Alpha-gal syndrome is an underrecognized, tick-associated allergic reaction that can cause delayed anaphylaxis, posing a growing diagnostic challenge in the emergency department. Transmitted most commonly by the bite of the lone star tick, this serious allergic reaction to red meat and other mammal products was once rare and geographically limited. However, owing to climate change, shifting bird migration patterns, and the movement of deer, the lone star tick is now found along the entire East Coast and is spreading into the western United States. As this tick moves into new regions, more people are being exposed to alpha-gal syndrome—often without awareness of the condition. Because symptoms are delayed and can vary widely, the syndrome is frequently misdiagnosed or overlooked entirely. Insufficient awareness during ED assessment may delay recognition and escalate patient risk, emphasizing the need for strengthened nursing education and heightened diagnostic vigilance in underrecognized regions.

Dizziness is a common clinical presentation that incurs huge financial costs. It is frequently misdiagnosed due to a wide differential involving both benign (inner ear disease) and serious (stroke) disorders. Traditional frameworks that emphasize symptom quality (dizziness/lightheadedness/vertigo) lack diagnostic utility. This Clinical Progress Note reviews the literature on acute dizziness evaluation in adult patients and presents an evidence-based framework for hospitalists to diagnose the majority of undifferentiated dizzy patients at the bedside. Future research should assess the validity of this approach with hospitalists' ability to accurately diagnose dizzy patients, and its impact on patient care and healthcare outcomes.

New-onset vertigo, dizziness and gait imbalance are amongst the most common symptoms presenting to the emergency department, accounting for 2.1–4.4% of all patients. The broad spectrum of underlying causes in these patients cuts across many specialties, which often results in diagnostic challenges. For patients meeting the diagnostic criteria for acute vestibular syndrome (AVS, i.e., presenting with acute-onset prolonged vertigo/dizziness with accompanying gait imbalance, motion intolerance, nausea/vomiting, with or without nystagmus), the typical differential diagnosis is vertebrobasilar stroke and acute unilateral vestibulopathy. However, other disorders may also present with AVS. These include non-neurological causes such as drug side-effects or intoxication, electrolyte disturbances, cardiac disease, severe anemia, carbon monoxide poisoning, endocrine disorders and others. Other non-stroke neurological disorders may also present with AVS or episodic vertigo/dizziness, including demyelinating CNS diseases, posterior fossa mass lesions, acute thiamine deficiency and vestibular migraine. Furthermore, acute physiological abnormalities (e.g., hypotension, fever, severe anemia) may unmask previous vestibular impairments that had been well-compensated. Here, we review the diagnostic approach to patients with acute-onset dizziness in the emergency room and discuss the most important differential diagnoses beyond stroke and acute unilateral vestibulopathy.

Headache accounts for 2% to 3% of emergency department visits annually. While the vast majority of these patients have a primary, non-serious cause, a small proportion of these patients have a "cannot miss" secondary cause that if misdiagnosed or have a delay in diagnosis, result in poor patient outcomes. The majority of serious diagnoses include subarachnoid hemorrhage, other types of intracranial hemorrhage including subdural hematoma, strokes, meningitis, and other non-neurologic etiologies. It is important for emergency physicians to identify through a careful history, physical examination, and consideration of epidemiologic factors which patients require extensive testing.

Headache is a common presenting complaint in the emergency department (ED).1 In the general population, primary headache disorders-migraine and tension-type headache-are incredibly common. Approximately 12% of the population has migraine headaches.2 The 1 year US prevalence is 47 million individuals with migraine and 65.6 million with tension-type headache.3 Most do not seek care in the ED, but migraine is still a common reason for ED visits. By contrast, secondary headache disorders are orders-of-magnitude less common, setting up the familiar emergency medicine conundrum of the needle in the haystack. Whereas knowledge about migraine is important for emergency clinicians,4 a missed migraine diagnosis does not have the same medico-legal implications than missing a subarachnoid hemorrhage (SAH) or a vertebral artery dissection. This article reviews diagnosis and misdiagnosis of secondary headaches in the ED. The author also proposes some practical methods to avoid or mitigate the effects of misdiagnosis based on a non-systematic literature search, my 40 years of clinical experience, my 25 years of attendance of weekly morbidity and mortality conferences, and over 20 years of

Importance:There is limited evidence regarding the frequency of diagnostic errors and outcomes associated with them in emergency care in the US. Objective:To examine rates of potential diagnostic errors and associated clinical outcomes among Medicare beneficiaries with emergency hospitalizations. Design, Setting, and Participants:This cohort study examined a national sample of fee-for-service Medicare beneficiaries aged 65 years or older with emergency hospitalizations for 10 high-risk conditions from 2016 to 2019. Data were analyzed from December 20, 2022, to April 16, 2025. Exposure:Potential diagnostic errors in the emergency department (ED). Main Outcome and Measures:The percentage of hospitalizations with an ED discharge (potential diagnostic error) in the preceding 9 days was calculated. From this observed ED visit rate, an adjusted rate of potential diagnostic errors was calculated by subtracting the rate of background ED discharges among a comparison cohort of beneficiaries with similar baseline risk. To examine the association between potential diagnostic error and outcomes, multivariable linear regression models were specified for the outcomes: 30-day mortality and healthy days at home (HDAH). Potential diagnostic error was the exposure, and the models were adjusted for diagnosis, patient demographics, and chronic conditions. Results:Among 302 837 emergency hospitalizations, 13 550 (4.5%) were preceded by an ED discharge (ie, potential diagnostic error) within 9 days. For the comparison group with similar baseline risk, 1.2% (95% CI, 1.2%-1.3%) had an ED discharge in a random 9-day period. After accounting for this background use, the adjusted potential diagnostic error rate was 3.2% (95% CI, 3.1%-3.3%) for all conditions in aggregate but ranged from 2.1% (95% CI, 1.9%-2.4%) for spontaneous intracranial hemorrhage to 15.6% (95% CI, 11.9%-19.3%) for spinal abscess. Having a potential diagnostic error was associated with higher adjusted 30-day mortality for emergency admissions (15.7% vs 14.9%; point absolute difference, 0.8 percentage points, 95% CI, 0.2 to 1.4 percentage points; P = .007) as well as fewer 30-day HDAH (13.5 days vs 15.0 days; difference, -1.4 days; 95% CI, -1.6 to -1.3 days; P < .001), although associations varied among conditions. Conclusions and Relevance:In this cohort study of Medicare beneficiaries aged 65 years and older with emergency hospitalizations, the adjusted potential diagnostic error rate was modest overall but varied by condition. Potential diagnostic errors were associated with worse outcomes for emergency conditions overall, with associations again varying among individual conditions.

Correct identification of those patients presenting with an acute vestibular syndrome (AVS) or an acute imbalance syndrome (AIS) that have underlying posterior-circulation stroke (PCS) and thus may benefit from revascularization (intravenous thrombolysis (IVT), endovascular therapy (EVT)) is important. Treatment guidelines for AVS/AIS patients are lacking. We reviewed the evidence on acute treatment strategies in AVS/AIS focusing on predictors for IVT/EVT and outcome. We performed a systematic search (MEDLINE, Embase) to identify studies reporting on acute treatment in PCS presenting as AVS/AIS (PROSPERO-registration = CRD42024537272). Key parameters were extracted. Risk of bias was assessed (Downs-and-Black quality assessment checklist). We identified 3883 citations and included seven study cohorts (n = 1000 patients including 950 ischemic strokes). Overall, 251/1000 patients (25.1 ≤ 2 after 90 days was noted in 68.4–69.6

Background A major systematic review and meta-analysis assessing trial data through 2014 (the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials, HERMES) demonstrated that particularly over the initial six hours of acute ischemic stroke (AIS), rapid performance of endovascular therapy (EVT) markedly improves outcomes. The current analysis, Success with Incrementally Faster Times to EVT (SWIFT-EVT), aimed to provide an updated metric summarizing latest estimates for modified Rankin Scale (mRS) improvements accrued by streamlining time to EVT. Methods A systematic review and meta-analysis was conducted using electronic databases. Eligible studies reported a time-benefit slope with times from AIS onset (or time last known normal) to EVT commencement; the predictor was onset-to-groin (OTG) time. Primary and secondary outcomes were 90-day functional independence (mRS 0-2) and 90-day excellent function (mRS 0-1), respectively. Results Five studies were included. Results showed increased change of good outcome with each hour of pre-EVT time savings for mRS 0-2 for 0-270’ (OR 1.25, 95% CI 1.16-1.35, I2 40%) and 271-360’ time frame (1.22, 95% CI 1.12-1.33, I2 58%). For the studies assessing mRS 0-1, estimates were found appropriate for both the 0-270’ time frame (OR 1.34, 95% CI 1.19-1.51, I2 27%) and the 271-360’ time frame (OR 1.20, 95% CI 1.03-1.38, I2 60%). Conclusions Each hour saved from AIS onset to EVT start is associated with a 22-25% increased odds of achieving functional independence, a useful metric to inform patient-specific and systems planning decisions.

Background and ObjectivesIntubation for acute stroke is common in the United States, with few established guidelines. MethodsThis is a retrospective observational study of acute stroke admissions from 2011 to 2018 among fee-for-service Medicare beneficiaries aged 65-100 years. Patient demographics and chronic conditions as well as hospital characteristics were identified. We identified patient intubation, stroke subtype (ischemic vs intracerebral hemorrhage), and thrombectomy. Factors associated with intubation were identified by a linear probability model with intubation as the outcome and patient characteristics, stroke subtype, and thrombectomy as predictors, adjusting for within-hospital correlation. We compared hospital characteristics between adjusted intubation rate quartiles. We specified a linear probability model with 30-day mortality as the patient-level outcome and hospital intubation rate quartile as the categorical predictor, again adjusting for patient characteristics. We specified an analogous model for quartiles of hospital referral regions. ResultsThere were 800,467 stroke hospitalizations at 3,581 hospitals. Among 2,588 hospitals with 25 or more stroke hospitalizations, the median intubation rate was 4.8%, while a quarter had intubation rates below 2.4% and 10% had rates above 12.5%. Ischemic strokes had a 21% lower adjusted intubation risk than intracerebral hemorrhages (risk difference [RD] -21.1%, 95% CI -21.3% to -20.9%; p < 0.001), whereas thrombectomy was associated with a 19.2% higher adjusted risk (95% CI RD 18.8%-19.6%; p < 0.001). Women and older patients had lower intubation rates. Large, urban hospitals and academic medical centers were overrepresented in the top quartile of hospital adjusted intubation rates. Even after adjusting for available characteristics, intubated patients had a 44% higher mortality risk than non-intubated patients (p < 0.001). Hospitals in the highest intubation quartile had higher adjusted 30-day mortality (19.3%) than hospitals in the lowest quartile (16.7%), a finding that was similar when restricting to major teaching hospitals (22.3% vs 18.1% in the 4th vs 1st quartiles, respectively). There was no association between market quartile of intubation and patient 30-day mortality. DiscussionIntubation for acute stroke varied by patient and hospital characteristics. Hospitals with higher adjusted rates of intubation had higher patient-level 30-day mortality, but much of the difference may be due to unmeasured patient severity given that no such association was observed for health care markets.

In The Prince, Niccol Machiavelli wrote, "[W]ith those hectic fevers, as the doctors say, ... at their beginning [they] are easy to cure but difficult to recognize, but in the course of time... [they] become easy to recognize but difficult to cure."(1) As with Renaissance politics, so with stroke; time plays a critical role in diagnosis and treatment. Since 2008, the investigators in the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT) have been incrementally replacing opinion with evidence regarding the treatment of hypertension in patients with spontaneous intracerebral hemorrhage diagnosed by brain computed tomography (CT).(2) Their current . . .

Diagnosing patients presenting to the emergency department with self-limited episodes of isolated dizziness (the episodic vestibular syndrome) requires a broad differential diagnosis that includes posterior circulation transient ischemic attack. Because these patients are, by definition, asymptomatic without new neurologic findings on examination, the diagnosis, largely based on history and epidemiologic context, can be challenging. We review literature that addresses the frequency of posterior circulation transient ischemic attack in this group of patients compared with other potential causes of episodic vestibular syndrome. We present ways of distinguishing posterior circulation transient ischemic attack from vestibular migraine, the most common cause of episodic vestibular syndrome. We also present a diagnostic algorithm that may help clinicians to work their way through the differential diagnosis.

Reversible cerebral vasoconstriction syndrome is a common, increasingly recognized cause of thunderclap headache. Most patients have some type of trigger that precedes the onset (e.g., orgasm, physical exertion, Valsalva maneuvers, exposure to vasoconstrictive medications) followed by multiple short-duration thunderclap headaches that occur over days to weeks. Physical examination is often without focal neurological deficits. Brain computed tomography may be normal, or show a convexal subarachnoid hemorrhage. Angiography shows multifocal areas of cerebral arterial vasoconstriction, although can be normal early in the course. The vasoconstriction is reversible and repeat angiography in three months will show normalization. The clinical outcomes are usually good despite some patients having hemorrhagic or ischemic strokes. Treatment is primarily analgesics and avoidance of triggers. Triptans, steroids and immunosuppressive agents, which are sometimes used if migraine or central nervous system angiitis is suspected, should be avoided. Improved recognition of RCVS will likely lead to earlier diagnosis and minimize potentially harmful empiric treatment strategies.