Mydriasis Health Dictionary

A rare type of food poisoning with a mortality greater than 50 per cent, caused by the presence of the exotoxin of the anaerobic bacterium Clostridium botulinum, usually in contaminated tinned or bottled food. Symptoms develop a few hours after ingestion.

The toxin has two components, one having haemagglutinin activity and the other neurotoxic activity which produces most of the symptoms. It has a lethal dose of as little as 1 mg/kg and is highly selective for cholinergic nerves. Thus the symptoms are those of autonomic parasympathetic blockade (dry mouth, constipation, urinary retention, mydriasis, blurred vision) and progress to blockade of somatic cholinergic transmission (muscle weakness). Death results from respiratory muscle paralysis. Treatment consists of supportive measures and 4 aminopyridine and 3, 4 di-aminopyridine, which may antagonise the e?ect of the toxin.... botulism

Linn.

Synonym: D. tatula Linn.

Family: Solanaceae.

Habitat: The Himalaya from Kashmir to Sikkim up to 2,700 m, hilly districts of Central and South India.English: Thornapple, Jimsonweed, Stramonium.Ayurvedic: Krishnadhattuura, Dhuurta (black seed var.), Unmatta, Kitav, Tuuri, Maatul, Madan.

Unani: Dhaturaa.

Action: Spasmolytic, antiasthmatic, anticholinergic, cerebral depressant, nerve-sedative. Controls spasms of bronchioles in asthma. Anticholinergic. Effects of overdose are similar to those of atropine. Temporary relief from Parkinsonian tremor recorded. (Contraindicated with depressant drugs.) Applied locally, stramonium palliates the pain of muscular rheumatism, neuralgia, also pain due to haemorrhoids, fistula, abscesses and similar inflammations. Prevents motion sickness.

Key application: In diseases of the autonomic nervous system. (Included among unapproved herbs by German Commission E.) The British Herbal Pharmacopoeia reported antispasmodic action of the leaf; Indian Herbal Pharmacopoeia accepted it as expectorant and antispasmodic. Whole plant contains 0.26% alkaloids (seeds 0.98% and stem 0.08%); also flavonoids, withanolides, cou- marins and tannins; the major alkaloid is hyoscyamine (44-67%), hyoscine (13.2-25.3%) and atropine (0.01-0.1%). The tropane alkaloids are similar to those found in Atropa belladonna. Hyoscine is five times as active as atropine in producing mydriasis, but its main use is as antimotion sickness drug; and in combination as a sedative.Toxic constituents include anti- cholinergic alkaloids.

Dosage: Leaf—60-185 mg powder; seed—60-120 mg powder (CCRAS.)

... datura stramonium

n. paralysis of the ciliary muscle of the eye (see ciliary body). This causes inability to alter the focus of the eye and is usually accompanied by paralysis of the muscles of the iris, resulting in fixed dilation of the pupil (mydriasis). It is induced by the use of atropine or similar drugs in order to inactivate the muscle in cases of inflammation of the iris and ciliary body and to objectively assess the refractive status of the eye, particularly in children. It may also occur after injuries to the eye.... cycloplegia

(myosis) n. constriction of the pupil. This occurs normally in bright light. It is also seen in *Horner’s syndrome, but persistent miosis is most commonly caused by certain types of eye drops used to treat glaucoma. See also miotic. Compare mydriasis. —miotic adj.... miosis