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Título

Dangerous HINTS and normal MRI: don’t forget inferior vestibular neuritis

RESUMO

Case Report: We describe two patients complaining of sudden dizziness in the emergency department whose examination revealed dangerous HINTS but normal image studies.
A 52-years-old woman presented with acute vertigo associated with vomiting, tinnitus and severe imbalance. She had left torsional spontaneous and positional downbeat and torsional to the left nystagmus and normal vestibulo-ocular reflex (VOR).
A 66-years-old man also presented with acute vertigo, vomiting and imbalance. He had positional downbeat and torsional to the left nystagmus, a normal VOR, felt to the right side with eyes closed when standing on foam, subjective visual vertical was abnormal (2,5º) to the right.
Both patients had normal brain MRI and abnormal video-head impulse test (vHIT), showing low gain (0.37 and 0.3 respectively) of VOR for the right posterior semicircular canal gain of the posterior semicircular canal and corrective saccades, receiving the diagnosis of vestibular neuritis of the inferior division of the right vestibular nerve.
Discussion: The HINTS has a high sensitivity (97%) and specificity (95%) in discerning central causes of acute vestibular syndromes. Nonetheless, some peripheral etiologies could mimic central patterns in the first evaluation. The isolated unilateral involvement of the inferior division of the vestibular nerve may manifest as positional downbeat nystagmus with normal horizontal VOR and must be included in the differential diagnosis in a patient with normal MRI.
Final Considerations: An acute onset vertigo, dangerous HINTS, with downbeat nystagmus and normal brain MRI should remind of vestibular neuritis of the inferior division of the vestibular nerve. The vHIT is of great help to confirm the diagnosis.

Palavras Chave

Inferior Vestibular Neuritis; HINTS; Dangerous HINTS; Posicional Central Nystagmus; Dizziness; Vertigo