A 6-year-old child develops acute flaccid paralysis (AFP) of the left leg 5 days after fever. The paralysis is asymmetric, involves one limb, sensation is intact, and reflexes are absent in the affected limb. CSF shows mild pleocytosis with normal glucose and protein. What is the MOST specific confirmatory test?

• A Nerve conduction studies showing absent motor potentials
• B MRI of the lumbar spine
• C Paired serum neutralization antibody titers
• D Stool PCR/culture for poliovirus (within 14 days of paralysis onset) ✓

Explanation

WHO recommends stool cultures/PCR as the gold standard for confirming poliovirus in AFP cases, with two stool specimens collected 24–48 hours apart within 14 days of paralysis onset having the highest yield (positive in 80–85% of true polio cases). Stool is superior to throat swab or CSF for virus isolation because poliovirus is shed in feces for 6–8 weeks. Serum antibody titers lack specificity as they may reflect vaccination. NCS and MRI support the diagnosis but do not confirm viral etiology.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.