Predictive Factors of Gastrointestinal Injuries after Exposure to Sodium Hypochlorite

Background: Sodium hypochlorite is found in bleaching agents used to cleaning dishes and bleach laundry. The ingestion of sodium hypochlorite causes acute corrosive esophagitis and gastritis. In establishing the diagnosis and therapeutic approach of acute corrosive poisonings, the upper endoscopy has great importance. The aim of this study was to determine predictive factors of gastrointestinal injuries that mandate early endoscopy. Methods: This study consisted of 65 patients presented to Loghman Hakim Toxicology Center, Tehran, Iran with history of sodium hypochlorite bleach exposure from 2010 to 2014. The postcorrosive damage classified according to Kikendal’s grading. Results: There were a total of 19 males and 46 females with a mean age of 34.21 yr old. In upper GI endoscopy, 20% of poisoned patients had abnormal findings. Male gender (P=0.029), presence of hoarseness (P=0.044), nausea and vomiting (P=0.007), sialorrhea (P=0.044) and higher age (P=0.05) were associated with the occurrence of gastrointestinal injuries, but only male gender (OR=5.04), nausea and vomiting (OR=8.97) were independent predictors of gastrointestinal injuries (P=0.03 and P=0.03, respectively). Conclusion: We proposed five factors associated with gastrointestinal injuries, which could be important factors that mandate urgent endoscopy.


INTRODUCTION
Sodium hypochlorite (NaOCl) is largely found in household bleaching agents.It is highly efficacious at disinfecting and cleaning hard surfaces, dishes and bleach laundry [1,2] Its medical usages are not limited to disinfection of devices such as dialysis machines, tunneled catheters and surgical equipment, but it is used for wound cleaning, hand hygiene, and root canal sterilization [3,4].
Victims may expose to NaOCl accidentally or intentionally [2].Poisoning due to ingestion of sodium hypochlorite bleach usually results in a benign clinical course [1,3,[5][6][7][8].Few studies have reported severe complications such as esophageal stenosis or perforation [1].Oral ingestion of sodium hypochlorite is accompanied with gastrointestinal symptoms and signs such as nausea, vomiting, esophageal burning, perforation, and strictures [9,10].Park et al. reported a case of esophageal perforation followed by acute mediastinitis [1].Some other rare complications are hypernatremia, hypercholeremia, and metabolic disturbance [5,11].The aim of this retrospective study was to investigate the prognostic factors of gastrointestinal injuries in patients poisoned with sodium hypochlorite admitted to a university hospital in Tehran, Iran.

Samples
We enrolled all patients with history of acute sodium hypochlorite bleach exposure

Data Gathering
Patient demographics, presenting features, physical examinations, clinical management, laboratory data and outcomes were recorded for each patient.The time of ingestion and the ingested volume was recorded based on patients' or their attendance reports.We enrolled only patients who underwent urgent endoscopy in addition to supportive management.Inclusion criteria were acute intoxication with sodium hypochlorite and exclusion criteria were multiple drug intoxication.The post-corrosive damage classified according to Kikendal's grading.Kikendal [12] suggested a classification in four grades: I: edema and erythema of the mucosa, II A: hemorrhage, erosions, blisters, superficial ulcers, II B: circumferential lesions, III: deep grey or brownish-black ulcers, IV: perforation.
All patients received standard care.Airway management and intravenous fluid resuscitation were the priorities.Treatment with a proton pump inhibitor (pantoprazole) was initiated but the steroids and prophylactic antibiotics had not been administered because the evidences were not strong enough.Pantoprazole was initiated at a dosage of 40 mg twice daily for all patients.If gastrointestinal bleeding occurred, the dosage would change to 80 mg bolus followed by 8 mg per hour.At the time of admission, ECG was taken and pulse oximetry was done, then blood samples were drown for arterial blood gas, complete blood count, serum electrolytes, blood urea nitrogen and creatinine.

Data Analysis
The statistical analyses were performed by SPSS 18.0 [SPSS Inc., Chicago, IL, USA].To test the normality of the distribution of the continuous variables, the Kolmogorov-Smirnov test was performed.Descriptive statistics are given by means and 95% confidence intervals.Categorical data are subsumed by absolute and relative frequencies.In analytical statistics, nominal or ordinal variables were compared between groups by chi-square test and Fisher's exact test, depending on the expected cell counts of the corresponding crosstabs.In addition, unpaired Student t test and one way ANOVA were used because all the variables fulfilled the presumption of normal distribution.Statistical significance was considered P<0.05.

DISCUSSION
The production of sodium hypochlorite is occurred when chlorine gas passed into cold dilute sodium hydroxide solution.When it dissolved in water , it forms hypochlorous acid (HOCl) that generates superoxide radicals.So sodium hypochlorite is a potent oxidizer and exhibit antimicrobial or pathogen activity [13].NaOCl is the frequently used as a disinfectant and an active ingredient in household bleach due to its alkaline nature [14,15].Household bleach is a solutions containing 1-6% of NaOCl [15].
The ingestion of NaOCl induces acute corrosive esophagitis and gastritis [16].The degree of gastrointestinal injury and alkaline esophagitis due to NaOCl ingestion is variable and the findings of endoscopic abnormalities within 48 hours of ingestion are associated with poor prognosis [17].NaOCl poisoning, results in minor transient adverse effects with rare permanent sequel [2].Satar and colleagues reported 24 patients who orally ingested NaOCl.The mean time interval after ingestion of NaOCl and admission to emergency department was 5.4±5.6 h, which was a little longer than our result.The endoscopic results were as follows: grade 0 (21.6%, n=8), grade 1 (45.9%,n=17), grade 2a (13.5%, n=5) and grade 2b (18.9%, n=7) patients.The authors stated "early signs and symptoms after caustic substance ingestion are not consistent with the extent of damage, and endoscopy is the only reliable method to assess the severity of injuries" [18].The quantity and concentration of ingested bleach were not as important as the symptoms and signs of patients and the clinical manifestations were more reliable for prediction of GI lesion [19].In a 15 years retrospective cohort study in a tertiary medical center, 50 cases of caustic ingestion were identified.The most common caustic agent ingested was alkaline (42%) followed by acidic (32%) and chlorine bleach (26%).The most frequent cause for ingestion was accidental (67%) as opposed to attempted suicide (33%).The adult victims who ingested sodium hypochlorite intentionally had poor outcome and higher rate of adverse effects (9).Chlorine bleach is usually stored inappropriately in home and children reach it easily [20].
Caustic agents are responsible for the most serious cases of poisoning, which are usually emergency cases [18].
As limitations of this study, although our study was conducted in one center but to our knowledge near all poisoned cases were transferred by Emergency Medical Service (EMS) or referred by other hospitals to our toxicology center (Loghman Hakim, Tehran, Iran), so these results may not be representative of the general population in Tehran.

CONCLUSION
Ingestion of sodium hypochlorite is usually benign, leading most poison centers to implement conservative cares.There are no known antidotes to NaOCl and currently most authorities recommend endoscopic examination of the upper gastrointestinal tract due to the poor correlation between clinical presentations and the degree of injury.Others suggest that patients require endoscopy only if they are symptomatic.We proposed five factors associated with gastrointestinal injuries, which could be important factors that mandate urgent endoscopy.

Table 1 .
The symptoms and signs of patients admitted to emergency department after sodium hypochlorite ingestion.