Question of the Week # 400

400)  A 28 year old woman with history of depression is brought to the emergency room by her friend after she purposefully took large number of acetaminophen tablets. Her friend can not estimate how many tablets she took but she says there were at least fifty extra strength tablets in the bottle and the bottle was found empty when she went to visit her. She last spoke with her 18  hours ago over the phone when she sounded very depressed. So, her friend reports she probably must have ingested these tablets at least  12 to 18 hrs ago. On examination, she is drowsy but arousable. Her liver function tests are within normal limits and an acetaminophen level is 15µg/ml . Serum electrolytes, creatinine , prothrombin time and INR are within normal limits. Which of the following is the initial step in management

A) Hemo-Dialysis

B) Supportive care with strict monitoring of Liver function, Creatinine and INR

C) Activated Charcoal

D) N-Acetyl Cysteine

E) Consult Liver Transplant expert

15 Responses

  1. B

  2. n-acetyl cysteine???

  3. But olso activated charcoal in the first 12 h will be usefull

  4. D) N-Acetyl Cysteine
    Although it is not within 8hrs of the ingestion, but not more than 24hrs.

  5. D) N-Acetyl Cysteine

  6. B) Supportive care with strict monitoring of Liver function, Creatinine and INR – if u go by Rumack Matthew normogram

    Click to access i%28study%29_line.pdf

    but is there a way to answer this q without refering to the chart?

    • Yes, is not 15ug toxic at any time even at presentation and patient is also lethargic showing she is affected by it ?. The purpose of NAC is that it should be given as early as possible before LFTs start rising.
      Activated charcoal is useful in first 1 to 2 hours after acetaminophen ingestion . ( unlike TCAs where GI decontamination can be done for several hours after ingestion because TCA slow GI motility by anticholinergic action and hence, slowly absorbed).

      • 15ug is exactly on the line if u take 18hrs since was wondering… but NAC always has a protective effect on the liver no matter what the dose.Thank u!

      • You are right regarding Rumack nomogram but lethargy indicates she needs treatment especially when the duration is quite unclear. Rumack nomorgram is only one factor in predicting the severity of the poisoning and to offer guidance regarding the therapy. In asymptomatic patients, as per Rumack nomogram; decisions can be made whether to administer NAC or not based on these levels. However, several other factors such as LFT elevation, symptoms must be taken in to consideration in decision to treat because some patients are very sensitive to even low levels of acetaminophen ( for example; chronic alcoholism, increased cytp450 activity, underlying liver disease etc) – whether these patients are having toxicity at even low levels of acetaminophen is more accurately indicated by symptoms/ labs rather than nomogram alone. Therefore, in symptomatic patients – NAC should be given irrespective of the levels on nomogram ( so, you actually do not need the chart in this question)

        KEY POINT : Rumack nomogram should be checked in ASYMPTOMATIC patients with acetaminophen ingestion to determine the need for therapy with NAC. In symptomatic patients or in those with biochemical abnormalities that relate to acetaminophen overdose, you should obtain acetaminophen level but do not check nomogram to assess need for treatment –> proceed to treatment because symptoms/ abnormal labs have already established the need to treat.

      • I read with enjoyment your teaching. Thank you !

  7. C

  8. is it D?

    Activated charcoal : administered within 4hrs of ingestion unless there are no contraindiations

    NAC :
    * Initiated empirically prior to results of serum APAP concentration and liver function testing if the time of ingestion is unknown
    * all patients with liver tenderness, elevations of aminotransferases, supratherapeutic serum acetaminophen concentrations (greater than 20 mcg/mL, 130 micromol/L), and those with history of excessive ingestion, risk factors for toxicity, and acetaminophen concentrations >10 mcg/mL (65 micromol/L).

    Ref: uptodate

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