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Atypical Posterior Stroke: Diagnosing Cause of Vertigo in Primary Care
A patient presenting with dizziness undergoes a thorough workup to identify a peripheral or central cause of vertigo.
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Example of an MRI in a patient with posterior ischemic stroke.
A57-year-old woman presents to her primary care provider with complaints of dizziness, which began 3 hours ago and is continuous. She describes the dizziness as a room-spinning sensation that is not relieved or associated with any particular position. The dizziness is associated with headache, nausea, vomiting, weakness, and loss of balance. She rates the dizziness severity as an 8 out of 10. The patient denies fever, chills, fatigue, night sweats, weight changes, head injury, tinnitus, hearing loss, otorrhea, otalgia, vision changes, recent upper respiratory tract illness, or syncopal episodes. She states she has never experienced anything like this before.
The patient’s medical history is significant for morbid obesity (body mass index, 48), type 2 diabetes, hypothyroidism, and hyperlipidemia. She notes that she does not exercise and that her diet consists of fast food most days of the week. She admits to occasional alcohol use once or twice a month and denies tobacco or drug use.
Examination
The patient appears disheveled but alert and oriented to person, place, time, and situation. Vital signs are shown in Table 1, page12. Her head and face are symmetrical with no signs of ptosis or facial droop. Eye examination (pupil, equal, round, reactive to light) is normal, and ophthalmoscopic examination shows initial signs of cataracts bilaterally. No exudates, hemorrhages,
or angiogenesis are present. Hearing and ear examinations are normal. No pain is reported on palpation of frontal sinuses. Mucous membranes appear moist without edema or erythema. Lips and gingiva are pink. Tonsils present bilaterally with no erythema or edema. Heart rate and rhythm are normal, and normal S1 and S2 sounds are heard with the patient leaning forward with no murmur appreciated. Cranial nerve examination is normal.
A neurologic examination nds the patient o balance with an unsteady gait when attempting to walk across the examination room; Romberg test is positive. All other tests are normal with re exes 2+ bilaterally. Complete blood cell count is within normal limits but the patient’s blood glucose level is elevated (180 mg/dL). An electrocardiogram is performed and shows normal sinus rhythm with no ischemic changes noted.
A Head Impulse, Nystagmus, and Test of Skew (HINTS) examination is performed because the patient reports continuous vertigo symptoms. The HINTS examination is used to di erentiate between a central or peripheral cause of dizziness. The results from the bedside HINTS assessment on this patient are as follows: • Nystagmus type is bidirectional • Skew deviation is positive for vertical deviation of the left eye • Head impulse test is normal
Treatment
The results from the HINTS examination are concerning for a central etiology of the patient’s vertigo. A posterior stroke is suspected. An ambulance is called and the patient is transported to a stroke center. The patient undergoes di use weighted magnetic resonance imaging (MRI) and is diagnosed with an ischemic posterior stroke located in the medial branch of the posterior inferior cerebellar artery.
The diagnosis is within the 4.5-hour window for administration of thrombolytics. She has full resolution of neurologic symptoms after administration of tissue plasminogen activator.
Discussion
Dizziness is a common complaint for which patients seek medical care. It has been reported that 5.6 million o ce visits per year are due to dizziness in the United States.1 Benign paroxysmal positional vertigo (BPPV) is the most common cause of vertigo and a ects 15% to 20% of adults annually.2
In addition to BPPV, causes of peripheral vertigo include Ménière disease, vestibular neuronitis, and vestibular migraine. Taking a detailed patient history and performing the correct physical examination is important for helping to identify the
POLL POSITION
What is the best test to differentiate between a central or peripheral cause of dizziness?
■ Dix-Hallpike maneuver
■ HINTS examination
■ Epley maneuver
■ Tilt test 15.15%
12.88% 35.23%
36.74%
For more polls, visit ClinicalAdvisor.com/Polls.
TABLE 1. Vital Signs
Weight, kg
Height, in
Body mass index
Temperature, °C
Blood pressure, mm Hg
Supine
Standing 127
65
48
36.5
124/76 120/72
Heart rate, bpm
Supine
Standing 80 84
Respiration rate, breaths per min 16
bpm, beats per minute
cause of vertigo and ruling out potentially life-threatening diseases, including posterior circulation stroke.
Posterior strokes can be missed in patients who present with dizziness.3 In a study of 1666 patients who presented to the emergency department with dizziness, 35% of those with stroke/transient ischemic attack were misdiagnosed.4 Medical providers need to recognize the subtle signs and symptoms of stroke and know when to perform the HINTS examination. In a comparative study, the sensitivity and specificity of the HINTS examination were found to be greater than those of MRI if performed less than 48 hours from symptom onset.3
When taking a patient history, it is best to determine the timing and triggers of vertigo rather than the characteristics. In one study, patients changed the description of their dizziness half of the time when asked repeated questions within a 10-minute time frame whereas reporting of the timing and triggers of symptoms was more consistent.5
The timing of vertigo is used to differentiate between 2 syndromes: episodic vestibular syndrome or acute vestibular syndrome. Episodic vestibular syndrome is classified by periods of transient vertigo, dizziness, or unsteadiness lasting seconds, hours, or occasionally days. Episodic vestibular syndrome is further classified into triggered or spontaneous subtypes. Triggered episodic vestibular syndrome (t-EVS) is aggravated by a trigger, the most common being head movement or changes in body position.6 Orthostatic hypotension is the most common cause of t-EVS followed by BPPV. Spontaneous episodic vestibular syndrome (s-EVS) lasts minutes to hours and has no associated trigger. The most common form of s-EVS is vestibular migraine.6
Acute vestibular syndrome (AVS) is continuous vertigo, dizziness, or unsteadiness that lasts days to weeks and includes symptoms of new vestibular system dysfunction, including vomiting, nystagmus, and impaired gait.6 Acute vestibular syndrome is further classified into traumatic/toxic or spontaneous subtypes. Traumatic/toxic AVS is caused by head trauma or drug intoxication. Spontaneous acute vestibular syndrome (s-AVS) has no apparent trigger. The most common cause of s-AVS is vestibular neuritis; however, 10% to 20% of patients with s-AVS present with stroke.6
Once the practitioner has taken a detailed history, a thorough physical examination should be performed and should include taking orthostatic vital signs, performing a cardiac examination, and detailed examination of the head, ears, eyes, and nervous system. In addition, patients with details consistent with AVS should undergo the HINTS examination to differentiate a peripheral cause of vertigo from a potentially devastating central cause. Evidence has shown that this examination alone can accurately help
How to Perform the HINTS Examination
To perform the Head Impulse, Nystagmus, and Test of Skew (HINTS) examination, have the patient sit comfortably in a chair. Nystagmus type is first observed. Nystagmus is observed in the patient first during primary gaze, then lateral gaze. If nystagmus is not present, then acute vestibular neuronitis or stroke is unlikely and the rest of the HINTS examination should be stopped as it may show false results.7 If nystagmus is present, the direction of the fast-beating component is noted. Unidirectional nystagmus is reassuring as it indicates a peripheral cause of vertigo. Bidirectional nystagmus is concerning for a central pathology.
The next component of the examination is a Test of Skew. This is done by performing the cover-uncover test for each eye and observing if there is any vertical movement of the uncovered eye. A normal response is no vertical correction whereas vertical skew is worrisome for a central pathology.
Finally, the Head Impulse test is performed by holding the patient’s head while the patient looks directly at the provider’s nose. The head is then moved back and forth slowly left to right and then briskly to the center. This tests the vestibulo-ocular reflex. A positive result will show the eyes moving with the head, then snap back in a fast corrective movement to look at the provider’s nose. This is called a corrective saccade.1 The test is negative if the eyes do not remain on target, therefore demonstrating a lack of corrective saccade.7 In this instance, a positive or abnormal head impulse indicates a peripheral cause of vertigo whereas a negative or normal head impulse test is worrisome for posterior stroke (Table 2).
A single central finding on any of the 3 components rules in a posterior circulation stroke.7 The acronym INFARCT can be used to remember the worrisome signs for stroke (Impulse Normal, Fast phase Alternating, Refixation on Cover Test).
TABLE 2. Interpretation of the HINTS Examination7
Positive Finding for Peripheral Cause Positive Finding for Central Cause
Head Impulse test Saccade No saccade
Nystagmus Unidirectional Bidirectional
Test of Skew No skew Vertical skew
identify 10% to 20% of patients with AVS resulting from posterior stroke.5
Primary care providers can learn to perform and interpret the HINTS bedside examination to help minimize misdiagnosis. The HINTS examination when performed within 48 hours of symptom onset has a sensitivity of 100% and speci city of 96% for diagnosing stroke.3 The bedside examination rules out stroke more accurately than early MRI; however, it is underutilized because of lack of training (see How to Perform HINTS Examination and Table 2).3,7
Primary care providers should also be aware that patients presenting with continuous vertigo secondary to posterior stroke are more likely to have associated gait disturbance, focal neurologic complaints, headache, sudden onset of symptoms, positional isolated vertigo, and auditory symptoms. When any of these symptoms are present, the HINTS examination should be utilized in the workup of the patient; however, these typical neurologic symptoms can be absent in some patients who present with mass e ect from large cerebellar infarction.3 Sometimes, the only symptom that these patients exhibit is severe truncal ataxia.3
If the HINTS examination does not suggest a central cause or the patient presents with episodic vertiginous symptoms then a peripheral cause of vertigo such as BPPV should be considered. The diagnosis of peripheral causes involves performing the Dix-Hallpike maneuver. When performing the maneuver, the latency, direction, time course, and duration of nystagmus are noted for diagnosis.8 The nystagmus produced by the Dix-Hallpike maneuver for the most common type of BPPV, posterior canal BPPV (pc-BPPV), is upward torsional nystagmus beating toward the lowermost ear.9 The nystagmus develops with a brief latency of several seconds and fatigues with repeated maneuvers.9 The Dix-Hallpike maneuver is the gold standard test for diagnosing pc-BPPV. The treatment of choice is to perform a canalith repositioning maneuver, also known as the Epley maneuver; however, BPPV can spontaneously resolve with time on its own. Spontaneous recovery occurs in 20% of patients within 1 month, and up to 50% of patients recover within 3 months.1 ■
Hannah Grachek, PA-C, practices in primary care in Buford, Georgia. Kelly S. Reed, PharmD, MPA, PA-C, is an assistant professor in the Physician Assistant Program at Augusta University in Augusta, Georgia.
References
1. Bhattacharyya N, Gubbels SP, Schwartz SR, et al. Clinical practice guideline: benign paroxysmal positional vertigo (update). Otolaryngol Head Neck Surg. 2017;156(3_suppl):S1S47. 2. Palmeri R, Kumar A. Benign paroxysmal positional vertigo. In: StatPearls. StatPearls Publishing; 2021. 3. Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504-3510. 4. Kerber KA, Brown DL, Lisabeth LD, Smith MA, Morgenstern LB. Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study. Stroke. 2006;37(10):2484-2487. 5. Edlow JA, Newman-Toker D. Using the physical examination to diagnose patients with acute dizziness and vertigo. J Emerg Med. 2016; 50(4):617-628. 6. Tehrani ASS, Kattah JC, Kerber KA, et al. Diagnosing stroke in acute dizziness and vertigo: pitfalls and pearls. Stroke. 2018;49(3):788-795. 7. Edlow JA, Gurley KL, Newman-Toker DE. A new diagnostic approach to the adult patient with acute dizziness. J Emerg Med. 2018;54(4):469-483. 8. von Brevern M, Bertholon P, Brandt T, et al. Benign paroxysmal positional vertigo: diagnostic criteria. J Vestib Res. 2015;25(3-4):105-117. 9. Lee SH, Kim JS. Benign paroxysmal positional vertigo. J Clin Neurol. 2010;6(2):51‐63.
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