What condition is characterized by inflammation and demyelination of the peripheral nervous system, presenting with symmetric ascending muscle weakness?

Guillain-Barré Syndrome (GBS) is indeed the condition characterized by inflammation and demyelination of the peripheral nervous system, which typically leads to symmetric ascending muscle weakness. The syndrome often follows an infectious illness, where the immune system mistakenly attacks the peripheral nerves after being triggered by a preceding viral or bacterial infection. Patients commonly experience weakness that starts in the lower limbs and ascends toward the upper body, sometimes accompanied by sensory changes.

The hallmark feature of GBS is its rapid progression, and while muscle weakness is a primary symptom, patients may also have reflex changes and, in severe cases, respiratory muscle involvement, necessitating close monitoring and management. The immunological nature of this condition is distinctive and differentiates it from other neuromuscular disorders, such as myasthenia gravis, which primarily affects neuromuscular transmission and presents differently.

Multiple sclerosis, on the other hand, is primarily a central nervous system disorder that affects myelin in the brain and spinal cord rather than the peripheral nerves, leading to a different symptom profile. Peripheral neuropathy generally describes a broad range of conditions affecting peripheral nerves but does not specifically denote the acute inflammatory and ascending weakness seen in Guillain-Barré Syndrome.

This characteristic presentation