HIT (head impulse test) ja puoli.

OIKEA korvavika eli nopea VASEMMALLE

Video 1a: Shown is a typical acute peripheral vestibulopathy with left-beating, unidirectional nystagmus and abnormal rightward h-HIT. A 54-year-old man with a history of diabetes mellitus on diet-control presented with a 24-hour history of vertigo, falling to the right, nausea and vomiting, without auditory symptoms. He displayed a primary gaze, unidirectional, left-beating nystagmus that increased when looking in the direction of the nystagmus fast phase (i.e., in left gaze), and with fixation removal, both findings typical for a (right) peripheral vestibular lesion. He had an abnormal (positive) h-HIT to the right, and a normal (negative) h-HIT to the left, as anticipated. In the video, the rightward h-HIT is demonstrated first, with a pathologic, leftward, re-fixation saccade evident at the end of the head rotation, indicating a failure of the normal VOR response to keep the eyes steady on the target (i.e., the video camera lens). The leftward h-HIT is demonstrated next, with no refixation saccade evident at the end of the head rotation,
...Brain MRI showed an incidental, 4 millimeter area of increased signal in the periventricular white matter, but no acute infarct by DWI. His clinical course was typical for vestibular neuritis. Note the subtle flattening of the left nasolabial fold apparent on the video was old (lifelong) and unrelated to his acute vestibular syndrome.

Vertikaalinen nystagmus viittaa vahvasti sentraaliseen leesioon, mutta horisontaaliselle voi olla myös sentraalinen syy. Huomaa seuraavassa nystagmus tulee toistuvasti vain, kun katsoo oikealle ja HIT oli normaali. 

Video 1b: Shown is an acute peripheral vestibulopathy mimic, with pseudo-labyrinthine nystagmus, but normal h-HIT, suggesting stroke. A 71-year-old hypertensive man presented with a two-hour history of ataxia, nausea and vomiting without auditory symptoms. He fell to the left when standing. He had right-beating nystagmus in right gaze, but no nystagmus in primary or left gaze. Fixation removal showed a unidirectional, primary gaze, right-beating nystagmus that increased in right gaze, compatible with a peripheral-type nystagmus. However, the h-HIT was normal (negative), decreasing the likelihood of APV substantially, and suggesting a pseudolabyrinthine presentation of stroke. The video, obtained 12 hours later, demonstrates saccadic rightward horizontal pursuits, but relatively smooth leftward pursuits. Fixation removal revealed a subtle oblique/down-beating component to the nystagmus, but the dominant vector remained horizontal and right-beating. Head CT scan showed a right inferior cerebellar stroke, associated with moderate mass effect and fourth ventricular compression. An open MRI obtained one month later showed an area of encephalomalacia involving the right inferior cerebellum, confirming the prior infarct evident by CT acutely.

Jos haluat perehtyä asiaan paremmin:

Alkuperäiset tekstit ja videot:
 H.I.N.T.S. to Diagnose Stroke in the Acute Vestibular Syndrome—Three-Step Bedside Oculomotor Exam More Sensitive than Early MRI DWI Kattah, Talkad, Wang, Hsieh, Newman-Toker (Stroke, 2009)

HINTS video (youtube): Dr. Peter Johns, MD, FRCPC Assistant Professor, Department of Emergency Medicine, University of Ottawa