Aconite poisoning in camouflage.

The Toxicology Reference Laboratory has confirmed 10 cases of aconite poisoning from March 2004 to May 2006. In four of these 10 cases, the aconite herb was not listed in the written prescription. We report these four cases to highlight the problem of 'hidden' aconite poisoning.

Nitrite-induced methaemoglobinaemia - aetiology, diagnosis and treatment.

A 41-year-old woman presented with the clinical features of methaemoglobinaemia after drinking Chinese herbal medicine. A life threatening methaemoglobin level of 68% was measured. Both clinical and laboratory diagnostic difficulties were encountered. The pitfalls of pulse oximeter, blood gas analysis and co-oximeter interpretation during diagnosis and after methylene blue administration are discussed.

Use of hair analysis in the diagnosis of heavy metal poisoning: report of three cases.

We report three paediatric cases of suspected heavy metal poisoning that presented with non-specific symptoms. Hair samples of the three patients were sent overseas for analysis; results showed abnormal levels of many elements, including some heavy metals. A diagnosis of heavy metal poisoning was made and chelation therapy was offered to each patient. Blood levels for some heavy metals were subsequently checked and all were within the normal range. The original diagnosis of heavy metal poisoning was therefore not substantiated. The patients did not have a history of exposure to heavy metals or specific clinical features of heavy metal poisoning. The non-invasive nature of hair analysis is tempting, but the validity of such testing in diagnosing heavy metal poisoning is questionable.

Poisoning due to Chinese proprietary medicines.

1. To determine the toxic potentials of those Chinese proprietary medicines (CPM) which are commonly used for self-poisoning by adults in Hong Kong, all patients admitted to four of the eight general medical wards at the Prince of Wales Hospital between January 1988 and December 1993 were retrospectively studied. 2. There were 54 women and 17 men with their age ranging from 15 to 86 years. Twenty-three subjects (32%) also took alcohol, chemicals or drugs. Of the 51 subjects (72%) who had taken topical medicaments, 22 had no symptoms while 28 had minor features of gastrointestinal irritation (n = 26), mild (n = 2) or severe (n = 1) salicylate poisoning. Of the 17 subjects (24%) who had taken CPM tablets/capsules, nine had mild symptoms including nausea/vomiting and drowsiness. The three remaining patients (4%) who had ingested liquid CPM preparations were asymptomatic. Elevated plasma salicylate or paracetamol concentrations (> 0.1 mmol l-1) were found in some patients who had taken topical medicaments and CPM tablets/capsules, respectively. All the 71 patients completely recovered. 3. Most of the CPM used for self-poisoning in Hong Kong were of low to moderate toxicity except for those containing wintergreen oil (methyl salicylate).

Hospital admissions due to adverse reactions to Chinese herbal medicines.

Chinese herbal medicines (CHM) are commonly used in Hong Kong. To determine the importance of adverse reactions to CHM as a cause of medical admissions in Hong Kong, all 1701 patients admitted to two general medical wards at the Prince of Wales Hospital over an eight-month period were prospectively studied. In only three patients (0.2%) was the admission attributed to the adverse effects of CHM. These were life-threatening in two cases ('dazao'-induced angio-neurotic oedema and liquorice-induced hypokalaemic periodic paralysis). Despite this low incidence of adverse reactions, in communities where CHM are commonly used, it is important that there is a continuing effort to collect new information on the safety of these compounds.