A 45-year-old man presents with bradycardia, heart block, and markedly elevated serum digoxin-like immunoreactive substances (DLIS) after consuming a herbal decoction containing yellow oleander (Thevetia peruviana) seeds. The correct statement about oleander glycoside toxicity compared to pharmaceutical digoxin toxicity is:
- A Specific anti-digoxin Fab fragments are contraindicated for oleander poisoning
- B Oleander glycosides (thevetin A and B) inhibit Na-K ATPase; anti-digoxin Fab fragments are effective because of cross-reactivity with these glycosides ✓
- C Oleander cardiac glycosides bind only to non-cardiac Na-K ATPase isoforms
- D Charcoal haemoperfusion is the definitive treatment unlike digoxin toxicity
Correct answer: B. Oleander glycosides (thevetin A and B) inhibit Na-K ATPase; anti-digoxin Fab fragments are effective because of cross-reactivity with these glycosides
Explanation
Yellow oleander (Thevetia peruviana) contains thevetin A and B, cardiac glycosides that inhibit Na-K ATPase by the same mechanism as digoxin, causing hyperkalaemia, bradyarrhythmias, and conduction blocks. Anti-digoxin Fab antibody fragments (Digibind/DigiFab) exhibit cross-reactivity with many cardiac glycosides including thevetins and have been used successfully in oleander poisoning. DLIS assays show false positives. Haemoperfusion is not the definitive treatment; Fab fragments are.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.