paracetamol poisoning

Question 1

MOA of paracetamol toxicity

Answer 1

inhibit prostaglandin synthesis
toxic metabolite production : N-acetyl-p- benzoquinone.
glutathione depletion
renal tubular necrosis.

Question 2

function of hepatic glutathione

Answer 2

inhibit binding of PCM metabolite

Question 3

how necrosis is caused in renal tubules

Answer 3

pcm metabolite binds covalently to protein in liver cells and renal tubules causing necrosis

Question 4

fatal dose of pcm

Answer 4

greater than 250 mg / kg

Question 5

fatal dose of pcm in chronic alcoholics

Answer 5

5-6gm/day for few days

Question 6

pcm poisoning is very common in

Answer 6

children with low hepatic glucuronide conjugating ability

Question 7

signs and symptoms of pcm poisoning

Answer 7

nausea and vomiting withinh hrs.
gen abd pain 2ndry to retching and liver tenderness.
hepatotoxicity ( 12- 36hrs)

Question 8

warning signs of pcm poisoning

Answer 8

continuation of vomiting
localized of abd pain to the right sub costal area , liver tenderness , early renal tubular necrosis causing renal angle pain , hepatic failure on 4th-5th day if necrosis is extensive with impaired consciousness, confusion , hyperventilation , hypoglycaemia and bleeding secondary to coagulation abnormalities ,

Question 9

Prognosis for Acute Acetaminophen Poisoning

Answer 9

international normalized ratio (INR) > 3. Serum creatinine > 2.6. Hepatic encephalopathy grade III (confusion and somnolence) or grade IV (stupor and coma) Hypoglycemia.

Question 10

investigations for pcm poisoning

Answer 10

highly inc in AST activity.
- inc in alt level , pt ratio within 24-36 hrs (max 48hrs - 72 hrs) , plasma creatinine and urea when renal failure develops.
- plasma bilirubin
exceed 190u/mol L in survivors
- severe hypoglycaemia with hepatic failure.

Question 11

treatment of pcm poisoning

Answer 11

gastric lavage = with activated charcoal within 1-2hs of ingestion and vomiting induction.

antidote administration =N acetyl cysteine 150mg/kg intravenously 15 minutes over 20hrs . 75 mg/kg given orally 4-6hrs for 2-3 days.
* oral methionine is alternative antidote (not in pt who are vomiting)

supportive measures = intravenous electrolytes , rehydration , vit k for bleeding , mannitol for cerebral edema .

Question 12

postmortem findings in pcm poisoning

Answer 12

external = jaundice , petechiae in skin.

internal = git congestion , centrilobular hepatic necrosis, acute tubular necrosis , cerebral edema , myocardial necrosis.

Question 13

medico legal aspects of pcm

Answer 13

suicidal , accidental overdose may occur.

Question 14

stages and phases of pcm poisoning

Answer 14

stage I = initial , 0-24hrs ,nausea , vomiting , diaphoresis , malaise , pallor .

stage II = middle , 24-72 hrs , discomfort disappears , false sense of relief , upper abd pain.

stage III = hepatic , 72 - 96 hrs , vomiting , jaundice , hepatic pain , bleeding , confusion , coma , asterixis , hepatic encephalopathy , cardiac arrhythmias , hemorrhagic pancreatitis , DIC .

stage IV = recovery , > 5 days , resolution of liver functions occurs in about 2-3 months.