Multiple Sclerosis (MS): Given the patient's presentation of bilateral lower extremity numbness and a history of anxiety, MS is a plausible diagnosis. MS is known for its unpredictable course and can present with a wide range of neurological symptoms, including numbness, weakness, and cognitive difficulties. The patient's scheduled MRI will be crucial in confirming this diagnosis by identifying any demyelinating lesions in the central nervous system.

Peripheral Neuropathy: This condition can cause numbness in the lower extremities due to damage to the peripheral nerves. It has various causes, including diabetes, vitamin deficiencies, and alcohol abuse. The patient's history and further diagnostic tests (like blood work) will help determine if this is a likely cause.
Lumbar Spinal Stenosis: This condition involves narrowing of the spinal canal in the lower back, which can compress the spinal cord or nerves, leading to numbness, weakness, or pain in the legs. Given the bilateral nature of the symptoms, this could be a consideration, especially if the patient has a history of back problems or degenerative changes.
Vitamin B12 Deficiency: A deficiency in vitamin B12 can lead to neurological symptoms, including numbness or tingling in the hands and feet. This is an important consideration given its potential for treatment with supplementation.

Spinal Cord Compression: This is a medical emergency that requires immediate attention. Causes can include trauma, tumors, or abscesses. The patient's symptoms of bilateral lower extremity numbness could be indicative of spinal cord compression, especially if there's associated back pain, weakness, or bowel/bladder dysfunction.
Guillain-Barré Syndrome: An autoimmune disorder where the body's immune system mistakenly attacks part of its peripheral nervous system, leading to muscle weakness, and sometimes paralysis, among other symptoms. It can present with ascending numbness or weakness, starting in the lower extremities.
Cauda Equina Syndrome: Another medical emergency, this condition occurs when the nerves in the spinal canal are compressed, leading to low back pain, numbness in the legs, and potentially bowel and bladder dysfunction. Prompt diagnosis and treatment are crucial to prevent long-term damage.

Neurosyphilis: A complication of untreated syphilis infection, which can cause a wide range of neurological symptoms, including numbness, personality changes, and difficulty with muscle coordination. Although rare, it's an important consideration in patients with risk factors for sexually transmitted infections.
Tangier Disease: A rare inherited disorder characterized by significantly low levels of high-density lipoprotein (HDL) cholesterol. It can lead to peripheral neuropathy among other symptoms, presenting as numbness or tingling in the extremities.
Leukodystrophies: A group of rare, genetic disorders characterized by the progressive degeneration of the white matter in the brain due to defects in the growth or maintenance of the myelin sheath. These conditions can present with a variety of neurological symptoms, including numbness or weakness in the lower extremities, though they are more commonly associated with cognitive and upper motor neuron signs.