Differential Diagnosis

• Single most likely diagnosis
  • Spinal epidural abscess: Given the patient's recent history of spinal surgery (cervicothoracic decompression and fusion, and laminectomy for resection of epidural mass infection), the development of upper back pain, progressive weakness, and numbness in the legs, along with systemic symptoms such as sweating and chills, strongly suggests a spinal epidural abscess. The patient's history of IV drug abuse also increases the risk for infectious complications.
• Other Likely diagnoses
  • Spinal cord compression or injury: The patient's history of neurogenic bladder, recent spinal surgeries, and progressive neurological deficits (weakness, numbness) could be indicative of spinal cord compression or injury, potentially due to a complication from the recent surgeries or a new injury.
  • Discitis or osteomyelitis: Infection of the intervertebral disc (discitis) or vertebral body (osteomyelitis) could explain the patient's back pain, systemic symptoms, and neurological deficits, especially given the recent surgical interventions and history of IV drug use.
  • Metastatic spinal cord compression: Although less likely given the acute presentation and recent surgeries, metastatic disease to the spine could cause cord compression, especially in the context of weight loss and a history of substance abuse, which might be associated with other health issues.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Spinal hematoma: A collection of blood in the spinal canal could compress the spinal cord, leading to neurological deficits. This is a medical emergency requiring immediate intervention.
  • Cauda equina syndrome: A condition where the nerves in the spinal canal are compressed, leading to loss of bladder and bowel control, among other symptoms. Prompt recognition and treatment are crucial to prevent permanent damage.
  • Meningitis: Infection of the meninges, the protective membranes covering the brain and spinal cord, could present with back pain, fever, and neurological symptoms. It is a medical emergency.
• Rare diagnoses
  • Spinal arachnoiditis: Inflammation of the arachnoid membrane surrounding the spinal cord could cause pain, numbness, and weakness, but it is less common and might not fully explain the acute progression and systemic symptoms in this case.
  • Neuromyelitis optica: An autoimmune condition affecting the spinal cord and optic nerves, which could explain some of the patient's symptoms, including eye pain and neurological deficits, but it is relatively rare and would not account for all aspects of the presentation.