Poisoning

Question 1

carbon monoxide poisoning

Answer 1

inhalation of smoke, car exhaust fumes or fumes from improperly maintained heating systems

Question 2

how does CO poison people

Answer 2

CO binds to haemoglobin to form carboxyhaemoglobin thus preventing the formation of oxyhaemoglobin

Question 3

clinical features carbon monoxide

Answer 3

non specific 
headache
mental impairment
convulsions 
cardiac arrest 
skin pink despite hypoxaemia

Question 4

venous carboxyhaemoglobin for confirmation of exposure

Answer 4

> 3% in non smoker

>10% in smokers

Question 5

treatment carbon monoxide

Answer 5

removing pt from CO source
giving 100% oxygen
oxygen via a face mask (do not use rebreathe reservoir)
hyperbaric oxygen treatment hastens CO elimination - indicated if victim unconscious or CV dysf

Question 6

Salicylate OD

Answer 6

aspirin OD

Question 7

what happens salicylate OD

Answer 7

aspirin stimulates the respiratory centre, directly inc the depth and rate of respiration and thereby producing resp alkalosis
comp mechanisms incl renal excretion of bicarb and k = metabolic acidosis
fall in arterial pH = serious poisoning

Question 8

what metabolism do salicylates interfere with

Answer 8

carbohydrate, fat and protein as well as oxidative phosphorylation
gives rise to lactate, pyruvate and ketone bodies
all of which = acidosis

Question 9

clinical features salicylate OD

Answer 9

tinnitus, nausea, vomiting, overbreathing, hyperpyrexia, sweating, tachycardia
or pt may appear well
cerebral and pulmonary oedema due to inc capillary permeability in severe OD
coma and depression

Question 10

investigations salicylate OD

Answer 10

plasma salicylate conc
serum U+E & blood glucose
prothrombin time
CXR + ABG
correct dehydration and hypokalaemia w fluids
IV vit K to correct hypoprothrombinaemia
activated charcoal if appropriate
sodium bicarb infusion
haemodialysis is plasma salicylate >700mg/L

Question 11

acetaminophen OD

Answer 11

paracetamol OD

Question 12

why acetaminophen OD bad?

Answer 12

may cause fatal hepatic necrosis

commonest form of poisoning encountered in UK today

Question 13

initial symptoms acetaminophen OD

Answer 13

malaise
nausea
vomiting
preserved consciousness
acute tubular necrosis may occur in the absence of severe liver failure

Question 14

management acetaminophen OD

Answer 14

N-acetylcysteine (NAC) first line - inc the availability of glutathione