A 6-year-old child presents with a head tilt to the left shoulder, chin down, and face turn to the right. Cover test reveals a right hypertropia that increases in left gaze and with right head tilt (Bielschowsky positive). The MOST likely diagnosis is:
- A Right lateral rectus palsy
- B Right superior oblique palsy (IV nerve palsy) ✓
- C Left superior oblique palsy
- D Brown syndrome — right eye
Explanation
Right superior oblique (SO) palsy (trochlear nerve palsy) produces a classic triad: vertical diplopia/hypertropia that worsens in left gaze (right SO acts as an intorter and depressor in adduction), a positive Bielschowsky head tilt test (right hypertropia increases on tilting head to the right, because the right superior rectus then acts unopposed), and compensatory head tilt to the opposite shoulder (left), chin down to use binocular vision. The child tilts toward the opposite shoulder to use the intact eye's movement. Brown syndrome causes limited elevation in adduction (restriction of right SO tendon), not vertical deviation in the described pattern.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.