Lumbar Radiculopathy or Cauda Equina Syndrome: Given the history of bulging disc and the progression of symptoms including back pain described as a "hot poker," trouble walking, falling, and recent clumsiness, this diagnosis is highly plausible. The pain in the thoracic region and the specific mention of a "hot poker" pain could indicate nerve root irritation or compression, which is consistent with lumbar radiculopathy. However, the increasing clumsiness and difficulty walking suggest a possible progression to cauda equina syndrome, which is a medical emergency.

Musculoskeletal Injury: The recent fall and injury to the left knee could be contributing to her current condition, potentially exacerbating existing back issues or causing new musculoskeletal problems.
Chronic Back Pain with Acute Exacerbation: Given her history of bulging discs, it's possible that she's experiencing an acute exacerbation of chronic back pain, which could be contributing to her clumsiness and difficulty walking.
Peripheral Neuropathy: Although less common in a 32-year-old without a clear risk factor like diabetes, peripheral neuropathy could explain some of her symptoms, including pain and clumsiness.

Spinal Cord Compression: This is a medical emergency that could explain her progressive weakness, clumsiness, and difficulty walking. Prompt diagnosis and treatment are crucial to prevent permanent damage.
Multiple Sclerosis: Although the age and sex of the patient make this a possibility, the acute onset of symptoms and the specific nature of the pain make it less likely. However, MS can present with a wide range of neurological symptoms, including pain, weakness, and clumsiness.
Spinal Infection (e.g., Abscess or Osteomyelitis): Infections of the spine can cause severe back pain, neurological deficits, and systemic symptoms. Given the severity of her symptoms and the potential for serious complications, this diagnosis must be considered.

Arachnoiditis: A rare condition characterized by inflammation of the arachnoid membrane, which can cause severe back and leg pain, as well as neurological symptoms. It's often associated with previous spinal surgery or infection.
Syringomyelia: A disorder in which a fluid-filled cavity forms within the spinal cord, leading to pain, weakness, and loss of reflexes. It's a rare condition but could explain some of her neurological symptoms.
Tumors (Spinal or Intracranial): Although rare, tumors affecting the spine or brain could cause a variety of neurological symptoms, including pain, weakness, and clumsiness. Given the potential severity of this diagnosis, it must be considered in the differential diagnosis.