Nutrition/Toxicity

Question 1

mechanism of action of nicotine?

Answer 1

nicotinic AChR agonist

leads to increased DA, etc
stimulates reward circuit, locus coeruleus

Question 2

how does caffeine work

Answer 2

competitive antagonist of adenosine receptors –> decreased adenosine activity –> increased excitatory neurotransmitters –> stimulant effect

adenosine usually inhibits excitatory neurotransmitters

Question 3

dude with HTN, tachycardia, nystagmus, decreased pain sensation (“super human strength”), rage, seizures, hallucinations

Answer 3

PCP (phencyclidine)

Question 4

PCP mechanism?

Answer 4

NMDAR blocker (noncompetitive)

Question 5

hallucinogens work at what receptor mainly

Answer 5

serotonin
5HT2

Question 6

excess zinc intake does what

Answer 6

copper deficiency

can be excess dietary intake, overuse of denture cream, GI surgery

resembles B12 deficiency - spastic paraparesis and posterior column dysfunction. tx with copper supp and limit zinc.

Question 7

chronic diarrhea, malabsorption and ataxia

Answer 7

vitamin E deficiency

ataxia, dysarthria, areflexia, large fiber sensory loss

a-tocopeherol-transfer protein mutation or abetalipoproteinemia

Question 8

what does thiamine deficiency cause (4 syndromes)

Answer 8

axonal, sensorimotor peripheral neuropathy (with mute toes) - dry beri beri
when associated with cardiomegaly, cardiomyopathy, CHF, arrhythmia, tachycardia and edema –> wet beri beri
Wernicke-Korsakoff syndrome
also reported to cause Leigh syndrome

Question 9

how does B12 deficiency cause neuro probs

Answer 9

B12 is a cofactor needed to convert homocysteine to methionine

methionine ultimately needed for methylation of myelin basic protein - defect in methionine = wonky myelin

subacute combined degeneration - sensorimotor periph neuropathy + myelopathy, spastic paraparesis and posterior column dysfunction

dont just check b12, check homocysteine and MMA which will be elevated

Question 10

GI symptoms, garlic breath, delirium, encephalopathy, seizures, alopecia, ulcerations

Answer 10

arsenic poisoning

Question 11

industrial plant worker, N/V/HA, cherry-red flushed skin, smelled a bitter almond odor

Answer 11

cyanide poisoning

Question 12

miner with tremor, cerebellar ataxia, tender and inflamed gums, change in personality

Answer 12

mercury toxicity

Question 13

odorless gas, change of season, family with HA, encephalopathy, cherry-red skin

Answer 13

carbon monoxide poisoning
tx: high flow oxygen

Question 14

kid with abd symptoms, seizures, bluish pigmentation of gum line, wrist/ankle drop

Answer 14

lead poisoning

Question 15

pt with chronic liver failure on TPN p/w parkinsonism, confusion, hallucinations

Answer 15

manganese toxicity
MRI shows high T1 signal in globus pallidus

Question 16

antifreeze drinker

Answer 16

methanol toxicity

Question 17

organophosphate poisoning(sx,tx)

Answer 17

SLUDE: salivation, lacrimation, urination, defecation, gastric emesis

cholinesterase inhibitors –> cholinergic toxicity

treat with atropine (competes at muscarinic receptors), pralidoxine (CHe reactivator), benzos, activated charcoal. NO GASTRIC LAVAGE - risk of aspiration

Question 18

chemo agent most likely to cause leukoencephalopathy

Answer 18

intrathecal methotrexate –> toxic to white matter

Question 19

chemo agents associated with aseptic meningitis

Answer 19

IT methotrexate, cytarabine

Question 20

bevacizumab (chemo) associated with what

Answer 20

hemorrhagic stroke and ICH, ischemic stroke

Question 21

toxicity of this leads to putamen necrosis

Answer 21

methanol

Question 22

toxicity leads to optic nerve necrosis

Answer 22

methanol

Question 23

alopecia and painful neuropathy

Answer 23

thallium

Question 24

most likely chemo to cause cerebellar syndrome

Answer 24

cytarabine

Question 25

most likely chemo agent to cause progressive multifocal leukoencephalopathy

Answer 25

rituximab (JC virus)