Fatal anaphylactic shock during a fluorescein angiography

Utility of biomarkers in the postmortem diagnosis of fatal Anaphylaxis: A scoping review

BACKGROUND

Diagnosing anaphylactic deaths is a challenging task for forensic pathologists. Although serum tryptase is considered to be a reliable biomarker, there are limitations to it. Thus, there is an urgent need to explore various other potential biomarkers which could be of diagnostic value, along with Tryptase, to diagnose anaphylactic shock at autopsy.

AIM

We want to systematically review the accuracy of newer postmortem biomarkers for anaphylaxis, such as chymase or eosinophilic cationic protein. Before embarking on this project, we intend to assess the feasibility of conducting systematic reviews on this topic. and identify any deficiencies in the existing literature to guide research priorities.

METHODOLOGY

We followed PRISMA guidelines and conducted the search in four databases, namely Medline, Scopus, EBSCO-CINAHL, and TRIP. Rayyan AI software was used to screen the articles.

RESULTS

A total of 6112 articles were retrieved from the search, and 5079 articles were screened after removing duplicates. Only 25 articles were finally available as per our inclusion criteria. Studies pertaining to post-mortem tryptase levels were found in large numbers, with two recently done systematic reviews on this topic. The number of studies available on other newer biomarkers was too few. More clinical studies are needed before a meta-analysis can be done. Hence, we could perform only a narrative review on the topic.

DISCUSSION

There is a scarcity of literature with definite cutoff levels for markers other than Tryptase. Based on the available studies, it is not possible to do diagnostic accuracy reviews at the moment. Hence, we narrate the usefulness of biomarkers like Immunoglobulin E, Chymase, Carboxypeptidase A3, Diamine Oxidase, Histamine and Eosinophilic Cationic Protein.

CONCLUSION

Based on the available evidence, serum tryptase is recognized as the primary biomarker for the postmortem diagnosis of anaphylactic death, with elevated levels strongly indicating anaphylaxis. Additionally, serum IgE, particularly allergen-specific IgE, is a valuable complementary biomarker. Further research is needed to understand the performance of other biomarkers.

Generative artificial intelligence in ophthalmology

Generative artificial intelligence (AI) has revolutionized medicine over the past several years. A generative adversarial network (GAN) is a deep learning framework that has become a powerful technique in medicine, particularly in ophthalmology for image analysis. In this paper we review the current ophthalmic literature involving GANs, and highlight key contributions in the field. We briefly touch on ChatGPT, another application of generative AI, and its potential in ophthalmology. We also explore the potential uses for GANs in ocular imaging, with a specific emphasis on 3 primary domains: image enhancement, disease identification, and generating of synthetic data. PubMed, Ovid MEDLINE, Google Scholar were searched from inception to October 30, 2022, to identify applications of GAN in ophthalmology. A total of 40 papers were included in this review. We cover various applications of GANs in ophthalmic-related imaging including optical coherence tomography, orbital magnetic resonance imaging, fundus photography, and ultrasound; however, we also highlight several challenges that resulted in the generation of inaccurate and atypical results during certain iterations. Finally, we examine future directions and considerations for generative AI in ophthalmology.

Macula vs periphery in diabetic retinopathy: OCT-angiography and ultrawide field fluorescein angiography imaging of retinal non perfusion

OBJECTIVES

To investigate the association between peripheral non-perfusion index (NPI) on ultrawide-field fluorescein angiography (UWF-FA) and quantitative OCT-Angiography (OCT-A) metrics in the macula.

METHODS

In total, 48 eyes with UWF-colour fundus photos (CFP), UWF-FA (California, Optos) and OCT-A (Spectralis, Heidelberg) were included. OCT-A (3 × 3 mm) was used to determine foveal avascular zone (FAZ) parameters and vessel density (VD), perfusion density (PD), fractal dimension (FD) on superficial capillary plexus (SCP). NPI's extent and distribution was determined on UWF-FA within fovea centred concentric rings corresponding to posterior pole (<10 mm), mid-periphery (10-15 mm), and far-periphery (>15 mm) and within the total retinal area, the central macular field (6×6 mm), ETDRS fields and within each extended ETDRS field (P3-P7).

RESULTS

Macular PD was correlated to NPI in total area of retina (Spearman ρ = 0.69, p < 0.05), posterior pole (ρ = 0.48, p < 0.05), mid-periphery (ρ = 0.65, p < 0.05), far-periphery (ρ = 0.59, p < 0.05), P3-P7 (ρ = 0,55 at least, p < 0.05 for each), central macula (ρ = 0.47, p < 0.05), total area in ETDRS (ρ = 0.55, p < 0.05). Macular VD and FD were correlated to NPI of total area of the retina (ρ = 0.60 and 0.61, p < 0.05), the mid-periphery (ρ = 0.56, p < 0.05) and far-periphery (ρ = 0.60 and ρ = 0.61, p < 0.05), and in P3-P7 (p < 0.05). FAZ perimeter was significantly corelated to NPI at posterior pole and central macular area (ρ = 0.37 and 0.36, p < 0.05), and FAZ area to NPI in central macular area (ρ = 0.36, p < 0.05).

CONCLUSIONS

Perfusion macular metrics on OCT-A correlated with UWF-FA's non-perfusion (NP), particularly in the retina's mid and far periphery, suggesting that OCT-A might be a useful non-invasive method to estimate peripheral retinal NP.

A light in the darkness: sodium fluorescein-assisted peripheral nerve sheath tumors resection - a comprehensive systematic review and single-arm meta-analysis

The treatment for peripheral nerve sheath tumors (PNSTs) is based on surgical excision and the primary goal is to improve symptoms whilst preserving neurological function. In order to improve this technique, surgeons may use sodium fluorescein (SF) to help visualize the neoplasm and, consequently, facilitate its removal. Aiming to assess the efficacy of this emerging surgical strategy, we conducted a systematic review and single-arm meta-analysis. We conducted a systematic search on the PubMed, Embase, and Web of Science databases, following the PRISMA guidelines. Studies without outcomes of interest, case series with less than four patients, letters, comments, technical notes, editorials, reviews, and basic research papers were excluded. The outcomes considered for this study were: the number of tumors that achieved total resection, subtotal resection, or near total resection, the approach/technique utilized by the surgeon, SF-related complications, and total complications. Five studies, with a total of 175 individuals, were included in our survey. Notably, 70% of the neoplasms presented by the patients were schwannomas. Considering extracranial lesions, we found a proportion of 96% (95% CI: 88 - 100%) in total resection, 0% (95% CI: 0-1%) in near total resection, and 4% (95% CI: 0-12%) in subtotal resection, all linked to an amount of 185 analyzed PNSTs. Furthermore, a proportion of 1% (95% CI: 0 - 2%) in SF-related complications was spotted among 183 patients. Finally, total complications analysis accounted for 11% (95% CI: 0 - 25%) among 183 individuals. We concluded that SF-assisted resection of PNSTs is a suitable and relatively safe technique, linked to minimum complications, of which the majority was not associated with the chemical compound itself. Future research is necessary to increase the number of patients available in the current literature and, therefore, enhance future analyses.

Multimodal In Vivo Imaging of Retinal and Choroidal Vascular Occlusion

Photoacoustic microscopy (PAM) is an emerging retinal imaging technique that can provide high spatial resolution and high contrast of chorioretinal vessels. PAM is compatible with optical coherence tomography (OCT) and fluorescence imaging, allowing for development of a multimodal imaging system that combines these imaging modalities into one. This study presents a non-invasive, label-free in vivo imaging of retinal and choroidal vascular occlusion using multimodal imaging system, including PAM and OCT. Both retinal vein occlusion (RVO) and choroidal vascular occlusion (CVO) were clearly identified selectively using a spectroscopic PAM imaging. RVO and CVO were created in six rabbits using laser photocoagulation. The dynamic changes of retinal vasculature were observed and evaluated using color fundus photography, fluorescein angiography, OCT, and PAM. The position of RVO and CVO were imaged with different wavelengths ranging from 532 to 600 nm. The data shows that occluded vessels were clearly distinguished from the surrounding retinal vessels on the PAM images. This advanced imaging system is a promising technique for imaging retinal ischemia in preclinical disease models.

Role of optical coherence tomography-angiography in diabetes mellitus: Utility in diabetic retinopathy and a comparison with fluorescein angiography in vision threatening diabetic retinopathy

Purpose:

To determine the utility of optical coherence tomography-angiography (OCT-A) in diabetic retinopathy (DR) and comparison versus fluorescein angiography (FA) in vision-threatening diabetic retinopathy (VTDR).

Methods:

In this cross-sectional observational study, 60 eyes with no DR (NDR), 60 eyes with non-proliferative diabetic retinopathy (NPDR), and 60 eyes with proliferative diabetic retinopathy (PDR) underwent OCT-A. FA was done in VTDR. OCT-A of the NDR eyes was analyzed by two independent retina specialists. Vessel density (VD) (mm/mm²), perfusion density (PD) (%), and foveal avascular zone (FAZ) (mm²) area was analyzed among the groups. Montage angiography with vitreoretinal interface (VRI) segmentation was done in PDR. A qualitative comparison was done between OCT-A and FA for features of DR.

Results:

OCT-A detected 16.66% of the eyes with microaneurysm and 57.5% of the patients with capillary non-perfusion (CNP) areas in the NDR group. The inter-grader coefficient between the two observers was 0.820 for microaneurysm and 0.880 for CNP. The mean VD in NDR, NPDR, and PDR was 16.865, 13.983, and 11.643 mm/mm². The mean PD in NDR, NPDR, and PDR was 30.595, 26.853, and 23.193%. The VD and PD values were statistically significant (P < 0.001). The mean FAZ area was not statistically significant (NPDR and PDR) (P > 0.05). The VRI showed elevated neovascularization in four eyes. OCT-A delineated microaneurysm and FAZ in 97/97 eyes who underwent FA. The FA failed to delineate FAZ in 2/37 NPDR eyes and 13/60 PDR eyes. The CNP areas (OCT-A) were detectable in all eyes. The FA demonstrated CNP areas in 17/37 and 36/60 eyes in NPDR and PDR, respectively. The FA could show peripheral CNP.

Conclusion:

The OCT-A helps in the early diagnosis of DR by providing vascular indices which are consistent with disease progression. OCT-A is non-invasive and ideal for follow-up. FA is a dynamic test with a larger field of view.

Fatal food-induced anaphylaxis: Determination of tryptase and specific IgE on cadaveric blood samples. What else for a better methodological standard?

Post-mortem investigation in cases of fatal anaphylaxis is required to provide clarifications on the presence of macroscopic pathological changes, histological features, and immunohistochemical positivity suggestive of the diagnosis, on biochemical evidence of anaphylaxis and on the presence of serological data indicative of the allergen responsible for the anaphylactic reaction. We describe the case of a 16-year-old boy with a medical history of allergic asthma, celiac disease, and known food-induced allergy for fish, fresh milk, peanuts, hazelnuts, walnuts, apples, kiwis, and peaches. Acute onset of dyspnea followed by cyanosis of the lips and respiratory failure was described immediately after having an ice cream sandwich. Unsuccessful rescues were immediately attempted with oral administration of betamethasone, intramuscular injection of adrenaline, and cardiopulmonary resuscitation. A complete post-mortem examination was performed. Serum dosage of mast cell beta-tryptase from femoral blood detecting serum values of 41.4 mg/l. Determination of specific IgE on cadaveric blood samples confirmed the anamnestic data related to sensitization for several food allergens, including cod parvalbumin, tropomyosin, brazil nut, omega-5-gliadin of foods derived from wheat and gluten. The cause of death was identified in a cardiorespiratory failure due to anaphylactic shock in a poly-allergic subject and anaphylaxis was ascribed to the wheat contained in the ice cream sandwich eaten immediately before the onset of respiratory symptoms. The need is to implement an interdisciplinary approach capable to ascertain the sensitivity and specificity of the diagnostic tests currently in use as well as to evaluate the possibility of introducing new biomarkers in practice.

The Fluorescent Patient: An Unusual Effect of Fluorescein Angiography

Although fluorescein is widely used for intraoperative angiography, some of its side effects remain obscure. In this report, we present the case of a 41-year-old patient with chronic ischemia caused by moyamoya syndrome who underwent bypass revascularization with intraoperative fluorescein angiography (FA). Immediately after the surgery, the patient presented homogeneous fluorescence of the entire skin. We discuss this curious phenomenon as well as other side effects that may arise due to FA.

Fatal anaphylactic shock: A review of postmortem biomarkers and diagnostics

Diagnosing anaphylactic shock postmortem is challenging since differential diagnoses exist and the forensic pathologist often faces subtle findings and lacks relevant information which prevents reaching an opinion of certainty. This review provides an overview of the literature covering research and existing recommendations on the postmortem diagnosis of anaphylactic shock. In order to harmonize the approach and provide guidance for diagnosing deaths from anaphylactic shock in the six forensic centers in Sweden, a guidance protocol aligned with the notion of a holistic view in the approach was devised. Areas in need of further studies include both immunohistological and biochemical investigations to stratify quantitative approaches based on condition and anaphylactic trigger and to lay the ground for and possibly establish alternative matrices.

A novel deep learning conditional generative adversarial network for producing angiography images from retinal fundus photographs

Fluorescein angiography (FA) is a procedure used to image the vascular structure of the retina and requires the insertion of an exogenous dye with potential adverse side effects. Currently, there is only one alternative non-invasive system based on Optical coherence tomography (OCT) technology, called OCT angiography (OCTA), capable of visualizing retina vasculature. However, due to its cost and limited view, OCTA technology is not widely used. Retinal fundus photography is a safe imaging technique used for capturing the overall structure of the retina. In order to visualize retinal vasculature without the need for FA and in a cost-effective, non-invasive, and accurate manner, we propose a deep learning conditional generative adversarial network (GAN) capable of producing FA images from fundus photographs. The proposed GAN produces anatomically accurate angiograms, with similar fidelity to FA images, and significantly outperforms two other state-of-the-art generative algorithms ([Formula: see text] and [Formula: see text]). Furthermore, evaluations by experts shows that our proposed model produces such high quality FA images that are indistinguishable from real angiograms. Our model as the first application of artificial intelligence and deep learning to medical image translation, by employing a theoretical framework capable of establishing a shared feature-space between two domains (i.e. funduscopy and fluorescein angiography) provides an unrivaled way for the translation of images from one domain to the other.

Immediate Reactions to Fluorescein and Indocyanine Green in Retinal Angiography: Review of Literature and Proposal for Patient's Evaluation

Introduction

Contrast rapid sequence angiography with fluorescein or indocyanine green (ICG) is a diagnostic procedure commonly used in ophthalmology. Adverse reactions to fluorescein and ICG are rare and may be classified as toxic, of hypersensitivity and non-specific. The evaluation and management of a patient with an adverse reaction is a challenge for the majority of ophthalmologists, as is the assessment of risk factors that may contraindicate the procedure.

Purpose

We aim to review the concepts underlying adverse reactions to fluorescein and ICG, especially those of hypersensitivity, and present a proposal or the evaluation of the patients in need to perform retinal angiography and for the treatment of immediate reactions to fluorescein and ICG.

Methods

The available literature was examined using PubMed-Medline, and using the MeSH terms "fluorescein", "Indocyanine green", "ophthalmic dyes", "retinal angiography", "adverse reactions", and "allergic reaction".

Conclusion

This review may help ophthalmologists to identify patients with higher risk of a hypersensitivity reaction and give them tools to recognize patients with suspected hypersensitivity that may benefit from an allergy study.

Safety and feasibility of low-dose fluorescein-guided resection of glioblastoma

OBJECTIVES

The extent of resection is an independent predictor of prognosis in patients with glioblastomas. Although fluorescein sodium may enhance intraoperative visualization of tumor margin and increase the extent of glioblastoma, the dose related anaphylactic reaction is still a major concern. In the present study, we used allergy skin testing to exclude the patients susceptible to anaphylaxis preoperatively, and then investigated the feasibility of low-dose fluorescein sodium to guide glioblastoma resection intraoperatively, thereby to improve the safety of fluorescein-guided glioma resection.

PATIENTS AND METHODS

Patients with suspected glioblastoma based on brain MRI were subjected to allergy skin intradermal tests for fluorescein sodium preoperatively. Only those with negative allergy skin tests received intravenous injection of low dose fluorescein sodium (1-2 mg/kg) during microsurgical tumor resection under dedicated Yellow 560 filter. The degree of fluorescent staining was documented and the extent of resection was evaluated by MRI scan.

RESULTS

One patient with positive allergy skin test was excluded from fluorescein sodium administration and no anaphylactic reaction was found during fluorescein sodium guided surgery in the patients who were negative for allergy skin tests. The low dose fluorescein sodium (1-2 mg/kg) could provide enough visualization of tumors with sufficient discrimination from surrounding normal brain tissue and improve the resection extent of glioblastoma.

CONCLUSION

Preoperative allergy skin test is a useful method to exclude the patients susceptible to anaphylaxis, together with intraoperative low dose fluorescein sodium administration, may facilitate glioblastoma resection by fluorescence guidance while avoid safety concern of dose-related anaphylaxis.

Diagnostic role of serum tryptase in anaphylactic deaths in forensic medicine: a systematic review and meta-analysis

Postmortem diagnosis of sudden death due to anaphylaxis can be very difficult due to the non-specific pathological findings in forensic practice. Postmortem serum tryptase has been used as an indicator of possible ante-mortem anaphylaxis. Though many previous studies have been conducted to explore the diagnostic significance of serum tryptase for lethal anaphylaxis, inconsistent results were documented. In this study, we made a retrospective study and presented a systematic review and meta-analysis that aims to summarize the diagnostic significance of postmortem serum tryptase in the deceased with and without anaphylactic shock and to calculate a cutoff value for future reference in the identification of deaths due to anaphylactic shock. A complete literature search in the PubMed, Cochrane Library, CNKI and Embase databases (published prior to March 1st, 2017) was performed. The quality of the eligible literature was evaluated according to the Newcastle-Ottawa Quality Assessment Scale (NOS), and the relevant data was extracted. The procedure of meta-analysis was performed by RevMan 5.3 software. Subgroup analysis was performed according to different causes of death. A total of nine studies with 296 patients were identified. The NOS of each included study was equal to 7. The results indicated that high concentrations of tryptase were significantly associated with anaphylactic shock when compared to the other causes of death. The weighted mean difference (WMD) was 29.53 (95% CI = 7.58-51.47, p = 0.008). Similar results were detected in the subgroup analysis when compared to deaths due to cardiovascular disease (CVD). However, no obvious elevation of tryptase in decedents with CVD compared to the other cause of death was observed (WMD = 4.42, 95% CI = -0.94-9.79). We concluded that high serum tryptase is a promising diagnostic biomarker for deaths due to anaphylactic shock, especially when it is higher than 30.4 μg/L.

Fluorescence Imaging/Agents in Tumor Resection

Intraoperative fluorescence imaging allows real-time identification of diseased tissue during surgery without being influenced by brain shift and surgery interruption. 5-Aminolevulinic acid, useful for malignant gliomas and other tumors, is the most broadly explored compound approved for fluorescence-guided resection. Intravenous fluorescein sodium has recently received attention, highlighting tumor tissue based on extravasation at the blood-brain barrier (defective in many brain tumors). Fluorescein in perfused brain, unselective extravasation in brain perturbed by surgery, and propagation with edema are concerns. Fluorescein is not approved but targeted fluorochromes with affinity to brain tumor cells, in development, may offer future advantages.

Select Features of Diabetic Retinopathy on Swept-Source Optical Coherence Tomographic Angiography Compared With Fluorescein Angiography and Normal Eyes

IMPORTANCE

Optical coherence tomographic angiography (OCTA) is a recently developed noninvasive imaging technique that can visualize the retinal and choroidal microvasculature without the injection of exogenous dyes.

OBJECTIVE

To evaluate the potential clinical utility of OCTA using a prototype swept-source OCT (SS-OCT) device and compare it with fluorescein angiography (FA) for analysis of the retinal microvasculature in diabetic retinopathy.

DESIGN, SETTING, AND PARTICIPANTS

Prospective, observational cross-sectional study conducted at a tertiary care academic retina practice from November 2013 through November 2014. A cohort of diabetic and normal control eyes were imaged with a prototype SS-OCT system. The stage of diabetic retinopathy was determined by clinical examination. Imaging was performed using angiographic 3 × 3-mm and 6 × 6-mm SS-OCT scans to generate 3-dimensional en-face OCT angiograms for each eye. Two trained Boston Image Reading Center readers reviewed and graded FA and OCTA images independently.

MAIN OUTCOMES AND MEASURES

The size of the foveal nonflow zone and the perifoveal intercapillary area on OCTA were measured in both normal and diabetic eyes using Boston Image Reading Center image analysis software.

RESULTS

The study included 30 patients with diabetes (mean [SD] age, 55.7 [10] years) and 6 control individuals (mean [SD] age, 55.1 [6.4] years). A total of 43 diabetic and 11 normal control eyes were evaluated with OCTA. Fluorescein angiography was performed in 17 of 43 diabetic eyes within 8 weeks of the OCTA. Optical coherence tomographic angiography was able to identify a mean (SD) of 6.4 (4.0) microaneurysms (95% CI, 4.4-8.5), while FA identified a mean (SD) of 10 (6.9) microaneurysms (95% CI, 6.4-13.5). The exact intraretinal depth of microaneurysms on OCTA was localized in all cases (100%). The sensitivity of OCTA in detecting microaneuryms when compared with FA was 85% (95% CI, 53-97), while the specificity was 75% (95% CI, 21-98). The positive predictive value and the negative predictive value were 91% (95% CI, 59-99) and 60% (95% CI, 17-92), respectively.

CONCLUSIONS AND RELEVANCE

Optical coherence tomographic angiography enables noninvasive visualization of macular microvascular pathology in eyes with diabetic retinopathy. It identified fewer microaneurysms than FA, but located their exact intraretinal depth. Optical coherence tomographic angiography also allowed the precise and reproducible delineation of the foveal nonflow zone and perifoveal intercapillary area. Evaluation of OCTA may be of clinical utility in the evaluation and grading of diabetic eye disease.

A Study of the Interaction of Bovine Hemoglobin with Synthetic Dyes Using Spectroscopic Techniques and Molecular Docking

Synthetic dyes are a very efficient class of dyes that are ingested or come into contact with the skin from numerous sources (cosmetics, textiles, leather, paper, and drugs). An important component of their safety profile is the interactions that they form after they enter the body. Hemoglobin is a functionally important protein that can form multiple interactions with soluble compounds present in the blood, and hence forms an important aspect of the toxicological or safety profile of the dyes. Here we study the interaction between bovine hemoglobin and organic dyes using UV-Vis absorbance and fluorescence spectroscopy. Molecular modeling was used to visualize the binding site and partners of the dye molecules, within the hemoglobin molecule. We find that all four dyes studied form sufficiently strong interactions with hemoglobin to allow for the formation of potentially toxic interactions. Molecular modeling showed that all four dyes bind within the central cavity of the hemoglobin molecule. However, binding partners could not be identified as multiple binding conformations with very similar energies were possible for each dye.

Incidence and risk factors for cystoid macular edema following scleral buckling

PurposeTo investigate the incidence of cystoid macular edema (CME) after scleral buckling (SB) and verify the possible risk factors of CME.MethodsA retrospective, non-comparative, interventional case series study was conducted. Clinical charts of 130 consecutive patients who were underwent successful SB for primary retinal detachment (RD) from 2009 to 2013 were reviewed. Optical coherence tomography (OCT) was applied to detect CME. Data pertaining to patient demographics, pre- and postoperative visual acuity, surgical procedures, and postoperative OCT findings were recorded. Factors associated with CME were also analyzed.ResultsThe incidence of CME was 9/130 (6.9%). Risk factors for developing CME were older age (non-CME vs CME: 44.8±14.8 vs 57.3±5.3 years, P<0.05), more extensive RD (RD extent by clock hours; non-CME vs CME: 4.61±1.57 vs 5.78±1.39, P<0.05), macular detachment (non-CME vs CME: 51.2 vs 88.9%, P<0.05), and external drainage (non-CME vs CME: 38.8% vs 77.8%, P<0.05). There was no significant difference between patient with and without CME regarding the use of gas tamponade and the lens status. In patients with more extensive RD (macular detachment plus RD of more than 3 clock hours before surgery), 8 of 68 patients had CME after SB and only older age and external drainage factors were associated with CME.ConclusionsThe risk factors associated with CME after SB were older age, more extended RD, macular detachment, and external drainage. External drainage should be used with caution in older patients with more extensive RD.

Diagnosis of anaphylactic death in forensics: Review and future perspectives

The diagnosis of anaphylaxis in a pre- or post-mortal phase involves the formulation of problems not yet solved by the international scientific literature, due to the complexity of pathogenic factors and pathophysiological processes that characterizes it. For forensic autopsies, further problems of differential diagnosis arise and often leave the forensic pathologist unable to express an opinion of certainty, as a result of lack of case history, circumstantial and autoptical-histopathological data. Nevertheless, in routine cases the postmortem diagnosis of anaphylactic death continues to be based on exclusion and circumstantial evidence. The author, after an extensive review of the literature relating to deaths from anaphylaxis of forensic pathological interest, and a discussion of the microscopical and biochemical findings, proposes a diagnostic protocol for forensic purposes and evaluates the diagnostic perspectives enabled by the newly available analytic techniques and markers. Maybe, the application of omics methodologies could help in the future for anaphylaxis diagnosis.

Imaging in diabetic retinopathy

While the primary method for evaluating diabetic retinopathy involves direct and indirect ophthalmoscopy, various imaging modalities are of significant utility in the screening, evaluation, diagnosis, and treatment of different presentations and manifestations of this disease. This manuscript is a review of the important imaging modalities that are used in diabetic retinopathy, including color fundus photography, fluorescein angiography, B-scan ultrasonography, and optical coherence tomography. The article will provide an overview of these different imaging techniques and how they can be most effectively used in current practice.

Comparison of adaptive optics scanning light ophthalmoscopic fluorescein angiography and offset pinhole imaging

Recent advances to the adaptive optics scanning light ophthalmoscope (AOSLO) have enabled finer in vivo assessment of the human retinal microvasculature. AOSLO confocal reflectance imaging has been coupled with oral fluorescein angiography (FA), enabling simultaneous acquisition of structural and perfusion images. AOSLO offset pinhole (OP) imaging combined with motion contrast post-processing techniques, are able to create a similar set of structural and perfusion images without the use of exogenous contrast agent. In this study, we evaluate the similarities and differences of the structural and perfusion images obtained by either method, in healthy control subjects and in patients with retinal vasculopathy including hypertensive retinopathy, diabetic retinopathy, and retinal vein occlusion. Our results show that AOSLO OP motion contrast provides perfusion maps comparable to those obtained with AOSLO FA, while AOSLO OP reflectance images provide additional information such as vessel wall fine structure not as readily visible in AOSLO confocal reflectance images. AOSLO OP offers a non-invasive alternative to AOSLO FA without the need for any exogenous contrast agent.

Fatal visit to the dentist

A 23-year-old woman was mortally afraid of dental interventions and decided to have her four wisdom teeth removed by outpatient surgery under endotracheal anaesthesia. According to the files, the patient was categorized as ASA I and Mallampati II, and surgery was considered an elective routine intervention. Soon after initiation of anaesthesia, O2 saturation and blood pressure dropped, and the young woman died shortly afterwards in spite of immediate resuscitation measures. At first, an allergic reaction to succinylcholine, which had been administered as a muscle relaxant, was suspected. Autopsy and histological examination showed haemorrhagic pulmonary oedema and a defined lesion in the midportion of the oesophageal mucosa in spite of correct placement of the endotracheal breathing tube. Ultimately, misintubation into the oesophagus, which had not been noticed at first, was determined as cause of death.

In vivo imaging of human retinal microvasculature using adaptive optics scanning light ophthalmoscope fluorescein angiography

The adaptive optics scanning light ophthalmoscope (AOSLO) allows visualization of microscopic structures of the human retina in vivo. In this work, we demonstrate its application in combination with oral and intravenous (IV) fluorescein angiography (FA) to the in vivo visualization of the human retinal microvasculature. Ten healthy subjects ages 20 to 38 years were imaged using oral (7 and/or 20 mg/kg) and/or IV (500 mg) fluorescein. In agreement with current literature, there were no adverse effects among the patients receiving oral fluorescein while one patient receiving IV fluorescein experienced some nausea and heaving. We determined that all retinal capillary beds can be imaged using clinically accepted fluorescein dosages and safe light levels according to the ANSI Z136.1-2000 maximum permissible exposure. As expected, the 20 mg/kg oral dose showed higher image intensity for a longer period of time than did the 7 mg/kg oral and the 500 mg IV doses. The increased resolution of AOSLO FA, compared to conventional FA, offers great opportunity for studying physiological and pathological vascular processes.

Allergy skin testing in predicting adverse reactions to fluorescein: a prospective clinical study

PURPOSE

To evaluate allergy skin testing as a diagnostic tool of adverse reactions to fluorescein and whether allergy and previous sodium fluorescein angiography (SFA) act as predisposing factors.

METHODS

Patients with adequate indication for fluorescein angiography and normal skin responsiveness were subjected to allergy skin-prick and intradermal tests for fluorescein, followed by SFA. During SFA, adverse reactions were monitored and classified as mild, moderate or severe. Previous SFAs and adverse reactions as well as the presence of atopy were also registered.

RESULTS

One thousand and thirty-seven patients were enrolled in the study and 1284 SFAs were executed. Forty-four patients (4.3%) developed 55 adverse reactions; among them 50 (3.8%) were mild, three (0.2%) moderate and two (0.16%) severe. None of the reactors produced positive skin tests to fluorescein. Patients with atopy and previous SFAs were not more susceptible to adverse reactions.

CONCLUSION

The vast majority of adverse reactions to fluorescein are mild and not attributed to immunological mechanisms. Allergy skin tests cannot predict non-immunological reactions but their utility remains substantial in predicting anaphylaxis during SFAs and must be performed in patients reporting risk factors in their past medical history.

Usefulness of post mortem determination of serum tryptase, histamine and diamine oxidase in the diagnosis of fatal anaphylaxis

The diagnosis of fatal anaphylaxis can be difficult for clinical features may not always be evident in necropsy. Therefore post mortem determination of tryptase and other blood parameters can be helpful in verifying the diagnosis. We compared post mortem tryptase, histamine and diamine oxidase (DAO) serum levels of two patients who had died after a Hymenoptera sting and one patient who died of bronchospasm during anaesthesia with data obtained from 55 control subjects who had died from other causes than anaphylaxis. In the three anaphylactic cases, serum tryptase level was 880, 68 and 200 μg/l (normal range in living subjects: <11.4 μg/l), histamine was 37.5, 8.5 and 23.2 ng/ml (normal range: <0.3 ng/ml) and DAO was 1, 30 and 4 U/ml (normal range 10-30 U/ml), respectively. Values in the control group were as follows: tryptase 1-340 μg/l (mean 24.2 ± 58.2), histamine 5.0-22.0 ng/ml (mean 14.7 ± 3.9) and DAO 0-114 U/ml (mean 21.1 ± 27.8). 19/55 (34.5%) of the controls had elevated tryptase levels >11.4 μg/l, with four of them showing values >45 μg/ml. Significantly higher histamine levels were seen in blood samples taken more than 24h post mortem (p<0.05), whereas the timing of blood collection had no effect on tryptase and DAO levels. While moderately elevated tryptase levels are common in post mortem sera, values above 45 μg/l may support the diagnosis of fatal anaphylaxis. Strongly elevated histamine levels might give an additional clue on fatal anaphylaxis, whereas DAO does not seem to be helpful.

Photoactive chitosan switching on bone-like apatite deposition

The work was focused on the synthesis and characterization of the chitosan-g-fluorescein (CHFL) conjugate polymer as a biocompatible amphiphilic water-soluble photosensitizer, able to stimulate hydroxyapatite deposition upon visible light irradiation. Fluorescein (FL) grafting to chitosan (CH) chains was confirmed by UV-vis analysis of water solutions of FL and CHFL and by Fourier transform infrared spectroscopy (FTIR-ATR) analysis of CHFL and CH. Smooth CHFL cast films with 4 microm thickness were obtained by solvent casting. Continuous exposure to visible light for 7 days was found to activate the deposition of calcium phosphate crystals from a conventional simulated body fluid (SBF 1.0x) on the surface of CHFL cast films. EDX and FTIR-ATR analyses confirmed the apatite nature of the deposited calcium phosphate crystals. CHFL films preincubated in SBF (1.0x) solution under visible light irradiation and in the dark for 7 days were found to support the in vitro adhesion and proliferation of MG63 osteoblast-like cells (MTT viability test; 1-3 days culture time). On the other hand, the mineralization ability of MG63 osteoblast-like cells was significantly improved on CHFL films preincubated under visible light exposure (alkaline phosphatase activity (ALP) test for 1, 3, 7, and 14 days). The use of photoactive biocompatible conjugate polymer, such as CHFL, may lead to new therapeutic options in the field of bone/dental repair, exploiting the photoexcitation mechanism as a tool for biomineralization.

Mast cell tryptase in a case of anaphylaxis due to repeat antibiotic exposure

Mast cell tryptase can be an indicator of type I hypersensitivity reaction and thus may serve as a surrogate marker of anaphylaxis. A 34-year-old white male patient presented with a history of systemic lupus erythematosus. Shortly after administration of cefazolin for dialysis, he developed pruritus and shortness of breath. He expired an hour later. Autopsy excluded anatomic causes of death. There was an elevated postmortem mast cell tryptase level, 29.2 ng/mL. For mast cell tryptase level to be useful, the patient must survive long enough after exposure to an allergen for mast cells to release this enzyme. A credible allergen must be identified. In this case such, mast cell tryptase could establish anaphylaxis as the cause of death. The case suggests that in a patient with autoimmune disease, it may be prudent to test for immune reaction to a drug before administering it a second time via pinprick or other method.

Management of anaphylactic shock during intravenous fluorescein angiography at an outpatient clinic

We report the proper management of a severe adverse reaction of anaphylactic shock during intravenous fluorescein angiography at an outpatient clinic. A 72-year-old male developed the severe, life-threatening complication after intravenous injection of sodium fluorescein dye for retinal angiography. Three minutes after receiving an intravenous injection of fluorescein, the patient developed syncope, apnea and circulatory shock. Fortunately, he recovered without any neurologic sequelae after immediate intensive resuscitation with fluid and inotropic support. We highlight the occurrence of anaphylactic shock as a potentially fatal complication during intravenous fluorescein angiography. Thus, one should be alert to the possibility of this adverse event and be prepared to deal with it when fluorescein angiography is performed. When it happens, immediate intensive medical resuscitation is essential to minimize morbidity and to avoid mortality.

Adverse effects of fluorescein angiography in hypertensive and elderly patients

PURPOSE

To evaluate adverse effects in patients undergoing fundus fluorescein angiography (FA), and to assess the level of these adverse effects in hypertensive and elderly patients.

METHOD

We carried out a retrospective study of 358 patients undergoing FA. They were assessed for adverse effects and their relationship to medical history, pre- and post-FA blood pressure and age.

RESULTS

The overall adverse reaction rate (AR) was 11.2%, the majority (80%) of which involved nausea. There were no mortalities and no cases of anaphylaxis or cardiac arrest. Hypertension (systolic or diastolic) did not increase the AR. Interestingly, raised initial systolic blood pressure (BP) > or = 160 showed a statistically significant decreased AR compared with that for BP < 160 (7% versus 15%, respectively; p = 0.04). There was no statistical correlation between AR and age.

CONCLUSIONS

FA is a relatively safe procedure, but serious side-effects have been reported in the past and therefore adequate measures need to be in place to cope with such emergencies. In our study, there was no increase in the incidence of adverse effects in patients who were hypertensive or elderly. Therefore, these patients should not be denied an important diagnostic procedure that may improve their quality of life purely because of hypertension or age.

Serum tryptase levels in sudden infant death syndrome in forensic autopsy cases

An elevated serum tryptase concentration is considered to be a specific marker for systemic mast-cell activation, a central feature of anaphylaxis, which has been observed in some cases of sudden infant death syndrome (SIDS). However, it is still unclear whether anaphylaxis is involved in the etiology for SIDS. In the present study, we measured serum tryptase levels in 21 infants with SIDS, and 14 control infants from forensic autopsy cases by Uni-CAP TRYPTASE Fluoroenzyme immunoassay system, which detects both alpha- and beta-tryptase. The assay did not show any significant elevation of tryptase levels in the SIDS group compared with controls. Additionally, increased concentrations of tryptase were not observed in any SIDS case. Our results indicated that anaphylaxis does not seem to be involved in the etiology of SIDS.

A fatal case of amniotic fluid embolism with elevation of serum mast cell tryptase

A case of a 40-year-old female who died of amniotic fluid embolism is presented. This case showed typical histological findings of this syndrome. Postmortem serum of this case showed an elevated tryptase level (67.2ng/ml, normal levels <10ng/ml). Tryptase is a neutral protease of mast cells, and an important indicator of mast cell activation and degranulation. Thus, mast cell activation, a central feature of anaphylaxis, may have been involved in the pathogenetic mechanism of this case.

Use of oral fluorescein angiography in the diagnosis of macular oedema within a diabetic retinopathy screening programme

AIMS

To assess if oral fluorescein angiography (OFA) is a suitable screening method to detect macular oedema in diabetic retinopathy.

METHODS

Eighty-four diabetic patients were included in the study. They were from a consecutive series of patients attending the diabetic eye-screening clinic, with retinopathy at the macula requiring ophthalmology assessment. All patients were subsequently examined in the eye hospital, by ophthalmologist slit lamp biomicroscopy assessment as the gold standard, followed by oral fluorescein angiography.

RESULTS

This study indicates a sensitivity of 92% and specificity of 81%. Only 4.8% of patients developed a minor reaction to oral fluorescein; 84.5% of images were of good quality.

CONCLUSIONS

Oral fluorescein angiography is an efficient and highly sensitive tool for the detection of macular oedema. It can be used as an adjunct in the diabetic screening service to identify patients with oedema within a disc diameter of the macula. Ultimately it will ensure that only necessary and smaller numbers of patients are referred to ophthalmologists.

Immunohistochemical quantification of pulmonary mast-cells and post-mortem blood dosages of tryptase and eosinophil cationic protein in 48 heroin-related deaths

Recent studies suggest that many fatal heroin overdoses are caused by anaphylactoid reaction. In the present study we measured tryptase and eosinophil cationic protein in post-mortem blood of 48 deaths after heroin injection. We also investigated the presence and pulmonary distribution of mast-cells using specific immunohistochemical antibody for tryptase and morphometric evaluation in those cases of heroin-related deaths. The data were compared with 44 subjects who died following head trauma and to 32 cases of fatal anaphylactic shock. In the heroin-related death cases, the measurements of serum tryptase levels and eosinophil cationic protein dosages resulted in particularly elevated concentrations compared with the trauma cases. Nevertheless, the data that our study supplies by immunohistochemical techniques indicate that when mast-cells count in the lung was determined, no definite pattern was obtained between fatal heroin overdose cases and the control groups. Furthermore, the wide range of morphine concentrations found in post-mortem blood samples suggest that the term 'overdose' is relative and does not sufficiently characterize death associated with heroin addiction. Our study confirms that elevated concentrations of serum tryptase are associated with many heroin-related deaths. At this moment to attribute the cause of these deaths to 'heroin overdose' ignores the likely causal contribution of other possible systemic reactions to the mechanism of death.