Concentration-associated pathology of alkali burn in a mouse model using anterior segment optical coherence tomography with angiography.

Pathological features of alkali concentration-associated burn were studied using non-invasive anterior segment optical coherence tomography (AS-OCT) and OCT angiography (OCTA). Alkali burn was induced in C57BL/6J mice (n = 20) by placing filter paper soaked in 0.1, 0.25, 0.5, and 1 M NaOH for 30s on the right eye (left eye control). Longitudinal imaging was performed with AS-OCT/OCTA and fluorescein angiography over 14 days, after which eyes were enucleated at 7 and 14 days for histology and immunofluorescence. Concentration-associated corneal swelling was maximal at 0.5M, increasing linearly in a concentration-dependent fashion at 0.1, 0.25, and 0.5 M NaOH, to levels of 50%, 100%, and 175% of control, respectively. At 0.1M, corneal swelling and surface erosions were prominent, while at 0.25M, deep tissue damage, limbal neovascularization, and stromal haze were evident at 7 days. At 0.5M and 1M, severe exacerbation of the corneal swelling, angle closure, Descemet's membrane detachment, hyphema, and profuse central neovascularization were noted as early as day 3, which further progressed to inflammation, fibrosis, and opacity by day 7. We conclude that alkali concentration-dependent burn intensity biomarkers can be assessed by non-invasive AS-OCT/OCTA, distinguishing between mild, moderate, and severe ocular injury, with potential relevance toward clinical utilization in human eyes.

Longitudinal assessment of the effect of alkali burns on corneal biomechanical properties using optical coherence elastography.

Eye injury due to alkali burn is a severe ocular trauma that can profoundly affect corneal structure and function, including its biomechanical properties. Here, we assess the changes in the mechanical behavior of mouse corneas in response to alkali-induced injury by conducting longitudinal measurements using optical coherence elastography (OCE). A non-contact air-coupled ultrasound transducer was used to induce elastic waves in control and alkali-injured mouse corneas in vivo, which were imaged with phase-sensitive optical coherence tomography. Corneal mechanical properties were estimated using a modified Rayleigh-Lamb wave model, and results show that Young's modulus of alkali-burned corneas were significantly greater than that of their healthy counterparts on days 7 (p = 0.029) and 14 (p = 0.026) after injury. These findings, together with the changes in the shear viscosity coefficient postburn, indicate that the mechanical properties of the alkali-burned cornea are significantly modulated during the wound healing process.

Role of anterior segment optical coherence tomography angiography in assessing limbal vasculature in acute chemical injury of the eye.

PURPOSE: To study the role of two anterior segment optical coherence tomography angiography (AS-OCTA) systems in eyes with acute chemical injury. METHODS: Prospective study in subjects with unilateral chemical injuries. Sequential slit-lamp assessment with spectral domain (SD) (AngioVue, Optovue, USA) and swept source (SS) (Plex Elite, Zeiss, Carl Zeiss Meditec, Dublin, California, USA) AS-OCTA was performed in both eyes within 24-48 hours of injury. Subjects were managed with a standard clinical protocol and followed-up for 3 months. We assessed limbal disruption (loss of normal limbal vessel architecture), limbal vessel density measurements and agreement (kappa coefficient, κ) between masked assessors of limbal disruption based on AS-OCTA scans and slit-lamp assessment. RESULTS: Ten subjects with median age 31 (25-33) years, 20% women, 60% suffered alkali injuries (Roper-Hall grade 1.5±0.7, Dua grade 2.3±1.2) at presentation. Mean limbal vessel density was lower in quadrants of affected eyes compared with controls detected by SD AS-OCTA (9.4%±2.0% vs 15.5%±1.8%, p<0.001) and SS AS-OCTA (8.8%±2.5% vs 13.9%±1.3%, p=0.01). There was substantial agreement when assessing limbal disruption on AS-OCTA (κ=0.7) compared with slit-lamp evaluation (κ=0.4). Overall, we found good agreement between SD and SS AS-OCTA systems in assessing limbal vessel density in eyes with chemical injury at presentation (mean paired difference: -1.08, 95% CI -3.2 to 0.5; p=0.189). CONCLUSIONS: In this pilot study, AS-OCTA provided objective, non-contact, rapid assessment of limbal vasculature involvement in eyes with acute chemical injury. Further studies are required to establish the role of AS-OCTA in determining the prognosis of eyes with chemical injury.

Role of anterior segment optical coherence tomography angiography in the assessment of acute chemical ocular injury: a pilot animal model study.

To examine the use of anterior segment-optical coherence tomography angiography (AS-OCTA) in the assessment of limbal ischemia in an animal model chemical ocular injury. We conducted a prospective study using an established chemical ocular injury model in 6 rabbits (12 eyes), dividing the cornea limbus into 4 quadrants. Chemical injury grade was induced based on extent of limbal injury (0 to 360 degrees) and all eyes underwent serial slit-lamp with AS-OCTA imaging up to one month. Main outcome measure was changes in AS-OCTA vessel density (VD) comparing injured and control cornea limbal quadrants within 24 h and at one month. AS-OCTA was able to detect differences in limbal VD reduction comparing injured (3.3 ± 2.4%) and control quadrants (7.6 ± 2.3%; p < 0.001) within 24 h of ocular chemical injury. We also observed that AS-OCTA VD reduction was highly correlated with the number of quadrants injured (r = - 0.89; p < 0.001; 95% CI - 5.65 to - 1.87). Corneal vascularization was detected by AS-OCTA in injured compared to control quadrants (10.1 ± 4.3% vs 7.0 ± 1.2%; p = 0.025) at 1 month. Our animal pilot study suggests that AS-OCTA was able to detect limbal vessel disruption from various severities of acute chemical insult, and in the future, could potentially serve as an adjunct in providing objective grading of acute ocular chemical injury once validated in a clinical trial.

Garlic-induced face burn.

There is inadequate research and study into the use of garlic and other herbal medicine in clinical practice; accordingly, the general population should be cautious when using such complementary and herbal treatments. We report a case which highlights the potential complications following the application of garlic-related naturopathic remedies mostly on skin burns.

Caustic ingestion: CT findings of esophageal injuries and thoracic complications.

Ingestion of caustic substances, whether accidental or for the purpose of suicide, can cause severe lesions of the lips, oral cavity, pharynx, upper gastrointestinal system, and upper airways. In particular, caustic agents could be responsible for severe esophageal injuries resulting in short- and long-term complications. Because of these important clinical implications, timely diagnosis and appropriate management are crucial. In the evaluation of esophageal injuries, thoraco-abdominal computed tomography (CT) is preferable to endoscopy as it avoids the risk of esophageal perforation and allows the evaluation of esophageal injuries as well as of the surrounding tissue. In this review, we report CT findings of esophageal injuries and possible related thoracic complications caused by caustic ingestion.

Computed Tomography to Diagnose Paranasal Sinus Chemical Burns and Tissue Damage: A Case Report.

Chemical burns of the paranasal sinus are rare; therefore, assessment methods for treatment of and prognoses for the exposure site are unknown. We experienced a case in which a hydrochloric acid burn of the paranasal sinuses caused irreversible tissue damage. Computed tomography is useful for identifying the exposure site and assessing tissue damage over time. Identification of the exposure site and proactive washing are recommended for patients with chemical burns of the paranasal sinuses. Laryngoscope, 131:E2490-E2493, 2021.

Accuracy of contrast swallow study in assessment of caustic esophageal stricture length in children: Agreement study.

BACKGROUND: Caustic esophageal stricture length assessment is essential for planning endoscopic management and predicting its prognosis. We aimed to assess the accuracy of contrast swallow study (CSS) in measuring stricture length in comparison to endoscopy (definitive investigation for actual length measurement). METHOD: Medical records of caustic esophageal strictures between 2010 and 2020 were retrospectively reviewed. Reliability study was done to compare between radiological and endoscopic measurement of stricture length. RESULT: 124 CSSs for 91 patients were analyzed. Six studies showed no stricture, single stricture was reported in 101 studies, double strictures were reported in 16 studies, triple strictures were reported in one study (136 radiological stricture). Endoscopy revealed 133 true strictures. Number of the strictures was consistent between CSS and endoscopy in 112 studies (90.3%) and different in 12 studies (9.7%). Eight endoscopies revealed strictures not reported in CSS (5.5% false negative strictures), while 10 CSSs reported 11 strictures that were not detected during the endoscopy (7.6% false positive strictures). Reliability analysis revealed interclass correlation coefficient = 0.6 (95% CI 0.5 to 0.7) indicating moderate reliability. CONCLUSION: CSS is not accurate in assessing caustic esophageal stricture length. Combination of CSS and endoscopic investigation is better for proper evaluation of these patients. Level III of evidence.

The role of endoscopy in caustic ingestion in the pediatric population: experience in a tertiary center.

INTRODUCTION: caustic ingestion in children is rare but has potentially serious consequences. AIM: to analyze the clinical and endoscopic features and the type of caustic ingested in our population. METHODS: the upper endoscopies performed in this setting, as well as the characteristics of patients and caustics, were analyzed from 2010 to 2018. RESULTS: fifty-one endoscopies were performed (48 cases of witnessed intake or high suspicion and three with a low suspicion) in patients with a mean age of 2.55 years. Alkali ingestion was more frequent (88.2 %) and 56.9 % of the endoscopies were normal, which was more frequent among those who ingested bleach (72 %). Alkali tended to produce more esophageal injuries (31.1 %) and acids tended to produce esophageal (20 %) and esophageal-gastric injuries (20 %). Four patients developed esophageal stenosis during follow-up. DISCUSSION: even though more than half of the studies were normal, endoscopy is important in the diagnosis and prognosis of these patients.

Case report of tracheobronchial injuries after acid ingestion: CT findings with serial follow-up: Airway complication after acid ingestion.

RATIONALE: Tracheobronchial injury from acid ingestion is a less reported clinical presentation than injury of the gastrointestinal tract, but it can occur due to direct exposure from acid aspiration and cause fatal complications. PATIENT CONCERNS: A 43-year-old man presented to the emergency department after ingesting nitric acid complaining of chest pain and dyspnea. DIAGNOSES: The initial chest computed tomography (CT) images revealed an acute lung injury related to acid aspiration. The follow-up chest CT showed acute and late tracheobronchial injures. INTERVENTIONS: Bronchoscopy showed deep caustic airway injuries consisting of hemorrhage, sloughing of the mucosa, and ulceration of the trachea and left-side bronchial tree. OUTCOMES: Progressive narrowing of the left main bronchus with total collapse of the left lung occurred as a late complication of acid ingestion. LESSONS: Tracheobronchial injury should be considered in cases of aspiration pneumonia after acid ingestion; chest CT can be used to detect and assess acute and late complications of tracheobronchial injuries.

Serial anterior segment optical coherence tomography post autologous simple limbal epithelial transplantation.

A 24-year-old young man presented to us with total limbal stem cell deficiency (LSCD) in the right eye 1 year post ocular chemical burn. The patient subsequently underwent limbal biopsy in the healthy contralateral eye and autologous simple limbal epithelial transplantation in the right eye. The patient was followed up with sequential imaging of the cornea with high-resolution anterior segment optical coherence tomography (HR-ASOCT) for 3 years. The serial HR-ASOCT imaging in the operated eye showed regeneration of the epithelium from the limbal transplant over the human amniotic membrane (hAM) with integration of the transplant within the cornea with subepithelial retention of the hAM. Over the long-term follow-up, thinning of the hAM and thickening of the epithelium was noted. At 3 years, the cornea maintained an intact epithelium with no signs of recurrence of LSCD.

Corrosive injury of the upper gastrointestinal tract: the evolving role of a radiologist.

Corrosive injury is a devastating injury which carries significant morbidity. The upper gastrointestinal tract is predominantly affected with severity ranging from mild inflammation to full thickness necrosis which may result in perforation and death. Among the complications, stricture formation is most common, causing dysphagia and malnutrition. Endoscopy has a pivotal role in the diagnosis and management, with a few shortcomings. Imaging has an important role to play. Besides radiography, there is an increasing role of CT scan in the emergency setting with good accuracy in identifying patients who are likely to benefit from surgery. Further, CT scan has a role in the diagnosis of complications. Oral contrast studies help in assessing the severity and extent of stricture formation and associated fistulous complications in the subacute and chronic phase. The scope of intervention radiology for this condition is increasing. Fluoroscopy-guided balloon dilatation, drainage of collections or mucoceles, endovascular embolization of point bleeders, placement of feeding jejunostomy and image-guided biopsy are among the procedures that are being performed. Through this review we aim to stress the role the radiologist plays in the diagnosis and follow-up of these patients and in performing radiological interventions. Besides this, we have also highlighted few salient points to help understand the pathophysiology and management of such injuries which is paramount to ensure a good long-term outcome.

"Virtual Biopsies" of Normal Skin and Thermal and Chemical Burn Wounds.

The search for noninvasive methods to image and measure the mechanical properties of skin has been a frequent subject of research for many years. Although suction testing, elastography, and other testing can be noninvasive, these tests fail to yield comparable results to destructive tests such as uniaxial tensile testing. Accordingly, researchers have developed a technique to combine optical coherence tomography with vibrational analysis (vibrational optical coherence tomography) to image and analyze the biomechanical properties of tissues noninvasively and nondestructively. The result of this analysis is a "virtual biopsy" of skin, along with a physical analysis of the major components of the epidermis and dermis.In this study, the authors compare virtual biopsies of thermal and chemical burns to that of normal skin. They conclude that the enhanced optical coherence tomography images and measurements of the resonant frequency after thermal or chemical burns exhibit large differences when compared with the morphology and moduli of normal skin. Using vibrational optical coherence tomography, it is possible to follow changes in the morphology and physical properties of the epidermis and dermis associated with skin diseases and therapeutic treatments in situ.

Evaluation of severe caustic gastritis by computed tomography and its impact on management.

INTRODUCTION: Serious caustic burns of the stomach that present with no clinico-biological severity criteria (CBSC) can be treated conservatively. However, even if there are no CBSC at admission, 20% of patients still require delayed emergency surgery for peritonitis due to gastric perforation thus showing the limitations of this strategy in the diagnosis of irreversible gastric necrosis lesions. The aim of this study was to identify reliable computed tomography (CT) signs of irreversible gastric necrosis in patients with stage 3 endoscopic lesions. PATIENTS AND METHODS: In a prospective study from March 2014 to January 2017, thoraco-abdomino-pelvic CT scan was performed in 30 consecutive patients with stage 3 endoscopic gastric lesions. The CT results were concealed from the clinicians and compared to CBSC results. RESULTS: Twenty patients were treated conservatively and ten patients were operated on. Seventy percent of the patients underwent urgent delayed surgery for symptoms that developed late but before alterations in the CBSC. The CT scan showed a perfusion defect (PD) of gastric mucosal enhancement in all patients operated on for gastrointestinal distress, and could have provided an early diagnosis of irreversible gastric necrosis. CONCLUSION: CT was a more effective diagnostic tool for the diagnosis of irreversible gastric necrosis following caustic ingestion than a strategy based on digestive endoscopy and the use of CBSC. CT could eventually replace gastrointestinal endoscopy in the emergency evaluation of gastroesophageal caustic burns.

The ocular surface after simple limbal epithelial transplant (SLET): A high-resolution OCT study of the early postoperative period.

Simple limbal epithelial transplantation (SLET) is an emerging technique for treating unilateral limbal stem cell deficiency. We report the high-resolution, anterior segment optical coherence tomography (OCT) features of the first 2 weeks of a patient undergoing SLET for an old acid injury of the right eye, repeatedly from postoperative day 1 through day 14. Three out of 11 explants with the subjacent human amniotic membrane (hAM) and the overlaid bandage contact lens were imaged. The hAM was intact and of the same thickness throughout the study period; the sub-hAM space increased from day 3 to 9 and disappeared by day 10; the explants started thinning from day 3 with the fibrin around them starting to decrease from day 2 and completely disappeared by day 4. Epithelialization occurred between day 8 and 14 and proceeded more rapidly towards the limbus than centrally. There was no change of the corneal stromal thickness or reflectivity. This case report uses high-definition, spectral-domain OCT to document the events on the ocular surface after a successful SLET surgery and opens up an avenue to study epithelialization in a convenient and noninvasive manner.

Emergency Computed Tomography Predicts Caustic Esophageal Stricture Formation.

BACKGROUND: Endoscopy is the best predictor of stricture formation after caustic ingestion. OBJECTIVE: Our aim was to compare the accuracy of emergency computed tomography (CT) and endoscopy in predicting risks of esophageal stricture. METHODS: We describe a CT classification of esophageal caustic injuries: Grade I show normal esophagus; Grade IIa display internal enhancement of the esophageal mucosa and enhancement of the outer wall conferring a "target" aspect; Grade IIb present as a fine rim of external esophageal wall enhancement. In 152 patients (56 males, median age 45) who underwent esophageal preservation after caustic ingestion we compared the accuracy of the CT and endoscopic (Zargar) classifications in predicting esophageal stricture. RESULTS: On endoscopy esophageal injuries were classified as grade 1 (n = 50; 33%), grade 2a (n = 11; 7%), grade 2b (n = 19; 13%), grade 3a (n = 14; 9%), and grade 3b (n = 58; 38%). On CT, 47 (31%) patients had grade I, 47 (31%) had grade IIa and 58 (38%) had grade IIb esophageal injuries. Fifty-six (37%) patients developed esophageal strictures. The risk of esophageal stricture formation was 0%, 17%, and 83%, for grade I, IIa, and IIb CT injuries and 0, 0, 28, 50, and 76% for endoscopic grade 1, 2a, 2b, and 3a and 3b injuries, respectively. ROC curve analysis at 120 days after ingestion showed that CT outperformed endoscopy in predicting stricture formation (AUC: 85.1 [95% CI, 74.9-95.3] vs 77.8 [95% CI, 66.5-89.0], P = 0.047) and did just as well as a combined CT-endoscopy algorithm (AUC: 85.8 [95% CI, 76.5-95.0] vs 85.1 [95% CI, 74.9-95.3], P = 0.73). CONCLUSION: Emergency CT outperforms endoscopy in predicting esophageal stricture formation after caustic ingestion. Emergency endoscopy evaluation after caustic ingestion is not indispensable.