Ergot is primarily a vasoconstricting agent which is present in the dried sclerotinum of the fungus claviceps purpurae, which grows on stale grains, particularly rye and maize and on grass.
Active principle – About 12 alkaloids of more or less similar actions are available from ergot. These are divided into 3 different combinations namely, ergotoxin, ergotamine and ergometrine. The last one is also known as ergonovine or ergobasine. Ergotoxin is a combination of ergocomine, ergocrystine and ergokryptine. Ergotamine has a less toxic derivative, dihydroergotamine. Ergo-metrine is specifically used as an oxytocic agent.
Apart from these groups of alkaloids, ergot also contains some amount of histamine, tyramine and acetylcholine.
Fatal dose –10 gm or 10 -12 ml of fluid extract.
Fatal period – Death occurs after a few days except when the victim suffers from some cardio-vascular diseases when death may occur within a very short period (some hours).
Action and signs and symptoms – Active principles are absorbed from the G.I. tract, except histamine. Poisoning effects may be acute or chronic.
In acute poisoning, there are G.I. tract irritation and vasoconstriction and contraction of other smooth muscles. There are nausea, vomiting and diarrhoea. There is respiratory distress with a feeling of tightness in the chest. There are dizziness, numbness, dimness of vision, raised blood pressure with occasional bleeding from nose. There may be unconsciousness.
Chronic ergotism may either be convulsive type or gangrenous type. Combination of both type may occur in the same individual, very occasionally. In convulsive type, there are twitching, tingling, numbness and pain in the muscles. There may be convulsions. Contracture of muscles are not uncommon. Dementia may result in some. In gangrenous type, there is burning pain (called St. Anthony’s fire) in the limbs with inflammation and swelling with alternating heat and cold sense, numbness, tingling or anaesthesia. There are vesicle formation and cyanosis of the affected limb with gangrenous ulceration and sloughing. In fingers, toes, ears, nose or hands and feet there may be dry gangrene without swelling and ulceration.
Treatment – In case of acute poisoning, where there has not been loss of much time, vomiting may be induced or stomach wash may be given. Purgative is also useful. Nitrite is given to counter vaso-constriction. Vit. A is useful in convulsive variety. Pentobarbital or bromides may be given to sedate the patient.
Postmortem appearance – In gangrenous type, there is primarily, degeneration of the intima of the arterioles with thrombus formation. Gangrenous change may be present in some part of the body. In convulsive type, degenerative changes may be seen in the posterior column of the spinal cord.
Medicolegal aspects – Poisoning is mostly accidental. Acute accidental poisoning may occur due to consumption of food prepared with affected rye or grain. This may cause mass poisoning in an area. Ergot is used as an abortifacient agent. Systemic poisoning may also occur from this use. Chronic poisoning occurs when ergot preparation is used in the treatment of migraine or prolonged uterine haemorrhage. With therapeutic dose, death may occur in patients of cardiac insufficiency or in arteriosclerotic persons.