Unit 2 - Toxic Plants in Small Animals Flashcards
What species are affected by rhododendron?
Dogs, cats, and ruminants
What do rhododendrons look like?
Large shrubs to small trees - terminial clusters of large, attractive pink to purple flowers
What parts of rhododendrons are toxic?
All parts - especially leaves
What is the toxic principle of rhododendron species?
Andromedotoxin
What is the MOA of andromedotoxin?
Binds and blocks the inactivation of sodium channels in cell membranes which results in prolonged neuronal depolarization and excitation
When do most cases of rhododendron toxicosis occur?
Most ruminant cases occur in the winter and early spring
When is the onset of clinical signs for rhododendron toxicosis?
Within 6 hours
What clinical signs are associated with rhododendron species?
Depression, salivation, abdominal pain, vomiting
Arrhythmia, abnormal heart rate, hypotension
High fever, seizures
What typically causes death in rhododendron toxicosis cases?
Death - aspiration pneumonia/uncontrolled seizures
How is rhododendron toxicosis treated?
Emesis, activated charcoal + cathartic
Supportive therapy
No specific antidote
How is rhododendron toxicosis diagnosed?
Clinical signs and leavs in GI tract - detection of grayanotoxins in serum/urine/GI contents
Macadamia nut toxicosis is only reported in what species?
Dogs
What is the toxic principle of macadamia nuts?
It is unknown
When is the onset of clinical signs for macadamia nut toxicosis?
They generally begin within 12 hours and last less than 24 hours
What clinical signs are associated with macadamia nut toxicosis?
Non-fatal paralysis; weakness, ataxia, reeversible paresis and paralysis
What chemistry changes are associated with macadamia nut toxicosis?
Increased triglycerides and lipase
How is macadamia nut toxicosis treated?
Supportive care
What do oleander plants look like?
Smooth green stems, dark green leathery flowers, white or colored flowers, and they can be in bush or tree forms
How are small animals exposed to oleander? Large animals?
Small animals - common ornamental plant in the southern states
Large animals - may be baled with hay or chopped into silage
What toxin does oleander produce?
Oleandrin
What type of toxin is oleandrin?
It is a cardiac glycoside
What parts of oleander are toxic?
Stems, leaves, and flowers
What is the MOA of oleander?
Inhibition of Na/K-ATPase pump: increased intracellular sodium and hyperkalemia
T/F: Oleander is highly toxic.
True - 0.005% of the BW is toxic
What clinical signs are associated with oleander toxicosis?
Acute gastroenteritis, vomiting and/or diarrhea, weakness, colic
Bradycardia followed by tachycardia;arrythmia
Death following 2-48 hours post ingestion
How is oleander toxicosis diagnosed?
History of exposure and presence of plant parts in feed or vomitus
Confirmed by detection of oleandrin in body fluids/GI contents
How is oleander toxicosis treated?
Supportive therapy and removal of the offending material
What are the toxic principles of foxglove?
Cardiac glycosides - digitoxin and digoxin
Where is foxglove absorbed?
in the GI tract
When is foxglove toxic?
When it is dried - it is also water soluble
What is the MOA of foxglove toxicosis?
Inhibition of Na/K-ATPase pump: increased intracellular sodium and hyperkalemia
When does the onset of clinical signs occur for foxglove?
2-4 hours post ingestion
What clinical signs are associated with foxglove toxicosis?
Local irritation of the mouth and stomach, abdominal pain, nausea, vomiting
Cardiac irregularities - Bradycardia and then tachycardia and arrythmias
Peripheral vasoconstriction
Mydriasis, dizziness, ataxia, and respiratory paralysis resulting in coma and death
What lesion is possible with foxglove toxicosis?
Epicardial hemorrhage
What does Lily-of-the-valley look like?
Slightly cupped, spear-shaped green leave
Flowers are white, bell-like and drooping
What is the toxic principle of lily-of-the-valley?
30+ cardiac glycoside compounds
What is the toxic principle of the allium species?
n-propyl disulfide
T/F: N-propyl disulfide is only present in raw onions.
False - it is present in raw, cooked, and dried onions
What is the MOA of n-propyl disulfide?
- Increased free radical formation
- Direct RBC membrane damage and denatured hemoglobin
- Heinz body formation and acute hemolysis
What does the amount of toxin in allium species vary depending on?
Species, time of year, growing conditions, raw/cooked/dried
What laboratory findings are consistent with allium toxicosis?
Hemolytic anemia - max will be 7-12 days post exposure
Heinz body formation
Ecccentrocytes that occur secondary to oxidative stress
What species are most offen affected by allium toxicosis? What other species are susceptible?
Dogs most affected; cats and cattle are susceptible
What clinical signs are associated with allium toxicosis?
Acute hemolytic crisis - weakness, tachypnea, tachycardia, pale mm, icterus, anemia, and hemoglobinuria
How is allium toxicosis treated?
Supportive care - transfusion may be needed if severe
What plants belong in the Araceae family?
Dumbcane, Philodendron, ceriman, elephant’s ear, calla lily, arum lilly, peace lily, and caladium
What is the toxic agent of the Araceae family?
Insoluble calcium oxalates
What is the MOA of insoluble calcium oxalates?
- Local reactions are from kinins which may be aggravated by calcium oxalate crystals
- Mechanically damage cells in the mouth
- Local inflammatory response of the mouth
What clinical signs are associated with Araceae toxicosis?
Immediate pain and irritation upon chewing
Headshaking, intense hypersalivation, swelling of mucous membranes of pharynx and tongue, severe dyspnea, but rarely obstruction
What clinical signs are associated with severe cases of Araceae toxicosis?
Nausea, vomiting, diarrhea, secondary dehydration, electrolyte imbalance, and shock
How is Araceae toxicosis treated?
Symptomatic and supportive care - rinse mouth, activated charcoal, oral calcium, antihistamines/anti-inflammatory drugs, IV fluids if vomiting or diarrhea are persistent
What do castor beans look like?
Black or mottled with grey or brown
What is the toxic principle for Castor bean? Rosary pea?
Lectins - found in moost beans
Castor bean - ricin
Rosary pea - abrin
What parts of the castor bean and rosary pea plants are toxic?
All parts of the pant, but especially seeds
T/F: Does castor oil contain ricin?
No it does not
What is the MOA of the castor bean toxin?
A-B toxin
B-chain: binds to proteins on cell surface and facilitates internalization
A-chain: Enters the ER and depurinates rRNA which inactivates ribosomes and inhibits protein synthesis
What clinical signs are associated with castor bean toxicosis?
Vomiting with blood and diarrhea
When do clinical signs due to castor bean toxicosis occur?
Few hours to days
What lesions are associated with castor bean toxicosis?
Catarrhal to hemorrhagic gastritis
Petechial hemorrhages on serosal surfaces
Necrotizing enteritis
Edematous mesenteric lymph nodes
How is castor bean toxicosis diagnosed?
History of exposure
Leukocytosis with increased AST and ALT
Detection of toxin in gastric contents
How is castor bean toxicosis treated?
No specific antidote, supportive care
How is castor bean toxicosis prevented?
Do not plant where animals may have access
Clip seed heads before maturity when used as an ornamental
Moist heat destroys ricin
What plants are spurges?
Poinsettia, Snow-on-the-Mountain, spotted surge, and leafy spurge
What is the toxic principle of spurges?
Diterpenoid phorbol esters
What do diterpenoid phorbol esters do?
They are direct irritants/blistering compounds
What parts of the spurges plants are toxic?
All parts
What clinical signs are associated with spurges toxicosis?
Irritation of the mouth and GI tract Blistering Periocular and perioral swelling Excessive salivation, vomiting, diarrhea Sap may cause contact dermatitis
What treatment is associated with spurges toxicosis?
Supportive care - dilute toxins orally with water or milk, wash topical exposure with alcohol
What is the prognosis of spurges toxicosis?
Generally very good
What trees are mistletoe commonly associated with?
Oak, walnut, or other deciduous trees
What is the toxic principle of mistletoe toxicosis?
It is unknown
What clinical signs are associated with mistletoe toxicosis?
Acute GI upset - vomiting, nausea, and diarrhea
Other systemic signs - hypotension, weakness, bradycardia, and collapse
How is mistletoe toxicosis treated?
Supportive care - removal from GI tract
What is the major toxin associated with sago palm?
Cycasin
What are the toxic parts of the sago palm?
All of the parts of the plalnt - the seeds are especially toxic
When is the onset of clinical signs for sago palm toxicosis?
Usually within 12 hours
What clinical signs are associated with sago palm toxicosis?
Acute: vomiting +/- blood, diarrhea, salivation
Depression, weakness, tremors, and seizures
Abdominal pain, jaundice, bruising, and dark tarry stool
What clinical pathology abnormalities are associated with sago palm toxicosis?
Elevated ALT, AST, Alk phos, and bilirubin
What lesions are associated with sago palm toxicosis?
Hemorrhage and necrosis of the GI mucosa
Liver: centrilobular and midzonal necrosis
How is sago palm toxicosis treated?
Aggressive decontamination of the GI tract, GI protectants, and fluids as needed
What is the prognosis for sago palm toxicosis?
Guarded to poor
What lilies are toxic?
Easter lily, tiger lily, and day lily
What species are uniquely sensitive to lily toxicosis?
Cats
T/F: The water from a flower vase with a lily is toxic.
True
Lilies are _____ excreted, so _____ hours of fluid diuresis can prevent death.
rapidly; 24
What gross lesions does lily toxicosis cause?
Pulmonary and hepatic congestion
Perirenal edema and swollen kidney
What microscopic lesions are associated with lily toxicosis?
Diffuse acute renal tubular necrosis typically in the proximal tubules with intact basement membraines
Granular and hyaline casts in collecting ducts
What clinical signs are associated with lily toxicosis?
Both renal and GI: vomiting and salivation, depression and anorexia, polyuria for 12-24 hours or until anuria develops, dehydration, weakness, recumbence and death
What laboratory results are associated with lilies?
Proteinuria, glucosuria, isosthenuria, casts, anuria
Stress leukogram
Increased BUN, Creatinine, P and K
Late in syndrome - increased ALT and ALP
What treatment is recommended for lily toxicosis?
GI decontamination - emesis, activated charcoal, cathartic
Fluid therapy prior to anuria to prevent dehydration
What is the prognosis for lily toxicosis?
IV fluid treatment prior to anuria is good
No treatment/late treatment is grave
How is lily toxicosis prevented?
Owner education
What species are most commonly affected by grape and raisin toxicois?
Dogs
Are raisins or grapes more toxic?
Raisins
What is the mechanism for grape/raisin toxicosis?
It is unknown
What clinical signs are associated with grape and raisin toxicosis?
Vomiting and/or diarrhea within a few hours of ingestion Anorexia Lethargy and weakness May show signs of abdominal pain Polydipsia Tremors Anuria in advanced cases Once anuric - death due to renal failure
What clinical pathology abnormalities are associated with grape and raisin toxicosis?
Hypercalcemia, hyperphosphatemia, and azotemia
What microscopic lesions are associated with grape and raisin toxicosis?
Degeneration and necrosis of PCT epithelium - intact basement membranes, +/- regeneration, mineralization
How is grape and raisin toxicosis treated?
Early - emetics and activated charcoal
Hospitalization with IV fluids
Monitor serum chemistries and urine output closely for 3 days
When is the prognosis for grape and raisin toxicosis guarded?
When there is evidence of renal failure
What species are primarly effected by stinging nettles?
Hunting dogs
What do stinging nettles do? What do they contain?
Plants express fine stinging hairs; contain varying amounts of acetylcholine, histamine, serotonin, and formic acid
What clinical signs are associated with stinging nettles?
Salivation/pawing at the mouth, emesis, respiratory distress, bradycardia/arrhythmia, and muscle weakness
How is stinging nettle toxicosis treated?
According to signs: atropine, antihistamines, and supportive care
