Metabolic acidosis and coma following a severe acetaminophen overdose

Prognostic factors of acetaminophen exposure in the United States: An analysis of 39,000 patients

Acetaminophen is a frequently used over-the-counter or prescribed medication in the United States. Exposure to acetaminophen can lead to acute liver cytolysis, acute liver failure, acute kidney injury, encephalopathy, and coagulopathy. This retrospective cohort study (1/1/2012 to 12/31/2017) investigated the clinical outcomes of intentional and unintentional acetaminophen exposure using the National Poison Data System data. The frequency of outcomes, chronicity, gender, route of exposure, the reasons for exposure, and treatments as described. Binary logistic regression was used to estimate the prognostic factors and odds ratios (OR) with 95% confidence intervals (CI) for outcomes. This study included 39,022 patients with acetaminophen exposure. Our study demonstrated that the likelihood of developing severe outcomes increased by aging (OR = 1.12, 95% CI: 1.08-1.015) and was lower in females (OR = 0.88, 95% CI: 0.78-0.99). Drowsiness/lethargy (OR = 1.48, 95% CI: 1.22-1.82), agitation (OR = 1.66, 95% CI: 1.11-2.50), coma (OR = 23.95, 95% CI: 17.05-33.64), bradycardia (OR = 2.29, 95% CI: 1.22-4.32), rhabdomyolysis (OR = 8.84, 95% CI: 3.71-21.03), hypothermia (OR = 4.1, 95% CI: 1.77-9.51), and hyperthermia 2.10 (OR = 2.10, 95% CI: 1.04-4.22) were likely associated with major outcomes or death. Treatments included intravenous N-acetylcysteine (61%), oral N-acetylcysteine (10%), vasopressor (1%), hemodialysis (0.7%), fomepizole (0.1%), hemoperfusion (0.03%), and liver transplant (0.1%). In conclusion, it is important to consider clinical presentations of patients with acetaminophen toxicity that result in major outcomes and mortality to treat them effectively.

Antidote removal during haemodialysis for massive acetaminophen overdose

CONTEXT

Haemodialysis is sometimes used for patients with massive acetaminophen overdose when signs of "mitochondrial paralysis" (lactic acidosis, altered mental status, hypothermia and hyperglycaemia) are present. The role of haemodialysis is debated, in part because the evidence base is weak and the endogenous clearance of acetaminophen is high. There is also concern because the antidote acetylcysteine is also dialyzable. We prospectively measured serum acetylcysteine concentrations during haemodialysis in three such cases.

CASE DETAILS

Three adults each presented comatose and acidemic 10 to ~18 h after ingesting > 1000mg/kg of acetaminophen. Two were hypothermic and hyperglycaemic. Serum lactate concentrations ranged from 7 mM to 12.5 mM. All three were intubated, and initial acetaminophen concentrations were as high as 5980 μM (900 μg/mL). An intravenous loading dose of 150 mg/kg acetylcysteine was initiated between 10.8 and ~18 h post ingestion, and additional doses were empirically administered during haemodialysis to compensate for possible antidote removal. A single run of 3-4 h of haemodialysis removed 10-20 g of acetaminophen (48-80% of remaining body burden), reduced serum acetaminophen concentrations by 56-84% (total clearance 3.4-7.8 mL/kg/min), accelerated native acetaminophen clearance (mean elimination half-life 580 min pre-dialysis, 120 min during and 340 min post-dialysis) and corrected acidemia. Extraction ratios of acetylcysteine across the dialysis circuit ranged from 73% to 87% (dialysance 3.0 to 5.3 mL/kg/min). All three patients recovered fully, and none developed coagulopathy or other signs of liver failure.

DISCUSSION

When massive acetaminophen ingestion is accompanied by coma and lactic acidosis, emergency haemodialysis can result in rapid biochemical improvement. As expected, haemodialysis more than doubles the clearance of both acetaminophen and acetylcysteine. Because acetylcysteine dosing is largely empirical, we recommend doubling the dose during haemodialysis, with an additional half-load when dialysis exceeds 6 h.

Sudden death of a young woman attributed to diabetic ketoacidosis

A young woman's death at home was attributed to new onset diabetic ketoacidosis with subsequent litigation supported by several expert consultants, despite a history and postmortem findings inconsistent with this diagnosis. More thorough tissue study of the heart and analysis of the circumstances led to a credible explanation of the entire scenario.

A gargantuan acetaminophen level in an acidemic patient treated solely with intravenous N-acetylcysteine

The objective of this report is to describe an acidemic patient with one of the largest recorded acetaminophen ingestions in a patient with acidemia who was treated with supportive care and intravenous (IV) N-acetylcysteine. A 59-year-old female with a history of depression was found comatose. In the Emergency Department, she was obtunded with agonal respirations and immediately intubated. Activated charcoal was given through a nasogastric tube. An initial acetaminophen serum level was 1141 mg/L. The patient was started on IV N-acetylcysteine. The acetaminophen level peaked 2 hours later at 1193 mg/L. She was continued on the IV N-acetylcysteine protocol. The next day her aspartate aminotransferase was 3150 U/L, alanine aminotransferase was 2780 U/L, and creatinine phosphokinase was 16,197 U/L. There was no elevation in bilirubin or international normalized ratio (INR). Transaminase levels decreased on day 3 and normalized by day 4 when she was transferred to a psychiatric unit. Few cases have been reported of strikingly elevated acetaminophen levels in poisoned patients who did not receive hemodialysis. These patients did have increased lactate levels, and some had normal liver function tests. All of these patients received N-acetylcysteine and survived the poisoning without sequelae. This patient in this report was unique in that she had the highest reported serum acetaminophen level with acidosis and was treated successfully with only IV N-acetylcysteine and supportive care.

Understanding lactic acidosis in paracetamol (acetaminophen) poisoning

Paracetamol (acetaminophen) is one of the most commonly taken drugs in overdose in many areas of the world, and the most common cause of acute liver failure in both the UK and USA. Paracetamol poisoning can result in lactic acidosis in two different scenarios. First, early in the course of poisoning and before the onset of hepatotoxicity in patients with massive ingestion; a lactic acidosis is usually associated with coma. Experimental evidence from studies in whole animals, perfused liver slices and cell cultures has shown that the toxic metabolite of paracetamol, N-acetyl-p-benzo-quinone imine, inhibits electron transfer in the mitochondrial respiratory chain and thus inhibits aerobic respiration. This occurs only at very high concentrations of paracetamol, and precedes cellular injury by several hours. The second scenario in which lactic acidosis can occur is later in the course of paracetamol poisoning as a consequence of established liver failure. In these patients lactate is elevated primarily because of reduced hepatic clearance, but in shocked patients there may also be a contribution of peripheral anaerobic respiration because of tissue hypoperfusion. In patients admitted to a liver unit with paracetamol hepatotoxicity, the post-resuscitation arterial lactate concentration has been shown to be a strong predictor of mortality, and is included in the modified King's College criteria for consideration of liver transplantation. We would therefore recommend that post-resuscitation lactate is measured in all patients with a severe paracetamol overdose resulting in either reduced conscious level or hepatic failure.

Massive acetaminophen ingestion with early metabolic acidosis and coma: treatment with IV NAC and continuous venovenous hemodiafiltration

CONTEXT

We report the extraction of acetaminophen by continuous venovenous hemodiafiltration (CVVHD) during treatment of an acute ingestion of 200 g with a peak recorded serum acetaminophen level of 1,614 mg/L (10,652 micromol/L).

CASE DETAILS

The patient presented with early onset of coma, metabolic acidosis, and hypotension in the absence of significant hepatic injury. In addition to N-acetylcysteine (NAC) therapy, CVVHD was performed to manage the acid-base disturbance. Flow rate, effluent volume, and serum and effluent drug concentrations were obtained at hourly intervals. During 16 h of CVVHD the acetaminophen level dropped from 1,212 to 247 mg/L.

DISCUSSION

The average clearance of acetaminophen by CVVHD was 2.53 L/h, with removal of 24 g of acetaminophen over 16 h. As NAC is effective in preventing hepatic injury after acute acetaminophen overdose, the role of dialysis or CVVHD is limited.

Potentially Fatal Paracetamol Overdose and Successful Treatment with 3 Days of Intravenous N-acetylcysteine Regime – A Case Report

Introduction: Paracetamol overdose is the most common drug overdose worldwide. To our knowledge, the maximum number of paracetamol tablets ingested reported in the literature is 45 g. Clinical Picture: We describe a 21-year-old patient who acutely ingested 120 tablets, each 500 mg paracetamol (i.e., 60 g equivalent to 1200 mg/kg body weight) in a suicidal attempt. Our patient also drank 2 bottles of codeine-based cough syrup equivalent to 360 mg of codeine. At 6 hours post ingestion, her serum paracetamol level was 207 mg/L. The poor prognostic factors for paracetamol overdose in our patient included massive paracetamol ingestion (confirmed by blood levels), codeine co-ingestion and elevated serum amylase (189 U/L). Treatment: She was treated with a 3-day modified regimen of intravenous N-acetylcysteine. Outcome: The liver function tests and the prothrombin time remained normal over the second and third day of admission and the patient was discharged without complications on the fifth day. Conclusion: From this experience we feel that in very severe paracetamol poisoning, a modified regime of intravenous N- acetylcysteine for 3 days is safe and efficacious. Key words: Codeine, Hyperamylasaemia, Ingestion, Suicidal

Early death from paracetamol (acetaminophen) induced fulminant hepatic failure without cerebral oedema

BACKGROUND

Paracetamol overdose is a frequent cause of fulminant hepatic failure. In fatal cases the most frequent causes of death are cerebral oedema in the early phase or sepsis and multiorgan failure later. However some patients do not fit this pattern.

AIM

To review cause of death in paracetamol induced fulminant hepatic failure.

METHODS

We reviewed all fatal cases of paracetamol induced fulminant hepatic failure in our liver unit between 1995 and 2000.

RESULTS

Twenty one patients died without liver transplantation and post mortem examinations were performed on all. Significant cerebral oedema was present in 13 patients and absent in eight. The patients without cerebral oedema were significantly older (55.4+/-5.3 versus 36.3+/-3 years: P=0.0034), had a lower arterial pH on admission (pH 7.0+/-0.03 versus 7.3+/-0.05: P=0.0008), a shorter interval between overdose and death (3.75+/-0.7 versus 7.6+/-1.3 days: P=0.043) and a shorter interval between admission and death (1.9+/-0.6 versus 5.7+/-1.0 days: P=0.0097) than patients with cerebral oedema. The cause of death in the sub-group of patients without cerebral oedema was predominantly cardiovascular collapse with rapidly progressive resistant hypotension and/or cardiac arrest. No source of sepsis was identified in 7/8 patients without cerebral oedema.

CONCLUSIONS

In this series the most frequent causes of death were cerebral oedema or cardiovascular collapse. Patients without cerebral oedema appear to form a distinct subgroup associated with early mortality and may require specific management strategies.

Warning note on a blood gas report leading to diagnosis of acetaminophen overdose

OBJECTIVE

To report a case of acetaminophen toxicity diagnosed after a warning note of "interfering substances" on the blood gas report, leading to early and successful treatment.

DESIGN

Case report.

SETTING

Tertiary-care pediatric intensive care unit.

PATIENT

A 14-yr-old boy admitted unconscious with lactic academia and hyperglycemia.

INTERVENTIONS

Routine investigations.

MEASUREMENTS AND MAIN RESULTS

His initial investigations revealed hyperglycemia and lactic acidosis. An annotation of "interfering substances" on the blood gas report prompted us to investigate for toxic substances, and an acetaminophen overdose was confirmed.

CONCLUSIONS

A persistent warning note on the blood gas report of a sick child with elevated lactate and glucose should alert the clinician to the possibility of an acetaminophen overdose.

Update: the clinical importance of acetaminophen hepatotoxicity in non-alcoholic and alcoholic subjects

Acetaminophen (paracetamol) is one of the most commonly used over-the-counter medications. Taken in doses greater than 150 mg/kg/day (>10 g), it usually causes acute liver failure. The authors review mainly the management of acetaminophen toxicity in both users and nonusers of alcohol. Chronic alcoholics are a special subgroup, who risk serious toxicity when taking acetaminophen, even in therapeutic doses. The acetaminophen-alcohol interaction is complex, because acute and chronic ethanol have opposite effects. This review also considers physiological and clinical changes, as well as the diagnosis and treatment of acetaminophen poisoning.