HSC Section 3 - Trauma, Critical Care and Sleep Medicine

J.H. Bird et al.

cleaners and phosphoric acid in metal cleaners. It is thought that acids with a pH < 2 are corrosive although the molarity and complex affinity are thought to determine the potential extent of injury. Acids cause injury by coagulative necrosis and the formation of thrombi within the vessels and the formation of scar tissue, and this reduces tissue penetration when compared to alkalis. This barrier effect results in acids potentially causing relatively less adjacent tissue damage. 10 Acid ingestion also often causes pain and thus are often consumed in smaller volumes. 6 Alkali ingestion. Alkalis are also common amongst domestic products. Sodiumhydroxide is often found in drain cleaners, sodium hypochlorite in bleach, sodium bicarbonate in automatic dishwasher detergents and ammonia-based prod- ucts in a variety of kitchen cleaners. The concern with regard to alkali ingestion is injury by liquefaction necrosis due to bonding with tissue protein; thus, injury continues until the alkali is neutralized by tissue fluids, which can take up to 3 – 4 days. 6 Alkaline fluid has a strong surface tension and will stay in the tissue for a longer period than acids. 11 These features of alkalis can result in extensive injury despite minimal ingestion of the substance and being less immedi- ately painful the volume consumed is often greater. 9 Keypoints. • Acid ingestion causes coagulative necrosis which reduces tissue penetration, which means there is less likely to be injury to adjacent structures. • Alkali ingestion causes liquefaction necrosis resulting in greater tissue penetration and potential complica- tions. • Attempts to estimate the volume of caustic material ingested are often inaccurate and are therefore not relied upon in the history to influence management. 2. Initial assessment. Crystal or solid ingestion are associated withmore damage to the oral cavity and pharynx due to their adherence to upper digestive mucosa. Liquids are more likely to cause oesophageal injury due to the ease in which they are swallowed. 12 The most common features are oropharyngeal pain, chest pain and dysphagia. 7 Associated symptoms include vomiting, drooling, odynophagia and stridor although the relationship between severity of symptoms and severity of injury is uncertain. 13 The oral cavity and oropharynx may give a clue to the caustic agent in the form of black slough (acid) or grey opaque membranes (alkalis). The degree of visible injury does not always correspond to oesophageal injury, and up to 70% of those with oropharyngeal burns do not have

Methods

A literature review (December 2014) searched PubMed citing variations on the areas of controversies with “caustic ingestion,” “corrosive ingestion,” “acid ingestion” and “alkali ingestion” – from 1956 to present with language restrictions. The titles and abstracts were initially screened, and full text of potentially relevant articles was obtained. The bibliographies of articles were searched for relevant references. The refer- ences were then compiled and reviewed independently by two authors (JB and SK), overseen by the senior author (JR). References were ranked according to their level of evidence and divided into areas of controversy. Following this, full-text articles were requested and authors discussed which papers were relevant and should be included. Quality assessment was carried out on all studies, assessing for limitations in study design, statistical analysis and inclusion of pertinent results. If there were deficiencies in this quality control assessment, then the study was rejected. Over 100 full-text articles were retrieved. Several specific areas of controversy were identified and addressed, with the highest available evidence referenced for each area: 1 History of substance ingested 2 Initial assessment 3 Imaging and investigations 4 Medical therapy including corticosteroids, antibiotics, PPI, neutralization 5 Surgical intervention 6 Follow-up and management of complications 1. Substance ingested. In combination with initial resuscita- tion, a focused history should be taken. Special attention should include whether the ingested corrosive is acid or alkaline and the strength of the agent consumed. The estimated volume ingested is worth documenting, but evidence suggests that healthcare professionals are poor at estimating this and that clinical evaluation should determine management. 8 Both acid and alkali ingestion have the potential to cause damage to the larynx, trachea, oesophagus and bronchi. 9 Areas of controversy Ethical considerations As a review article of the current literature, it was felt no ethical approval was required. Results

Acid ingestion. Household availability of acids is often widespread. Hydrochloric acid is often found in toilet

© 2016 John Wiley & Sons Ltd Clinical Otolaryngology 42 , 701–708

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