Question

Assertion (A): Lumbar puncture is indicated in a child with fever and asymmetric flaccid limb weakness.

Reason (R): The diagnosis of Guillain-Barre syndrome can be established by albuminocytologic dissociation on CSF analysis.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is NOT the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Hint:

Compare the classic pattern of polio with the classic pattern of Guillain-Barre syndrome.

Answer 1

The Correct Option is B

This question wants us to notice that fever plus asymmetric weakness is not the textbook picture of Guillain-Barre syndrome, even though the CSF fact quoted about GBS is correct. Let's go through the options.

1. Both true, R explains A: This does not fit, because the child's picture, fever with lopsided weakness, fits paralytic poliomyelitis better than GBS.
2. Both true, R does not explain A: A lumbar puncture is genuinely useful here to separate the causes of sudden flaccid paralysis, since polio usually shows raised CSF cell counts while GBS shows albuminocytologic dissociation, that is high protein with a near normal cell count. Both facts stand on their own, but the CSF finding used to diagnose GBS is not what is guiding the tap in a febrile, asymmetric case that looks more like polio. This option fits.
3. A true, R false: This fails because the statement about GBS CSF findings is accurate, not false.
4. A false, R true: This fails because doing a lumbar puncture in this child is a reasonable and indicated step.

The trap here is assuming any child with limb weakness must have GBS. Fever and one-sided weakness point away from GBS and toward polio, so the GBS specific CSF pattern is not the real justification for the tap.

Let's summarize:

• GBS classically causes symmetric, afebrile weakness with albuminocytologic dissociation on CSF.
• Fever with asymmetric weakness fits polio more closely, and the lumbar puncture here helps tell the two apart.

So both statements are true, but the reason does not explain the assertion in this case.