Patients experiencing dizziness typically give descriptions that are unclear, inconsistent, and unreliable, casting doubt on the validity of the traditional categorization of dizziness (i.e., vertigo, presyncope/lightheadedness, and disequilibrium.)
Instead, dizziness may be better categorized as 4 syndromes:
- Acute vestibular syndrome (AVS)
- Characteristics: abrupt, persistent dizziness that does not completely resolve
- Key exam maneuvers: HINTS exam
- DDx: vestibular neuritis, stroke
- Chronic vestibular syndrome (CVS)
- Characteristics: prolonged dizziness with insidious onset, often post-exposure
- Key exam maneuvers: head and ear exam
- DDx: adverse drug effect, tumor
- Episodic vestibular syndrome (EVS)
- Characteristics: intermittent episodes of dizziness that completely resolve
- Key exam maneuvers: cardiac and neurologic exams
- DDx: vestibular migraine, TIA, Meniere’s disease, arrhythmia
- Triggered vestibular syndrome (TVS)
- Characteristics: short episodes (<1 minute) of dizziness triggered by movement
- Key exam maneuvers: Dix-Hallpike, Epley
- DDx: benign paroxysmal positional vertigo (BPPV), orthostasis
“TiTrATE” is a novel diagnostic approach to determining the probable etiology of dizziness or vertigo. TiTrATE stands for the Timing of the symptom, the Triggers that provoke the symptom, And a Targeted Examination.
In general, a targeted exam for the patient with dizziness should incorporate aspects of the HEENT, cardiac, and neurological exams. We’ll focus on a few of these below.
When we stand up, gravity causes a shift of 500-800 mL of blood from the upper body to both the lower body and splanchnic circulation. This redistribution of blood decreases venous return to the heart, reducing stroke volume and causing a fall in blood pressure. To compensate, autonomic baroreceptors stimulate a sympathetic response, causing generalized vasoconstriction, increased HR, and contractility. An adequate response increases HR by 10-15 bpm, maintains SBP, and elevates DBP by 10 mmHg.
When autonomic reflexes are impaired or intravascular volume is markedly depleted, a significant reduction in BP occurs upon standing, a phenomenon termed orthostatic hypotension (OH).
- OH, which may be symptomatic or asymptomatic, is defined as a sustained reduction of SBP of at least 20 mmHg or DBP of 10 mmHg within 3 min of standing or head-up tilt to at least 60° on a tilt table
Traditionally, orthostatic vital signs are checked 3-5 minutes after changing positions from supine to standing. However, a 2017 study in JAMA found that OH measurements performed within 1 minute of standing were the most strongly related to dizziness and individual adverse outcomes, suggesting that OH be assessed within 1 minute of standing.
- The ratio between the increase in HR and the fall in BP provides a sensitive and specific way to differentiate between neurogenic (i.e., baroreflex failure) and nonneurogenic OH (i.e., volume depletion). An increase ≤0.5 beats/minute for every 1 mmHg drop in SBP during tilt-table testing or active standing may be useful to diagnose neurogenic OH
- An increase in HR of >30 bpm in the absence of OH suggests postural tachycardia syndrome (POTS)
Nystagmus is an involuntary, rapid, and repetitive movement of the eye that typically appears as a slow eye movement driving the eye off a target followed by a fast movement (i.e., jerk) bringing the eye back to the target. The movement can be horizontal, vertical, torsional, or a combination of these.
By convention, the direction of jerk nystagmus is named after the fast movement. For example, in right-beating nystagmus, the fast phase is toward the patient’s right ear.
Peripheral nystagmus tends to be either horizontal or horizontal with a torsional component; it is inhibited by fixation or fatigue (e.g., repeating maneuvers to elicit nystagmus). In contrast, central nystagmus may be any direction or direction-changing.
The Dix-Hallpike maneuver is a test for peripheral vertigo, and should generally only be performed on patients with symptoms suggesting TVS. A classic example is a patient with dizziness triggered by head movement or rolling over in bed, suggesting BPPV.
- With the patient sitting, the head is turned to one side and neck slightly extended. The patient is then rapidly placed supine, so that the head hangs over the edge of the bed (the downward ear is the one being tested.) The patient is kept in this position until 30 seconds have passed if no nystagmus occurs. The patient is then returned upright, observed for another 30 seconds for nystagmus, and the maneuver is repeated with the head turned to the other side
- The maneuver usually provokes paroxysmal vertigo and nystagmus if posterior canal dysfunction is present. Nystagmus and vertigo usually appear after a latency period of a few seconds and last less than 30 seconds. It has a typical trajectory, beating upward and torsionally when supine. After the patient sits up, the nystagmus will recur but in the opposite direction. Multiple repetitions of this maneuver will result in less nystagmus
The Epley maneuver is a repositioning technique that helps relieve peripheral vertigo, and is essentially an extension of the Dix-Hallpike maneuver. The Epley maneuver allows gravity to draw canaliths from the posterior semicircular canal to the vestibule, where they can be absorbed.
Example: In-depth review (includes Dix-Hallpike maneuver, described above)
The HINTS exam is a set of 3 tests can help us discern between central and peripheral causes of AVS. “HINTS” stands for Head Impulse, Nystagmus, and Test of Skew.
Head Impulse (HI) assesses the vestibulo-ocular reflex by having the patient fix their gaze on the examiner’s nose while the examiner passively (but rapidly) rotates the patients head 10-20°, watching for a corrective saccade.
- If the reflex is intact, the patient can maintain their gaze on the clinician’s nose during rapid head movements, and no corrective saccades are observed at the end of the head movement
- If the reflex is abnormal, the eyes move away with the rotating head when turned to the abnormal side and, at the end of rotation, the patient’s eyes quickly move back toward the clinician’s nose (i.e., the clinician observes a corrective saccade)
- The ear being tested is the one towards which the head is being turned
- A positive HI test suggests a peripheral cause of vertigo. A normal HI test has a LR of 11.9 for ischemic stroke in a patient with AVS.
“Any head movement is involuntarily matched by opposing conjugate movements of the eyes through the actions of the vestibulo-ocular reflex. Without this reflex, it would be impossible to focus on objects when walking, riding, or even breathing… The vestibulo-ocular reflex stabilizes retinal images by specific connections between the semicircular canals and eye muscles. When there is unilateral damage to the neural pathways of this reflex, two consequences follow: (1) Unopposed stimulation of six eye muscles, three on each side, causes prominent vertigo and nystagmus. (2) A deficient vestibulo-ocular reflex is conspicuous when the head is turned to the affected side, a disorder detected by the head impulse test.”Source: McGee, SR. (2012). Evidence-based physical diagnosis.
Nystagmus in the HINTS exam refers to direction-changing nystagmus. In most patients, whether their vertigo is peripheral or central, nystagmus will persist or worsen when a patient looks in the direction of the rapid phase of nystagmus. In a patient with peripheral vertigo who looks in the opposite direction (i.e., contralateral to the rapid component of the nystagmus), nystagmus disappears or at least diminishes. In contrast, nystagmus reverses directions in a proportion of patients with a stroke manifesting as AVS (LR of 3.3).
Test of Skew (TS) assesses vertical refixation through the alternate cover test. In a patient with AVS, the presence of skew deviation has a LR of 8.5 for ischemic stroke.
HINTS exam findings suggesting a peripheral lesion requires all of the following:
- Abnormal head impulse
- Unidirectional nystagmus
- No skew deviation
HINTS exam suggesting a central lesion requires any of the following:
- Normal head impulse
- Direction-changing nystagmus
- Skew deviation
Exam pearl: There is never a reason to perform both the HINTS exam and Dix-Hallpike maneuver on the same patient!
Further Reading & Viewing!
- Peter Johns’ YouTube channel focusing on examining patients with vertigo
- Steven McGee’s Evidence-Based Physical Diagnosis
- JAMA’s The Rational Clinical Examination
Blog post based on Med-Peds Forum talk by Chelsea Boyd, Fritz Siegert, and Julia Solomon, PGY4s