Masterclass 9 - Toxicology Services

Novel psychotrophic substances (NPS), also known as emerging drugs of abuse, are constantly evolving structural analogues of traditional drugs of abuse that have become a threat to public health worldwide and within our locality. This study reviewed the NPS detected in cases referred to the Hospital Authority Toxicology Reference Laboratory – the only tertiary clinical toxicology laboratory in Hong Kong. The associated clinical features and toxicological were also documented. 
A total of 111 cases involving 104 patients and 22 types of NPS were identified. The identified NPS included 2-phenyl-2-(ethylamino)-cyclohexanone (2-oxo-PCE, a ketamine analogue), para-methoxymethamphetamine, 4-fluoroamphetamine, phenazepam, 3-trifluoromethylphenylpiperazine, 5-methoxy-diisopropyltryptamine, 2-diphenylmethylpyrrolidine, methoxyphenidine, the N-methoxybenzyl drugs, cathinones, synthetic cannabinoids and opioids. 
Among the acute poisoning cases attributable to NPS use, the severity was fatal (n = 3), severe (n = 17), moderate (n = 67) and minor (n = 17). And 11 patients required intensive care unit admission. All three fatal cases were associated with paramethoxymethamphetamine use.
It is concluded that a rising trend of new psychoactive substance use is observed locally, which is associated with considerable morbidity and mortality. Continued vigilance from frontline clinicians and medical professionals is imperative in the combat against NPS use.

Poisoning is not uncommon in Hong Kong.  According to the Annual Report 2017 published by Hong Kong Poison Information Centre (HKPIC), there were around 4,000 cases of poisoning recorded yearly between 2013 and 2017.  While the majority of the cases had uneventful recovery, some poisoning could cause major clinical outcomes or even death.  Supportive treatment, decontamination and antidote use are important treatment options for poisoning.
Antidote is a substance that is administered specifically to counteract the toxic effects of a poison.  Its use can be life-saving, but only if it is available and administered timely.  Some antidotes with low frequency of use are unregistered products and may not be readily available in Hong Kong.  To be prepared for the need of antidote use in emergency situations, Hospital Authority (HA) has set up a 3-Level Antidotes Mechanism to maintain adequate stock of different types of antidotes at acute hospital, cluster and central levels respectively in a cost-effective manner.   The HA Central Committee of Toxicology Services (CCTox) plays an important role in recommending the list of antidotes of each level and the stock level to be kept.  The antidote list is reviewed regularly and updated based on the trend and frequency of poison exposures as reflected by the latest toxicovigilance data.
In view of the importance to ensure availability and accessibility of antidotes for timely treatment of poisoning patients, the CCTox has taken initiative to enhance the management of antidotes at hospital level on top of the 3-Level Antidotes Mechanism.  In the presentation, the review and actions taken to improve the availability and accessibility of antidotes will be discussed.

E-cigarette was created in 2003, and gained popularity over the past decade. It has been perceived to be good in term of a harm reduction product for chronic smoker, environmental friendly, or even “fashionable”. Although user of e-cigarette may expose to less known toxic substances such as nitrosamines from conventional cigarette, e-cigarette is definitely harmful. The existing evidence shows that e-cigarette aerosol contain multiple toxicants. 
Thousands of e-cigarette refill liquid or e-liquid are available in the market. E-liquid commonly contains nicotine of varying concentration, glycerin, propylene glycol and flavour chemicals. The exact ingredients of e-liquid may not be reliably listed. It was found about one-fifth of e-liquid samples had significant discrepancy (>20%) in the labelled nicotine content. Besides, e-liquid may contain high concentration of different flavor chemicals of potential toxicity. One example is the flavor chemical “diacetly”, which is a culprit for “popcorn lung disease”. 
From a clinical perspective, e-cigarette poisonings have increased significantly in recent years. Poison centres data suggest majority of the e-cigarette exposure involve children. Although severe toxicity is uncommon, fatality from accidental exposure did occur. The major toxicological concern is acute nicotine poisoning. Besides, e-cigarette “explosion’ resulted in significant burn and blast injury were noted in case reports.