Michael Ashworth

The role of post-mortem investigations in determining the cause of sudden unexpected death in infancy

Introduction: Several autopsy protocols have been suggested for investigating sudden unexpected deaths in infancy (SUDI). The aim of this study is to provide data on the utility of such post-mortem investigations from a large paediatric autopsy series to inform future policy. Methods: Retrospective analysis of >1500 consecutive post-mortem examinations carried out by specialist paediatric pathologists at a single centre during a 10-year period according to a common autopsy protocol that included the use of detailed ancillary investigations. SUDI was defined as the sudden unexpected death of an infant aged from 7 to 365 days. All data capture and cause of death classification were carried out according to defined criteria. Results: Of 1516 paediatric post-mortem examinations, 546 presented as SUDI. In 202 infants (37%), death was explained by the autopsy findings. The other 344 cases (63%) remained unexplained. Of the explained deaths, over half (58%) were infective, most commonly due to pneumonia (22%). The component of the post-mortem examination that primarily determined the final cause of death was histological examination in 92 infants (46%), macroscopic examination in 61 (30%), microbiological investigations in 38 (19%) and clinical history in 10 (5%). Conclusion: This constitutes the largest single-institution autopsy study of SUDI. Ten years on from the Confidential Enquiry into Stillbirths and Deaths in Infancy (CESDI) SUDI studies, the ascertainment of a cause of death at autopsy has improved. However, with almost two thirds of SUDI remaining unexplained, alternative and/or additional diagnostic techniques are required to improve detection rates of identifiable causes of death at autopsy.

Sirolimus Therapy in Infants with Severe Hyperinsulinemic Hypoglycemia

Hyperinsulinemic hypoglycemia is the most common cause of severe, persistent neonatal hypoglycemia. The treatment of hyperinsulinemic hypoglycemia that is unresponsive to diazoxide is subtotal pancreatectomy. We examined the effectiveness of the mammalian target of rapamycin (mTOR) inhibitor sirolimus in four infants with severe hyperinsulinemic hypoglycemia that had been unresponsive to maximal doses of diazoxide (20 mg per kilogram of body weight per day) and octreotide (35 μg per kilogram per day). All the patients had a clear glycemic response to sirolimus, although one patient required a small dose of octreotide to maintain normoglycemia. There were no major adverse events during 1 year of follow-up.

Detergent enzymatic treatment for the development of a natural acellular matrix for oesophageal regeneration

PurposeTissue engineering of the oesophagus has been proposed as a therapeutic alternative to organ transplantation. We previously demonstrated that a detergent enzymatic treatment (DET) is a valid method to obtain an acellular matrix with preservation of the native architecture. In this study, we aimed to develop a natural acellular matrix from pig oesophagus, as a valid framework for oesophageal replacement.MethodsPig oesophagi (nxa0=xa04) were decellularized with continuous luminal infusion of DET. To evaluate the efficiency of the decellularization, samples were assessed by histology and DNA quantification. Moreover, the ultra-structural characteristics of the acellular matrix were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).ResultsDecellularization of the oesophagus was achieved after three cycles of DET. Histological analysis showed the maintenance of tissue matrix architecture with absence of cellular elements, verified by measurement of DNA. SEM and TEM analysis confirmed preservation of the ultra-structural characteristics of the native tissue.ConclusionsOesophageal acellular matrix can be successfully obtained by decellularization of pig oesophagus using a gentle DET via the oesophageal lumen. This decellularization method preserves the ultrastructure of the native tissue and could represent the basis for a tissue-engineered oesophagus.

Postmortem Cardiovascular Magnetic Resonance Imaging in Fetuses and Children A Masked Comparison Study With Conventional Autopsy

Background— Perinatal and pediatric autopsies have declined worldwide in the past decade. We compared the diagnostic accuracy of postmortem, cardiovascular magnetic resonance (CMR) imaging with conventional autopsy and histopathology assessment in fetuses and children. Methods and Results— We performed postmortem magnetic resonance imaging in 400 fetuses and children, using a 1.5-T Siemens Avanto magnetic resonance scanner before conventional autopsy. A pediatric CMR imager reported the CMR images, masked to autopsy information. The pathologists were masked to the information from CMR images. The institutional research ethics committee approved the study, and parental consent was obtained. Assuming a diagnostic accuracy of 50%, 400 cases were required for a 5% precision of estimate. Three cases were excluded from analysis, 2 with no conventional autopsy performed and 1 with insufficient CMR sequences performed. Thirty-eight CMR data sets were nondiagnostic (37 in fetuses ⩽24 weeks; 1 in a fetus >24 weeks). In the remaining 359 cases, 44 cardiac abnormalities were noted at autopsy. Overall sensitivity and specificity (95% confidence interval) of CMR was 72.7% (58.2–83.7%) and 96.2% (93.5–97.8%) for detecting any cardiac pathology, with positive and negative predictive values of 72.7% (58.2–83.7%) and 96.2% (93.5–97.8%), respectively. Higher sensitivity of 92.6% (76.6–97.9%), specificity of 99.1% (97.4–99.7%), positive predictive value of 89.3% (72.8–96.3%), and negative predictive value of 99.4% (97.8–99.8%) were seen for major structural heart disease. Conclusions— Postmortem CMR imaging may be a useful alternative to conventional cardiac autopsy in fetuses and children for detecting cardiac abnormalities. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01417962.Background— Perinatal and pediatric autopsies have declined worldwide in the past decade. We compared the diagnostic accuracy of postmortem, cardiovascular magnetic resonance (CMR) imaging with conventional autopsy and histopathology assessment in fetuses and children.nnMethods and Results— We performed postmortem magnetic resonance imaging in 400 fetuses and children, using a 1.5-T Siemens Avanto magnetic resonance scanner before conventional autopsy. A pediatric CMR imager reported the CMR images, masked to autopsy information. The pathologists were masked to the information from CMR images. The institutional research ethics committee approved the study, and parental consent was obtained. Assuming a diagnostic accuracy of 50%, 400 cases were required for a 5% precision of estimate. Three cases were excluded from analysis, 2 with no conventional autopsy performed and 1 with insufficient CMR sequences performed. Thirty-eight CMR data sets were nondiagnostic (37 in fetuses ≤24 weeks; 1 in a fetus >24 weeks). In the remaining 359 cases, 44 cardiac abnormalities were noted at autopsy. Overall sensitivity and specificity (95% confidence interval) of CMR was 72.7% (58.2–83.7%) and 96.2% (93.5–97.8%) for detecting any cardiac pathology, with positive and negative predictive values of 72.7% (58.2–83.7%) and 96.2% (93.5–97.8%), respectively. Higher sensitivity of 92.6% (76.6–97.9%), specificity of 99.1% (97.4–99.7%), positive predictive value of 89.3% (72.8–96.3%), and negative predictive value of 99.4% (97.8–99.8%) were seen for major structural heart disease.nnConclusions— Postmortem CMR imaging may be a useful alternative to conventional cardiac autopsy in fetuses and children for detecting cardiac abnormalities.nnClinical Trial Registration— URL: . Unique identifier: [NCT01417962][1].nn# CLINICAL PERSPECTIVE {#article-title-31}nn [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01417962&atom=%2Fcirculationaha%2F129%2F19%2F1937.atom

Virological investigations in sudden unexpected deaths in infancy (SUDI)

Previous studies have implicated viral infections in the pathogenesis of sudden unexpected death in infancy (SUDI), and routine virological investigations are recommended by current SUDI autopsy protocols. The aim of this study is to determine the role of post-mortem virology in establishing a cause of death. A retrospective review of 546 SUDI autopsies was carried out as part of a larger series of >1,500 consecutive paediatric autopsies performed over a 10-year period, 1996–2005, in a single specialist centre. Virological tests were performed as part of the post-mortem examination in 490 (90%) of the 546 SUDI autopsies, comprising 4,639 individual virological tests, of which 79% were performed on lung tissue samples. Diagnostic methods included immunofluorescence assays (using a routine respiratory virus panel; 98% of cases), cell culture (61%), rapid culture techniques such as the DEAFF test for CMV (55%), PCR (13%), electron microscopy (10%), and others. Virus was identified in only 18 cases (4%), viz. five cases of enterovirus, four of RSV, three of HSV and CMV, and one each of adenovirus, influenza virus and HIV. In seven of the 18 cases the death was classified as due to viral infection, whilst of the remaining 11 cases, death was due to bacterial infection in five, a non-infective cause in one and unexplained in five. Virus was identified in 33% of deaths due to probable viral infections, but also in 6% of SUDI due to bacterial infections, and in 2% of SUDI due to known non-infective causes and unexplained SUDI. When predominantly using immunofluorescence, virus is identified in only a small proportion of SUDI autopsies, resulting in a contribution to the final cause of death in <2% of SUDI post-mortem examinations. Routine post-mortem virological analysis by means of an immunofluorescence respiratory virus panel appears to be of limited benefit in SUDI for the purposes of determining cause of death. Application of a broader panel using more sensitive detection techniques may reveal more viruses, although their contribution to the final cause of death requires further exploration.

Reappraising myocardial fibrosis in severe aortic stenosis: an invasive and non-invasive study in 133 patients

Abstract Aims To investigate myocardial fibrosis (MF) in a large series of severe aortic stenosis (AS) patients using invasive biopsy and non-invasive imaging. Methods and results One hundred thirty-three patients with severe, symptomatic AS accepted for surgical aortic valve replacement underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) quantification. Intra-operative left ventricular (LV) biopsies were performed by needle or scalpel, yielding tissue with (nu2009=u200953) and without endocardium (nu2009=u200980), and compared with 10 controls. Myocardial fibrosis occurred in three patterns: (i) thickened endocardium with a fibrotic layer; (ii) microscopic scars, with a subendomyocardial predominance; and (iii) diffuse interstitial fibrosis. Collagen volume fraction (CVF) was elevated (Pu2009<u20090.001) compared with controls, and higher (Pu2009<u20090.001) in endocardium-containing samples with a decreasing CVF gradient from the subendocardium (Pu2009=u20090.001). Late gadolinium enhancement correlated with CVF (Pu2009<u20090.001) but not ECV. Both LGE and ECV correlated independently (Pu2009<u20090.001) with N-terminal pro-brain natriuretic peptide and high-sensitivity-troponin T. High ECV was also associated with worse LV remodelling, left ventricular ejection fraction and functional capacity. Combining high ECV and LGE better identified patients with more adverse LV remodelling, blood biomarkers and histological parameters, and worse functional capacity than each parameter alone. Conclusion Myocardial fibrosis in severe AS is complex, but three main patterns exist: endocardial fibrosis, microscars (mainly in the subendomyocardium), and diffuse interstitial fibrosis. Neither histological CVF nor the CMR parameters ECV and LGE capture fibrosis in its totality. A combined, multi-parametric approach with ECV and LGE allows best stratification of AS patients according to the response of the myocardial collagen matrix.

Autopsy findings of co-sleeping-associated sudden unexpected deaths in infancy: Relationship between pathological features and asphyxial mode of death

Aim:u2003 Co‐sleeping is associated with increased risk of sudden unexpected death in infancy (SUDI)/sudden infant death syndrome (SIDS). The aim of this study is to examine autopsy findings from a single UK specialist centre to determine the relationship between co‐sleeping and cause of death.

Clinical utility of postmortem microcomputed tomography of the fetal heart: diagnostic imaging vs macroscopic dissection

Congenital cardiac malformations are commonly identified at perinatal autopsy, which can be challenging in fetuses of early gestation and in macerated fetuses. Our objective was to examine fetal complex congenital heart disease by microcomputed tomography (micro‐CT), using standard autopsy as the gold standard.

Insulinoma in childhood: clinical, radiological, molecular and histological aspects of nine patients

BACKGROUNDnInsulinomas are a rare cause of hyperinsulinaemic hypoglycaemia (HH) in children. The clinical features, investigations, management and histology of these rare pancreatic tumours in children have not been described in a large cohort of patients.nnnMETHODSnWe conducted a retrospective review of cases diagnosed between 2000 and 2012, presenting to two referral centres in the United Kingdom. Clinical, biochemical, imaging (magnetic resonance imaging (MRI) and 6-L-¹⁸F-fluorodihydroxyphenylalanine (¹⁸F-DOPA) PET/CT scanning) and histological data were collected.nnnRESULTSnNine children (age range 2-14.5 years) were diagnosed during the study period at Great Ormond Street Hospital (n=5) and Royal Manchester Childrens Hospital (n=4). The combination of abdominal MRI scan (7/8) and ¹⁸F-DOPA PET/CT scan (2/4) correctly localised the anatomical location of all insulinomas. Before surgery, diazoxide therapy was used to treat hypoglycaemia, but only four patients responded. After surgical resection of the insulinoma, hypoglycaemia resolved in all patients. The anatomical localisation of the insulinoma in each patient was head (n=4), uncinate process (n=4) and tail (n=2, one second lesion) of the pancreas. Histology confirmed the diagnosis of insulinoma with the presence of sheets and trabeculae of epithelioid and spindle cells staining strongly for insulin and proinsulin, but not for glucagon or somatostatin. Two children were positive for MEN1, one of whom had two separate insulinoma lesions within the pancreas.nnnCONCLUSIONSnWe describe a cohort of paediatric insulinoma patients. Although rare, insulinomas should be included in the differential diagnosis of HH, even in very young children. In the absence of a single imaging modality in the preoperative period, localisation of the tumour is achieved by combining imaging techniques, both conventional and functional.

Large ABCA3 and SFTPC deletions resulting in lung disease.

RATIONALEnMutations in genes encoding proteins important in the function and metabolism of pulmonary surfactant are recognized causes of lung disease. Clinical genetic testing is available for these disorders, but children with phenotypes consistent with surfactant dysfunction and no identifiable mutations in the known causative genes have been reported.nnnOBJECTIVESnTo identify the mechanism(s) for lung disease in two children with the phenotype of surfactant dysfunction who had negative testing in clinical laboratories for gene mutations causing surfactant dysfunction.nnnMETHODSnAmplicons spanning multiple exons of candidate genes were generated by polymerase chain reaction and sequenced.nnnMEASUREMENTS AND MAIN RESULTSnA 4,335-base deletion that included all of exon 12 of the gene encoding member A3 of the adenosine triphosphate-binding cassette transporter was identified in a full-term infant with respiratory failure. A 333-base deletion involving part of exon 4 and the adjacent intron of the gene encoding surfactant protein C was identified in a child with interstitial lung disease.nnnCONCLUSIONSnLarge deletions are a cause of surfactant dysfunction disorders and may need to be sought for specifically in children whose phenotypes suggest these syndromes but in whom clinical genetic testing is unrevealing.