Harlequin Syndrome After Thoracic Paravertebral Block

Area of Science:

• Neurology
• Anesthesiology

Background:

• Harlequin syndrome presents as sudden unilateral facial flushing and sweating.
• It is often linked to sympathetic nervous system interruption, though mechanisms are not fully understood.

Observation:

• A patient developed Harlequin syndrome with right-sided facial flushing post-left-sided thoracic paravertebral nerve block for mastectomy.
• Notably, this instance did not involve Horner syndrome.

Findings:

• The case suggests thoracic paravertebral nerve block can interrupt sympathetic and parasympathetic pathways.
• The specific spinal nerve block levels involved require further investigation.

Implications:

• This case expands the understanding of Harlequin syndrome's potential triggers and presentations.
• It underscores the importance of considering autonomic nervous system effects after regional anesthesia.