An 18-year-old male presented with acute onset descending paralysis of 3 days duration. There is also history of blurring of vision for the same duration. On examination, the patient has quadriparesis with areflexia. Both the pupils are non-reactive. The most probably diagnosis is:

**Core Concept**
The patient's presentation suggests a severe neuromuscular disorder characterized by acute onset descending paralysis, areflexia, and non-reactive pupils, indicating a disruption in the normal transmission of nerve impulses.

**Why the Correct Answer is Right**
The patient's symptoms are consistent with a diagnosis of **Guillain-Barré Syndrome (GBS)**, a post-infectious autoimmune disorder where the body's immune system mistakenly attacks the myelin sheath surrounding nerve fibers, leading to demyelination and disruption of nerve conduction. The involvement of cranial nerves, as evidenced by the non-reactive pupils, suggests a more widespread involvement of the peripheral nervous system. The descending pattern of paralysis and areflexia are also characteristic features of GBS.

**Why Each Wrong Option is Incorrect**
**Option A:** **Rabies** typically presents with ascending paralysis, fever, and hydrophobia, which are not seen in this patient.

**Option B:** **Botulism** causes descending paralysis but is characterized by bilateral descending flaccid paralysis with preserved deep tendon reflexes and pupillary reactions, which are in contrast to the patient's presentation.

**Option C:** **Myasthenia Gravis** is an autoimmune disorder that affects the neuromuscular junction, leading to muscle weakness and fatigue, but it does not typically present with areflexia or non-reactive pupils.

**Clinical Pearl / High-Yield Fact**
GBS is a medical emergency that requires prompt recognition and treatment to prevent long-term disability.

**Correct Answer:** C.

✓ Correct Answer: B. Botulism