Poisoning by toxic plants in Hong Kong: a 15-year review.

INTRODUCTION: Hong Kong has a great diversity of plants, many of which are toxic to humans. The aim of this study was to identify the plant species most commonly involved in cases of plant poisoning in Hong Kong and to provide clinicians with a reference tool for the diagnosis and management of plant poisoning. METHODS: We retrospectively reviewed all plant poisoning cases referred to the Hospital Authority Toxicology Reference Laboratory from 1 January 2003 to 31 December 2017. Demographics, clinical presentation, laboratory findings, treatment and outcomes of patients, as well as morphological identification and analytical testing of the plant specimens, were investigated. RESULTS: A total of 62 cases involving 26 poisonous plant species were identified, among which Alocasia macrorrhizos (Giant Alocasia), Gelsemium elegans (Graceful Jessamine), and Rhododendron (Azalea) species were the three most commonly encountered. Gastrointestinal toxicity (n=30, 48%), neurological toxicity (n=22, 35%), and hepatotoxicity (n=6, 10%) were the three most common clinical problems. Forty-nine (79%) and eight (13%) patients had mild and moderate toxicity, respectively; they all recovered shortly with supportive treatment. The remaining five (8%) patients experienced severe toxicity requiring intensive care support. Most patients (n=61, 98%) used the plants intentionally: as a medicinal herb (n=31), as food (n=29), and for attempting suicide (n=1). Reasons for using the poisonous plants included misidentification (n=34, 55%), unawareness of the toxicity (n=20, 32%), and contamination (n=6, 10%). CONCLUSIONS: Although most plant exposure resulted in a self-limiting disease, severe poisonings were encountered. Epidemiology of plant poisonings is geographically specific. Clinicians should be aware of local poisonous plants and their toxicities.

Sudden arrhythmia death syndrome in young victims: a five-year retrospective review and two-year prospective molecular autopsy study by next-generation sequencing and clinical evaluation of their first-degree relatives.

OBJECTIVE: Sudden arrhythmia death syndrome (SADS) accounts for about 30% of causes of sudden cardiac death (SCD) in young people. In Hong Kong, there are scarce data on SADS and a lack of experience in molecular autopsy. We aimed to investigate the value of molecular autopsy techniques for detecting SADS in an East Asian population. METHODS: This was a two-part study. First, we conducted a retrospective 5-year review of autopsies performed in public mortuaries on young SCD victims. Second, we conducted a prospective 2-year study combining conventional autopsy investigations, molecular autopsy, and cardiac evaluation of the first-degree relatives of SCD victims. A panel of 35 genes implicated in SADS was analysed by next-generation sequencing. RESULTS: There were 289 SCD victims included in the 5-year review. Coronary artery disease was the major cause of death (35%); 40% were structural heart diseases and 25% were unexplained. These unexplained cases could include SADS-related conditions. In the 2-year prospective study, 21 SCD victims were examined: 10% had arrhythmogenic right ventricular cardiomyopathy, 5% had hypertrophic cardiomyopathy, and 85% had negative autopsy. Genetic analysis showed 29% with positive heterozygous genetic variants; six variants were novel. One third of victims had history of syncope, and 14% had family history of SCD. More than half of the 11 first-degree relatives who underwent genetic testing carried related genetic variants, and 10% had SADS-related clinical features. CONCLUSION: This pilot feasibility study shows the value of incorporating cardiac evaluation of surviving relatives and next-generation sequencing molecular autopsy into conventional forensic investigations in diagnosing young SCD victims in East Asian populations. The interpretation of genetic variants in the context of SCD is complicated and we recommend its analysis and reporting by qualified pathologists.

Genetic basis of channelopathies and cardiomyopathies in Hong Kong Chinese patients: a 10-year regional laboratory experience.

INTRODUCTION: Hereditary channelopathies and cardiomyopathies are potentially lethal and are clinically and genetically heterogeneous, involving at least 90 genes. Genetic testing can provide an accurate diagnosis, guide treatment, and enable cascade screening. The genetic basis among the Hong Kong Chinese population is largely unknown. We aimed to report on 28 unrelated patients with positive genetic findings detected from January 2006 to December 2015. METHODS: Sanger sequencing was performed for 28 unrelated patients with a clinical diagnosis of channelopathies or cardiomyopathies, testing for the following genes: KCNQ1,KCNH2,KCNE1,KCNE2, and SCN5A, for long QT syndrome; SCN5A for Brugada syndrome; RYR2 for catecholaminergic polymorphic ventricular tachycardia; MYH7 and MYBPC3 for hypertrophic cardiomyopathy; LMNA for dilated cardiomyopathy; and PKP2 and DSP for arrhythmogenic right ventricular dysplasia/cardiomyopathy. RESULTS: There were 17 males and 11 females; their mean age at diagnosis was 39 years (range, 1-80 years). The major clinical presentations included syncope, palpitations, and abnormal electrocardiography findings. A family history was present in 13 (46%) patients. There were 26 different heterozygous mutations detected, of which six were novel-two in SCN5A (NM_198056.2:c.429del and c.2024-11T>A), two in MYBPC3 (NM_000256.3:c.906-22G>A and c.2105_2106del), and two in LMNA (NM_170707.3:c.73C>A and c.1209_1213dup). CONCLUSIONS: We have characterised the genetic heterogeneity in channelopathies and cardiomyopathies among Hong Kong Chinese patients in a 10-year case series. Correct interpretation of genetic findings is difficult and requires expertise and experience. Caution regarding issues of non-penetrance, variable expressivity, phenotype-genotype correlation, susceptibility risk, and digenic inheritance is necessary for genetic counselling and cascade screening.

The first pilot study of expanded newborn screening for inborn errors of metabolism and survey of related knowledge and opinions of health care professionals in Hong Kong.

INTRODUCTION: Newborn screening is important for early diagnosis and effective treatment of inborn errors of metabolism (IEM). In response to a 2008 coroners' report of a 14-year-old boy who died of an undiagnosed IEM, the OPathPaed service model was proposed. In the present study, we investigated the feasibility of the OPathPaed model for delivering expanded newborn screening in Hong Kong. In addition, health care professionals were surveyed on their knowledge and opinions of newborn screening for IEM. METHODS: The present prospective study involving three regional hospitals was conducted in phases, from 1 October 2012 to 31 August 2014. The 10 steps of the OPathPaed model were evaluated: parental education, consent, sampling, sample dispatch, dried blood spot preparation and testing, reporting, recall and counselling, confirmation test, treatment and monitoring, and cost-benefit analysis. A fully automated online extraction system for dried blood spot analysis was also evaluated. A questionnaire was distributed to 430 health care professionals by convenience sampling. RESULTS: In total, 2440 neonates were recruited for newborn screening; no true-positive cases were found. Completed questionnaires were received from 210 respondents. Health care professionals supported implementation of an expanded newborn screening for IEM. In addition, there is a substantial need of more education for health care professionals. The majority of respondents supported implementing the expanded newborn screening for IEM immediately or within 3 years. CONCLUSION: The feasibility of OPathPaed model has been confirmed. It is significant and timely that when this pilot study was completed, a government-led initiative to study the feasibility of newborn screening for IEM in the public health care system on a larger scale was announced in the Hong Kong Special Administrative Region Chief Executive Policy Address of 2015.

Corticosteroid adulteration in proprietary Chinese medicines: a recurring problem.

OBJECTIVES: To investigate adulteration of proprietary Chinese medicines with corticosteroids in Hong Kong. DESIGN: Case series with cross-sectional analysis. SETTING: A tertiary clinical toxicology laboratory in Hong Kong. PATIENTS: All patients using proprietary Chinese medicines adulterated with corticosteroids and referred to the authors' centre from 1 January 2008 to 31 December 2012. MAIN OUTCOME MEASURES: Patients' demographic data, clinical presentation, medical history, drug history, laboratory investigations, and analytical findings of the proprietary Chinese medicines were analysed. RESULTS: The records of 61 patients who consumed corticosteroid-adulterated proprietary Chinese medicines were reviewed. The most common corticosteroid implicated was dexamethasone. Co-adulterants such as non-steroidal anti-inflammatory drugs and histamine H1-receptor antagonists were detected in the proprietary Chinese medicine specimens. Among the patients, seven (11.5%) required intensive care, two (3.3%) died within 30 days of presentation, and 38 (62.3%) had one or more complications that were potentially attributable to exogenous corticosteroids. Of 22 (36.1%) patients who had provocative adrenal function testing performed, 17 (77.3% of those tested) had adrenal insufficiency. CONCLUSION: The present case series is the largest series of patients taking proprietary Chinese medicines adulterated with corticosteroids. Patients taking these illicit products are at risk of severe adverse effects, including potentially fatal complications. Adrenal insufficiency was very common in this series of patients. Assessment of adrenal function in these patients, however, has been inadequate and routine rather than discretionary testing of adrenal function is indicated in this group of patients. The continuing emergence of proprietary Chinese medicines adulterated with western medication indicates a persistent threat to public health.

Surveillance of emerging drugs of abuse in Hong Kong: validation of an analytical tool.

OBJECTIVE: To validate a locally developed chromatography-based method to monitor emerging drugs of abuse whilst performing regular drug testing in abusers. DESIGN: Cross-sectional study. SETTING: Eleven regional hospitals, seven social service units, and a tertiary level clinical toxicology laboratory in Hong Kong. PARTICIPANTS: A total of 972 drug abusers and high-risk individuals were recruited from acute, rehabilitation, and high-risk settings between 1 November 2011 and 31 July 2013. A subset of the participants was of South Asian ethnicity. In total, 2000 urine or hair specimens were collected. MAIN OUTCOME MEASURES: Proof of concept that surveillance of emerging drugs of abuse can be performed whilst conducting routine drug of abuse testing in patients. RESULTS: The method was successfully applied to 2000 samples with three emerging drugs of abuse detected in five samples: PMMA (paramethoxymethamphetamine), TFMPP [1-(3-trifluoromethylphenyl)piperazine], and methcathinone. The method also detected conventional drugs of abuse, with codeine, methadone, heroin, methamphetamine, and ketamine being the most frequently detected drugs. Other findings included the observation that South Asians had significantly higher rates of using opiates such as heroin, methadone, and codeine; and that ketamine and cocaine had significantly higher detection rates in acute subjects compared with the rehabilitation population. CONCLUSIONS: This locally developed analytical method is a valid tool for simultaneous surveillance of emerging drugs of abuse and routine drug monitoring of patients at minimal additional cost and effort. Continued, proactive surveillance and early identification of emerging drugs will facilitate prompt clinical, social, and legislative management.

Chinese talismans as a source of lead exposure.

We describe a case of lead exposure after prolonged intake of ashes from burnt Chinese talismans. A 41-year-old woman presented with elevated blood lead level during screening for treatable causes of progressive weakness in her four limbs, clinically compatible with motor neuron disease. The source of lead exposure was confirmed to be Chinese talismans obtained from a religious practitioner in China. The patient was instructed to burn the Chinese talismans to ashes, and ingest the ashes dissolved in water, daily for about 1 month. Analysis of the Chinese talismans revealed a lead concentration of 17 342 µg/g (ppm).

Recipes and general herbal formulae in books: causes of herbal poisoning.

Traditional Chinese medicine is commonly used locally, not only for disease treatment but also for improving health. Many people prepare soups containing herbs or herbal decoctions according to recipes and general herbal formulae commonly available in books, magazines, and newspapers without consulting Chinese medicine practitioners. However, such practice can be dangerous. We report five cases of poisoning from 2007 to 2012 occurring as a result of inappropriate use of herbs in recipes or general herbal formulae acquired from books. Aconite poisoning due to overdose or inadequate processing accounted for three cases. The other two cases involved the use of herbs containing Strychnos alkaloids and Sophora alkaloids. These cases demonstrated that inappropriate use of Chinese medicine can result in major morbidity, and herbal formulae and recipes containing herbs available in general publications are not always safe.

A rare cause of severe diarrhoea diagnosed by urine metabolic screening: aromatic L-amino acid decarboxylase deficiency.

A 15-year-old Chinese male with infantile-onset hypotonia, developmental delay, ptosis, and oculogyric episodes presented with a history of chronic diarrhoea since the age of 5 years. At presentation, he had an exacerbation of diarrhoeal symptoms resulting in dehydration and malnutrition with a concurrent severe chest infection. In view of his infantile-onset hypotonia, oculogyric crises, and protracted diarrhoea, an autonomic disturbance related to neurotransmitters was suspected. Urine organic acid profiling was compatible with aromatic L-amino acid decarboxylase deficiency. The diagnosis was confirmed based on cerebrospinal fluid analysis and genetic mutation analysis. The patient was treated with a combination of bromocriptine, selegiline, and pyridoxine; a satisfactory reduction in diarrhoea ensued. Our report highlights the importance of urine organic acid screening in infantile-onset hypotonia, especially when accompanied by oculogyric crises, and severe diarrhoea which could manifest as a result of autonomic disturbance.

Adenosine testing in atrial flutter ablation: unmasking of dormant conduction across the cavotricuspid isthmus and risk of recurrence.

BACKGROUND: Adenosine-induced hyperpolarization may identify pulmonary veins at risk of reconnection following electrical isolation for atrial fibrillation. The potential role of adenosine testing in other arrhythmic substrates, such as cavotricuspid isthmus (CTI)-dependent atrial flutter, remains unclear. We assessed whether dormant conduction across the CTI may be revealed by adenosine after ablation-induced bidirectional block, and its association with recurrent flutter. METHODS AND RESULTS: Patients undergoing catheter ablation for CTI-dependent flutter were prospectively studied. After confirming bidirectional block across the CTI by standard pacing maneuvers, adenosine (≥ 12 mg IV) was administered to assess resumption of conduction, followed by isoproterenol (ISP) bolus. Further CTI ablation was performed for persistent (but not transient) resumption of conduction. Bidirectional block across the CTI was achieved in all 81 patients (63 males), age 61.2 ± 11.0 years. The trans-CTI time increased from 71.9 ± 18.1 milliseconds preablation to 166.2 ± 26.4 milliseconds postablation. Adenosine elicited resumption of conduction across the CTI in 7 patients (8.6%), 2 of whom had transient recovery. No additional patient with dormant conduction was identified by ISP. Over a follow-up of 11.8 ± 8.0 months, atrial flutter recurred in 4 (4.9%) patients, 3/7(42.9%) with a positive adenosine challenge versus 1/74 (1.3%) with a negative response, P = 0.0016 (relative risk 31.7). CONCLUSION: Adenosine challenge following atrial flutter ablation provoked transient or persistent resumption of conduction across the CTI in almost 9% of patients and identified a subgroup at higher risk of flutter recurrence. It remains to be determined whether additional ablation guided by adenosine testing during the index procedure may further improve procedural outcomes.

A patient with congenital hyperlactataemia and Leigh syndrome: an uncommon mitochondrial variant.

We report an uncommon mitochondrial variant in a baby girl with congenital hyperlactataemia and Leigh syndrome. The patient presented with a single episode of generalised clonic convulsion at day 19, and was found to have isolated and persistent hyperlactataemia ranging from 3.34 to 9.26 mmol/L. She had elevated serum lactate-to-pyruvate ratios of up to 35 and high plasma alanine concentration, indicative of a respiratory chain defect. At the age of 8 months, she developed evolving neurological and imaging features compatible with Leigh syndrome. Genetic testing for common mitochondrial DNA mutations, large mitochondrial DNA deletions, and selected nuclear genes was negative. Further analysis of lymphocyte mitochondrial DNA by sequencing revealed an uncommon heteroplasmic variant, NC_012920.1(MT-ND5):m.13094T>C (p.Val253Ala), which was previously shown to reduce complex I activity. In patients in whom there was a high suspicion of mitochondrial disorder, entire mitochondrial DNA analysis may be warranted if initial screening of common mitochondrial DNA mutations is negative.

Emergence of new psychoactive substance 2-fluorodeschloroketamine: Toxicology and urinary analysis in a cluster of patients exposed to ketamine and multiple analogues.

New psychoactive substances (NPS) emerge continually, amongst which is a growing class of ketamine analogues with an arylcyclohexylamine backbone. Recently we reported a poisoning outbreak associated with 2-oxo-PCE (deschloro-N-ethyl-ketamine). The present report describes the emergence of another ketamine analogue, 2-fluorodeschloroketamine (2F-DCK). The compound was first detected in a patient's urine, its identity confirmed by accurate mass analysis and comparison with reference standard. Four putative metabolites were identified, including nor-2F-DCK, dehydronor-2F-DCK (major metabolite) and two hydroxylated derivatives of nor-2F-DCK. Between January and July 2019, 20 cases of analytically confirmed 2F-DCK exposure were encountered. In 19 out of 20 cases, at least one more ketamine-type drug was detected concurrently with 2F-DCK, including ketamine (90%), deschloroketamine (DCK, 50%), 2-oxo-PCE (45%) and tiletamine (10%). In particular, six of the cases showed the presence of 4 ketamine-type drugs in the same urine sample. The clinical effects observed in patients exposed to 2F-DCK are predominantly neurological (impaired consciousness, agitation, abnormal behaviour) and cardiovascular (hypertension, tachycardia); five patients had loss of consciousness or convulsion. Management was mainly supportive; all patients recovered uneventfully. This is the first clinical case series involving 2F-DCK and frontline medical personnel are urged to be aware of this rapidly expanding class of NPS, in particular the co-ingestion of multiple ketamine analogues.

Hereditary spastic paraplegias.

We report a case of hereditary spastic paraplegia. This 38-year-old Chinese man has had lower limb weakness and spasticity for 10 years. He has normal cognition, no sensory deficits, ataxia or cataracts. There is a strong family history of spastic paraplegia. His paternal grandmother, great uncle, father, and elder brother all had weakness and spasticity. A genetic analysis showed that our patient was heterozygous for the mutation p.P361L in SPG4. He was diagnosed with spastic paraplegia type 4, autosomal dominant (SPG4, MIM#182601). About 40% of cases of hereditary spastic paraplegia are due to mutations in SPG4 encoding for spastin, while 10% are due to mutations in SPG3A encoding for atlastin. To date, 38 hereditary spastic paraplegia loci and 16 hereditary spastic paraplegia-related genes have been identified. Other features include sphincter disturbance and dorsal column disturbance. Our patient may be the first case of SPG4 confirmed by genetic analysis locally. We hope to raise clinicians' awareness of this disease and its possible molecular diagnosis.

Hereditary spastic paraplegia: identification of an SPG3A gene mutation in a Chinese family.

Hereditary spastic paraplegias are a heterogeneous group of chronic central motor system disorders, characterised by progressive lower limb spasticity. Hereditary spastic paraplegia is clinically classified into pure and complicated forms, by the absence or presence of additional neurological or extra-neurological features. Hereditary spastic paraplegias follow all modes of inheritance and the pure-form autosomal dominant type is the one most commonly reported. Spastic paraplegia 4, autosomal dominant (SPG4, MIM#182601) and spastic paraplegia 3, autosomal dominant (SPG3A, MIM#182600), account for most autosomal dominant hereditary spastic paraplegias. Using DNA mutation analysis, the authors identified an SPG3A missense mutation (p.R239C) in a Chinese family where three members have early-onset pure spastic paraplegia. To our knowledge, this is the first report of a gene mutation in hereditary spastic paraplegias in our locality. DNA-based diagnosis plays a key role in the early diagnosis of familial hereditary spastic paraplegias.

Outbreak of hypoglycaemia: sexual enhancement products containing oral hypoglycaemic agent.

OBJECTIVES: To describe a cluster of Hong Kong subjects with hypoglycaemia, after they had taken various non-prescription sildenafil products containing glibenclamide. DESIGN: Retrospective study. SETTING: A tertiary referral centre for clinical toxicology analysis in Hong Kong. PATIENTS: All men referred to the laboratory for investigation of suspected drug-induced hypoglycaemia from December 2007 to September 2008. MAIN OUTCOME MEASURES: The characteristics of these patients, including their clinical presentations, outcomes, drug history, urine toxicology analysis results, and in some instances, analysis results of unused products. RESULTS: A total of 144 male patients were referred for suspected drug-induced hypoglycaemia. Sildenafil and glibenclamide, or their metabolites, were detected in the urine specimens of 68 (47%) patients, none of whom had been prescribed either drug by a registered medical practitioner. Among these subjects, 24 (35%) denied any use of sexual enhancement products despite repeated questioning. Eight patients had repeated exposure resulting in re-admission. The sources of these sexual enhancement products included pharmacies in Mainland China, friends, local pharmacies, peddlers, or were unknown. Three patients died, one remains in a vegetative state and one suffered cognitive impairment; the remaining 63 recovered fully. Twenty-five unused sexual enhancement products of seven different kinds were recovered for analysis. The median (range) of sildenafil and glibenclamide per unit dose was 64 (0.05-198) mg and 70 (0-158) mg, respectively. CONCLUSION: These illegal products pose a severe and continued threat to society and therefore deserve widespread vigilance, so that such products can be eradicated at their source.

Circulatory collapse in a patient with gastrinoma after metoclopramide administration.

A patient who was given metoclopramide for vomiting and diarrhoea developed circulatory collapse with his blood pressure dropping to 50/20 mm Hg. A gastrinoma was diagnosed histologically. The extent of the tumour was defined by octreotide scanning and magnetic resonance imaging. Metoclopramide was again given for colicky abdominal pain and the patient developed circulatory collapse a second time. A laparotomy involving extensive resection of the tumour was performed. The MEN1 mutation was not detected in blood or tumour tissue. Follow-up octreotide scanning did not show any residual tumour. Possible causes for the circulatory collapse are discussed. Our case is probably the first patient with gastrinoma to develop circulatory collapse after being given metoclopramide.

Bromadiolone toxicokinetics: diagnosis and treatment implications.

INTRODUCTION: Ingestion of bromadiolone can lead to prolonged and life-threatening coagulopathy. Traditional treatment of bromadiolone intoxication relies on the coagulation profile. Currently, there is scanty information on bromadiolone elimination kinetics and half-life. CASE REPORT: We report a case of bromadiolone poisoning in a 40-year old female who, by history, ingested four 42.5-gram bags of rat poison (0.005% bromadiolone), equivalent to 8.5 mg bromadiolone (0.17 mg/kg body weight), four days prior to admission. On admission, her prothrombin time was 92.0 seconds, international normalized ratio was 5.7, and activated partial thromboplastin time was 50.2 seconds with no bleeding on clinical examination. The first plasma bromadiolone level (5 days post-ingestion) was 92 ng/mL. Serial measurement of plasma bromadiolone levels confirmed the diagnosis and demonstrated that bromadiolone obeys the elimination kinetic of a two-compartment model with a rapid, fairly steep decline phase (half-life 3.5 days) followed by a slower termination phase (half-life 24 days). Plasma bromadiolone level of less than 10 ng/mL in our patient was associated with a consistently normal coagulation profile without vitamin K1 therapy. CONCLUSIONS: There is a lack of information on the toxicodynamics and toxicokinetics of bromadiolone in humans; further studies are needed before the plasma bromadiolone level can serve as one of the logical and safe therapeutic endpoints for vitamin K1 therapy.

Hazards posed by a banned drug--phenformin is still hanging around.

The Hospital Authority Toxicology Reference Laboratory confirmed six cases of phenformin use, with or without complications, from July 2005 to November 2006. Two of the patients presented with potentially fatal phenformin-induced lactic acidosis. Phenformin was found (or suspected to be) adulterating Chinese proprietary medicine in five of the six cases. We report these six cases to highlight the underrecognised hazards posed by phenformin, a banned drug in Hong Kong.