficits. An urgent MRI of the spine with contrast is the gold standard for diagnosis and is crucial to detect an abscess early before neurological compromise occurs. Plain radiographs are insensitive for early spinal infection. Lumbar puncture is generally avoided in suspected epidural abscess. Discharge is dangerous. While admission for IV antibiotics is appropriate, it should follow, or be initiated concurrently with, the definitive imaging diagnosis.

Question 6682

Topic: 6. Spine

A patient who works with livestock develops chronic low back pain, fevers, and sacroiliitis on imaging. Blood cultures are negative for common bacteria. What should be considered in the differential diagnosis for a spinal infection?

. Cryptococcus neoformans
. Brucella species
. Nocardia asteroides
. Clostridium perfringens
. Mycoplasma hominis

Correct Answer & Explanation

. Brucella species

Explanation

Brucellosis is a zoonotic infection, often acquired through contact with infected animals or contaminated dairy products. It commonly causes spondylitis, discitis, and sacroiliitis, often with chronic back pain and systemic symptoms. It should be strongly considered in patients with appropriate epidemiological exposure when routine bacterial cultures are negative. The other options are less likely given the specific history.

Question 6683

Topic: 6. Spine

In the context of surgical management of a spinal epidural abscess with associated extensive vertebral osteomyelitis, when is spinal fusion indicated?

. Always, regardless of bone destruction
. Only if neurological deficits are absent
. If there is significant bony destruction leading to mechanical instability or risk of future deformity
. To improve antibiotic penetration
. As a last resort for chronic pain

Correct Answer & Explanation

. If there is significant bony destruction leading to mechanical instability or risk of future deformity

Explanation

Spinal fusion is indicated in the surgical management of spinal infections if there is significant bony destruction (e.g., >50% vertebral body collapse, severe kyphosis), multi-level involvement, or iatrogenic destabilization from decompression (e.g., extensive laminectomy) that results in mechanical instability or a high risk of progressive deformity. Fusion is necessary to restore spinal alignment and stability after debridement. It is not always indicated, not for improving antibiotic penetration, and not solely for chronic pain (though pain can be a symptom of instability).

Question 6684

Topic: 6. Spine

Which of the following is the most effective measure to prevent surgical site infection in elective spine surgery?

. Routine post-operative prophylactic antibiotics for 7 days
. Pre-operative skin preparation with chlorhexidine gluconate
. Intra-operative pulsatile lavage with normal saline
. Post-operative wound drain placement for 48 hours
. Use of topical antibiotics in the wound

Correct Answer & Explanation

. Pre-operative skin preparation with chlorhexidine gluconate

Explanation

Meticulous pre-operative skin preparation with an antiseptic solution like chlorhexidine gluconate (CHG) is a highly effective and evidence-based measure to reduce the bacterial load on the skin and significantly lower the risk of surgical site infections. Routine prolonged post-operative antibiotics are not recommended due to increased risk of antibiotic resistance and lack of proven benefit beyond 24 hours (or shorter). Pulsatile lavage efficacy is debatable. Wound drains do not prevent infection and can sometimes be a source. Topical antibiotics have limited evidence for routine use and can contribute to resistance.

Question 6685

Topic: 6. Spine

When assessing a patient with suspected spinal epidural abscess, which component of the neurological examination is MOST crucial for rapidly identifying an evolving spinal cord compression?

. Deep tendon reflexes
. Proprioception in the toes
. Sensory level to pinprick
. Cranial nerve function
. Plantar reflexes (Babinski)

Correct Answer & Explanation

. Sensory level to pinprick

Explanation

Identifying a distinct sensory level to pinprick or light touch is often the most critical and earliest sign of an evolving spinal cord compression from an epidural abscess. It helps localize the level of pathology and indicates a transverse lesion of the spinal cord. While other elements are important, a clear sensory level is highly indicative of a serious and potentially rapidly progressing problem requiring urgent attention. Cranial nerve function is usually unaffected in spinal cord compression.

Question 6686

Topic: 6. Spine

Which of the following factors is most strongly associated with increased mortality in patients with spinal epidural abscess?

. Abscess location in the cervical spine
. Age less than 40 years
. Concurrent endocarditis or other systemic sepsis
. Staphylococcus epidermidis as pathogen
. History of previous spine surgery

Correct Answer & Explanation

. Concurrent endocarditis or other systemic sepsis

Explanation

The presence of concurrent endocarditis, active bacteremia, or systemic sepsis (e.g., septic shock, multiorgan failure) is a major predictor of increased mortality in patients with spinal epidural abscess, reflecting a more severe and widespread systemic infection. While cervical location can be associated with worse neurological outcomes, and age can impact overall prognosis, systemic sepsis is a direct and immediate threat to life. S. epidermidis is less virulent than S. aureus. Previous spine surgery is a risk factor for developing SEA but not a direct mortality predictor to the same extent as systemic sepsis.

Question 6687

Topic: 6. Spine

After 4 weeks of appropriate intravenous antibiotic therapy for a stable, culture-proven spinal epidural abscess, a patient's inflammatory markers (ESR, CRP) have normalized, and they are neurologically intact. What is the most appropriate next step regarding antibiotics?

. Discontinue all antibiotics
. Transition to oral antibiotics for an additional 4-8 weeks
. Continue IV antibiotics for another 4 weeks
. Switch to a different IV antibiotic
. Repeat MRI before any change in therapy

Correct Answer & Explanation

. Transition to oral antibiotics for an additional 4-8 weeks

Explanation

Once clinical improvement is evident, inflammatory markers normalize, and the patient is stable and neurologically intact after an adequate initial IV course (typically 2-4 weeks or longer for complex cases), it is appropriate to transition from intravenous to highly bioavailable oral antibiotics. The total duration of antibiotic therapy for spinal epidural abscess is typically 6-12 weeks, with the oral component ensuring eradication. Discontinuing all antibiotics is too early, and continuing IV for longer without specific indication is not optimal. Switching IV antibiotics is only indicated for treatment failure or resistance. Repeating MRI before transition might be considered but is not universally mandatory if clinical and lab parameters are excellent.

Question 6688

Topic: 6. Spine

A patient undergoes successful surgical and antibiotic treatment for a lumbar epidural abscess. Six months later, he presents with a new epidural abscess at a different lumbar level. What should be strongly investigated as an underlying cause?

. Undiagnosed diabetes mellitus
. Persistent distant infectious focus
. Inadequate initial antibiotic duration
. Poor surgical technique
. New trauma to the spine

Correct Answer & Explanation

. Persistent distant infectious focus

Explanation

Recurrence of a spinal epidural abscess at a different level, especially after seemingly successful initial treatment, strongly suggests an ongoing or persistent distant infectious focus that is hematogenously seeding the spine. Common sources include endocarditis, skin infections, urinary tract infections, or deep-seated abscesses elsewhere that were not identified or adequately treated during the initial workup. While diabetes is a risk factor, anundiagnosedcondition would not explain a recurrent abscess at a new site. Inadequate antibiotic duration typically leads to recurrence at thesamesite or persistent infection. Poor surgical technique is less likely for anewsite. Trauma is less likely to cause a spontaneous recurrent abscess.

Question 6689

Topic: 6. Spine

A patient with a known spinal epidural abscess at L4-L5 presents with fever and progressive lower extremity weakness. Blood cultures are negative. What is the most critical next step?

. Repeat blood cultures in 24 hours
. Start empiric broad-spectrum IV antibiotics
. Order a CT-guided biopsy of the abscess
. Proceed to urgent surgical decompression and debridement
. Initiate a pain management regimen

Correct Answer & Explanation

. Proceed to urgent surgical decompression and debridement

Explanation

The most critical factor here is the 'progressive lower extremity weakness,' indicating neurological deterioration due to cord or cauda equina compression. This necessitates urgent surgical decompression and debridement to prevent irreversible neurological damage, regardless of culture results. While obtaining cultures and starting antibiotics are generally important, the immediate priority in the face of neurological decline is mechanical decompression. A CT-guided biopsy would delay definitive treatment for a known abscess with progressive symptoms.

Question 6690

Topic: 6. Spine

What is the primary mechanism by which spinal epidural abscesses lead to neurological deficits?

. Direct neural invasion by bacteria
. Systemic toxicity from bacterial endotoxins
. Spinal cord compression and associated ischemia
. Electrolyte imbalances causing neuronal dysfunction
. Direct demyelination of nerve fibers

Correct Answer & Explanation

. Spinal cord compression and associated ischemia

Explanation

The primary mechanism by which spinal epidural abscesses cause neurological deficits is direct mechanical compression of the spinal cord or cauda equina, often compounded by ischemia due to compromise of the vascular supply (e.g., radicular arteries, anterior spinal artery) by the expanding abscess and surrounding inflammation. While bacterial toxins may contribute to inflammation, they are not the main cause of acute mechanical deficit. Direct neural invasion or demyelination are not primary mechanisms of typical pyogenic SEA.

Question 6691

Topic: 6. Spine

A 70-year-old patient with rheumatoid arthritis on immunosuppressive therapy develops a cervical epidural abscess. The causative organism is identified as Aspergillus fumigatus. What is the most appropriate long-term management strategy?

. Oral antibiotics for 6 weeks
. Systemic antifungal therapy for several months, often with surgical debridement
. Immediate surgical fusion without decompression
. Discontinue all medications and observe
. Short course of high-dose corticosteroids

Correct Answer & Explanation

. Systemic antifungal therapy for several months, often with surgical debridement

Explanation

Fungal spinal infections, particularly in immunocompromised patients, are notoriously difficult to treat. Management typically involves aggressive surgical debridement of infected tissue and bone, along with prolonged courses (often several months to a year) of systemic antifungal therapy (e.g., voriconazole, amphotericin B). Oral antibiotics are ineffective for fungal infections. Surgical fusion might be part of stabilization if needed, but not without decompression and debridement. Discontinuation of medications or short-course steroids are inappropriate and potentially harmful.

Question 6692

Topic: 6. Spine

Which factor is most likely to predispose a patient to developing a spinal epidural abscess via direct extension?

. Intravenous drug use
. Recent dental procedure
. Untreated urinary tract infection
. Vertebral osteomyelitis
. Remote skin boil (furuncle)

Correct Answer & Explanation

. Vertebral osteomyelitis

Explanation

Vertebral osteomyelitis is the most common predisposing factor for spinal epidural abscess via direct extension, where the infection erodes through the vertebral body and into the epidural space. Intravenous drug use, recent dental procedures, untreated urinary tract infections, and remote skin boils are all common sources ofhematogenous spreadof infection to the spine and epidural space, but not direct extension.

Question 6693

Topic: 6. Spine

What is the primary concern when performing a lumbar puncture in a patient with suspected spinal epidural abscess?

. Risk of introducing new infection
. Difficulty in obtaining CSF due to inflammation
. Risk of iatrogenic neurological deterioration (e.g., herniation)
. Misinterpretation of CSF findings due to parameningeal inflammation
. High cost of the procedure

Correct Answer & Explanation

. Risk of iatrogenic neurological deterioration (e.g., herniation)

Explanation

The primary concern when performing a lumbar puncture in a patient with suspected spinal epidural abscess is the risk of iatrogenic neurological deterioration. If there is significant mass effect from the abscess, a lumbar puncture can alter pressure gradients, potentially leading to upward or downward herniation of the spinal cord or cerebellum, or worsening neurological deficits. While introducing new infection is a general risk for any invasive procedure, and CSF findings can be misleading, acute neurological compromise is the most critical and specific contraindication.

Question 6694

Topic: 6. Spine

A patient with a lumbar epidural abscess has positive blood cultures for Gram-negative rods (later identified as E. coli). What empiric antibiotic component would typically be most appropriate to add to Vancomycin to cover this pathogen?

. Penicillin G
. Clindamycin
. Ceftriaxone
. Doxycycline
. Linezolid

Correct Answer & Explanation

. Ceftriaxone

Explanation

For empiric coverage of Gram-negative rods like E. coli in a spinal epidural abscess, a broad-spectrum Gram-negative agent is needed. Ceftriaxone (a third-generation cephalosporin) is an excellent choice for its activity against common Gram-negative enteric bacteria and good CNS penetration. Penicillin G, Clindamycin, and Linezolid lack sufficient Gram-negative coverage. Doxycycline has some Gram-negative activity but is not typically first-line for serious E. coli infections.

Question 6695

Topic: 6. Spine

In an anterior cervical discectomy and fusion (ACDF) for cervical epidural abscess, what is the primary goal of the interbody graft or cage placement?

. To provide immediate stabilization and restore spinal alignment
. To deliver local antibiotics directly to the infection site
. To prevent dural tears during decompression
. To facilitate a posterior fusion later
. To reduce post-operative pain only

Correct Answer & Explanation

. To provide immediate stabilization and restore spinal alignment

Explanation

After debridement of infected disc and bone in an ACDF for cervical epidural abscess, an interbody graft or cage (often packed with autograft/allograft or sometimes antibiotic-impregnated material) is placed to provide immediate mechanical stability to the decompressed segment and restore cervical lordosis/alignment. This helps prevent kyphotic deformity and further neural compression. While local antibiotics might be used, the primary biomechanical role is stabilization. It does not primarily prevent dural tears or solely reduce pain, and is not necessarily to facilitate a later posterior fusion unless indicated.

Question 6696

Topic: 6. Spine

What is the typical inflammatory cell profile found in the CSF of a patient with a bacterial spinal epidural abscess (if a lumbar puncture were safely performed)?

. Lymphocytic pleocytosis with normal protein and glucose
. Neutrophilic pleocytosis with elevated protein and normal glucose
. Neutrophilic pleocytosis with elevated protein and low glucose
. Eosinophilic pleocytosis with high protein
. Acellular CSF with normal parameters

Correct Answer & Explanation

. Neutrophilic pleocytosis with elevated protein and normal glucose

Explanation

If a lumbar puncture were safely performed in a patient with a bacterial spinal epidural abscess (which is usually avoided), the CSF findings would typically show a neutrophilic pleocytosis (increased white blood cells, predominantly neutrophils) and elevated protein levels due to inflammation and leakage of plasma proteins into the CSF. Glucose levels are typically normal or mildly reduced, but usually not as profoundly low as seen in bacterial meningitis, as the infection is primarily epidural rather than leptomeningeal. Lymphocytic or eosinophilic pleocytosis are atypical for pyogenic bacterial SEA. Acellular CSF would be normal.

Question 6697

Topic: 6. Spine

A patient is undergoing surgical decompression for a L1-L2 epidural abscess. During surgery, significant purulent material is evacuated. What is the most appropriate next step in terms of surgical closure and drains?

. Primary closure of the wound without a drain
. Placement of a closed suction drain (e.g., Jackson-Pratt) prior to closure
. Packing the wound open and delayed primary closure
. Irrigation with antibiotic solution and primary closure without a drain
. Placement of a Penrose drain

Correct Answer & Explanation

. Placement of a closed suction drain (e.g., Jackson-Pratt) prior to closure

Explanation

After evacuating purulent material from a spinal epidural abscess, placement of a closed suction drain (e.g., Jackson-Pratt) is generally recommended prior to closure. This helps to evacuate any residual pus, serum, or blood, reducing dead space and minimizing the risk of hematoma or seroma formation, which can act as a nidus for recurrent infection. Primary closure without a drain, packing the wound open, or using a Penrose drain are less ideal for a deep spinal wound with a significant infection burden. Irrigation alone may not be sufficient for continued drainage.

Question 6698

Topic: 6. Spine

In cases where cervical radiculopathy (C6/C7) mimics lateral epicondylitis, which of the following findings would be most indicative of a cervical origin?

. Pain with resisted wrist extension.
. Point tenderness over the lateral epicondyle.
. Positive Spurling's test (neck compression/rotation).
. Normal neurological exam of the upper extremity.
. Pain relief with a counterforce brace.

Correct Answer & Explanation

. Positive Spurling's test (neck compression/rotation).

Explanation

A positive Spurling's test, which reproduces radicular symptoms by extending, rotating, and laterally flexing the neck while applying axial compression, is highly indicative of cervical nerve root irritation and would strongly suggest a cervical origin for the pain. While pain with resisted wrist extension and lateral epicondyle tenderness can be present with referred pain from the neck, a specific neck provocative test is key. A normal neurological exam would make radiculopathy less likely, but subtle changes may exist. Pain relief with a counterforce brace would typically point to elbow pathology.

Question 6699

Topic: 6. Spine

For a patient with symptomatic L5-S1 isthmic spondylolisthesis (Grade II) and significant L5 radiculopathy, what is the primary goal of posterior decompression?

. To reduce the vertebral slip
. To stabilize the segment and prevent further slippage
. To relieve compression on the exiting L5 and/or traversing S1 nerve root
. To correct sagittal balance of the lumbar spine
. To improve hamstring flexibility

Correct Answer & Explanation

. To relieve compression on the exiting L5 and/or traversing S1 nerve root

Explanation

The primary goal of decompression in the setting of radiculopathy is to relieve the neural element compression. In L5-S1 isthmic spondylolisthesis, the exiting L5 nerve root can be compressed by the pars defect, pedicle, or scar tissue in the foramen, and the traversing S1 nerve root can be compressed by the slipped superior vertebral body or disc. While fusion stabilizes and can indirectly help, decompression specifically targets the neural impingement.

Question 6700

Topic: Thoracolumbar Spine & Deformity

Which factor is most strongly associated with progression of a low-grade (Grade I or II) spondylolisthesis in children?

. Presence of sacral dome rounding
. Age greater than 15 years
. Female gender
. Participation in non-contact sports
. Development of hamstring tightness

Correct Answer & Explanation

. Presence of sacral dome rounding

Explanation

Sacral dome rounding (or dome-shaped sacrum) is a key morphological risk factor associated with the progression of spondylolisthesis, especially in the setting of Type I dysplastic slips, as it indicates a less stable articulation. While hamstring tightness is a symptom, and other factors may play minor roles, sacral morphology is a strong radiological predictor of progression.

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