Archive Of Standardized Exam Questions: Caudal Equina Syndrome


This page is dedicated to organizing various examples of standardized exam questions whose topic is cauda equina syndrome. While this may seem a odd practice, it is useful to see multiple examples of how cauda equina syndrome will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a traditional question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a topic is quite valuable.


When it comes to standardized exams, each topic has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for cauda equina syndrome

Chief Complaints:

  • Lower back pain that can travel down the back of the legs.
  • Recent falls due to decreased strength/sensation
  • Pain/paresthesia in saddle region
  • Urinary issues: can be difficulty initiating urination or urinary incontinence

Clinical Workup:

  • Loss of reflexes in the knees/ankles
    • Loss of perianal sensation
    • Loss of anal reflex/anal wink
    • Loss of anal tone

Question # 1

A 55 year old male comes to the hospital because he has been experiencing severe lower back pain. He explains that the pains tarted about 3 weeks ago, and he denies any type of trauma. He is very upset because the pain has been keeping him up at night, and he feels very tired. The pain has been worsening over the past few days, and has not been getting better with over the counter medications. This patient’s past medical history is not notable for any allergies or chronic conditions. He denies using any illicit drugs. Vital signs are all with thin reference fang, and a physical exam reveals that the patient has tenderness in the lower back with flexing of the back and raising of his legs. Pinprick with a cotton swab in the perianal region does not cause contraction of the anal sphincter. What is the likely diagnosis in this patient?

Explanation # 1

Lower back pain + loss of anal reflex/anal wink = cauda equina syndrome

Question # 2

A 66 year old male comes to the ER with a stabbing pain in his back that travels down the back of his legs. He has been having issues with recent falls these past few weeks. Recently he has been having issues with initiating urination, and has paresthesias/pains in this saddle region. He was diagnosed with prostate cancer a two years ago, and was treated with radiation therapy. A physical exam is notable for lower extremity weakness, and absent knee/ankle reflexes bilaterally. Sensations are decreased in the lower extremities, and the patient has decreased anal tone noted on a rectal exam. What is the likely diagnosis in this patient?

Explanation # 2

Back pain (travels down legs) + recent falls + urinary issues + paresthesias/pains in this saddle region + decreased anal tone = cauda equina syndrome

Question # 3

A 55 year old male has low back pain that radiates down his left buttock and the posterior thigh to his knee after he lifted heavy boxes at work about 15 hours ago. He has been having urinary incontinence since this event. His ankle reflex is absent on the left side, and he has decreased pinprick sensation in the perianal region. Straight-leg raises causes a increase ein pain in the leg and posterior thigh. What is the likely cause of this patient’s symptoms?

Explanation # 3

Back pain (travels down leg) +  urinary issues + loss of perianal sensation = cauda equina syndrome

Question # 4

A 35 year old woman with metastatic breast cancer is borough to the emergency room after she has a 10 hour history of severe pelvic pain and numbness. She has not been able to urinate for the past day. Her only prescribed mediation as of now is hydrocodone. A rectal exam shows decreased anal tone, and the patient’s muscle strength is diminished in her lower extremities. Sensation to light touch is decreased in a saddle distribution, and an abdominal exam reveals distention in the lower abdomen. A urinary catheter is placed and 900 mL of urine is drained, and relieves the patient’s pelvic pain, but not her numbness. What is the likely diagnose sin this patient?

Explanation # 4

Urinary issues + decreased anal tone + loss of sensation in saddle distribution = cauda equina syndrome


Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:


  • Compression of the spinal nerve roots 


  • First step is IV administration of steroids such as high dose dexamethoasone to decrease inflammation in the area.
  • Long term treatment will be surgery


Page Updated: 10.07.2017