A 25-year-old woman is brought to the emergency department by her family. They found her somnolent next to her computer with an empty pill bottle around 3 hours ago. The family cannot recall the types of pill bottles that they found and did not bring them to the ED. The patient's medical history is notable for anxiety, obesity, hypertension, and polycystic ovarian syndrome. She is currently not on any medications. She was given an exercise program but she has not been compliant with these exercises. Her temperature is 99.5°F (37.5°C), pulse is 82/min, blood pressure is 125/85 mmHg, respirations are 11/min, and oxygen saturation is 97% on room air. Physical exam is within normal limits. The patient begins communicating with the physician and states that she did take acetaminophen but it was only a few pills. Her parents are certain the bottle was new. Which of the following is the most appropriate next step in management?
Lactated ringer bolus
N-acetylcysteine
Charcoal
Syrup of ipecac
N-acetylcysteine
This patient is presenting with acute acetaminophen intoxication. The most appropriate next step in management is to administer the antidote N-acetyl cysteine (NAC).

In a toxicology case where the ingestion is unknown, the most appropriate initial step in management is to begin treatment empirically with IV fluids, charcoal, NAC, naloxone, and glucose if needed. These agents are effective against the most common causes of intoxication. In cases where there is known acetaminophen ingestion, the most important treatment is prompt administration of NAC. This medication works by increasing the hepatic production of glutathione, which detoxifies the toxic metabolite of acetaminophen N-acetyl-p-benzoquinone imine (NAPQI). NAC is a safe, cheap, and effective treatment that could be life-saving if administered in a timely fashion. In massive overdoses, it is appropriate to start treatment empirically as it can be discontinued later. Otherwise, a 4 hour acetaminophen level should be collected and the level should be plotted on the Rumack Matthew nomogram to determine treatment. In chronic acetaminophen toxicity, the acute serum level play no role in guiding treatment.

Chiew et al. performed a meta-analysis regarding the treatment of acetaminophen overdose. They found that the administration of charcoal immediately after ingestion can decrease the rate of absorption of acetaminophen. They recommend early administration of N-acetyl cysteine in order to decrease the hepatotoxicity of this substance.

Incorrect Answers:
Answer A: Blood acetaminophen levels should be ordered, but it is much less dire to confirm the diagnosis than it is to begin treatment given the high fatality rate with untreated acetaminophen overdose. Testing for all common intoxication should proceed while treatment is being administered. In this case, the concern for consumption of an entire bottle of acetaminophen would make it reasonable to treat first.

Answer B: Charcoal is an appropriate intervention if it is given in a timely manner; however, this patient consumed acetaminophen over 2 hours ago. In general, if the patient's airway is secure, it does no harm and could offer some benefit by decreasing the absorption of the substance of interest.

Answer C: IV fluid administration is the most appropriate initial step in the management of trauma when there is suspected bleeding and vitals are unstable (hypotension and tachycardia). Fluids are not urgently needed in this toxicity case with a patient who has stable vitals.

Answer E: Syrup of ipecac induces emesis in patients and was previously used in an attempt to have the patient vomit the toxic substance. This is no longer a preferred method of managing toxicities as patients can aspirate the vomitus or the toxic substance can induce more tissue damage during vomiting. In general, syrup of ipecac is the wrong answer choice for all toxicity cases.

Bullet Summary:
Acetaminophen toxicity should be treated immediately with N-acetyl cysteine followed by further diagnostic workup including serum acetaminophen levels.