Attending Physician University of Toledo Toledo, Ohio, United States
Case Diagnosis: Eight and a half syndrome following dorsal pontine stroke
Case Description: A 61-year-old female initially presented to the ED after calling EMS for herself due to sudden onset left sided apraxia, right facial droop, and dysconjugate gaze. CT head and MRI brain showed an acute intraparenchymal hemorrhage in the right dorsal pons. Examination revealed right facial droop, inability to raise the right eyebrow, right conjugate gaze palsy, and right internuclear ophthalmoplegia (INO), which is consistent with eight-and-a-half syndrome. Additional exam findings included, left upper extremity (LUE) ataxia and decreased sensation to the LUE and left lower extremity (LLE). The patient’s past medical history was significant for hypertension, which is thought to be the cause of the hemorrhage.
Discussions: Eight-and-a-half syndrome is a rare neurological condition that combines the features of one-and-a-half syndrome (ipsilateral horizontal gaze palsy and INO) with an ipsilateral facial nerve (CNVII) palsy. Eight-and-a-half syndrome results from a lesion affecting the paramedian pontine reticular formation (PPRF), abducens nucleus, and the medial longitudinal fasciculus (MLF), along with the facial nerve nucleus in the dorsal pons. It is most frequently caused from a stroke to the dorsal pons, but may also occur due to multiple sclerosis, tumors, infections, or trauma. Recovery from eight-and-a-half syndrome after a stroke varies, with improvements often occurring within the first 6 to 12 months, but full recovery is not guaranteed and may depend on stroke severity, rehabilitation efforts, and management of risk factors.
Conclusions: Eight and a half syndrome has a unique combination of signs, including horizontal gaze palsy, INO, and CNVII palsy. Recognizing these clinical symptoms may aid with diagnosis and localization of a lesion to the dorsal pons.
