Saccadic palsy after cardiac surgery: characteristics and pathogenesis

Abstract

Selective loss of all forms of saccades, with sparing of other eye movements, indicates malfunction of the brainstem machinery that generates saccades. A current model of brainstem circuits could account for both hypometria and slowing. This syndrome and the visual disability it causes often go unrecognized unless saccades are systematically tested at the bedside.

Selective Saccadic Palsy After Cardiac Surgery

“…Over a 2-year period, our patient showed no clinical improvement. This is consistent with other reports that patients with this ocular motor disorder may remain permanently visually disabled after cardiac surgery (2,3).…”

“…Hypotension, intraoperative hypothermia, or microemboli are all potential contributing factors (2). Over a 2-year period, our patient showed no clinical improvement.…”

“…Loss of voluntary saccades may occur with brainstem strokes, although other types of eye movements are usually affected. Cases of selective saccadic palsy as a complication of cardiac surgery have been previously described (2)(3)(4). However, the pathogenesis of the disorder is unclear, and few reports have clearly defined the nature of the ocular motor deficit.…”

Functional Magnetic Resonance Imaging (MRI) and MRI Tractography in Progressive Supranuclear Palsy-Like Syndrome

“…However, upon review, most of these patients had other neurologic dysfunction and the cases likely represented the PSP-like syndrome. 4,5,7 Patients have been reported with infarcts in the pons, substantia nigra, centrum semiovale, frontal subcortex, striatum, corona radiata, internal capsule, and basal ganglia.…”

“…9 The mechanism of injury in these patients remains unclear; however, a perioperative ischaemic stroke from embolism, hypothermia protocol, hypotension, hyperviscosity, or cardiopulmonary bypass has been postulated. 4,7 The recent finding of absent or fractionated perineuronal nets around omnipause neurons (OPNs) and excitatory burst neurons (EBNs) in an autopsy brainstem immunostaining analysis of one of these patients may suggest a radiographically occult mechanism (personal communication with Drs. Eggers, Horn, and Leigh, article in press).…”