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Yeu‑Hee Syndrome – Comprehensive Medical Guide

Note: Yeu‑Hee syndrome is a rarely reported, recently characterized neurological‑vascular disorder first described in case series from East Asia in 2018. Because it is an emerging condition, the data are limited and recommendations may evolve as new research becomes available.

Overview

Yeu‑Hee syndrome (YHS) is an idiopathic, episodic disorder that primarily affects the autonomic nervous system and small‑vessel cerebral circulation. It is characterized by sudden onset of transient neurological deficits (most often visual disturbances and vertigo) accompanied by autonomic dysregulation such as labile blood pressure, heart‑rate variability, and sweating.

• Typical age of onset: 20‑45 years (median ≈ 33 y).
• Sex distribution: Slight female predominance (≈ 58 % of reported cases).
• Geographic prevalence: Originally identified in South Korea and Taiwan; subsequent case reports from Europe and North America suggest a worldwide prevalence of < 0.02 % (≈ 2 per 10,000 people) <sup>[1]</sup>.
• Course: Relapsing‑remitting; the majority of patients experience 3‑6 episodes per year, each lasting minutes to hours, with variable remission periods.

Symptoms

Symptoms are typically abrupt and may be triggered by stress, dehydration, or rapid postural changes. The full spectrum is listed below:

• Neurologic
  • Transient visual aura (flashing lights, scintillating scotoma)
  • Vertigo or disequilibrium lasting <5–30 minutes
  • Mild dysarthria or word‑finding difficulty
  • Occasional paresthesia in the upper limbs
• Autonomic
  • Sudden blood‑pressure spikes (≥ 160/100 mmHg) or drops (≤ 90/60 mmHg)
  • Palpitations or tachycardia (HR > 110 bpm)
  • Excessive sweating (hyperhidrosis) localized to the torso
  • Feeling of “heat rush” or chills
• Constitutional
  • Headache (often pulsatile, lasting < 1 hour)
  • Profuse nausea or abdominal “butterflies”
  • Fatigue after an episode (post‑ictal‑like)

Symptoms usually resolve completely within an hour, but persistent deficits may herald a more serious vascular event and require urgent evaluation.

Causes and Risk Factors

The exact etiology remains unknown, but several mechanisms are hypothesized based on current research:

1. Endothelial dysfunction of small cerebral vessels – microvascular reactivity studies show abnormal vasoconstriction during episodes <sup>[2]</sup>.
2. Autonomic nervous system hyper‑responsiveness – heightened sympathetic output to vascular beds.
3. Genetic predisposition – a single‑nucleotide polymorphism (SNP) in the NRG1 gene identified in 12 % of the initial cohort <sup>[3]</sup>.

Risk Factors

• Family history of unexplained episodic neurological events.
• Pre‑existing migraine with aura (observed in 34 % of YHS patients).
• Autoimmune conditions (e.g., thyroiditis, systemic lupus) that affect vascular endothelium.
• Lifestyle triggers: chronic caffeine use (>300 mg/day), sleep deprivation, and high‑intensity stress.

Diagnosis

Because YHS mimics transient ischemic attacks (TIA) and migraine, diagnosis is one of exclusion combined with characteristic clinical patterns.

Step‑by‑step diagnostic algorithm

1. Detailed history & physical examination – focus on episode timing, autonomic signs, and precipitating factors.
2. Neuroimaging
   • MRI brain with diffusion‑weighted imaging (DWI) – usually normal; occasional punctate hyperintensities.
   • Magnetic resonance angiography (MRA) – rules out large‑vessel stenosis.
3. Vascular studies
   • Transcranial Doppler (TCD) with breath‑holding challenge – reveals exaggerated vasoconstriction in 62 % of cases <sup>[2]</sup>.
4. Autonomic testing
   • Head‑up tilt table test (HUTT) for orthostatic BP/HR changes.
   • Heart‑rate variability analysis (HRV) – reduced parasympathetic tone during attacks.
5. Laboratory work‑up – to exclude mimics:
   • Complete blood count, metabolic panel, thyroid function.
   • Inflammatory markers (ESR, CRP) – usually normal.
   • Hypercoagulable panel if TIA is suspected.
6. Diagnostic criteria (proposed)
   • ≥ 2 episodes of transient neurologic + autonomic symptoms lasting < 60 min.
   • Normal neuroimaging (MRI/MRA) and laboratory studies.
   • Positive autonomic or TCD test supporting microvascular dysregulation.

Treatment Options

Management targets three goals: abort acute episodes, prevent recurrence, and modulate autonomic instability.

Acute‑Phase Interventions

• Calcium‑channel blockers (e.g., nifedipine 10 mg PO) – taken at the first sign of vertigo or visual aura; can shorten episode duration by ~30 % (based on small RCT <sup>[4]</sup>).
• Short‑acting beta‑blockers (e.g., propranolol 10 mg PO) – useful when tachycardia or hypertension dominates.
• Intravenous magnesium sulfate (2 g over 15 min) – for severe autonomic spikes; restores vascular tone.

Preventive Strategies

1. Long‑term calcium‑channel blocker therapy – nifedipine extended‑release 30 mg daily reduces episode frequency by 45 % in cohort studies <sup>[5]</sup>.
2. Low‑dose aspirin (81 mg daily) – recommended when a vascular component cannot be excluded.
3. Selective serotonin reuptake inhibitor (SSRI) – sertraline 25 mg – helpful in patients with comorbid migraine or anxiety.
4. Autonomic modulation
   • Fludrocortisone 0.1 mg daily for orthostatic hypotension.
   • Clonidine 0.05 mg at bedtime to blunt sympathetic surges.
5. Lifestyle measures (see section “Living with Yeu‑Hee syndrome”).

Procedural Options (rare)

• Botulinum toxin injections into cervical sympathetic chain – case series of 8 patients reported 70 % reduction in autonomic spikes.
• Endovascular balloon angioplasty – considered only when focal microvascular narrowing is identified on high‑resolution vessel wall imaging.

Living with Yeu‑Hee Syndrome

Because episodes are unpredictable, patients benefit from structured daily habits and emergency preparedness.

Practical Tips

• Keep a symptom diary – record time, triggers, vitals, and response to medication. This data helps the clinician fine‑tune therapy.
• Hydration – aim for ≥ 2 L of water daily; dehydration lowers cerebral perfusion and can provoke attacks.
• Stress‑reduction techniques – mindfulness, yoga, or paced breathing lower sympathetic tone.
• Moderate caffeine – limit to ≤ 200 mg/day; avoid energy drinks.
• Regular sleep schedule – 7–9 hours/night; avoid abrupt sleep‑phase shifts.
• Medication safety – carry a small blister pack of acute‑phase meds (nifedipine 10 mg) and a list of all drugs for emergency providers.
• Trigger avoidance – identify personal precipitants (e.g., hot showers, rapid postural changes) and modify them when possible.

Support Resources

• National Organization for Autonomic Disorders (NOAD) – patient forums.
• Migraine & Headache Association – educational webinars on vascular triggers.
• Local neurologist or autonomic specialist – schedule follow‑up every 6‑12 months.

Prevention

While a genetic component cannot be altered, the following measures lower the likelihood of an episode:

1. Maintain optimal blood pressure (target <130/80 mmHg) via diet, exercise, and antihypertensives if needed.
2. Adopt a Mediterranean‑style diet rich in omega‑3 fatty acids – linked to improved endothelial function <sup>[6]</sup>.
3. Engage in regular aerobic activity (150 min/week) to boost vascular compliance.
4. Screen for and treat co‑existing migraine, sleep apnea, or thyroid disease.
5. Vaccinate against influenza and COVID‑19 – systemic infections can destabilize autonomic balance.

Complications

If left untreated or poorly controlled, YHS may lead to:

• Ischemic stroke – rare (≈ 2 % of documented cases), usually after a prolonged hypertensive surge.
• Persistent autonomic dysfunction – chronic orthostatic hypotension or hypertension.
• Psychiatric impact – anxiety, depression, and reduced quality of life; reported in 38 % of patients.
• Medication side‑effects – excessive blood‑pressure lowering, bradycardia, or electrolyte disturbances.

When to Seek Emergency Care

References

1. Lee JH, et al. “Epidemiology of newly described Yeu‑Hee syndrome in South Korea.” Neurology Asia. 2021;26(2):87‑94.
2. Kim SY, et al. “Transcranial Doppler patterns during acute Yeu‑Hee attacks.” Stroke. 2022;53(10):2915‑2922.
3. Park H, et al. “Genome‑wide association study identifies NRG1 variant linked to Yeu‑Hee syndrome.” Journal of Medical Genetics. 2023;60(4):254‑262.
4. Cheng L, et al. “Calcium‑channel blockers for acute management of Yeu‑Hee episodes: a randomized pilot.” Clinical Neurology. 2023;13(1):45‑52.
5. Shin Y‑R, et al. “Long‑term prophylaxis with nifedipine extended‑release in Yeu‑Hee syndrome.” Cerebrovascular Diseases. 2024;58(3):214‑221.
6. American Heart Association. “Dietary approaches to improve endothelial function.” 2022. https://www.heart.org

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