Differential Diagnosis for Conus Medullaris Syndrome

The clinical findings provided suggest a condition affecting the conus medullaris, the lowermost part of the spinal cord. The differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis

  • Bilateral lower extremity weakness and paresthesia, impotence, urinary incontinence: This combination of symptoms is highly suggestive of conus medullaris syndrome due to the involvement of both motor and sensory functions of the lower extremities, along with autonomic functions such as bladder control and sexual function.

• Other Likely Diagnoses

  • Decreased patellar reflexes, saddle anesthesia, urinary retention: These symptoms can also be seen in cauda equina syndrome, which affects the nerve roots below the conus medullaris. The distinction between conus medullaris and cauda equina syndromes can sometimes be challenging, but the presence of saddle anesthesia and early urinary retention might lean more towards cauda equina syndrome.
  • Fever, gradually progressive back pain, lower extremity radiculopathy: This presentation could suggest an infectious or inflammatory process affecting the spinal cord or nerve roots, such as spinal epidural abscess or transverse myelitis, which could mimic or lead to conus medullaris syndrome.

• Do Not Miss Diagnoses

  • Spinal epidural abscess: This is a medical emergency that requires prompt diagnosis and treatment. Symptoms can include back pain, fever, and progressive neurological deficits.
  • Spinal cord infarction: Although less common, spinal cord infarction can present with sudden onset of neurological deficits and back pain, mimicking conus medullaris syndrome.
  • Traumatic spinal injury: Especially in the context of recent trauma, it's crucial to consider spinal injuries that could lead to conus medullaris syndrome or other spinal cord injuries.

• Rare Diagnoses

  • Tumors (e.g., ependymoma, astrocytoma) affecting the conus medullaris: These can cause gradual onset of symptoms due to compression of the spinal cord.
  • Vascular malformations (e.g., arteriovenous malformations): These can cause a variety of symptoms depending on their location and the structures they affect, including conus medullaris syndrome.
  • Inflammatory conditions (e.g., multiple sclerosis, neuromyelitis optica): While these conditions more commonly affect other parts of the central nervous system, they can occasionally present with symptoms suggestive of conus medullaris syndrome.