"Congenital" Horner's syndrome and carotid dissection

The authors describe a child presenting with Horner's syndrome after the repeated application of birthing forceps to the head and neck during vaginal delivery. Magnetic resonance imaging and angiography confirmed that the proximal right internal carotid artery (ICA) showed injury caused by dissection. Carotid duplex and transcranial ultrasonography provided supporting evidence of distal right ICA occlusion with the development of intracranial collaterals. The authors interpret these findings to indicate that the child suffered a traumatic dissection of the distal right ICA to mimic "congenital" Horner's syndrome (CHS). In a review of English medical literature published since 1972, the authors found 70 cases of CHS, none of which was attributed to carotid dissection. This case demonstrates that carotid dissection is an underreported cause of CHS.