Orthopaedics & MSK Practice Questions

Q: A 45-year-old man presents with acute severe lower back pain and leg weakness. MRI shows large central disc herniation with cauda equina compression. What is the surgical urgency?

Emergency (hours). ***Emergency (hours)***- **Cauda Equina Syndrome (CES)** caused by acute central disc herniation requires immediate surgical decompression, ideally within **6 to 24 hours**, to maximize the chances of recovering full **neurological function**.- Delaying intervention significantly increases the risk of permanent disabling deficits, particularly **bladder and bowel incontinence** and **irreversible muscle weakness**.*Elective (weeks)*- Elective scheduling is appropriate only for stable conditions or those where chronic pain management is the primary goal, not for acute **nerve root compression syndromes**.- Delaying care by weeks in a confirmed CES case guarantees a poor prognosis regarding **sphincter and motor function**.*Urgent (days)*- While CES is highly urgent, characterizing it over *days* risks missing the critical window for decompression; the condition deteriorates rapidly.- Intervention for CES must be initiated immediately upon diagnosis (within **hours**), differentiating it from conditions that can safely wait 24–72 hours.*No surgery needed*- A mass lesion (large central disc herniation) causing acute **cauda equina compression** will not resolve adequately through conservative management alone.- Surgery is necessary to mechanically relieve the pressure on the nerve roots and prevent **permanent paralysis and sensory loss**.*Depends on symptoms*- The provided clinical presentation (acute severe low back pain and **leg weakness**) already suggests significant neurological compromise.- The combination of symptoms and the confirmed **cauda equina compression** on MRI elevates this to a non-negotiable surgical emergency, regardless of the precise degree of **sphincter dysfunction** at presentation.

Q: A 24-year-old man presents with acute onset severe lower back pain and bilateral leg weakness. He has urinary retention and saddle anesthesia. What is the time frame for surgical intervention?

Within 24-48 hours. ***Within 24–48 hours*** - This clinical presentation (severe low back pain, bilateral weakness, urinary retention, and **saddle anesthesia**) defines **Cauda Equina Syndrome (CES)**, a true neurosurgical emergency. - Urgent **surgical decompression** performed within the **24–48 hour** window is critical to maximize the likelihood of recovery, especially of fragile **bladder and bowel function**. *Within 6 hours* - While immediate intervention is ideal and preferred, **6 hours** is often an unfeasible or highly strict cutoff given the variability in symptom presentation and necessary preparatory steps (MRI, planning). - The key critical window recognized for achieving maximal recovery after diagnosis of **CES** spans up to 48 hours. *Within 1 week* - Delaying surgical decompression past the 48-hour mark dramatically increases the risk of **irreversible neurological injury**, particularly to the **sacral roots** controlling continence. - This timeframe is too slow for an acute compressive syndrome that leads to potential permanent **paralysis** and disability. *Within 1 month* - A delay of one month ensures **permanent neurological deficits**, including irreversible loss of motor function and **bladder/bowel control**. - This time frame is irrelevant to the management of an acute, progressive **cauda equina compression**. *No time limit* - **Cauda Equina Syndrome** is an urgent condition where prolonged compression results in direct **ischemic injury** and necrosis of the spinal nerve roots. - Lack of timely decompression guarantees poor long-term outcome and **permanent functional disability**, thus a time limit is essential.

Q: A 72-year-old man presents with confusion and agitation 3 days after hip surgery. He sees people who aren't there and is disoriented to time and place. What is the most likely diagnosis?

Postoperative delirium. ***Postoperative delirium*** - This diagnosis perfectly fits the clinical picture: an acute onset of confusion, agitation, and **visual hallucinations** (seeing people who aren't there) in an elderly patient following a major stressor like hip surgery. - Delirium is an **acute, fluctuating disturbance** of attention and cognition, and advanced age combined with recent surgery is the most common risk factor for the postoperative subtype.*Dementia* - Dementia is characterized by a **chronic, progressive decline** in memory and other cognitive domains, which is inconsistent with the acute change observed over 3 days. - While individuals with pre-existing dementia are at high risk for delirium, the acute change itself is defined as **superimposed delirium**, not just dementia.*Alcohol withdrawal* - This diagnosis (especially **delirium tremens**) can cause agitation and prominent visual or tactile hallucinations, but it requires a history of **heavy chronic alcohol use** which is not specified. - Symptoms typically peak 48–96 hours after cessation, and while the timing is plausible, the recent major surgery provides a more direct and common cause for the observed presentation in the absence of a known history of substance abuse.*Depression* - Depression presents with mood disturbances, anhedonia, and vegetative symptoms, but it does **not cause acute, global disorientation** or **frank visual hallucinations**. - Although severe depression can cause cognitive slowing (**pseudodementia**), it lacks the acute-onset, hyperactive agitated state frequently seen in delirium.*Anxiety* - Anxiety is characterized by excessive worry, tension, and autonomic symptoms, but it does **not cause acute disorientation** to time and place or complex **visual hallucinations**. - The patient's confusion and disorientation indicate a global disturbance of cortical function, which is not characteristic of primary anxiety disorders.

Q: A 25-year-old man presents with acute onset severe lower back pain radiating down his left leg to the foot. He has difficulty walking and reports numbness in his left foot. Straight leg raise test is positive at 30 degrees. What is the most likely diagnosis?

Lumbar disc herniation. ***Lumbar disc herniation*** - The presentation of **acute onset severe lower back pain** radiating down the left leg to the foot, along with **numbness in the left foot** and difficulty walking, are classic signs of nerve root compression. - A **positive straight leg raise test at 30 degrees** is a strong indicator of nerve root irritation, highly suggestive of lumbar disc herniation. *Mechanical back pain* - **Mechanical back pain** is typically localized axial pain, aggravated by movement, and **does not cause radicular symptoms** or objective neurological deficits such as foot numbness or weakness. - This diagnosis would not explain the **positive straight leg raise test** or the specific neurological symptoms in the left leg and foot. *Spinal stenosis* - **Spinal stenosis** usually affects older patients, presenting with **neurogenic claudication** (leg pain relieved by sitting or forward flexion) rather than acute, severe unilateral radiculopathy in a 25-year-old. - The onset is typically insidious and chronic, not acute, and it often involves bilateral leg symptoms. *Cauda equina syndrome* - **Cauda equina syndrome** is a serious emergency characterized by **saddle anesthesia**, **bowel or bladder dysfunction** (e.g., urinary retention), and often bilateral leg weakness, none of which are reported here. - While it can cause severe lower back pain and leg symptoms, the absence of these hallmark

Question 1

A 29-year-old man presents with acute onset severe lower back pain and bilateral leg weakness after heavy lifting. He has saddle anesthesia and urinary retention. MRI shows central disc herniation at L4-L5. What is the expected outcome with prompt treatment?

Accepted Answer

Variable outcome depending on delay

Answer

Complete recovery in all cases

Answer

Good functional recovery in most cases

Answer

Poor prognosis regardless of treatment

Answer

Recovery limited to bladder function

Question 2

A 45-year-old man presents with acute severe lower back pain and leg weakness. MRI shows large central disc herniation with cauda equina compression. What is the surgical urgency?

Accepted Answer

Emergency (hours)

Answer

Elective (weeks)

Answer

Urgent (days)

Answer

No surgery needed

Answer

Depends on symptoms

Question 3

A 24-year-old man presents with acute onset severe lower back pain and bilateral leg weakness. He has urinary retention and saddle anesthesia. What is the time frame for surgical intervention?

Accepted Answer

Within 24-48 hours

Answer

Within 6 hours

Answer

Within 1 week

Answer

Within 1 month

Answer

No time limit

Question 4

A 72-year-old man presents with confusion and agitation 3 days after hip surgery. He sees people who aren't there and is disoriented to time and place. What is the most likely diagnosis?

Accepted Answer

Postoperative delirium

Answer

Dementia

Answer

Alcohol withdrawal

Answer

Depression

Answer

Anxiety

Question 5

A 25-year-old man presents with acute onset severe lower back pain radiating down his left leg to the foot. He has difficulty walking and reports numbness in his left foot. Straight leg raise test is positive at 30 degrees. What is the most likely diagnosis?

Accepted Answer

Lumbar disc herniation

Answer

Mechanical back pain

Answer

Spinal stenosis

Answer

Cauda equina syndrome

Answer

Ankylosing spondylitis

Orthopaedics & MSK — MCQs

Orthopaedics & MSK — MCQs

On this page

Practice by Chapter

Want unlimited practice?