Differential Diagnosis for Severe Pain in Sacrum with Chin to Chest Motion or Straight Leg Raise

• Single most likely diagnosis
  • Lumbar Disc Herniation: This condition is the most likely cause of severe pain in the sacrum that worsens with chin to chest motion or straight leg raise. The pain is typically radicular, meaning it follows the path of a nerve, and these maneuvers can exacerbate the compression of the nerve root, leading to increased pain.
• Other Likely diagnoses
  • Spondylolisthesis: This condition, where one vertebra slips forward over the one below it, can cause severe pain in the lower back and sacrum, especially with movements that increase the slippage, such as straight leg raise.
  • Sacroiliac Joint Dysfunction: The sacroiliac joints connect the sacrum to the ilium bones of the pelvis. Dysfunction in these joints can cause pain in the sacrum that may worsen with certain movements, including those that involve bending forward or lifting the leg.
  • Piriformis Syndrome: The piriformis muscle runs from the base of the spine to the thighbone, and when it compresses or irritates the sciatic nerve, it can cause pain in the sacrum and buttock that may radiate down the leg, worsening with straight leg raise.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cauda Equina Syndrome: A serious condition that occurs when the nerves in the spinal canal are compressed, leading to loss of bladder and bowel control, among other symptoms. Severe pain in the sacrum with radicular symptoms and worsening with straight leg raise or other maneuvers could be indicative of this condition.
  • Spinal Epidural Abscess: An infection that forms in the space between the bones of the spine and the outer membrane covering the spinal cord, which can compress the spinal cord and nerves, leading to severe pain, neurological deficits, and potentially life-threatening complications if not promptly treated.
• Rare diagnoses
  • Tarlov Cysts: Abnormal fluid-filled sacs that can form on the nerve roots in the sacrum, which can cause pain, especially with certain movements.
  • Sacral Stress Fracture: A fracture in one of the sacral bones, which can occur due to repetitive stress or osteoporosis, leading to severe pain in the sacrum that may worsen with movement.