Labyrinthitis presents with rotational vertigo and nystagmus. What is the characteristic direction of nystagmus?

Labyrinthitis presents with rotational vertigo and nystagmus. What is the characteristic direction of nystagmus?

• A. Horizontal-rotary away from affected side
• B. Vertical
• C. Rotatory toward affected side
• D. Horizontal-rotary toward the unaffected side

Answer: (A)

In acute unilateral inner ear loss such as labyrinthitis, the brain receives imbalanced vestibular input, so the eyes develop a spontaneous horizontal-rotary nystagmus with the fast phase directed away from the damaged labyrinth. The slow phase drifts toward the lesioned side, and a quick corrective saccade beats toward the healthy side, giving a horizontal-rotary nystagmus whose fast component is away from the affected ear. Vertical nystagmus is more suggestive of a central problem, not a peripheral labyrinthitis. The important point is that the nystagmus beat is toward the healthy side (away from the affected side), which is described as horizontal-rotary away from the affected side.

In acute unilateral inner ear loss such as labyrinthitis, the brain receives imbalanced vestibular input, so the eyes develop a spontaneous horizontal-rotary nystagmus with the fast phase directed away from the damaged labyrinth. The slow phase drifts toward the lesioned side, and a quick corrective saccade beats toward the healthy side, giving a horizontal-rotary nystagmus whose fast component is away from the affected ear. Vertical nystagmus is more suggestive of a central problem, not a peripheral labyrinthitis. The important point is that the nystagmus beat is toward the healthy side (away from the affected side), which is described as horizontal-rotary away from the affected side.