Bee Sting–Induced Ischemic Stroke with Divergent Outcomes: A Case Report and Review of 39 Cases

Technical Summary: Bee Sting–Induced Ischemic Stroke with Divergent Outcomes

Problem Statement
Bee and wasp stings (Hymenoptera envenomation) frequently cause local reactions, but systemic complications such as anaphylaxis, renal failure, and rhabdomyolysis are well-documented. However, ischemic stroke resulting from envenomation remains a rare, underdiagnosed, and clinically challenging entity. Prior to this report, fewer than 40 imaging-confirmed cases existed in global literature. The pathophysiology is complex and likely multifactorial, involving cerebral vasospasm, immune-mediated thrombosis, disseminated intravascular coagulation (DIC), and direct neurotoxicity. Crucially, no standardized management protocol exists for stroke following mass envenomation, and the clinical spectrum ranges from full recovery to death, often depending on the burden of stings and the presence of multi-organ dysfunction.

Methodology
This study presents a comparative case report of two Asian Indian male patients who sustained mass honeybee stings and subsequently developed ischemic strokes with divergent clinical trajectories.

• Case 1: A 70-year-old coal-mine worker with limited mobility sustained approximately 200 stings. He presented with acute neurological deterioration, acute kidney injury (AKI), and multi-organ failure.
• Case 2: A 47-year-old previously healthy man sustained over 100 stings. He developed a delayed posterior circulation syndrome on Day 2.
• Diagnostic Approach: Both patients underwent comprehensive evaluation including non-contrast CT, MRI with diffusion-weighted imaging (DWI), transthoracic echocardiography, and 24-hour Holter monitoring to exclude cardioembolic sources.
• Literature Review: The authors conducted a systematic review of 39 previously published cases (spanning 1962–2026) to contextualize their findings regarding onset timing, vascular territories, mechanisms, and outcomes.

Key Results

1. Divergent Clinical Outcomes:

   • Case 1 (Severe): Characterized by a massive sting burden (~200), multifocal embolic infarcts across anterior and posterior circulations, and severe systemic toxicity. Complications included AKI requiring hemodialysis, recurrent tracheostomy occlusion, nosocomial carbapenem-resistant superinfection, and progressive multi-organ failure. The patient was discharged against medical advice in a comatose, ventilator-dependent state.
   • Case 2 (Favorable): Characterized by a delayed onset (Day 2) of posterior circulation syndrome. MRI confirmed embolic infarcts in the bilateral cerebellar hemispheres, vermis, right occipital lobe, right thalamus, and splenium of the corpus callosum. The patient recovered fully with anticoagulation and supportive care, with no significant organ dysfunction.

2. Literature Synthesis (39 Cases):

   • Demographics: A strong male predominance (96.6% in reviewed cohorts) is observed, attributed to higher outdoor occupational exposure. Ages range from 17 months to 75 years.
   • Onset Timing: Neurological symptoms can appear from minutes to 14 days post-sting, with a median of 16 hours. Delayed presentations (e.g., Day 2 or later) are common and require prolonged vigilance.
   • Vascular Involvement: No vascular territory is exempt. The Middle Cerebral Artery (MCA) is most common, but posterior circulation and bilateral multi-territory infarctions occur. A rare case of cerebral venous sinus thrombosis was also documented.
   • Mechanisms: The review supports concurrent mechanisms:
     • Vasospasm: Supported by angiographic evidence of reversible arterial narrowing.
     • Immune-mediated Thrombosis: Involving mast cell degranulation and Kounis syndrome.
     • DIC and Systemic Inflammation: Dominant in mass envenomation, driven by hemolysis and venom proteases.
   • Outcomes: Outcomes vary from full neurological recovery to death. Mass envenomation burden, DIC, and multi-organ dysfunction are consistent predictors of poor prognosis.

Key Contributions

• Comparative Analysis: This report provides a rare two-case comparison from the Indian subcontinent highlighting how similar etiology (mass bee stings) can lead to vastly different outcomes based on sting burden, systemic response, and timing of intervention.
• Unique Clinical Features: Case 1 documents an extreme burden of envenomation with specific complications rarely detailed in literature, including live bee removal from the ear canal, extraction of >15 intraocular stingers, ecchymotic abdominal wall discoloration, and recurrent airway clotting requiring bronchoscopy. Case 2 adds a unique infarct pattern involving the splenium of the corpus callosum alongside posterior circulation territories.
• Diagnostic Clarity: The study reinforces the necessity of early MRI with DWI in patients with mass envenomation, even in the absence of immediate neurological signs, as demonstrated by the delayed onset in Case 2.

Significance and Claims
The authors assert that bee sting–induced ischemic stroke is a serious, potentially fatal complication that requires high clinical suspicion. The paper claims that:

1. Early Recognition is Critical: Neurological assessment and prompt MRI are essential following mass envenomation, particularly when new headaches or focal deficits appear hours to days later.
2. Multidisciplinary Management: Severe cases require coordinated care involving emergency medicine, neurology, nephrology, pulmonology, ophthalmology, and ENT to manage both the stroke and systemic envenomation sequelae.
3. Mechanistic Complexity: Clinicians must consider vasospasm, immune-mediated thrombosis, and DIC as concurrent mechanisms rather than mutually exclusive causes.
4. Treatment Gaps: While anti-allergic therapy and stroke-specific management (anticoagulation, thrombolysis in select cases) are used, no evidence-based protocol exists. The authors call for larger prospective registries to establish standardized guidelines for this rare emergency.

The paper concludes that while some patients (like Case 2) may achieve full recovery, the trajectory can be devastating (like Case 1) if mass envenomation triggers a systemic inflammatory cascade and multi-organ failure.