Ocular Flutter and Opsoclonus

What is it?

Bursts of rapid involuntary binocular conjugate saccades that take the eyes off primary gaze position
No pause (“intersaccadic interval”) between the two halves of the oscillations
Called “ocular flutter” if the saccades are limited to the horizontal plane
Called “opsoclonus” if the saccades also occur in the vertical plane
Ocular flutter is probably a mild version of opsoclonus
Attributed to dysfunction of pontine burst cells
Common causes in children: viral and para-infectious autoimmune encephalitis, paraneoplastic disorder associated with neuroblastoma
Common causes in adults: viral and para-infectious autoimmune encephalitis, paraneoplastic disorder associated with metastatic lung, breast, ovarian cancers
Uncommon causes at any age: toxicity of lithium, amitriptyline, cocaine, phenytoin, toluene, thallium, chlordecone, organophospates, strychnine; hyperosmolar coma, brainstem hemorrhage, multiple sclerosis

Core clinical features
- Bursts of binocular conjugate saccades in the horizontal plane (ocular flutter) or...
- Bursts of binocular conjugate saccades in all planes (opsoclonus)
- Tip: these eye movements are distinctive in being visible under closed lids and during sleep
Possible accompanying clinical features
- Brief jerky limb movements (“myoclonus”)
- Head and trunk oscillations (“titubation”)
- Tremor
- Psychic distress, impaired cognition
- Ataxia
- Tip: acute onset is associated with a para-infectious cause; subacute onset is associated with a paraneoplastic cause
Other features
- Brain imaging is often negative, but may show high T2/FLAIR signal in the cerebellum
- Lumbar puncture may disclose mild pleocytosis, protein elevation
- Underlying neuroendocrine cancer may be known or become evident
- Paraneoplastic panel may be positive

In children, look for signs of neuroblastoma: high urine catecholamines, mass on CT chest/abdomen/pelvis imaging, positive MIBG nuclear medicine scan
In adults, look for signs of a primary cancer on MRI or positron emission tomography (PET)
In para-infectious and paraneoplastic cases, treat with ACTH, corticosteroids, plasmapheresis, or intravenous immunoglobulin, which are sometimes effective in reducing neurologic manifestations
Tip: in paraneoplastic cases, treatment directed at the underlying cancer is probably more effective than treatment directed at the oscillations and other neurologic manifestations
Neuroblastoma with ocular flutter or opsoclonus has a better cancer prognosis than neuroblastoma without ocular flutter or opsoclonus
In adult paraneoplastic cases, survival time is short
In para-infectious cases, eye findings resolve within months, but ataxia and cognitive dysfunction may persist