If a patient had a right stellate ganglion block, which syndrome would be expected?

If a patient had a right stellate ganglion block, which syndrome would be expected?

• A. Horner's syndrome (miosis, ptosis)
• B. Mydriasis
• C. Increased tearing
• D. No ocular effects

Answer: (A)

Blocking the stellate ganglion stops sympathetic signals to the same side of the face and eye. That loss of sympathetic tone affects the iris dilator muscle and Muller's muscle of the eyelid, producing miosis (constricted pupil) and ptosis (slightly drooped upper eyelid). It also reduces sympathetic input to the sweat glands, causing anhidrosis on the blocked side. Because the pupil dilation and eyelid elevation rely on sympathetic activity, you wouldn’t expect dilation or increased tearing as a result of the block; Horner’s syndrome with miosis and ptosis is the typical ocular finding.

Blocking the stellate ganglion stops sympathetic signals to the same side of the face and eye. That loss of sympathetic tone affects the iris dilator muscle and Muller's muscle of the eyelid, producing miosis (constricted pupil) and ptosis (slightly drooped upper eyelid). It also reduces sympathetic input to the sweat glands, causing anhidrosis on the blocked side. Because the pupil dilation and eyelid elevation rely on sympathetic activity, you wouldn’t expect dilation or increased tearing as a result of the block; Horner’s syndrome with miosis and ptosis is the typical ocular finding.