Arthrogryposis multiplex congenita and bilateral mid-brain infarction following maternal overdose of co-proxamol

We report a case of arthrogryposis multiplex congenita secondary to fetal hypokinesia in a 41-week gestation infant following antenatal central nervous system injury. The mother's pregnancy was complicated by an episode of attempted self harm, with an overdose of co-proxamol at 22 weeks of gestational age, and by the use of cocaine in combination with excess alcohol intake. Magnetic resonance imaging showed bilateral mid-brain cysts and marked atrophy of the basal ganglia and thalami.

Placental transfer of N-acetylcysteine following human maternal acetaminophen toxicity

OBJECTIVE

To determine whether the antidote for acetaminophen poisoning, N-acetylcysteine, administered to pregnant women with acetaminophen toxicity, crosses the placenta and can be measured in the newborn circulation following delivery.

DESIGN

Over a 15-month period, four pregnant women with acetaminophen toxicity, who delivered their infants while receiving the antidote N-acetylcysteine, were studied. Maternal and cord blood from three viable infants, and cardiac blood sampled during an autopsy on the fourth, were analyzed for the presence of N-acetylcysteine using high-performance liquid chromatography. Maternal and cord blood aminotransferase activities, and autopsy findings on the nonviable infant were used to assess hepatic injury.

RESULTS

N-Acetylcysteine was detected in the cord blood of three viable infants and in cardiac blood of a fourth, sampled at the time of autopsy. The mean N-acetylcysteine concentration in cord blood was 9.4 micrograms/mL (+/-1.3). This is well within the range associated with therapeutic doses of N-acetylcysteine typically administered to adults with acetaminophen poisoning. No adverse sequelae developed in the three viable infants. The fourth infant, delivered at 22 weeks gestational age died 3 h after birth. All mothers recovered and none of the four infants had evidence of acetaminophen-related toxicity.

CONCLUSIONS

This is the first study documenting placental transfer of N-acetylcysteine in humans and provides impetus for research establishing a direct antidotal effect of N-acetylcysteine in the fetus.

Cost-effectiveness of regional poison control centers

BACKGROUND

Poison exposures are a significant public health concern. Despite the impact that regional poison control centers have on reducing morbidity and mortality associated with poison exposures, they are facing a serious financial crisis today resulting in an increased emphasis on their economic justification.

METHODS

Using decision-analysis techniques, the cost-effectiveness of the treatment of poison exposures with the services of a regional poison control center compared with treatment without access to any poison control center was evaluated. The relative cost-effectiveness was modeled based on 2 outcomes (morbidity and mortality) for each of 4 typical poison exposures. Additionally, analyses were conducted to test the sensitivity of the cost-effectiveness ratios to outcome probability, average inpatient and emergency department costs, and proportion of poison exposures treated on site by the regional poison control center. A societal perspective was adopted.

RESULTS

The regional poison control center was substantially more cost-effective than the treatment of poison exposures without the services of a regional poison control center for both outcomes (morbidity and mortality) in each of the poison exposures considered. The results of the sensitivity analyses demonstrated that the outcomes of the decision analyses do not change regardless of the type of poison exposure, outcome considered, clinical outcome probabilities, average inpatient and emergency department costs, and proportion of poison-exposure cases treated on site by a regional poison control center.

CONCLUSIONS

The regional poison control center is consistently more cost-effective in the treatment of poison exposures with an average cost-effectiveness ratio (cost per successful outcome) approximately half of that achieved without the services of a regional poison control center. Finally, significant cost savings to society are realized for each additional successful outcome obtained with a regional poison control center.

Involvement of codeine in drug-related deaths

The incidence and role of codeine in drug-related deaths in Victoria was investigated over a 5-year period. There were a total of 107 cases involving codeine, representing 8.8% of all drug-related deaths in this period in Victoria. There were only six fatalities in which codeine was considered the major poison. The mean (+/- SD) concentration of codeine in femoral blood was 4.0 +/- 2.3 mg/L (range, 2.1-8.0 mg/L). The mean concentration of free codeine was 1.3 +/- 0.9 mg/L (range, 0.4-2.8 mg/L). The remaining 101 cases involved a combination of codeine and other drugs. The mean total codeine blood concentration was 1.8 +/- 3.3 mg/L (range, 0.04-26 mg/L), which was significantly lower than in those cases where codeine was the major poison (p < 0.002). The mean concentration of free codeine was 0.82 +/- 4.9 mg/L (range, 0.02-9.0 mg/L), which was not significantly different (p > 0.05) from the six codeine-only cases. The most common drugs found in this group, other than codeine, were acetaminophen (62%), diazepam (46%), salicylate (20%), and ethanol (25%). The association of other psychoactive drugs in these deaths made the contribution of codeine difficult to assess. Free codeine concentrations > 0.4 mg/L and total codeine concentrations > 2.0 mg/L may be sufficient to cause death in the absence of any other contributing factors.

The epidemiology of acetaminophen (paracetamol) poisoning in Hong Kong

The prince of Wales Hospital is in a unique position for the study of the actual incidence of acetaminophen poisoning in Hong Kong because it is the sole general teaching hospital in the New Territories East and the age and sex distribution of the population in the region are readily available. Between 1991 and 1994, the rate of admission in subjects aged > or = 15 years slightly increased from 5.7 to 7.3/100,000. In both 1991 and 1994, the highest rates in women were in the 15-19 age group (from 22.8 to 53.0/100,000) and in men in the 25-29 age group (from 10.5 to 6.0/100,000). The rates of admission with toxic plasma acetaminophen concentrations were higher in 1994 than in 1991 (10.8 vs 0.6/100,000). The annual incidence of acetaminophen-induced liver damage remained unchanged (0.3/100,000). None of the patients with liver damage developed fulminant liver failure. There were no deaths. Thus, acetaminophen poisoning appears to cause less fulminant liver failure and deaths in Hong Kong than in other Western societies. Reasons for such differences need to be better understood.

Changing patterns of self-poisoning in a UK health district

Details of admissions to a dedicated district poisons treatment unit in South Glamorgan were analysed to assess changes in self-poisoning patterns between 1987-1988 and 1992-1993. Self-poisoning rates increased in both men and women, with male rates showing a relatively larger increase, resulting in a fall in female to male ratio for person-based rates from 1.33:1 to 1.13:1. The highest age-specific rates in both period were found in 15-19-year-old females. Paracetamol was the most commonly ingested poison in 1992-1993, with 43.4% of episodes involving its use, compared with 31.3% of episodes in 1987-88. Antidepressant involvement in self-poisoning also increased from 11.3% of episodes in 1987-1988 to 17.6% of episodes in 1992-1993. Repetition of self-poisoning was relatively common, with 18% of admissions per year in 1992-1993 representing repeats. Although hospital admission increased in this health district over the study periods, this was not reflected in an increase in in-patient all-cause mortality, which was only 0.5% in 1987-1988 and 0.1% in 1992-1993.

[Recommendations for treatment of paracetamol poisoning. Danish Medical Society, Study of the Liver]

Based on recent reports concerning the efficacy of N-acetylcysteine (NAC) in paracetamol (acetaminophen) poisoning, guidelines for treatment and control of these patients are reviewed by a study group under the Danish Association for the Study of the Liver. It is recommended that NAC-treatment is initiated immediately after referral and continued for 36 hours in all cases. Further NAC-treatment should not be discontinued before a decrease in INR has been observed.

[Gc-globulin in paracetamol poisoning]

Gc-globulin scavenges actin liberated from necrotic cells. We measured serum Gc-globulin and the degree of complexing with monomeric actin (complex ratio) in the initial phase of paracetamol (acetaminophen) intoxication and related this to the severity of liver necrosis and the clinical course. In eighteen patients with paracetamol intoxication serial measurements of serum Gc-globulin and complex ratio were determined from admission and every three hours thereafter. Eight patients developed hepatic encephalopathy (HE) and two of them died. On admission all patients had significantly reduced serum Gc-globulin levels compared to normal individuals, and patients with HE had significantly lower values than patients without HE. All patients with HE had at least three samples, where Gc-globulin was below 120 mg/l (35% of normal). Complex ratio on admission did not differ significantly in the patients with and those without HE. The peak complex ratio was higher in patients with HE than in patients without HE, and three of four patients with peak complex ratio above 75% had HE. In conclusion, Gc-globulin levels were found to be decreased in patients with paracetamol intoxication; this decrease correlated with the most severe sign of liver dysfunction, HE. Serum Gc-globulin below 120 mg/l and peak complex ratios above 75% may be critical values.

Classification, etiology, and considerations of outcome in acute liver failure

Clinical descriptions of fulminant hepatic failure as originally reported, along with the subgroups of subfulminant and late onset hepatic failure identified later, are considered in relation to the proposed new classification of hyperacute, acute, and subacute liver failure. This reflects different clinical patterns of illness, etiology, and most importantly, prognosis. In addition to the defining state of encephalopathy and other manifestations directly related to the severe derangement in function and structure of the liver, the constellation of clinical symptoms and signs in acute liver failure (ALF) includes, to varying degrees, those of multiorgan failure. The latter develops because of tissue hypoxia from microcirculatory changes consequent on endotoxemia, and activation of macrophages and release of cytokines as a result of secondary bacteria infection due to an early failure of host defenses to infection in ALF. Paracetamol overdose-the commonest cause of acute liver failure in the United Kingdom-is increasing in frequency in other Western countries, but fulminant viral hepatitis is the most frequent etiology worldwide. Marked geographical variations are seen in the frequency with which the viral types A to E are implicated. Whereas hepatitis C is the major cause of ALF in Japan and the Far East, fulminant hepatitis C is seen rarely in America and European countries where most series show that in about one third of cases of presumed viral ALF, no specific agent can be identified. Over the past 10 years, the survival of those with grade 3 to 4 encephalopathy has shown a steady rise as a result of improvements in medical care, quite apart from the introduction and now widespread availability of transplantation for the treatment of this condition. As shown by a number of groups, a variety of different hematologic, biochemical, and clinical features can be used as predictive indices of the likely outcome and in determining the approach to treatment.

Characterization of acetaminophen: molecular microanalysis with Raman microprobe spectroscopy

The in situ spectroscopic identification of acetaminophen in a fatal overdose case is described. Numerous techniques have been used to analyze acetaminophen in biological fluids, however, the use of nondestructive spectroscopic techniques has not been documented. In this investigation, the demonstration of the drug material was established by using the laser Raman microprobe technique, providing an accurate identification by virtue of the drug's molecular fingerprint characteristics. Material found on the deceased was collected and placed on metal (aluminum-coated) plated slides and excited with the 514.5 nm line of an argon ion laser, which was focused to a 1 micron spot size using a high-resolution optical microscope. Spectra of acetaminophen particles with an average size of 5 to 8 microns were obtained. The Raman spectrum of this drug contains characteristic group frequencies assigned to the C = O at 1649 cm-1, the N-H deformation mode at 1620 to 1612 cm-1, the bendstretch mode of the H-N-C = O at 1562 cm-1, the C-H bending mode at 1325 cm-1, and the phenyl ring stretch at 799 cm-1, respectively. The results reported here demonstrate the capability of laser Raman microprobe as a useful adjunct tool for the identification of foreign materials in forensic pathology.

Site to site variability of postmortem drug concentrations in liver and lung

We evaluated postmortem diffusion of gastric drug residue into tissues and blood in eight suicidal overdoses. Analyses were performed on liver (five sites), lung (four sites), spleen, psoas muscle and kidney (left and right), blood (peripheral and torso), vitreous, pericardial fluid, bile and, urine as well as residual gastric contents. Standard analytical techniques and instrumentation gas chromatograph/mass spectrometer and high performance liquid chromatography (GC-MS and HPLC) were used throughout. These case studies confirm previous studies of an animal and human cadaver model of gastric diffusion, in that in several instances there was drug accumulation in the left posterior margin of the liver and, to a lesser extent, the left basal lobe of the lung. Uncontrollable variables, such as postmortem interval, refrigeration before autopsy, and position of the body appear to influence significantly drug accumulation in a specific site. We suggest that autopsy sampling techniques should be standardized on blood taken from a ligated peripheral (preferably femoral or external iliac) vein, and liver from deep within the right lobe.

Late increase in acetaminophen concentration after overdose of Tylenol Extended Relief

We report a case demonstrating a late increase in acetaminophen concentration after ingestion of Tylenol Extended Relief (extended-release acetaminophen; McNeil Consumer Products) along with drugs known to slow gastrointestinal motility. Coingestants that slow gastrointestinal motility are known to affect the interpretation of serum drug concentrations. However, this case illustrates potentially significant differences between extended-release and immediate-release acetaminophen and demonstrates an exception to the current manufacturer recommendation for the use of the Rumack-Matthew nomogram in this setting.