儿童铅中毒（下篇）

儿童铅中毒状况的评价指标通常有两种：一是儿童平均血铅浓度（BPb）;二是铅中毒流行率,即BPb≥100mg／L（0．05mol／L）的儿童数占调查总人数的百分比。我国虽尚无全国性流行病学数字,但大多数城市调查结果显示儿童平均BPb为50-90mg／L,儿童铅中毒流行率为10％-50％;高于200mg／L的约1％-2％,较10年前明显减少。     

Childhood lead poisoning in 2 families associated with spices used in food preparation

Although most cases of childhood lead poisoning are caused by contaminated paint and dust in older homes, a variety of unusual sources of lead exposure are occasionally found. We report here 2 families whose children were poisoned by lead-contaminated spices that were purchased in foreign countries, brought to the United States, and then used in the preparation of the family's food. Six children (2-17 years old) in a family from the Republic of Georgia were poisoned by swanuri marili (lead content: 100 and 2040 mg/kg in separately sampled products) and kharchos suneli (zafron) lead content: 23,100 mg/kg) purchased from a street vendor in Tbilisi, Georgia. The second family had purchased a mixture of spices called kozhambu (lead content: 310 mg/kg) while traveling in India. Both the parents and their 2-year-old child subsequently suffered lead poisoning. The young children in both families required short-term chelation to bring their blood lead levels down to a safer range. Clinicians should be vigilant for all sources of lead contamination, including spices, when whole families are found to have elevated blood lead levels despite a confirmed lead-safe home environment. Families traveling abroad should be aware of the potential health risks associated with the purchase and use of spices that have not been tested for purity.     

Childhood poisoning in Sri Lanka

Poisoning in children is a common accident and poison information services should be aware of the toxic agents responsible for poisoning in the community. A retrospective hospital based study was performed, before-the establishment of the National Poisons Information Centre in Sri Lanka. There were 4,556 admissions of poisoning to the selected hospitals in the Western Province in 1986 and of this, 540 (11.4%) were below 15 years. Males accounted for 66%. Kerosene oil was responsible for 47% of the poisoning cases in less than 5 years age group, while kerosene oil, pesticides and plants/mushrooms were the commonest toxic agents in the 5 to 14 years age group. The case fatality rate was 3.2%.     

Childhood poisoning: access and prevention

OBJECTIVES: To investigate the circumstances and means of access to six poisoning agents by children under 5 years of age and to make recommendations for countermeasures and strategies for implementation. METHODOLOGY: A case series study of access to six poisoning agents was conducted. Cases were identified prospectively through a poisons information centre and hospital emergency departments. Interviews were conducted with 523 parents and caregivers using a structured questionnaire. RESULTS: The majority of children (94.1%) accessed the agent in their own home or another home and, in 38% of cases (excluding mistakes in administration), the parent or caregiver was present in the immediate area at the time of the incident. In cases in which the child was alone in the room, caregivers were frequently involved in household duties (51%), with only 10% undertaking leisure activities and 8% on the telephone. The span of unsupervised time reported was 5 min or less in 79.5% of these cases. The means of access was generally during periods of use of the agent (75.3%), including just purchased, rather than when agents were in their usual storage place. CONCLUSIONS: There is little scope for improved supervision as a major intervention. Design and regulatory changes such as local safe storage for bench tops and while travelling, improved labelling and packaging, improved child-resistant packaging and its more general application are required. These and agent-specific interventions, including child-resistant bait stations for rodenticides and well covers for vaporizers, are more likely to prevent poisoning. The recent identification of childhood poisoning prevention as a national priority may lead to coordinated action to implement these and other preventive measures.     

Iron deficiency in lead poisoning

The anemia of lead poisoning is multifactorial. Of 44 hematologically evaluated children with class III or IV lead intoxication, 50 per cent were anemic and 39 per cent were iron deficient. Iron deficiency may play an important role in the anemia of lead poisoning. Early diagnosis and correction of nutritional deficiencies may decrease the metabolic toxicity of lead poisoning.     

Six children with lead poisoning

Although most commonly seen in children from lower socioeconomic backgrounds, all children are at risk for lead poisoning. Management is a potential problem for all primary care providers. Because few individuals in the primary care practice of pediatrics have many patients with lead poisoning, it may be difficult to understand the nuances of management. We describe six patients, each of whom reflects different aspects of lead poisoning in children, and discuss the lessons we have learned in the course of their treatment. We have found that graphic representation of the blood lead and erythrocyte protoporphyrin values is helpful in the longitudinal follow-up of these youngsters.     

Prevention of childhood lead poisoning

Although past national public health efforts have reduced lead exposure significantly, lead poisoning remains the most common environmental health problem affecting American children. Currently, lead exposure occurs predominantly through ingestion of lead-contaminated household dust and soil in older housing containing lead-based paint; exposure can be increased with housing deterioration or renovation. Environmental prevention efforts focus on improvement in risk assessment, development of housing-based standards for lead-based paint hazards, and safe and cost-effective lead hazard remediation techniques. Educational efforts address parental awareness of lead exposure pathways, hygiene, and housekeeping measures to prevent ingestion of dust and soil. Blood lead screening is recommended either universally at ages 1 and 2 years or in a targeted manner where local health departments can document a low prevalence of elevated blood lead levels. Nutritional interventions involve provision of regular meals containing adequate amounts of calcium and iron and supplementation for iron deficiency. Lead chelation should complement environmental, nutritional, and educational interventions, when indicated. Collaboration of multiple federal agencies in a new strategy to eliminate childhood lead poisoning should further prevention efforts.