RACGP KFP 2017.2.1 – RUQ Pain

by | Dec 11, 2017

Bob is a 70kg 35 year old male who has presents with 3 weeks of fevers initially (now subsided) followed by right upper quadrant pain, nausea, vomiting which he has been managing with 30 tabs of paracetamol daily. Bob last took some Paracetamol at 0600, it is now 1100.

You perform bloods which are normal except for ALT of 150 and AST of 500 on his LFTs. FBC, Hepatitis serology are all normal

 

What are the most likely differentials for Bob’s presentation? List 3

Paracetamol Overdose

  • 30 tabs = 15g per day which is his maximum. (Max is 150-200mg/kg x 75kg = 12-15g)
  • Normal safe limit is 4g.
  • Other causes of fevers, RUQ pain:
    • Acute Hepatitis
    • Acute Cholecystitis
    • Acute Pancreatitis
    • EBV
    • CMV
    • Ascending Cholangitis
      • (though jaundice could/would be a feature)

 

What is the most important first immediate management step?

  • Immediate provision of N-Acetyl-Cysteine
    • If the patient presents 8 or more hours after ingestion and has ingested a toxic dose (or where the paracetamol concentration will not be known for 8 or more hours post ingestion)—acetylcysteine should be commenced, then ceased if the paracetamol concentration indicates that treatment is not required and if liver biochemistry is normal. (Source)
    • The risk assessment in patients with repeated ingestion of supratherapeutic doses is difficult and the paracetamol treatment nomogram should not be used. (Source)
    • Most patients present with an acute overdose where the clinical sequelae are fairly predictable based on the dose ingested. However, repeated supratherapeutic ingestion can occur, for example in the following common clinical situations:
      • ingestions of more than 150 to 200 mg/kg daily for a period of a few days, usually for severe pain such as dental pain
      • repeated ingestion of combination products of paracetamol and codeine for weeks to months, usually to obtain the codeine
      • use of supratherapeutic doses in unwell and dehydrated children for greater than 48 hours.
    • All patients with abnormal liver transaminases or paracetamol concentrations greater than 133 micromol/L should be treated with acetylcysteine. Reassessment should occur, with repeated liver biochemistry, following 8 hours of therapy with acetylcysteine, and acetylcysteine may be discontinued if these remain static or are normalising.

 

What is the pharmacological management of this condition? (List 3 phases of drug, dose, route, duration)

  • Acetylcysteine 150 mg/kg IV infusion, over 15 to 60 minutes
  • Acetylcysteine 50 mg/kg IV infusion, over 4 hours
  • Acetylcysteine 100 mg/kg IV infusion, over 16 hours

 

RACGP Feedback from 2017.2 Exam

This case focused on a middle-aged male patient who presented with a history of prolonged fever, with initial investigations showing abnormal liver function tests. Candidates needed to consider the possible diagnoses, given the abnormal findings and the details in the history.

The most common error within this case was not taking all of the information into account and missing the details of the patient’s excessive use of paracetamol.

When looking at the possible differential diagnoses, candidates failed to answer within the context of the case and listed all causes demonstrated by the liver function results, or described the results rather than providing a diagnosis.

 

GPCC Comment on Content

Coverage of supratherapeutic paracematol overdose is (barely) touched on in Murtaghs, I cant find it anywhere in the AFPs or Checks, but is present in eTG.

Its a relatively untouched part of eTG though, and I’d put this more in Emergency content than in day-to-day General Practice. I think to have memorised this particular guideline within eTG, you’d have to have read and memorised all of eTG.

Best source = eTG

 

References for Paracetamol Toxicity

  • Most Useful – eTG – in depth discussion with guidelines.
  • Murtaghs – p12 – does describe daily dose excursions (in passing).

 

References for RUQ Pain

  • Murtaghs
    • Table 34.2, p332 of Murtaghs 6th Ed lists all the causes of acute abdominal pain
    • Table 34.3, p333 of Murtaghs 6th Ed lists all the causes of chronic abdominal pain
    • Figure 34.3 lists the causes of RUQ abdominal pain by location
    • Chapter 58 – Jaundice, discusses RUQ pain in more detail from a perspective of this presentation, listing all causes of Jaundice and drugs that can cause Jaundice
  • Patient.info – https://patient.info/doctor/right-upper-quadrant-pain (I like patient.info)
  • AAFP – http://www.aafp.org/afp/2008/0401/p971.html has causes broken down by location as well.