Question

A patient admitted with acute organophosphorous insecticide poisoning develops ptosis, inability to lift the head and difficulty in breathing on the third day. The most likely diagnosis is

• A. hypokalemia
• B. inflammatory polyneuropathy
• C. intermediate syndrome
• D. polymyositis

Hint:

Weakness of the neck, eyelids, and breathing muscles 1 to 4 days after organophosphorus poisoning has a specific name.

Answer 1

The Correct Option is C

Step 1: Understanding the Question.
A patient with organophosphorus poisoning develops drooping eyelids (ptosis), weak neck muscles that cannot lift the head, and breathing trouble, and this happens on the third day, not right at the start. We need the name for this delayed weakness.

Step 2: Key Concept: the three phases of organophosphorus poisoning.
Organophosphorus poisoning has three recognised phases. The acute cholinergic phase happens in the first few hours, with excess secretions, small pupils, vomiting and a slow heart rate, from too much acetylcholine. If this settles, a second phase called the intermediate syndrome can appear about 24 to 96 hours after exposure. A much later, rare phase called organophosphate induced delayed polyneuropathy can occur after 2 to 3 weeks.

Step 3: Why this fits intermediate syndrome.
Intermediate syndrome affects proximal limb muscles, neck flexors and the muscles of respiration and eye opening, so it causes exactly this pattern: ptosis, a head that cannot be lifted off the pillow (neck flexor weakness), and breathing difficulty from weak respiratory muscles. It typically shows up between one and four days after poisoning, which matches the third day timing here.

Step 4: Why the other options are wrong.
Hypokalemia causes generalised muscle weakness but is not a typical direct feature of organophosphorus poisoning at this timing, and does not classically cause ptosis. Inflammatory polyneuropathy (a Guillain-Barre type illness) develops over days to weeks after an infection or vaccination, not as a direct effect of an organophosphate, and is not the standard diagnosis taught for this scenario. Polymyositis is a chronic autoimmune muscle disease that develops over weeks and is unrelated to acute pesticide poisoning.

Step 5: Final Answer.
The most likely diagnosis is
\[ \boxed{\text{Intermediate syndrome}} \]