Episode 22: MAAAYYYBEEE We’re Not Great at Spotting Atypical Strokes

Listen here or download on iTunes, Podcast Addicts, or Podcast Republic.

An article from Frontline Medical News in 2014 was heavily critical of the amount of missed strokes by prehospital providers. A retrospective study that lasted from January 1st, 2010 to December 31st, 2011 reported that out of the 10,384 patients that were transported to an emergency department via EMS and that 41% of stroke positive patients were missed. To quote one of the reviewing physicians, “if a paramedic called us to say a stroke was going on, the likelihood was extremely high it was a true stroke. However, when they didn’t think it was a stroke, it didn’t mean much.” McStrokeOuch. We’ve all been taught about the Cincinnati Prehospital Stroke Scale. It works, and it’s a great assessment tool. But what about the patients that don’t present with limb ataxia, dysarthria, or facial drooping? Is there a stroke patient that might be having an atypical stroke? Well… yes, and we’re going to be getting into that now. What about the patients that we are convinced are having a stroke, but are actually experiencing something differently entirely. For today, the subject will be missed stroke activation.We’re going to be focusing on a very niche market of stroke patients today. These are the patients that don’t fit into the typical criteria that prehospital providers have pigeon-holed stroke victims in. The majority of the patients that stroke activation were missed on, were patients of atypical ages and symptoms. Well if they don’t have any traditional symptoms, do you just expect us to ask our Magic 8 Ball if they are having a stroke or not? Hold your horses… we’re getting there. Let’s start with a scenario. 

SCENARIO

You and your partner are called to the home of a mid-60s female with a report of dizziness and near syncope. As you know on the door, the patient calls out from the living room advising that the door is unlocked. She is lying on the floor complaining that “the room is spinning”. As you the story unravels, the patient tells you that she has been feeling this way for the last six hours. Your initial interview and assessment reveal no likely cause of hypovolemia, metabolic factors (i.e. hypoglycemia, diabetic/alcoholic ketoacidosis), or cardiac arrhythmias. The patient states that this is the first time that she has ever experienced symptoms like this before and denies any recent illnesses. Her blood pressure is 162/94, heart rate is 76, SpO2 is 96% on R/A with no obvious signs of distress and clear lung sounds. You assess her blood glucose and see that is 143mg/dl. She is afebrile and there are no orthostatic changes to her vital signs. The patient is A/O x4 with no limb ataxia, dysarthria, or unilateral facial drooping. She states that she has a history of hypertension and GERD, and that she is not compliant with her medications. She denies any recent trauma. As you sit her up, she cries out that her symptoms have worsened greatly and that her nausea turns to active vomiting. Sounds like it’s a just a case of vertigo, right? How do you know for sure? In the list of possible differential diagnoses, did you even consider that this could be a stroke?

WHY WE NEED TO START TAKING VERTIGO SERIOUSLY

  • A 2009 AHA article states that >25% of all patients that present with vertigo-like symptoms actually are found to have some element of posterior circulation infarcts, which is gravely concerning! How many of these patients are we not screening?!
  • A significant number of these patients did not present with limb ataxia, dysarthria, or other concerning neuro deficits (i.e. facial droop, etc). A common symptom of posterior stroke is acute dysphagia (inability or difficulty swallowing due to pharyngeal weakness)
  • A 2013 Lancet article tracked 1,141 patients and their preceding symptoms leading to posterior brain circulation infarct.Out of the studied patients, 54 of them had isolated vertigo symptoms. A statistically small percentage of around 0.05%, right? Yeah, that’s still 54 people that were either misidentified or told that nothing was wrong.

DIFFERENTIATING STROKE FROM ACUTE VESTIBULAR SYNDROME

Enter the HINTS exam.

  • Who do you perform the HINTS exam on?
    • Patients that have been experiencing hours/days of vertigo
    • Patients that are experiencing spontaneous nystagmus
    • Vertigo symptoms worsen going from lying to standing
  • Why perform the HINTS Exam?
    • Assists in differentiation between vertigo and posterior stroke
  • The Three Steps of the HINTS Exam
    • Nystagmus
      • Primary Gaze
        • Is there nystagmus at rest?
      • Lateral Gaze
        • Be careful while you are assessing for lateral nystagmus; having a singular object that you are looking at can reduce the severity of the nystagmus
        • Patients with vestibular neuritis (common cause of dizziness/vertigo symptoms) will typically experience unidirectional nystagmus… and that’s okay
        • Patients experiencing bidirectional nystagmus… not so good
      • Test of Skew
        • Covering/uncovering a patient’s eye(s)
          • Does the eye have any vertical movement when it is uncovered?
      • Head Impulse Test
        • Looking for catch-up saccade
          • Catch-up saccade is good!

  • HINTS Exam leading to probable vestibular neuritis
    • Must have ALL of the above
      • Unidirectional nystagmus
      • No vertical skew
      • Abnormal HIT
  • HINTS Exam leading to probable Posterior Circulation Infarct
    • Can have ANY of these three
      • Bidirectional nystagmus
      • Vertical Skew
      • Normal HIT
  • How sensitive is the HINTS exam in differentiating between vestibular neuritis and a stroke?
    • Same AHA article published in 2009 states that the HINTS exam was 100% sensitive and 96% for identifying stroke patients that were concurrently experiencing vertigo symptoms for several hours/days
    • Not only that, but a comprehensive HINTS exam proved to be sensitive for early detection of stroke patients that early MRI

**SOAPBOX MINUTE WITH MIKE**

So what are we driving at? Maybe the reason that we are missing so many stroke positive patients is that we aren’t considering possible life threats that don’t fit into our limited understanding. By not looking for atypical symptoms or considering textbook symptoms in patient demographics that aren’t typical, we are causing harm to our patients. It’s time to start doing more aggressive follow-up and research.

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