An 18-year-old male presented with acute onset descending paralysis of 3 days duration. There is also a 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 probable diagnosis is -

Botulism is caused by neurotoxins of Clostridium botulinum, which are extremely potent & cause disease after ingestion of even picogram amounts. Its classical form is an acute onset of bilateral cranial neuropathies associated with symmetric descending weakness.The toxin causes predominantly bulbar & ocular palsies(difficulty in swallowing ,blurred or double vision ,ptosis),progressive to limb weakness & respiratory paralysis . Reference Harrison20th edition pg 1027