Cleistanthus collinus poisoning.
Cleistanthus collinus, a toxic shrub, is used for deliberate self-harm in rural South India. MEDLINE (PUBMED) and Google were searched for published papers using the search/ MeSH terms "Cleistanthus collinus," "Euphorbiaceae," "Diphyllin," "Cleistanthin A," Cleistanthin B" and "Oduvanthalai." Non-indexed journals and abstracts were searched by tracing citations in published papers. The toxic principles in the leaf include arylnaphthalene lignan lactones - Diphyllin and its glycoside derivatives Cleistanthin A and B. Toxin effect in animal models demonstrate neuromuscular blockade with muscle weakness, distal renal tubular acidosis (dRTA) and type 2 respiratory failure with conflicting evidence of cardiac involvement. Studies suggest a likely inhibition of thiol/thiol enzymes by the lignan-lactones, depletion of glutathione and ATPases in tissues. V-type H+ ATPase inhibition in the renal tubule has been demonstrated. Mortality occurs in up to 40% of C. collinus poisonings. Human toxicity results in renal tubular dysfunction, commonly dRTA, with resultant hypokalemia and normal anion gap metabolic acidosis. Aggressive management of these metabolic derangements is crucial. Acute respiratory distress syndrome (ARDS) is seen in severe cases. Cardiac rhythm abnormalities have been demonstrated in a number of clinical studies, though the role of temporary cardiac pacemakers in reducing mortality is uncertain. Consumption of decoctions of C. collinus leaves, hypokalemia, renal failure, severe metabolic acidosis, ARDS and cardiac arrhythmias occur in severe poisonings and predict mortality. Further study is essential to delineate mechanisms of organ injury and interventions, including antidotes, which will reduce mortality.
Department of Medicine, Unit 2, Christian Medical College, Vellore, Tamil Nadu, India.
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