Lecture 8- toxicants affecting the nervous system- 3

muscarinic signs of cholinesterase inhibitors

salivation

lacrimation

urination

defecation

GI pain

emesis

SLUDGE

cholinesterase inhibitors nicotinic signs

M: Muscle fasciculations, tremors, paresis, paralysis

A: Adrenal medulla stimulation

T: Tachycardia

C: Cramping

H: Hypertension

organophosphates mainly used in

insecticides but also in fuel additives, hydraulic fluids, and lubricants

organophsophates acts as

AChE inhibitor

organophosphates absorbed through

GI or respiratory tract or skin

organophosphates 3 manifestations

1. Acute cholinergic syndrome

2. Intermediate syndrome

3. Organophosphate-Induced Delayed Neuropathy

what is the best known manifestation of Organophsophates toxicosis

acute cholinergic syndrome

what is development time of acute cholinergic syndrome

within a few minutes to a few hours post exposure

the second potential manifestation of OP toxicosis

intermediate syndrome

what is intermediate syndrom

excess Ach at the Neuromuscular junction causes down regulation of postsynaptic AChRs

the decrease in ACh stimulation can lead to muscle weakness, crainal nerve palsies, and even respiratory muscle paralysis

once AChE has aged what happens

2-PAM no longer works to reactivate

the AChE enzyme. The body must synthesize new AChE.

Signs of cholinergic toxicity are still responsive to atropine.

what is the most delayed of organophosphates

OPIDN delayed 10-21 days

signs of OPIDN

pain, tingling, weakness in pelvic limbs, unsteady gait, possible limb paralysis if severe

aging of different OP

Nerve agents like sarin age in minutes

Dimethyl pesticides like malathion – few hours

Diethyl compounds like parathion – hours to a day

OP aging effects

Aged AChE – 2PAM no longer works, can only tx signs with atropine

Aged NTE – OP-Induced Delayed Neuropathy can develop

carbamates cause

acute cholinergic syndrome

what does not occur at the same time as carbamates

OPIDN

atropine causes

• Drying of secretions

• Mydriasis

• Arrhythmias

• Flushing

• Confusion

• Hallucination

• Ileus

OP/ carbamate treatment

low test dose for diagnosis

extreme caution in horses can cause fatal ileus

neurotoxicity nicotinic signs

M: Muscle fasciculations, tremors, paresis, paralysis

A: Adrenal medulla stimulation

T: Tachycardia

C: Cramping

H: Hypertension

consumed pyrethrin

whta is pyrethrin derived from

chrysanthemum plants

clearance of pyrethrin

metabolized thru glucoronidation pathway present in dogs very minimal in cats

consumed strychnine

what animals are the most susceptible to strichnine

dogs, cats, pigs. horses can withstand a large amount

what are signs of strychnine poisoning

muscular convulsions and eventually death through asphyxia

how does strychnine poisoning typically occur

from ingestion of bats designed for use against gophers, moles and coyotes

strychnine

where else can methylxanthines be found outside of chocolate

caffeine tablets

what does neurotoxin from ticks cause

lower motor neuron paralysis