Accidental Charcoal Aspiration:

Systematic review on the use of activated charcoal for gastrointestinal decontamination following acute oral overdose

INTRODUCTION

The use of activated charcoal in poisoning remains both a pillar of modern toxicology and a source of debate. Following the publication of the joint position statements on the use of single-dose and multiple-dose activated charcoal by the American Academy of Clinical Toxicology and the European Association of Poison Centres and Clinical Toxicologists, the routine use of activated charcoal declined. Over subsequent years, many new pharmaceuticals became available in modified or alternative-release formulations and additional data on gastric emptying time in poisoning was published, challenging previous assumptions about absorption kinetics. The American Academy of Clinical Toxicology, the European Association of Poison Centres and Clinical Toxicologists and the Asia Pacific Association of Medical Toxicology founded the Clinical Toxicology Recommendations Collaborative to create a framework for evidence-based recommendations for the management of poisoned patients. The activated charcoal workgroup of the Clinical Toxicology Recommendations Collaborative was tasked with reviewing systematically the evidence pertaining to the use of activated charcoal in poisoning in order to update the previous recommendations.

OBJECTIVES

The main objective was: Does oral activated charcoal given to adults or children prevent toxicity or improve clinical outcome and survival of poisoned patients compared to those who do not receive charcoal?  Secondary objectives were to evaluate pharmacokinetic outcomes, the role of cathartics, and adverse events to charcoal administration. This systematic review summarizes the available evidence on the efficacy of activated charcoal.

METHODS

A medical librarian created a systematic search strategy for Medline (Ovid), subsequently translated for Embase (via Ovid), CINAHL (via EBSCO), BIOSIS Previews (via Ovid), Web of Science, Scopus, and the Cochrane Library/DARE. All databases were searched from inception to December 31, 2019. There were no language limitations.  One author screened all citations identified in the search based on predefined inclusion/exclusion criteria. Excluded citations were confirmed by an additional author and remaining articles were obtained in full text and evaluated by at least two authors for inclusion. All authors cross-referenced full-text articles to identify articles missed in the searches. Data from included articles were extracted by the authors on a standardized spreadsheet and two authors used the GRADE methodology to independently assess the quality and risk of bias of each included study.

RESULTS

From 22,950 titles originally identified, the final data set consisted of 296 human studies, 118 animal studies, and 145 in vitro studies. Also included were 71 human and two animal studies that reported adverse events. The quality was judged to have a Low or Very Low GRADE in 469 (83%) of the studies. Ninety studies were judged to be of Moderate or High GRADE. The higher GRADE studies reported on the following drugs: paracetamol (acetaminophen), phenobarbital, carbamazepine, cardiac glycosides (digoxin and oleander), ethanol, iron, salicylates, theophylline, tricyclic antidepressants, and valproate. Data on newer pharmaceuticals not reviewed in the previous American Academy of Clinical Toxicology/European Association of Poison Centres and Clinical Toxicologists statements such as quetiapine, olanzapine, citalopram, and Factor Xa inhibitors were included. No studies on the optimal dosing for either single-dose or multiple-dose activated charcoal were found. In the reviewed clinical data, the time of administration of the first dose of charcoal was beyond one hour in 97% (n = 1006 individuals), beyond two hours in 36% (n = 491 individuals), and beyond 12 h in 4% (n = 43 individuals) whereas the timing of the first dose in controlled studies was within one hour of ingestion in 48% (n = 2359 individuals) and beyond two hours in 36% (n = 484) of individuals.

CONCLUSIONS

This systematic review found heterogenous data. The higher GRADE data was focused on a few select poisonings, while studies that addressed patients with unknown and or mixed ingestions were hampered by low rates of clinically meaningful toxicity or death.  Despite these limitations, they reported a benefit of activated charcoal beyond one hour in many clinical scenarios.

Black bronchoscopy

A presence of black pigmentation involving the endobronchial tree is not uncommon. It was first described in the literature in association with occupational exposure in the early 1940s. However, in 2003, Packham and Yeow formally used the term black bronchoscopy to describe endobronchial metastasis from a malignant melanoma. Hyperpigmentation of the airway, however, is associated with multiple etiologies such as congenital disease, inborn errors of metabolism, infections, environmental exposures, neoplasm, and iatrogenic causes. Although the majority of these conditions are benign, a proper diagnosis is important for optimal management. In this article, we review the etiology of black bronchoscopy and discuss its presentations and current management guidelines.

"Pills" and the air passages

Aspiration of a medication in the airways in any form produces a variety of adverse effects, both local and systemic. Furthermore, specific reaction of the airways to each type of pill strongly affects the outcome. It is crucial for pulmonologists and emergency medicine specialists to acknowledge this clinical entity. In addition, airways have been increasingly used to deliver medications such as insulin and prostacycline. These aerosolized medications can also cause local as well as systemic side effects. We review the local and systemic reactions of these "pills" accessing the airways either by incidental aspiration or iatrogenic administration. We address clinical presentation, mechanism of injury, diagnosis, and management of complications of these pills in the air passages.

"Black bronchoscopy"-a case of endobronchial metastases from melanoma

The presence of black pigmentation in the airways during flexible bronchoscopy is uncommon. We report an unusual case of "black bronchoscopy" as a result of endobronchial metastases in a 77-year-old Chinese man, who presented with hemoptysis and postobstructive pneumonia 3 years after initial excision of a skin melanoma. Chest radiograph showed right lower lobe consolidation and collapse. Bronchoscopy showed narrowed airways with black pigmentation involving the lower trachea and right main bronchus. Biopsy confirmed metastatic melanoma. The patient received palliative radiation and died 6 months later. We review the causes of black airway pigmentation. We also briefly review the prevalence, clinical presentation, and prognosis of endobronchial metastases.