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Biomedical subjects

Frederick M Karrer

Publications and source records attributed to Frederick M Karrer.

At least 19 recordsLinked to original sources
PubMed2006

Resection of neurogenic tumors in children: is thoracoscopy superior to thoracotomy?

BACKGROUND: Minimally invasive resection of solid tumors is controversial because of concerns of inadequate resection and local recurrence. Thoracoscopy has been used in the diagnosis of mediastinal tumors in children, but its role in resection is unproved. The purpose of this study was to compare thoracoscopic and open approaches to the resection of thoracic neurogenic tumors in children. STUDY DESIGN: The tumor registry of a regional children's hospital was queried to identify patients who underwent resection of neurogenic tumors over a 6-year period. Thoracoscopic and open groups were compared for demographic, operative, oncologic, and outcomes characteristics. RESULTS: Seventeen children underwent resection of mediastinal neurogenic tumors (10 thoracoscopic resections, 7 open resections). Mean age was 4.7 years (range 6 months to 12 years). The thoracoscopic and open groups showed no difference in operative time or blood loss. Tumors in the two groups were comparable in size (5.2+/-2.2 cm versus 5.7+/-2.6 cm), histology, surgical margin, and stage. Hospital stay was shorter after thoracoscopic resection (1.9+/-0.7 days versus 4.1+/-2.5 days, p<0.05). There were no regional recurrences. Distant metastases developed in one patient in each group. Eight of 10 children with malignant tumors remain disease-free at an average of 25 months of followup (range 3 to 80 months). CONCLUSIONS: Thoracoscopic resection of neurogenic tumors achieved similar local control and disease-free survival when compared with open resection in this preliminary series. These results were accompanied by a shorter hospital stay. These findings suggest that thoracoscopic resection of neurogenic tumors in children may offer advantages to open resection and should be studied in the context of a large, cooperative trial.

Child↗
PubMed2006

Xanthogranulomatous pyelonephritis.

Xanthogranulomatous pyelonephritis is a rare condition in children. A 7-year-old boy developed right flank pain and tenderness 1 month after an appendectomy. Abdominal computed tomography scan documented a right renal mass. A right nephrectomy was performed. The pathological report documents xanthogranulomatous pyelonephritis. He experienced an uneventful recovery. Xanthogranulomatous pyelonephritis should be included in the differential diagnosis of children with fever, weight loss, flank tenderness, and a renal mass.

Child↗
PubMed2006

Nonaccidental trauma is a major cause of morbidity and mortality among patients at a regional level 1 pediatric trauma center.

BACKGROUND: Traumatic injuries are a major cause of morbidity and mortality in children. The purpose of the present study was to determine the incidence of nonaccidental trauma (NAT) and to compare the outcomes of accidental trauma (AT) patients with NAT patients at a large pediatric trauma center. METHODS: A retrospective chart review of 6186 trauma patients younger than 18 years evaluated during the period of 1996 to 2004. RESULTS: During the period of study, NAT accounted for 7.3% (n = 453) of trauma evaluations (n = 6186). Compared to AT, the NAT patient was younger, 12 vs 76 months (P < .05); were more severely injured, injury severity score 18 vs 9 (P < .05); and required both longer intensive care unit stay, 2 vs 1 day (P < .05), and overall hospital stay, 6 vs 3 days (P < .05). Craniotomy was required in 4.4% of NAT patients compared with 2.7 % of AT patients (P < .05). Abdominal exploration was necessary in 3.5% of NAT patients compared to 1.6% of AT patients. The mortality rate for NAT was 9.7% compared to 2.2% for AT (P < .05). CONCLUSIONS: The surgeon caring for children must appreciate the high incidence of NAT with its increased morbidity and mortality relative to AT patients. A surgical evaluation should be performed promptly in NAT patients because of their frequent need for emergent intervention.

Child↗
PubMed2005

Characterization of acute liver failure and development of a continuous risk of death staging system in children.

BACKGROUND/AIMS: Acute liver failure (ALF) in children has been associated with an overall mortality of approximately 70% in the pretransplant era and 50-80% survival in those undergoing orthotopic liver transplantation. There is currently no system for staging severity of ALF in children. The aim of this study was to characterize pediatric ALF in a tertiary hospital and to derive a scoring system to stratify severity of ALF based on predicted mortality. METHODS: Prospective data collection of 81 children from December 1993-2003 who presented with ALF. Data recorded included peak laboratory values, clinical characteristics, and survival. RESULTS: Transplant-free survival was 56% with overall survival including those undergoing OLT of 72%. Transplantation rate was 22% with transplant survival of 72%. Of the peak laboratory values analyzed, total bilirubin, prothrombin time/INR, and ammonia were the most predictive of death or a need for liver transplant. A simple risk staging system was developed based on the ability of these three laboratory measurements to predict mortality. CONCLUSIONS: The survival in pediatric ALF has improved in recent years. Risk staging for ALF could potentially be used in clinical research for risk-adjusted outcomes analysis and to help stratify patients for clinical studies according to mortality risk.

Ammonia↗
PubMed2005

Visceral injuries in nonaccidental trauma: spectrum of injury and outcomes.

BACKGROUND: Nonaccidental trauma (NAT) causes significant morbidity and mortality in children. The purpose of this study was to characterize visceral injuries associated with NAT and the management and outcomes of children with these injuries. METHODS: During a 7-year period, children admitted to our regional pediatric trauma center with a diagnosis of NAT were identified and their injuries characterized. RESULTS: NAT accounted for 7% (n = 265 of 3705) of all trauma admissions during the period of study. Visceral injuries were diagnosed in 9% (n = 24 of 265) of NAT patients. Compared with the remaining NAT population, children with visceral injuries were similar in age and sex but had higher injury severity scores (21 vs. 17, P < .05). There was a high coincidence of thoracic trauma and nonburn integumental injuries in abdominally injured NAT patients. Children with visceral injuries were more likely to undergo emergent operations (46% [11 of 24] vs. 5% [15 of 241], P < .0001) than those without. However, there was no difference in Intensive Care Unit stay, hospital stay, or overall mortality for children with visceral injuries compared with those without. CONCLUSIONS: Visceral injuries are not uncommon in NAT, and these injuries often require emergent operative intervention. Thus, prompt evaluation and treatment by a surgeon remains a critical step in the management of children with NAT.

Abdominal Injuries↗
PubMed2004

Biliary atresia is associated with CD4+ Th1 cell-mediated portal tract inflammation.

A proposed mechanism in the pathogenesis of biliary atresia involves an initial virus-induced, progressive T cell-mediated inflammatory obliteration of bile ducts. The aim of this study was to characterize the inflammatory environment present within the liver of infants with biliary atresia to gain insight into the role of a primary immune-mediated process versus a nonspecific secondary response to biliary obstruction. Frozen liver tissue obtained from patients with biliary atresia, neonatal giant cell hepatitis, total parenteral nutrition (TPN)-related cholestasis, choledochal cysts, and normal control subjects was used for fluorescent immunohistochemistry studies of cellular infiltrates, cytokine mRNA expression, and in situ hybridization for localization of cytokine-producing cells. Immunohistochemistry revealed increases in CD8(+) and CD4(+) T cells and Kupffer cells (CD68(+)) in the portal tracts of biliary atresia. Reverse transcription-PCR analysis of biliary atresia tissue showed a Th1-type cytokine profile with expression of IL-2, interferon-gamma, tumor necrosis factor-alpha, and IL-12. This profile was not seen in normal, neonatal hepatitis or choledochal cyst livers but was present in TPN-related cholestasis. In situ hybridization revealed that the Th1 cytokine-producing cells were located in the portal tracts in biliary atresia and in the parenchyma of TPN-related cholestasis. A distinctive portal tract inflammatory environment is present in biliary atresia, involving CD4(+) Th1 cell-mediated immunity. The absence of similar inflammation in other pediatric cholestatic conditions suggests that the portal tract inflammation in biliary atresia is not a secondary response to cholestasis but rather indicates a specific immune response involved in the pathogenesis of biliary atresia.

Bile Ducts, Extrahepatic↗
PubMed2004

Pediatric liver transplantation.

PURPOSE OF REVIEW: Pediatric liver transplantation is a challenging and exciting field for all healthcare providers involved with children who have end-stage liver disease. Graft and patient survival continue to improve due to improvements in medical, surgical, and anesthetic management, organ availability, immunosuppression, and identification and treatment of postoperative complications. This review will describe recent advances in pediatric liver transplantation. RECENT FINDINGS: Although pediatric cases only represent approximately 10% of the total patients on the waiting list, the number of deaths on the waiting list increased from 196 to 1753 between 1988 and 1999. Recently, a new pediatric liver allocation policy was instituted. The utilization of cut down "reduced" livers, split liver grafts, and living-related donors has provided more organs for pediatric patients. Newer immunosuppression regimens, including induction therapy, continue to have a significant impact on graft and patient survival. Excellence in peri-operative management and identification and treatment of complications or infections also has had an impact on graft and patient survival. Finally, investigation and analysis of the postoperative quality of life, for both the patient and parents, is being conducted. SUMMARY: Pediatric liver transplantation is a challenging and rewarding field with continued improvements in patient and graft survival. A multidisciplinary team approach coupled with improvements in organ availability, immunosuppression, and peri-operative management has had a dramatic impact on survival.

Adolescent↗
PubMed2004

Blunt diaphragmatic rupture in children.

BACKGROUND: Although several series of blunt diaphragmatic rupture in adults have been published, this injury remains largely uncharacterized in the pediatric population. METHODS: We queried our trauma registry for all children admitted with blunt diaphragmatic rupture over a 10-year period at a Level I pediatric trauma center. RESULTS: Six children (aged 2-15 years; mean, 7 years) were identified with blunt diaphragmatic rupture (three right, two left, one bilateral), representing 0.4% of admissions. All of the children had associated injuries (4.5 per child), with a mean Injury Severity Score of 32. Four diaphragmatic injuries were identified during the initial evaluation. The two missed injuries were diagnosed at postinjury days 5 and 8. There were no deaths and all children were eventually discharged without sequelae. CONCLUSION: Blunt diaphragmatic rupture occurs in children with a frequency and severity commensurate with that observed in adults. Our data suggest improved survival compared with adults with this injury.

Adolescent↗
PubMed2003

Increased CT scan utilization does not improve the diagnostic accuracy of appendicitis in children.

BACKGROUND/PURPOSE: Appendicitis continues to present a diagnostic dilemma in children of all ages leading to increased utilization of radiographic studies. Focused computed tomography (CT) scanning has become the diagnostic test of choice in many hospitals. The purpose of this study was to critically evaluate the use of radiographic studies for the evaluation of acute appendicitis in children and to determine if diagnostic accuracy has improved. METHODS: Children undergoing appendectomy for acute appendicitis were reviewed from 1997 to 2001. Diagnostic workup (CT scan, ultrasound [US], or no radiographic study) was recorded as were the final pathology results. RESULTS: Six hundred sixteen appendectomies were performed. Mean age was 10.4 +/- 4.1 years, and 60% were boys. Overall, 184 children (30%) underwent CT scanning, 104 (17%) had US performed, and 310 (50%) had no radiographic study (18 patients had both CT and US performed). A pathologically normal appendix was removed in 7% (14 of 202) of CT patients, 11% (14 of 122) of US patients, and 8% (26 of 310) of patients without a study. The frequency of CT scanning increased from 1.3% of all children in 1997 to 58% in 2001, whereas utilization of US decreased from 40% to 7%. Over the same period, the overall negative appendectomy rate did not change significantly from 8% to 7%. CONCLUSIONS: With increased utilization of focused CT scanning, the negative appendectomy rate has remained unchanged. History and physical examination by an experienced surgeon is as accurate as CT in correctly diagnosing acute appendicitis in children.

Adolescent↗
PubMed2003

Is a routine chest x-ray necessary for children after fluoroscopically assisted central venous access?

PURPOSE: The aim of this study was to determine in a pediatric population whether a routine chest x-ray after central venous access is necessary when the central venous catheter is placed with intraoperative fluoroscopy. METHODS: This was a retrospective review of the charts of all patients at Children's Hospital in Denver, Colorado who underwent subclavian or internal jugular central venous catheter placement from January 1, 1998 through December 31, 2001. Age, sex, primary reason for access, access site, number of venipuncture attempts, type of catheter, intraoperative fluoroscopy results, chest x-ray results, location of the tip of the catheter, and complications were analyzed. RESULTS: There were 1,039 central venous catheters placed in 824 patients, 92.6% in the subclavian vein and 7.4% in the internal jugular vein. There were 604 (58.1%) children who had both fluoroscopy and a postprocedure chest x-ray, there were 308 (29.6%) who had only fluoroscopy, there were 117 (11.3%) who had only a postprocedure chest x-ray, and there were 10 (1.0%) who had neither fluoroscopy nor chest x-ray. On completion of the procedure, there were 12 (1.1%) children with misplaced central venous catheters, only 1 (0.1%) when intraoperative fluoroscopy was used. There were 17 (1.6%) complications; 9 (0.9%) were pulmonary (pneumothorax, hemothorax, or an effusion). All children with pulmonary complications experienced clinical signs and symptoms suggestive of the complication after their central venous catheter insertion but before their postprocedure chest x-ray. CONCLUSIONS: The number of complications encountered in children who had central venous access of the subclavian vein or internal jugular central vein with intraoperative fluoroscopy was infrequent, the number of misplaced catheters was minimized with intraoperative fluoroscopy, and all children with pulmonary complications showed clinical signs suggestive of pulmonary complications before postoperative chest x-ray. Therefore, children who have had central venous access of the subclavian and internal jugular vein with intraoperative fluoroscopy do not appear to require a routine chest x-ray after catheter placement unless clinical suspicion of a complication exists.

Adolescent↗
PubMed2003

Spectrum of anorectal anomalies in pygopagus twins.

BACKGROUND/PURPOSE: The literature lacks a concise description of the anorectal anomalies encountered in pygopagus twins. METHODS: This is a retrospective literature review of 34 pygopagus twins highlighting their anorectal malformations. RESULTS: Overall pygopagus twins represent 17% of all conjoined twins. Live-birth pygopagus twins are more commonly female (86%), whereas stillborns are commonly male (80%). Half of the twins had nonfused rectums, and half had fused rectums. The nonfused had 2 rectums (80%) or one rectum and one rectovaginal fistula (20%). The fused had high (46%) or low (54%) rectal junctions. All reported living male pygopagus twins have had nonfused rectums. All can be managed applying the principles of posterior sagittal anorectoplasty. CONCLUSIONS: In general, live-born male pygopagus twins are likely to survive with a nonfused rectum and good bowel function, whereas live-born female pygopagus twins have a good chance of surviving with a fused rectum (high or low), which requires appropriate operative reconstruction.

Abnormalities, Multiple↗
PubMed2003

The positive predictive value of rib fractures as an indicator of nonaccidental trauma in children.

BACKGROUND: Rib fractures have a strong association with nonaccidental trauma (NAT) and severe trauma. The purposes of this study were to evaluate rib fractures in children to determine (1) the positive predictive value of a rib fracture in defining NAT and (2) the frequency of rib fractures as the only skeletal manifestation of NAT. METHODS: We reviewed the medical records and imaging of all children with rib fractures over a 6-year period. NAT was determined by the Child Advocacy and Protection team. RESULTS: In children younger than 3 years of age, the positive predictive value (PPV) of a rib fracture as an indicator of NAT was 95%. The positive predictive value increased to 100% once historical and clinical circumstance excluded all other causes for rib fractures. CONCLUSION: In this study, rib fracture(s) were the only skeletal manifestation of NAT in 29% of the children.

Adolescent↗
PubMed2002

Is hypotension a reliable indicator of blood loss from traumatic injury in children?

BACKGROUND: Traditional surgical teaching stresses that hypotension is an indicator of loss of circulating blood volume. The purpose of this study is to critically evaluate hypotensive injured children for evidence of a hemorrhagic insult. METHODS: Over a 2-year period, data were collected prospectively from children injured via a blunt mechanism. Systolic blood pressure (SBP) was recorded in the field and on arrival to the emergency department. RESULTS: In all, 194 injured children were identified as hypotensive. Only 82 (42%) had identifiable injuries to account for significant volume loss. Children 0 to 5 years old had a 61% incidence of isolated head injury (46 of 76) and only a 34% incidence of hemorrhagic insult (26 of 76). Children 6 to 12 years old had a 31% incidence of isolated head injury (22 of 72) and a 52% incidence of hemorrhagic insult (38 of 72). Finally, patients more than 12 years old had a 33% incidence of isolated head injury (15 of 46) and a 39% incidence of hemorrhagic insult (18 of 46). CONCLUSIONS: Hypotension should not be viewed only as a potential marker of loss of circulating volume, but also as a possible indicator of head injury in young trauma victims.

Adolescent↗
PubMed2002

A critical analysis of outcome for children sustaining cardiac arrest after blunt trauma.

PURPOSE: Injury is the leading cause of cardiac arrest in children older than 1 year. Previous findings suggest that children who require cardiopulmonary resuscitation (CPR) administered by paramedics for any reason rarely survive to hospital discharge. The authors evaluated the outcome of children sustaining cardiac arrest after blunt trauma in a Regional Pediatric Trauma Center. METHODS: Children (age < 16) who underwent CPR in the field or in the emergency department (ED) after blunt trauma were identified from the trauma registry of a regional pediatric trauma center over a 3-year period (1997 to 2000). Patient demographics, rate of survival to discharge, factors influencing survival, and organ donation data were obtained from the trauma registry and medical record. Probability of survival (Ps) was calculated by TRISS analysis. RESULTS: Twenty-five children were identified with a history of cardiac arrest after blunt injury (mean age; 3.3 years; range, 0.1 to 10; mean ISS, 30.7; range, 13-75; mean RTS, 1.58). Mean calculated Ps was 22.7%. However, only 2 (8%) survived. Death in the majority (91%) of the 23 patients who died occurred secondary to brain or spinal cord injury, and only 2 (9%) occurred as the result of exsanguinating hemorrhage. CPR was first performed in the field in 10 patients (40%), en route in 6 (24%), and in the ED in 9 (36%). Of the children who survived, both had vitals in the field, and CPR was administered initially in the ED. Mean length of ED resuscitation before death was 80 minutes. Of the children who died, organ donation occurred in only 3 (13%). The 2 survivors had no head injury and were discharged within 3 weeks of injury. CONCLUSIONS: Cardiopulmonary resuscitation after blunt injury in children rarely results in survival. The majority of deaths occur as a result of isolated intracranial injury and not exsanguinating hemorrhage. Although all children should receive aggressive resuscitation after injury, the need for CPR in the field portends a poor outcome. Furthermore, these data would suggest that prolonged or heroic efforts for children sustaining cardiac arrest in the field are not indicated.

Accidents, Traffic↗
PubMed2002

Altered neutrophil function in the neonate protects against sepsis-induced lung injury.

BACKGROUND/PURPOSE: Neutrophils (PMNs) are well known effectors of lung injury after sepsis. The accumulation of PMNs into the lung is dependent on a complex cascade of events that includes the local production of chemokines. Interestingly, neonates are protected from lung injury after zymosan-induced sepsis. The authors hypothesized that this protection was caused by either altered PMN function or diminished lung chemokine production compared with the adult. METHODS: Sepsis was induced in neonatal and adult rats by an intraperitoneal injection of zymosan. Animals were killed 24 hours later and lungs examined for PMN accumulation and function, chemokine production, and lung injury. RESULTS: Septic neonates (SN) were protected from pulmonary edema when compared with septic adults (SA). Lung PMN number and chemokine (MIP-2) production increased in both septic neonates and adults when compared with vehicle (V) treated animals. Conversely, PMN function was decreased significantly in neonates when compared with adults. CONCLUSIONS: Despite equivalent lung PMN accumulation and chemotactic protein production, PMN function and lung injury in septic neonates was diminished when compared with that of adults. These findings suggest that neonates may be relatively protected from sepsis-induced lung injury caused by immature PMN function.

Animals↗
PubMedDate not supplied

Molecular genetic analysis of a small bowel primitive neuroectodermal tumor.

We present a pediatric peripheral primitive neuroectodermal tumor (pPNET) localized exclusively to the small bowel. The tumor presented in an adolescent male and the diagnosis was confirmed by electron microscopy, CD99 immunopositivity, and molecular genetic analysis that demonstrated an EWS-FLI1 type 2 fusion transcript. This case report and a review of the literature underscore the considerable phenotypic overlap in EWS-related tumors in this site and the necessity for molecular genetic analysis to permit accurate classification.

Adolescent↗