Delayed Vasospastic Limb Ischemia Following Jellyfish Sting Successfully Treated With Intravenous Iloprost

Technical Summary: Delayed Vasospastic Limb Ischemia Following Jellyfish Sting Successfully Treated With Intravenous Iloprost

Problem Statement
Jellyfish envenomation is a common marine hazard, typically presenting with transient local pain and inflammation. However, rare, severe, and delayed complications can occur, specifically arterial vascular insufficiency and digital ischemia resulting from profound local vasospasm. These conditions are limb-threatening and often lack evidence-based localized management protocols. The authors highlight a specific clinical challenge: distinguishing venom-induced vasospasm from other causes of acute limb ischemia, such as compartment syndrome or thrombosis, particularly when symptoms manifest days after the initial sting. In the reported cases, the delayed onset (four days post-sting) of critical ischemia in two pediatric siblings complicated the initial diagnosis and management.

Methodology
This study is a retrospective case report detailing the clinical course, diagnostic workup, and therapeutic intervention for two siblings (a 9-year-old boy and a 7-year-old girl) who suffered delayed vasospastic limb ischemia following a jellyfish sting in Batu Feringghi, Malaysia.

• Diagnostic Approach: Upon presentation with cyanosis, diminished or absent pulses, and motor deficits, the medical team performed a rigorous differential diagnosis. Orthopedic consultation and compartment pressure assessment ruled out compartment syndrome. Imaging included Computed Tomography Angiography (CTA) and serial Doppler ultrasound. While CTA showed poor contrast opacification distal to the brachial artery (unable to exclude thrombosis), the clinical context of delayed toxicological insult without atherosclerotic disease or embolic sources pointed toward functional arterial spasm.
• Therapeutic Intervention: The primary intervention was a continuous intravenous (IV) infusion of Iloprost (Ilomedin®), a potent prostacyclin analogue acting as a vasodilator and platelet aggregation inhibitor.
  • Dosing Strategy: Due to the risk of systemic adverse events (hypotension, tachycardia), the infusion was initiated at a low dose (approx. 0.16–0.17 ng/kg/min) and carefully up-titrated every 30 minutes to a maximum target of 1.5 ng/kg/min.
  • Adjunctive Therapy: Patients received oral Aspirin (5 mg/kg/day) and empirical antibiotics.
  • Weaning Protocol: A critical methodological refinement involved a gradual tapering of the Iloprost over 10 days. To prevent rebound vasoconstriction during withdrawal, topical Glyceryl Trinitrate (GTN) patches were introduced as a pharmacological bridge.
• Monitoring: Objective response was monitored via twice-daily Doppler ultrasound measurements of arterial calibre (diameter) and Peak Systolic Velocity (PSV), alongside clinical assessment of pulse palpability, capillary refill time, and tissue oxygen saturation.

Key Results
Both patients demonstrated marked clinical and hemodynamic improvement within days of initiating Iloprost therapy.

• Clinical Recovery: The 9-year-old boy, who initially presented with weak radial/ulnar pulses and cyanosis, regained strong pulses and normal coloration. The 7-year-old girl, who presented with absent brachial/radial/ulnar pulses and profound motor loss, regained palpable pulses and full motor function. Both achieved full functional recovery without surgical intervention (e.g., fasciotomy or amputation) or long-term disability.
• Hemodynamic Metrics: Serial Doppler data confirmed the reversal of vasospasm.
  • Boy: The affected left brachial artery calibre increased from 0.15 cm (Day 2) to 0.30 cm (Day 10). PSV in the brachial artery rose from 18.0 cm/s to 45.6 cm/s.
  • Girl: The affected right brachial artery calibre expanded from 0.18 cm (Day 2) to 0.29 cm (Day 10). Crucially, the radial artery PSV, which was critically low at 9.8 cm/s on Day 2, recovered to 35.2 cm/s by Day 10.
• Tolerance: Both patients tolerated the high-dose continuous infusion well, with no reported systemic adverse reactions such as headache, gastrointestinal distress, or cardiovascular compromise.

Significance and Claims
The paper posits that these cases contribute to a growing body of evidence supporting the use of intravenous Iloprost as a critical, non-operative management strategy for delayed, jellyfish-sting-induced vasospastic ischemia.

• Therapeutic Efficacy: The authors claim that Iloprost effectively reversed severe arterial spasm that was unresponsive to standard first-line treatments (such as nitrates and calcium channel blockers in other reported cases) and prevented tissue necrosis.
• Protocol Refinement: The report emphasizes the importance of a specific weaning protocol involving the concurrent use of topical GTN to prevent rebound vasoconstriction, a lesson learned from a previous index case at the same institution where premature discontinuation led to symptom recurrence.
• Clinical Awareness: The authors underscore the necessity for medical practitioners to maintain a high index of suspicion for delayed vascular complications following jellyfish envenomation, even in the absence of immediate systemic toxicity.
• Limitations: The paper maintains a modest stance regarding its conclusions. It explicitly states that the findings are limited by the nature of a single case report involving two patients. The authors do not claim Iloprost as a definitive standard of care but rather as a promising off-label option that warrants further clinical experience and larger studies to establish evidence-based treatment algorithms. They note that current first-aid recommendations (e.g., vinegar application) are not species-specific and may vary in efficacy, highlighting a need for broader public education.