Toxic plants - 20% Flashcards
Guava- toxin principle, mechanism of action, species affected
common guava, has an opiate-like effect, causing ileus. The fruit and the leaves, when eaten by horses, thus causes colic, so rectal palpation must be performed.
Kiawe (mesquite)- taxonomy/characteristics, toxic principles, mechanism of action, HI cattle event
- Prosopis pallida- shade tree, invasive, kills plants by depriving them of water aka mesquite tree, thorns and pods (toxic)
- Toxicity- Ingestion pods by cattle, sheep, goats causes vacuolation of the trigeminal nucleus, resulting in tremors of the jaw and an inability to prehend food and thus to graze> paralysis. unknown principle in beans/ pods + high sucrose content destroys rumen microflora- GI disease with chronic exposure> ketosis, GI impaction with fibrous pods
Cattle event on Molokai- ketosis, impactions, liver cirrhosis.
Lantana- taxonomy, characteristics, toxic principles, pathogenesis, susceptible species, mechanism of action, clinical signs, treatment.
Verbenaceacae- flower with multicolors blossoms aka red sage, pungent aroma and taste
Toxic principle is pentacyclic triterpine alkaloids= lantadene A and B (triterpenoids).
Forage and ripe berries contain toxic substance - green berries have higher concentration of toxin.
Susceptible species are sheep cattle, horses, rabbits, guinea pigs, and children.
MOA - hepatotoxic/ gall bladder paralysis and photosensitive dermatitis.
Tx for 12-24 hrs. activate charcoal in known ingestions, physostigmine may initiate dramatic reversal of some signs within minutes. Watch for contraindications of physiostigmine such as obstruction, asthma, cardiovasc. dz etc.
Naalehu disease- what is it, species affected, plant species, mechanism of action, clinical signs/ diagnosis, treatment/ prevention
Enzootic calcinosis is a disease complex of ruminants and horses caused by plant poisoning or mineral imbalances and characterized by extensive calcification of soft tissues.
Cestrum diurinum (wild jasmine), Trisetum flavescens (golden oats, yellow oat grass)- plants containing 1,25 cholcalciferol> calcinogenic mimetic compounds- kidneys prevented from regulating calcium due to calcitrol in leaves, can also be caused by mineral imbalances in soil.
Higher altitude favors growth of these plants
Dx- suspicion of exposure to plants, dystrophic mineralization, abnormal Ca/Ph, ALP
Tx- change pasture exposure, feed oat hay (drying/ maturing reduces risk) vs. pasture grazing
Oleander- plant taxonomy, recognition, toxin, mechanism of action, treatment
Nerium oleander- most poisonous plant in the world- all parts, fresh or dried
Deadly cardioglycoside- oleandrine and nerine- positive ionotrope> arrhythmias (inhibiting the cellular membrane sodium-potassium (Na+-K+ ATPase enzyme system= depletion of intracellular potassium and an increase in serum potassium> decrease in electrical conductivity> arrhythmias> heart block> death
Tx induce emesis, GI binding, ECG for cardiac arrythmias and support, atropine/ glycopyrrolate, antiarrhythmics.
Paraquat (herbicide)- method of exposure/risk, target organs, clinical signs> pathophysiology, treatment, diagnosis,
Inhaled or ingested- main target organs are the gastrointestinal tract, lung and kidney. Malicious poisonings are common with this herbicide.
Immediately following exposures, abdominal tenderness, vomiting, anorexia, diarrhea and mucosal ulcers > respiratory compromise (e.g., tachypnea, dyspnea, exercise intolerance, cyanosis, rales) due to severe edema> congestion, hemorrhage and necrosis of the bronchiolar and alveolar epithelium within the lung +/- fibrosis of the lung and necrosis of the renal tubule epithelium
Successful treatment rare, supportive measures may make the condition worse (chronic phase typically due to lung fibrosis and non-responsive to oxygen). Poisonings are generally confirmed postmortem by residue testing of urine, liver, kidney and lung tissue, along with characteristic histologic lesions of the lung and kidney.
Taro- taxonomy, toxic principle, clinical signs
The taro is in the family Araceae which also includes Calla lilies, philodendron and dumb cane.
These plants have idioblast cells contain calcium oxalate crystals.
When the plant is chewed upon the idioblasts break open, “injecting” the calcium oxalate cells into the mucous membranes of the mouth. Boiling the Taro root removes the calcium oxalate crystals, making them safe to eat (commonly made into poi).
Clinical signs can include immediate swelling of the lips and tongue, hypersalivation, retching, and vomiting, along with more species-specific signs of oral pain (bruxism in rabbits for example).
There is some concern that if a large amount of plant material was ingested that the swelling could be severe enough to cause an upper airway obstruction.
