A few weeks ago in Morning Report, we discussed the case of a 70 year old man who was referred for non-specific feelings of ‘dizziness’, ‘imbalance’, and ‘unsteadiness’.
These symptoms are common reasons for presentation to ED and/or referral to Internal Medicine, but can be quite diagnostically challenging for physicians. As one doctor put it, “dizziness is associated with nausea, fear, anxiety, and frustration — and that’s in the physician. Never mind the patient!”
In this Morning Report, we discussed how to develop a robust and confident approach to the ‘weak and dizzy patient’ and reliably distinguish between benign and more ominous causes of ‘dizziness’.
1. Pearls for history-taking from a patient who is feeling ‘dizzy’
- We are taught to start with ‘do you feel lightheaded or is the room spinning’ to distinguish between lightheadedness or vertigo, but this is not always useful — patients often have both!
- Instead, try: “Without using the word dizzy, describe to me what you are feeling and experiencing”
- Similarly to a falls history, ask the patient to describe what they experienced BEFORE, DURING, and AFTER their episode
- The duration of symptoms is critical to obtaining a good dizziness/vertigo history. Vertigo feels absolutely terrible, and patients often unintentionally overestimate duration. To get an accurate estimate, try: “Count out loud when it starts and tell me when it stops”
- Try the ATTEST approach to structured history, physical, and investigation:
- Associated Symptoms: aural fullness, hearing loss, tinnitus, nausea/vomiting, headache, neck pain, slurred speech, double vision, vision loss, unsteady gait, rash, hiccups
- Timing: constant vs. intermittent, seconds vs. minutes vs. hours
- Triggers: Specific positions, preceding head trauma/neck manipulation, recent URTIs, and don’t forget medications (aminoglycosides, anticholinergics, antipsychotics…to name a few)
- Examination Signs: Vitals, Neuro Exam (Tone/Motor/Power/Coordination/Reflexes/Gait), HINTS exam, +/- Cerebellar Exam
- Testing: Decision re further imaging, e.g. CT or MRI with Diffusion Weighted Imaging
2. The Four Big Buckets (contentious but useful)
Both ‘dizziness’ and ‘vertigo’ can be caused by a huge number of diagnoses, and it is often useful to categorize your history into a few ‘buckets’ to guide your differential diagnosis. In your history taking, try to move from the broad umbrella of ‘dizziness’ into one of the 4 categories below:
Once you identify the main syndrome, you can proceed to a differential diagnosis. This table from Clinical Methods is old but provides an excellent summary of common diagnoses not to miss:
3. Differentiating between Central and Peripheral Vertigo
Once you establish that the patient is experiencing true vertigo, you must differentiate between central (more ominous) and peripheral vertigo (more benign). We discussed the following differentiating features which may be helpful, as well as some common causes of central vs. peripheral vertigo.
Remember that timing can often help you distinguish between various causes of an acute vertiginous syndrome. This table from Kim and Zee (2014) in NEJM provides an excellent summary of onset and timecourse for various causes of vertigo.
4. Nailing the HINTS Exam
The HINTS exam (Head Impulse, Nystagmus, and Test of Skew) is a 3-step bedside oculomotor exam proposed by Kattah et al. in 2009 to help identify central causes of vertigo in acute vertigo syndromes. When performed by neurologists or neuro-ophthalmologists, the exam is highly sensitive (97%) and specific (95%), but the accuracy drops with other providers. Interestingly, in the original study, the HINTS exam was more sensitive than MRI in the first 24hrs for cerebellar stroke, and several patients with a positive HINTS exam but negative initial MRI went on to have positive MRI findings later on.
We discussed that the most common mistake is doing the HINTS exam on a patient who is not having an acute vestibular episode. Don’t do a HINTS exam on a patient who is not having symptoms right now!
I strongly recommend that you watch this video by Dr. Peter Johns from Ottawa, which demonstrates real-life HINTS exam findings. Remember that ANY positive finding on the HINTS exam should prompt you to search for a central etiology of vertigo.
4. Further investigations and management
We mostly focused this talk on diagnosis, which will heavily guide your decision to pursue further investigations (i.e., neuroimaging). If you strongly suspect vertigo with ominous features (e.g., any criteria positive on HINTS exam and/or other neurological deficits), consider getting a CT head (overnight) and/or an MRI with diffusion weighted imaging. Speaking of, here’s a nice article on Radiopedia about what diffusion weighed imaging actually means and why it’s important in early identification of ischemic strokes.
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