Differential Diagnosis

• Single most likely diagnosis
  • Lumbar Disc Herniation: This condition is likely given the symptoms of numbness, pain with extension, and the duration of 3 months. The fact that it's only on the left leg and there's no sciatic pain or scoliosis doesn't rule out a disc herniation, as symptoms can vary widely.
• Other Likely diagnoses
  • Lumbar Spondylosis: This condition involves wear and tear on the spine and can cause pain with extension, numbness, and is more common in older adults.
  • Piriformis Syndrome: Although typically associated with sciatic pain, piriformis syndrome can cause numbness and pain in the leg without sciatica, especially if the piriformis muscle is compressing a nerve branch.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Cauda Equina Syndrome: A serious condition that requires immediate medical attention, characterized by numbness in the legs, loss of bladder or bowel control, and potentially severe back pain. Although the patient doesn't report other typical symptoms, any suspicion of cauda equina syndrome warrants urgent investigation.
  • Spinal Tumor or Metastasis: Although rare, a tumor in the spine could cause localized pain, numbness, and could be deadly if not diagnosed and treated promptly.
• Rare diagnoses
  • Peripheral Neuropathy: Could cause numbness but typically would be more widespread or have other systemic symptoms.
  • Osteoid Osteoma: A benign bone tumor that could cause nocturnal pain and might fit some of the patient's symptoms, though it's less common and usually presents with more localized pain that is worse at night.