Link to Problems for Discussion - Plant Poisonings
Link to Problems for Discussion - Strychnine
Link to Problems for Discussion - Mushroom
Link to Problems for Discussion - Colchicine-containing plants
Link to Problems for Discussion - Herbals
Link to Problems for Discussion - Volatile Oils
This sections aims to cover the toxicology of the following important poisonings:
Plants containing nicotinic alkaloids lead to sympathetic over stimulation. In severe cases these patients can develop coma, seizures, cardiovascular collapse followed by respiratory paralysis. Tobacco and Poison Hemlock are well known plants that contain nicotinic alkaloids.
Strychnine poisoning was a common pharmaceutical poison in the past. Plants containing strychnine give rise to similar clinical manifestations. Strychnine inhibits glycine, an important inhibitory neurotransmitter in the spinal cord. This leads to generalized muscle contractions.
Unintentional ingestion of mushrooms is still an important problem with deaths occurring in some parts of the world. Toxic mushrooms can present various clinical presentations due to the differing toxins present. Cyclopeptides ( e.g. Amanita phalloides), glyromitrin ( e.g. G. californica), Muscarine (Clitocybe dealbata), Coprine e.g. C. atramentarius) and Psilocybin (e.g. C. cubensis) are some of the toxins present in this group of mushrooms.
Colchicine cantained in plants such as Gloria superba and Colchicium autumnale inhibits microtubular formation within cells. This leads to interference with cellular mitosis and cell death. Interference of microtubular functions in all organs of the body can result in multi organ failure with the greatest effect manifesting in rapidly dividing cells such as the gastrointestinal tract.
Initial clinical presentation is in the gastrointestinal tract with nausea, vomiting and diarrhoea leading to volume depletion. In severe poisoning this initial clinical stage leads to multiorgan failure and finally death or recovery.