The temporal profile of increased transaminase levels in patients with acetaminophen-induced liver dysfunction

STUDY OBJECTIVE

It is often taught that acetaminophen-induced liver dysfunction occurs only after a latent period of 24 to 48 hours. This study was designed to evaluate the temporal profile of transaminase levels in patients with acetaminophen-induced hepatotoxicity.

DESIGN

Prospective data collection using standard poison control center data sheets.

PARTICIPANTS

Hospitalized patients with acetaminophen exposure who were reported to the Long Island Poison Control Center between January 1993 and June 1994. Patients who presented within 24 hours of ingestion and in whom increased aspartate aminotransferase (AST) levels developed during hospitalization were included in the data analysis. Patients who presented more than 24 hours after ingestion, who had ingested another potentially hepatotoxic agent, or who had ingested acetaminophen over a period of more than 2 hours were excluded.

RESULTS

Of 1,825 patients with reported acetaminophen exposure, 779 had potentially toxic ingestions and were examined in an emergency department. Of 291 patients with toxic acetaminophen levels who were admitted, 36 (12%) had increased levels of AST at some point during hospitalization. All received oral N-acetylcysteine within 2.5 hours of presentation. In 11 of 19 patients who met all inclusion criteria (58%), AST levels were noted to be increased in the 24 hours after ingestion. The median peak AST level was 422 IU/L (range, 74 to 8,538 IU/L). AST levels peaked within 48 hours in 4 patients (21%) and within 72 hours in 18 patients (95%). Six of eight patients with peak AST levels greater than 1,000 IU/L had increased transaminase levels during the 24 hours after acetaminophen ingestion.

CONCLUSION

Acetaminophen poisoning may cause the serum transaminase level to increase during the 24 hours after ingestion.

Serial measurements of serum Gc-globulin in acetaminophen intoxication

OBJECTIVES

To describe serum Gc-globulin and the extent to which it complexes with monomeric actin in the initial phase of acetaminophen (Paracetamol) intoxication and to relate this to the severity of liver necrosis and the clinical course.

PATIENTS AND METHODS

Serial measurements of Gc-globulin and the proportion of Gc-globulin complexed to G-actin (complex ratio) were made on admission and every 3 h thereafter in eighteen consecutive patients with acetaminophen intoxication. Eight patients developed hepatic encephalopathy (HE) and two died.

RESULTS

On admission, all patients had significantly reduced serum Gc-globulin levels compared with normal individuals (P < 0.0001); patients with HE had significantly lower values than patients without HE (P < 0.001). Gc-globulin levels in the two patients who died did not differ from those in patients who survived hepatic encephalopathy. Fourty-four of 52 serum samples with Gc-globulin levels below 120 mg/l were from patients with encephalopathy (all eight of these patients provided at least three samples). The complex ratio on admission did not differ significantly between patients with and those without HE and fluctuated considerably during the observation period. The peak complex ratio was, however, higher in patients with HE than in patients without HE (P < 0.01), and three of four patients with peak complex ratios above 75% had HE. In addition, the mean complex ratio was greater in the two patients who died than in those who survived HE (P < 0.05).

CONCLUSION

Gc-globulin levels were decreased in individuals suffering from acetaminophen intoxication; this decrease correlated with the most severe sign of liver dysfunction, HE. Serum Gc-globulin levels below 120 mg/l and peak complex ratios above 75% may be critical values. However, as a result of considerable fluctuations in the complex ratio, serial measurements are needed to evaluate the Gc-globulin complexing capacity.

Acute renal failure due to acetaminophen ingestion: a case report and review of the literature

Acetaminophen is the most commonly reported drug overdose in the United States. Acute renal failure occurs in less than 2% of all acetaminophen poisonings and 10% of severely poisoned patients. At the therapeutic dosages, acetaminophen can be toxic to the kidneys in patients who are glutathione depleted (chronic alcohol ingestion, starvation, or fasting) or who take drugs that stimulate the P-450 microsomal oxidase enzymes (anticonvulsants). Acute renal failure due to acetaminophen manifests as acute tubular necrosis (ATN). ATN can occur alone or in combination with hepatic necrosis. The azotemia of acetaminophen toxicity is typically reversible, although it may worsen over 7 to 10 days before the recovery of renal function occurs. In severe overdoses, renal failure coincides with hepatic encephalopathy and dialysis may be required. Recognition of acetaminophen nephropathy requires the following: (1) a thorough drug history, including over-the-counter medications such as Tylenol or Nyquil; (2) knowledge of the risk factors that lessen its margin of safety at therapeutic ingestions, i.e., alcoholism; and (3) consideration of acetaminophen in the differential diagnosis of patients who present with combined hepatic dysfunction and ATN.

[Acute liver failure caused by paracetamol: should treatment with N-acetylcysteine be prolonged?]

BACKGROUND

Some cases of paracetamol-induced acute hepatic failure may require liver transplantation but the present shortage of graft urges the search for an alternate therapeutic approach.

CASE REPORT

A 17 year-old girl was admitted for sleepingness and vomiting after about 15 hours of voluntary but denied absorption of paracetamol. Plasma paracetamol concentration was 120 mg/l; factors VII+X level were 55% and factor V 106%. The patient was given IV N-acetylcysteine, 150 mg/kg/30 min, then 50 mg/kg/4 hours. Further decrease in facteur VII level led to pursue administration of N-acetylcysteine (total dose: 350 mg/kg/2 hours). While indication of liver transplantation was considered, clinical and laboratory findings definitely improved.

CONCLUSIONS

N-acetylcysteine may be effective even if administered late. Repeated determination of factor VII could be a good means for managing such a severe condition.

[Paracetamol poisoning--case report]

A case of paracetamol poisoning in 17-month-old girl is presented. Clinical features and therapeutic procedures are described. Differences in paracetamol metabolism between children and adults are compared. Differences in the incidence of paracetamol poisoning between Croatia and USA are surveyed. The role of a physician in the education of parents and medical stuff on paracetamol toxicity is emphasized.

Paracetamol intoxication and N-acetyl-cysteine treatment

N-acetylcysteine is a good and reasonable specific antidotum in case of paracetamol intoxication. It is very active when administered within eight hours after intoxication. It can be used as well as in intravenous as peroral administration. There are few side effects.

Renal failure is uncommon in Chinese patients with paracetamol (acetaminophen) poisoning

The reported incidence of renal failure in unselected patients with paracetamol poisoning is about 1-2%. Since the introduction of antidotal therapy for paracetamol poisoning in 1973, renal failure is now mainly seen in those admitted too late for effective therapy and is usually associated with liver damage. To determine the incidence of renal failure in Chinese patients with paracetamol poisoning, a retrospective survey was conducted of 224 patients admitted to the Prince of Wales Hospital, Hong Kong, with paracetamol poisoning from January 1988 to January 1994. Of the 28 patients at risk (plasma paracetamol concentrations above the recommended treatment line), 13 developed liver damage which was severe in 5. One patient with severe liver damage developed a transient increase in plasma creatinine concentration from 90 to 116 umol/L. All 28 patients completely recovered. Renal failure was uncommon in Chinese subjects (0.4%), and this was probably related to a lower incidence of liver damage which may be due to less chronic alcoholism as well as ethnic differences in paracetamol metabolism resulting in an inherent reduced susceptibility to its liver and renal toxicity.

Acute lung injury in fulminant hepatic failure following paracetamol poisoning

BACKGROUND

There is little information on the incidence of acute lung injury or changes in the pulmonary circulation in acute liver failure. The aim of this study was to record the incidence of acute lung injury in fulminant hepatic failure caused by paracetamol poisoning, to document the associated pulmonary circulatory changes, and to assess the impact of lung injury on patient outcome.

METHODS

The degree of lung injury was retrospectively assessed by a standard scoring system (modified from Murray) in all patients with fulminant hepatic failure caused by paracetamol poisoning, admitted to the intensive care unit over a one year period. The severity of liver failure and illness, other organ system failure, and patient outcome were also analysed.

RESULTS

Twenty four patients with paracetamol-induced liver failure were admitted and nine developed lung injury of whom eight (33%) had severe injury (Murray score > 2.5). In two patients hypoxaemia contributed to death. Patients with lung injury had higher median encephalopathy grades (4 v 2 in the non-injured group) and APACHE II scores (29 v 16). Circulatory failure, requiring vasoconstrictor support, occurred in all patients with lung injury but in only 40% of those without. Cerebral oedema, as detected by abnormal rises in intracranial pressure, also occurred in all patients with lung injury but in only 27% of the non-injured patients. The incidence of renal failure requiring renal replacement therapy was similar in both groups (67% and 47%). Pulmonary artery occlusion pressures were normal in the lung injury group. Cardiac output was high (median 11.2 1/min), systemic vascular resistance low (median 503 dynes/s/cm-5), and pulmonary vascular resistance low (median 70 dynes/s/cm-5), but not significantly different from the group without lung injury. Mortality was much higher in the lung injury group than in the non-injured group (89% v 13%).

CONCLUSIONS

Acute lung injury was common in patients with paracetamol-induced fulminant hepatic failure and was associated with systemic circulatory failure and cerebral oedema. The development of acute lung injury was associated with high mortality.

[Paracetamol poisoning at a department of hepatology]

In this retrospective study we evaluated the frequency of complications in 108 patients with acetaminophen poisoning admitted to the Department of Hepatology, Rigshospitalet, Copenhagen from 1.10.1990-30.9.1993. Twenty-five patients (23%) developed hepatic encephalopathy grade II-IV, with a survival rate of 44%. In patients who developed grade IV encephalopathy the median time from intoxication to INR > 3.7 was 60 hours. At a median of only five hours later grade II encephalopathy was present, and grade IV at a median of a further 20 hours later. Ninety-three patients were re-evaluated according to the nomogram indicated by Prescott (6). If the initial position was in the "very severe" area the risk of developing encephalopathy was 34% (20-51%), if not the risk was 6% (1-16%). Serum creatinine above 200 microM at admission indicated a risk of hepatic encephalopathy of 64% (35-87%). INR > 1.54 was associated with a 35% risk of hepatic encephalopathy. Patients in the "very severe" area should be referred to a unit where liver transplantation is possible, even if other factors known to indicate poor prognosis are not present.

[A case of paracetamol retard poisoning with fatal outcome]

A case of fatal paracetamol (acetaminophen) poisoning in a 26-year-old woman who developed liver necrosis is described. The patient reported having ingested 11 g of a slow-release paracetamol preparation and a certain amount of alcohol and benzodiazepine. An unknown dose of phenobarbital (phenemal) had been ingested 24 hours previously, leading to a serum phenobarbital concentration of 0.195 mmol/l at the time of admission. The patient was initially treated with N-acetylcysteine intravenously. This treatment was discontinued after five hours due to a serum paracetamol concentration of 0.49 mmol/l, well below the "treatment line" paracetamol concentration of 0.8 mmol/l six hours after ingestion. Possible aggravating factors are discussed, including sustained high serum concentration of paracetamol due to the slow-release preparation and enzyme induction caused from concomitant phenobarbital and alcohol intake, as well as benzodiazepines displacing paracetamol from liver enzymes. These factors make serum paracetamol concentrations undependable; the importance of continuing N-acetylcysteine treatment in spite of "safe" serum concentrations in the above cases is stressed.

[Deaths due to paracetamol poisoning in Denmark 1979-1992]

A significant relationship between the amount of paracetamol (acetaminophen) sold in Denmark after the drug became available on an over-the counter basis in 1984 and an increase in paracetamol (acetaminophen) related deaths has been demonstrated.

[Fulminant liver failure before and after introduction of liver transplantation at Rikshospitalet]

The impact of liver transplantation on the survival in fulminant hepatic failure was evaluated in a retrospective study including 87 patients admitted to Rigshospitalet over a three and a half year period before and a three and a half year period after the Danish liver transplantation programme was started. The number of admissions increased by 178% in the second period. Fifty-two percent of the patients had acetaminophen induced liver failure, which over the last seven years has become the most common cause of severe acute liver disease in Denmark. In about half of the patients high volume plasmapheresis was used as liver-assist either alone or in combination with liver transplantation. Three patients in grade 4 hepatic coma (one with Hepatitis B, two with acetaminophen intoxication) were withdrawn from the waiting list for emergency liver transplantation after high volume plasmapheresis due to recovery. In patients with an estimated survival chance of less than 5-10% liver transplantation was performed with a survival rate of 60%. The survival rate for the non-liver transplanted patients was 49% in the same period compared to 30% in the three and a half year period before liver transplantation started.

[Paracetamol poisoning]

Administration of paracetamol (acetaminophen) has analgetic and antipyretic effect. After trauma paracetamol has an anti-inflammatory activity. It was presumed that paracetamol in therapeutic doses had fewer and more acceptable side-effects than other analgetic drugs such as acetylsalicylic acid and NSAID-drugs. However, in toxic concentrations, paracetamol is more life-threatening. The toxic effects of paracetamol most often occur in the liver and kidneys. Phosphate and lactate turn-over can also be impaired. Paracetamol poisoning can induce temporary liver dysfunction or even irreversible liver failure with liver transplantation as the only therapeutic possibility. Chronic alcoholics are especially at risk, as liver damage may occur following paracetamol even in recommended doses. When intoxication with paracetamol is presumed, administration of N-acetylcysteine is vital. N-acetylcysteine therapy should be initiated not later than 15 hours after paracetamol intake. Moreover, the antitoxic effect has been observed even when N-acetylcysteine therapy is initiated 24-36 hours after presumed paracetamol intake. Measures of preventing further absorbtion of paracetamol from the gastrointestinal tract should be taken. Activated charcoal should be given if less than two hours have passed since paracetamol intake. Between two and four hours following paracetamol intake gastric lavage should be performed. During the last 10 years the incidence of paracetamol self-poisoning has increased, but death following paracetamol poisoning is relatively constant at around nine per year in Denmark. It is suggested that the incidence of serious cases of paracetamol poisoning could be reduced by simple measures. Special attention should be paid to the risk-group of chronic alcoholics.

The clinical value of screening for paracetamol in patients with acute poisoning

In this retrospective study, we determined the clinical value of screening for paracetamol in 294 Chinese patients with acute poisoning presenting to the general medical wards at the Prince of Wales Hospital between January 1992 and June 1993. Of the 86 patients suspected of having ingested paracetamol, eight had levels above the recommended 'treatment line'. Of the 208 patients with no suspected paracetamol ingestion, four were found to have elevated but non-toxic plasma levels. The incidence of missed, potentially serious paracetamol poisoning in our patients with no suspected paracetamol ingestion is extremely uncommon. Routine screening of all patients with acute poisoning for toxic plasma paracetamol concentrations is therefore not indicated and should never be a substitute for thorough history taking and physical examination.