1637 - Seeing snowflakes, a unique visual phenomenon following mild traumatic brain injury

Visual snow syndrome (VSS) is a clinically diagnosed visual disorder characterized by persistent flickering dots resembling television static that can occur following infection, medication use or brain injury. VSS is a chronic, nonprogressive and potentially debilitating syndrome whose symptoms overlap with other diagnoses such as visual hallucinations or migraine with visual aura, which can lead to misdiagnosis.

Case Description:

A 15-year-old male sustained a mild traumatic brain injury (mTBI) during a football game when his helmet hit the ground. Initial symptoms included headaches and spots in his vision. He did not report motion sickness, nausea, vomiting or premorbid history of headaches. He had weekly retroorbital headaches and constant bright flashes in all visual fields. The flashes were constant and didn't worsen with headaches or activity. On exam, he had intact extraocular movements, no vertical or horizontal nystagmus and no worsening of visual symptoms with eye movement testing and vestibular ocular reflex assessment. His neurologic exam was otherwise normal. He was referred to ophthalmology and physical therapy. He was counseled on pacing both physical activity and schoolwork and maintaining hydration. He returned after completing physical therapy with resolution of all symptoms apart from visual symptoms. Ophthalmologic exam was non-focal, the diagnosis of VSS was made and he was treated conservatively.

Discussions: This case demonstrates why it is critical for VSS to be considered in the differentia of post-mTBI visual disturbances. As demonstrated by this case, it is possible to have full clinical and neurocognitive recovery after concussion, with isolated VSS.

Conclusions: More research is needed to characterize the incidence of VSS after mTBI in adolescents, the associated pathophysiology, and the intersection of VSS with vestibular and ocular motor issues after mTBI.