Risk of acute brain lesions in dizzy patients presenting to the emergency room: who needs imaging and who does not?

Abstract

The usefulness of brain imaging studies in dizzy patients presenting to the emergency department (ED) is controversial. We aimed to assess the 'real-world' probability of ischemic stroke and other acute brain lesions (ABLs) in these patients to create an algorithm that helps decision-making on whether which and when brain imaging is needed. By reviewing medical records, we identified 610 patients presenting with dizziness, vertigo or imbalance to our university hospital's ED and receiving neurological workup. We collected timing/triggers of symptoms, ABCD² score, focal neurological abnormalities, HINTS (head impulse, nystagmus, test-of-skew) and other central oculomotor signs. ABLs were extracted from CT/MRI reports. Uni-/multivariate logistic regression analyses investigated associations between clinical parameters and ABLs. Finally, the likelihood of ABLs was assessed for different clinically defined subgroups ('dizziness syndromes'). Early CT (day 1) was performed in 539 (88%) and delayed MR imaging (median: day 4) in 299 (49%) patients. ABLs (89% ischemic stroke) were revealed in 75 (24%) of 318 patients with adequate imaging (MRI or lesion-positive CT). The risk for ABLs increased with the presence of central oculomotor signs (odds ratio 2.8, 95% confidence interval 1.5-5.2) or focal abnormalities (OR 3.3, 95% CI 1.8-6.2). The likelihood of ABLs differed between dizziness syndromes, e.g., HINTS-negative acute vestibular syndrome: 0%, acute imbalance syndrome with ABCD²-score ≥ 4: 50%. We propose a clinical pathway, according to which patients with HINTS-negative acute vestibular syndrome should not receive brain imaging, whereas imaging is suggested in dizzy patients with acute imbalance, central oculomotor signs or focal abnormalities.

Keywords: CT; Dizziness; MRI; Nystagmus; Stroke; Vertigo.

Fig. 1

Probability of an acute brain lesion as detected by early CT a or delayed MR imaging b in dependence of the patients’ clinical sub-specification (‘dizziness syndrome’). For the purpose of clarity, we color coded the probability/risk to have an acute brain lesion (ABL) revealed by the respective imaging study (green: no risk, yellow: low–medium risk, red: high risk). a Early CT imaging performed in 534 of 610 ‘dizzy’ patients revealed ABLs in 36 of them (5.9%). Further stratification of the patients by using information from targeted history taking and clinical examination can increase the probability of detecting ABLs on CT to over 20% (e.g., ‘acute imbalance syndrome (AIS) with high-risk ABCD²-score’). b Delayed MRI is more sensitive in detecting ABLs and identifies high-risk subgroups (e.g., ABLs in 50% of AIS patients with ABCD² ≥ 4), but also no-risk subgroups (e.g., 0% ABLs in HINTS-negative AVS patients). Notably, b also includes those patients with an ABL already detected on the early CT (‘lesion-positive’ CT) who did not receive a redundant MRI. *Patients with benign paroxysmal positional vertigo (BPPV) were generally rare in our study cohort as they were usually identified and directly discharged from the ED

Fig. 2

Clinical pathway to help decision-making on brain imaging in patients presenting to the ED with dizziness, vertigo or imbalance and without a general medical cause⁺. TIA transient ischemic attack, BPPV benign paroxysmal positional vertigo, CPV central positional vertigo. ⁺General medical causes comprise various toxic, metabolic, infectious, or cardiovascular diseases (see Edlow et al. 2018 [8]). ^#Central oculomotor signs include: vertical or purely torsional spontaneous nystagmus, horizontal/vertical gaze-evoked nystagmus, gaze palsies, bilaterally disrupted smooth pursuit eye movements.*HINTS are positive (‘central’) if any of the following signs is present: normal head impulse test, the nystagmus’ fast phase alternating with gaze, skew deviation with a refixation on cover test. ^§The MRI may be dispensable if the lesion has already been detected by early CT. ^&Only the most likely and most relevant differential diagnosis is stated.