A 52-year-old man recovering from a left Bell's palsy reports tearing from the left eye every time he eats. Examination shows recovered facial movement with mild synkinesis. The mechanism of this 'crocodile tears' phenomenon is:

• A Loss of stapedius function causing reflex hyperlacrimation via trigeminal stimulation
• B Aberrant regeneration of lacrimal fibres into the chorda tympani supplying the submandibular gland
• C Aberrant regeneration of salivary fibres into the greater petrosal nerve supplying the lacrimal gland ✓
• D Denervation hypersensitivity of the lacrimal gland to circulating acetylcholine

Explanation

After proximal facial nerve injury, secretomotor fibres originally destined for the submandibular and sublingual glands via the chorda tympani regenerate along the greater petrosal pathway and reach the lacrimal gland. Gustatory stimuli therefore trigger inappropriate lacrimation. Option B reverses the direction of misdirection, and options A and D describe mechanisms unrelated to aberrant regeneration, which is the established basis of this Bogorad syndrome.

Reference: Diseases of Ear, Nose and Throat (Dhingra), 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.