ACETAMINOPHEN (PARACETAMOL) OVERDOSE

A very common OSCE scenario presented as:

• Obtaining History
• Management
• Psychiatric Assessment
• Assessing Capacity
• Assessing Mental Status

OBTAINING HISTORY:

Hi, My Name is Dr ABC, one of the ED Registrars who will be taking care of you today. May I know you name please? How old are you? And what do you do for your living?

Are you having any discomfort or pain? I want to assure you that I would provide you with every assistance, including pain killers to make you more comfortable.

If attendant is present, ask her name and relationship?

Ask the patient if she wants him/her to be present or can they wait outside in the Lobby?

If unstable, begin resuscitation.

I would like to ask you what brought you here today?

 Current Symptoms:

 Do you have any pain in abdomen? Vomiting? 

Event:

What have you taken? Do you have any packets or labels? Exactly when did you take it? How many tablets? Did you take anything else along with it,.... like any other medications or drugs, or alcohol?

Psychiatry:

Why did you take the overdose? Did you want to kill yourself or was it a cry for help?

Did you plan about doing it? Like trying not to be found? Closure of bank accounts? Suicide note?

How do you feel now?

Did you come here by yourself or under duress?

Did you try hurting yourself before too?

Assess risk of severe depression by asking about Sleep, Loss of interest, Guilt feeling, memory and concentration, appetite, psychomotor symptoms.

Assess Suicidal risk by asking SAD PERSONS Score: (Male 1945, single without social support and feeling hopeless and has a plan)

Social History:

Smoking, drugs, alcohol, Social support, Schooling, Stress at work or home

Medical illness:

Do you have any other medical illnesses? like liver disease, kidney disease or infections

Do you take any medications routinely? 

Are you allergic to any medications?

Have you been diagnosed of any psychiatric illnesses like depressions?

Management:

Bloods for CBC, U & Es, glucose, Coagulations Panel, group and type, LFTs, Serum Acetaminophen level, VBGs, lactate. Urine Toxicology screen

Ask for a nomogram

If less than one hour of intake, 50 gm of Charcoal PO

IV NAC

Hospitalize

Psychiatric referral

If denies NAC/treatment:

• Assess Capacity : Understand what is proposed, retain, weigh the benefits and risks involved, make a decision and communicate it
• If capacitated and no risk of repetition discharge (0 - 4 SAD PERSONS)
• If Capacitated, but risk of repetition of self harm (4+ SAD PERSONS), use section under Mental Capacity Act and hold.
• Explore Needle phobia
• Offer Oral Methionine

Pearls:

• Fatal dose >150 mg/kg or 12 gm
• The fatal dose is halved to 75 mg/kg if chronic liver disease or chronic alcoholism, anorexia, HIV, or on Phenytoin or Rifampicin
• NAPQI is the toxic metabolite
• Levels at 4 hours
• Dose of NAC 150 mg/kg in 200 cc Dextrose over 15 mins, then 50 mg/kg in 500 cc dextrose over 4 hours, then 100 mg/kg in 1 litre dextrose over 16 hours
• Indications of Liver Transplant: (PLACE Mnemonic)

1. PT > 100 sec
2. Lactate > 3.5 mmol/L
3. Acidosis ph < 7.3
4. Creatinine > 300 micromol/L
5. Encephalopathy Grade 3/4