Posterior circulation CVA and the HINTS exam

Today in ICU report we heard about a case of posterior fossa CVA unfortunately resulting in brain death and transition to comfort care.

One of the most challenging clinical questions in the emergency room is how to differentiate central vs peripheral causes of vertigo. This is especially challenging when a patient has existing gait abnormalities and a previous diagnosis of BPV.

One prediction tool is the HINTS exam. This was studied in a cross-sectional study of patients who presented with acute vestibular syndrome (hours or days of persistent vertigo/dizziness, nystagmus, nausea or vomiting, head motion intolerance, new gait unsteadiness).

Patients underwent a neurologic exam and MRI. ABCD2 scores were calculated (Age >60, SBP>140 or DBP > 90, Clinical features of TIA (unilateral weakness 2pts, speech impairment 1pt), Duration > 10 min (1pt) or > 60 min (2 pts), Diabetes) and compared to the HINTS exam to see how HINTS did identifying stroke and other central causes.

HINTS was found to have a sensitivity of 96.5% and specificity of 84.4% in identifying central causes of vertigo, which was much better than ABCD2.

HINTS exam involves 3 steps (nystagmus type, head impulse, test of skew) and can be seen in this youtube video:

 

To summarize: a REASSURING HINTS exam is ALL of the following 1) unidirectional nystagmus 2) no vertical skew 3) abnormal head impulse test.

#LTpearl: The sun never sets on the posterior circulation, so if you are concerned about central vertigo then obtain an MRI.

 

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