2024 Clinical Practice Guideline Update by the Infectious Diseases Society of America on Complicated Intra-abdominal Infections: Risk Assessment, Diagnostic Imaging, and Microbiological Evaluation in Adults, Children, and Pregnant People.

As the first part of an update to the clinical practice guideline on the diagnosis and management of complicated intra-abdominal infections in adults, children, and pregnant people, developed by the Infectious Diseases Society of America, the panel presents twenty-one updated recommendations. These recommendations span risk assessment, diagnostic imaging, and microbiological evaluation. The panel's recommendations are based upon evidence derived from systematic literature reviews and adhere to a standardized methodology for rating the certainty of evidence and strength of recommendation according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach.

Italian guidelines for the diagnosis and management of colonic diverticulosis and diverticular disease.

Colonic diverticulosis and diverticular disease are among the most common gastrointestinal disorders encountered in clinical practice. These Italian guidelines focus on the diagnosis and management of diverticulosis and diverticular disease in the adult population, providing practical and evidence-based recommendations for clinicians. Experts from five Italian scientific societies, constituting a multidisciplinary panel, conducted a comprehensive review of meta-analyses, systematic reviews, randomised controlled trials, and observational studies to formulate 14 PICO questions. The assessment of the quality of the evidence and the formulation of the recommendations were carried out using an adaptation of the GRADE methodology. The guidelines covered the following topics: i) Management of diverticulosis; ii) Symptomatic uncomplicated diverticular disease: diagnosis and treatment; iii) Acute diverticulitis: diagnosis and treatment; iv) Management of diverticular disease complications; v) Prevention of recurrent acute diverticulitis; vi) Interventional management of diverticular disease.

Special stent for draining the abdominal abscess respectively from colon and duodenum: A case report.

BACKGROUND: Postoperative abdominal infections are an important and heterogeneous health challenge. Many samll abdominal abscesses are resolved with antibiotics, but larger or symptomatic abscesses may require procedural management. CASE SUMMARY: A 65-year-old male patient who suffered operation for the left hepatocellular carcinoma eight months ago, came to our hospital with recurrent abdominal pain, vomit, and fever for one month. Abdominal computed tomography showed that a big low-density dumbbell-shaped mass among the liver and intestine. Colonoscopy showed a submucosal mass with a fistula at colon of liver region. Gastroscopy showed a big rupture on the submucosal mass at the descending duodenum and a fistula at the duodenal bulb. Under colonoscopy, the brown liquid and pus were drained from the mass with "special stent device". Under gastroscopy, we closed the rupture of the mass with a loop and six clips for purse stitching at the descending duodenum, and the same method as colonoscopy was used to drain the brown liquid and pus from the mass. The symptom of abdominal pain, vomit and fever were relieved after the treatment. CONCLUSION: The special stent device could be effectively for draining the abdominal abscess respectively from colon and duodenum.

Myeloid Sarcoma of the Colon Initially Presenting as a Paracolic Abscess in a Patient with Relapsed Acute Myeloid Leukemia.

Myeloid sarcoma, a rare extramedullary manifestation of acute myeloid leukemia (AML), can occur in various anatomic sites but seldom involves the gastrointestinal tract. We report the unusual case of a 49-year-old man with a history of AML who initially presented with abdominal pain and imaging findings suggestive of a paracolic abscess. However, the lesion rapidly progressed to a large descending colon mass with peritoneal involvement over five weeks. Surgical resection and histopathological examination confirmed a diagnosis of myeloid sarcoma. This case highlights the potential of myeloid sarcoma to mimic an inflammatory colonic process at initial presentation prior to manifesting as an overt mass lesion. Although exceedingly rare, myeloid sarcoma should be considered in patients with a history of AML presenting with colon lesions, particularly in those with an aggressive clinical course. Early recognition may expedite appropriate treatment and prevent unnecessary procedures. This report also underscores the importance of correlating imaging findings with clinical history and histopathology findings to establish an accurate diagnosis.

Immunoglobulin G4-related disease mimicking an appendiceal neoplasm: a case report.

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition characterized by chronic activation of the immune system and a tendency to form tumorous lesions. IgG4-RD is frequently characterized by the presence of tumor-like masses affecting multiple organs and is easily mistaken for a malignant neoplasm. However, IgG4-RD affecting the appendix is extremely rare, with only seven cases reported previously. We report the case of a woman in her early 60s who presented with insidious abdominal pain and radiological findings mimicking appendiceal neoplasms. After diagnosing appendiceal neoplasms, surgery was performed. The patient had a serum IgG4 concentration of <1.35 g/L, which did not satisfy one of the three revised comprehensive diagnostic criteria for IgG4-RD. A pathological examination was conducted, and the patient was diagnosed with appendiceal IgG4-RD. To the best of our knowledge, there have been no previously reported cases of IgG4-RD affecting the appendix in patients with low serum IgG4 concentrations. This report may prove beneficial for the future understanding of IgG4-RD and for the revision of diagnostic and treatment strategies.

Empyema associated with peritoneal dialysis peritonitis.

A 65-year-old woman on peritoneal dialysis (PD) was admitted due to abdominal pain with cloudy PD effluent. The white blood cell count in PD effluent was 5860/µL with 85% polymorphonuclear neutrophils. Therefore, she was clinically diagnosed with peritonitis. The cultures of PD effluent were negative. Initial abdominal computed tomography did not find suggest any intraabdominal pathology. The patient was treated with empirical intraperitoneal antibiotics. Because abdominal pain with cloudy PD effluent persisted, the PD catheter was removed eventually. The culture of the removed PD catheter grew Klebsiella pneumoniae. However, intermittent fever was noted over the following days and empyema developed approximately 2 weeks after PD catheter removal. The culture of pleural fluid also grew K. pneumoniae. Another computed tomography revealed multiple intraabdominal abscesses that was assumed to come from a complication of PD-associated peritonitis. We postulate that the empyema might be caused by transdiaphragmatic extension of the intraabdominal abscesses into the pleural space.

Pyogenic liver abscesses in peritoneal dialysis patients: A single-centre retrospective case series.

Peritoneal dialysis (PD)-related infection rates have improved, but serious complications such as liver abscesses remain an issue, posing unique management challenges including safety of continuing PD versus early PD catheter removal. Current literature describing this is unfortunately limited. This study aims to describe the characteristics, management and outcomes of liver abscesses in PD patients from a retrospective review of prevalent PD patients on follow-up at Tan Tock Seng Hospital between 1st January 2016 and 30th June 2021. A total of 11/383 PD patients (2.9%) were treated for liver abscesses. Most were diabetic (n =10, 90.9%), with a median PD vintage of 541 days (interquartile range: 310-931 days). Fever (n = 7, 63.6%), bacteraemia (n = 7, 63.6%) and concomitant PD peritonitis (n = 7, 63.6%) were the most common presenting symptoms. Majority of patients underwent radiological aspiration of abscess in addition to antibiotics (n = 7, 63.6%). PD catheter was removed in eight patients (72.7%), with the most common indications being empirical removal due to intra-abdominal abscess (n = 5, 62.5%) followed by septic shock (n = 2, 25%) and refractory PD peritonitis (n = 1, 12.5%). Only three patients (37.5%) remained on PD, as they did not develop PD peritonitis during their course of treatment. The overall mortality remains high with three patients (27.3%) passing away within 6 months of presentation. Liver abscesses in PD patients is associated with poor technique and overall survival. Absence of PD peritonitis appears to be a good prognostic factor, but larger studies are required to guide the optimal management of liver abscesses in PD patients.

Abdominal abscess caused by Raoultella ornithinolytica secondary to postoperative gastric fistula: case report and review of literature.

BACKGROUND: In recent years, Raoultella ornithinolytica (R. ornithinolytica) have attracted clinical attention as a new type of pathogen. A wide range of infections with these germs is reported, and commonly found in urinary tract infections, respiratory infections, and bacteremia. CASE PRESENTATION: We report the case of an elderly woman with liver abscess, choledocholithiasis and cholangitis, who developed gastric fistula and abdominal abscess after underwent choledocholithotomy, and R. ornithinolytica were isolated from the abdominal drainage fluid. The patient was treated with meropenem and levofloxacin and had a good outcome. CONCLUSIONS: To the best of our knowledge, case of isolating R. ornithinolytica from a patient with non-viscerally abdominal abscess was extremely rare. We share a case of a woman with non-viscerally abdominal abscess secondary to postoperative gastric fistula, R. ornithinolytica was isolated from the patient's pus, and the pathogenic bacteria may originate from the gastrointestinal tract. Based on this case, We should be cautious that invasive treatment may greatly increase the probability of infection with this pathogenic bacterium.

First in human measurements of abscess cavity optical properties and methylene blue uptake prior to photodynamic therapy by in vivo diffuse reflectance spectroscopy.

Significance: Efficacious photodynamic therapy (PDT) of abscess cavities requires personalized treatment planning. This relies on knowledge of abscess wall optical properties, which we report for the first time in human subjects. Aim: The objective was to extract optical properties and photosensitizer concentration from spatially resolved diffuse reflectance measurements of abscess cavities prior to methylene blue (MB) PDT, as part of a phase 1 clinical trial. Approach: Diffuse reflectance spectra were collected at the abscess wall of 13 human subjects using a custom fiber-optic probe and optical spectroscopy system, before and after MB administration. A Monte Carlo lookup table was used to extract optical properties. Results: Pre-MB abscess wall absorption coefficients at 665 nm were 0.15±0.1 cm-1 (0.03 to 0.36 cm-1) and 10.74±15.81 cm-1 (0.08 to 49.3 cm-1) post-MB. Reduced scattering coefficients at 665 nm were 8.45±2.37 cm-1 (4.8 to 13.2 cm-1) and 5.6±2.26 cm-1 (1.6 to 9.9 cm-1) for pre-MB and post-MB, respectively. Oxygen saturations were found to be 58.83%±35.78% (5.6% to 100%) pre-MB and 36.29%±25.1% (0.0001% to 76.4%) post-MB. Determined MB concentrations were 71.83±108.22 µM (0 to 311 µM). Conclusions: We observed substantial inter-subject variation in both native wall optical properties and MB uptake. This underscores the importance of making these measurements for patient-specific treatment planning.

Curative resection after percutaneous drainage followed by preoperative panitumumab monotherapy for locally advanced sigmoid colon cancer with intra-abdominal abscess: a case report.

BACKGROUND: The gold standard treatment for locally advanced colon cancer is curative surgery followed by adjuvant chemotherapy, although this approach is associated with serious concerns, such as high recurrence rates and occasionally unnecessary oversurgery. Neoadjuvant chemotherapy may be a promising strategy for overcoming these issues. This study reports a case of a recurrence-free patient who underwent curative resection without significant organ dysfunction after preoperative chemotherapy for locally advanced sigmoid colon cancer. The tumor coexisted with a large intra-abdominal abscess, and the patient was quite frail at the first visit. We performed percutaneous drainage followed by preoperative panitumumab monotherapy, which yielded favorable outcomes. CASE PRESENTATION: A 78-year-old frail woman was emergently transferred to our hospital with fever and abdominal pain. The diagnosis was locally advanced sigmoid colon cancer stage IIIC (T4bN2aM0) with a large intra-abdominal abscess. Immediate curative surgery was inappropriate, considering both tumor progression and the patient's frailty. We performed percutaneous drainage and colostomy construction, which was followed by seven cycles of preoperative panitumumab monotherapy without significant adverse events. After these treatments, inflammation was well controlled, and the tumor shrank remarkably. Furthermore, the patient recovered well from frailty; therefore, curative sigmoidectomy combined with resection of the left ovary and stoma closure was possible without any postoperative complications. The final pathological finding was T3N0M0, stage IIA disease. The patient was recurrence-free and had no significant organ dysfunction 21 months after the curative surgery. CONCLUSIONS: The management of intra-abdominal abscesses and tailor-made preoperative chemotherapy based on the patient's frailty may have been the key factors responsible for the favorable course of this patient. Although further research is needed on the appropriateness of percutaneous drainage for malignancies related to intra-abdominal abscesses and preoperative panitumumab use for locally advanced colon cancer, the study findings can serve as reference for managing similar cases in an aging society.

Effect of intraoperative abdominal lavage versus suction alone on postoperative wound infection in patients with appendicitis: A meta-analysis.

There is much controversy about the application of abdominal irrigation in the prevention of wound infection (WI) and intra-abdominal abscess (IAA) in the postoperative period. Therefore, we performed a meta-analysis of the effect of suctioning and lavage on appendectomy to assess the efficacy of either suctioning or lavage. Data were collected and estimated with RevMan 5.3 software. Based on our research, we found 563 publications in our database, and we eventually chose seven of them to analyse. The main results were IAA after the operation and WI. Inclusion criteria were clinical trials of an appendectomy with suctioning or lavage. In the end, seven trials were chosen to meet the eligibility criteria, and the majority were retrospective. The results of seven studies showed that there was no statistically significant difference between abdominal lavage and suctioning treatment for post-operative WI (OR, 1.82; 95% CI, 0.40, 2.61; p = 0.96); There was no statistically significant difference between the two groups in the risk of postoperative abdominal abscess after operation (OR, 1.16; 95% CI, 0.71, 1.89; p = 0.56). No evidence has been found that the use of abdominal lavage in the treatment of postoperative infectious complications after appendectomy is superior to aspiration.

Lack of Routine Postoperative Labs Not Associated With Complications in Pediatric Perforated Appendicitis.

INTRODUCTION: Postoperative (postop) management of pediatric perforated appendicitis varies significantly, and postop intra-abdominal abscesses (IAA) remain a significant issue. Between 2019 and 2020, our standardized protocol included routine postop labs after an appendectomy for perforated appendicitis. However, given the lack of predictive utility of these routine labs, we discontinued this practice in 2021. We hypothesize that discontinuing routine postop labs will not be associated with an increase in complication rates after an appendectomy for pediatric perforated appendicitis. METHODS: A single-institution, retrospective review of all pediatric appendectomies for perforated appendicitis from January 2019 to December 2021 was conducted at University Hospitals Rainbow Babies and Children's Hospital in Cleveland, Ohio. Data were collected on rate of complications (IAA development, re-admissions, bowel obstructions, superficial surgical site infections, intensive care unit transfers, Clostridium difficile infections, allergic reactions, and transfusions), postop imaging, postop interventions, and length of stay. Statistical analysis was completed using Fisher's exact test and Mann-Whitney U-test. RESULTS: A total of 109 patients (2019-2020 n = 61, 2021 n = 48) were included in the study. All 61 patients from 2019 to 2020 had postop labs compared to only eight patients in 2021. There was no statistically significant difference between the two groups in overall complication rates, but there was a decrease in IAAs reported in 2021 (P = 0.03). There were no statistically significant differences in other complications, postop imaging usage, or postop interventions. The median length of stay was 4.5 d in 2021 compared to 6.0 d in 2019-2020 (P = 0.009). CONCLUSIONS: Discontinuing routine postop labs is not associated with an increase in overall complications rates. Further studies are needed to determine whether routine postop labs can be safely removed in pediatric patients with perforated appendicitis, which would reduce patient discomfort and care costs.

MultiCenter Study of Intra-Abdominal Abscess Formation After Major Operative Hepatic Trauma.

INTRODUCTION: One of the significant complications of operative liver trauma is intra-abdominal abscesses (IAA). The objective of this study was to determine risk factors associated with postoperative IAA in surgical patients with major operative liver trauma. METHODS: A retrospective multi-institutional study was performed at 13 Level 1 and Level 2 trauma centers from 2012 to 2021. Adult patients with major liver trauma (grade 3 and higher) requiring operative management were enrolled. Univariate and multivariate analyses were performed. RESULTS: Three hundred seventy-two patients were included with 21.2% (n = 79/372) developing an IAA. No difference was found for age, gender, injury severity score, liver injury grade, and liver resections in patients between the groups (P > 0.05). Penetrating mechanism of injury (odds ratio (OR) 3.42, 95% confidence interval (CI) 1.54-7.57, P = 0.02), intraoperative massive transfusion protocol (OR 2.43, 95% CI 1.23-4.79, P = 0.01), biloma/bile leak (OR 2.14, 95% CI 1.01-4.53, P = 0.04), hospital length of stay (OR 1.04, 95% CI 1.02-1.06, P < 0.001), and additional intra-abdominal injuries (OR 2.27, 95% CI 1.09-4.72, P = 0.03) were independent risk factors for IAA. Intra-abdominal drains, damage control laparotomy, total units of packed red blood cells, number of days with an open abdomen, total abdominal surgeries, and blood loss during surgery were not found to be associated with a higher risk of IAA. CONCLUSIONS: Patients with penetrating trauma, massive transfusion protocol activation, longer hospital length of stay, and injuries to other intra-abdominal organs were at higher risk for the development of an IAA following operative liver trauma. Results from this study could help to refine existing guidelines for managing complex operative traumatic liver injuries.

Association between bacterial resistance profile and the development of intra-abdominal abscesses in pediatric patients with perforated appendicitis: cohort study.

PURPOSE: The objective of this study was to determine the association between the presence of a microorganism resistant to the antibiotic used in empirical therapy and the development of intra-abdominal abscesses in children with perforated appendicitis. METHODS: A prospective cohort study was conducted in patients under 18 years of age who underwent laparoscopic appendectomy between November 1, 2019, and September 30, 2020, in whom perforated appendicitis was documented intraoperatively. Peritoneal fluid samples were taken for bacteria culture purposes, and clinical and microbiological data were collected from all patients. RESULTS: A total of 232 patients were included in the study. The most isolated microorganisms were Escherichia coli (80.14%) and Pseudomonas aeruginosa (7.45%). In addition, 5.31% of E. coli isolates were classified as ESBL-producing organisms. No association was found between a germ resistant to empiric antimicrobial therapy and the development of a postoperative intra-abdominal abscess. Multivariate analysis showed that being a high-risk patient on admission (OR 2.89 (p = 0.01)) was associated with the development of intra-abdominal abscesses postoperatively. CONCLUSION: E. coli was the most commonly isolated microorganism, with a low rate of ESBL-producing isolates. No association between resistance and risk of postoperative intra-abdominal abscess was found. However, it was identified that being a high-risk patient on admission was associated with this complication. TYPE OF STUDY: Prognosis study. LEVEL OF EVIDENCE: Level I.

Fístula colecisto-cutánea espontánea: a propósito de dos casos / Spontaneous cholecysto-cutaneous fistula: about two cases

Resumen La fístula colecisto-cutáneas (FCC) es una rara com plicación de la patología biliar no tratada, habiendo menos de 100 casos documentados en la literatura. La mayoría son secundarias a infección bacteriana, aunque también fue descripta en el adenocarcinoma de vesícula y posterior a traumatismo. Su presentación clínica es variable, pudiendo presentar afección sistémica, y su sitio más frecuente de drenaje externo es en hipocon drio derecho. Debido a la baja incidencia de esta afección, y a la variedad de formas de presentación, su manejo no tiene hasta el momento bases estandarizadas. Presentamos dos casos de pacientes que consulta ron por guardia de urgencias en el Hospital Nacional de Clínicas por presentar fistula colecisto-cutánea. El tratamiento de ambos fue quirúrgico.

Abstract Cholecysto-cutaneous fistula (CCF) is a rare com plication of untreated biliary pathology, with fewer than 100 cases documented in the literature. Most are secondary to bacterial infection, although it has also been described in gallbladder adenocarcinoma and post trauma. Its clinical presentation is variable, being able to present systemic affection, and its most frequent exter nal drainage site is in the right hypochondrium. Due to the low incidence of this pathology, and the variety of forms of presentation, its management does not have, to date, standardized bases. We present two cases of patients who consulted in the emergency room at the Hospital Nacional de Clínicas for presenting cholecysto-cutaneous fistula. The treat ment of both was surgical.

[Spontaneous cholecysto-cutaneous fistula: about two cases]. / Fístula colecisto-cutánea espontánea: a propósito de dos casos.

Cholecysto-cutaneous fistula (CCF) is a rare complication of untreated biliary pathology, with fewer than 100 cases documented in the literature. Most are secondary to bacterial infection, although it has also been described in gallbladder adenocarcinoma and post trauma. Its clinical presentation is variable, being able to present systemic affection, and its most frequent external drainage site is in the right hypochondrium. Due to the low incidence of this pathology, and the variety of forms of presentation, its management does not have, to date, standardized bases. We present two cases of patients who consulted in the emergency room at the Hospital Nacional de Clínicas for presenting cholecysto-cutaneous fistula. The treatment of both was surgical.

La fístula colecisto-cutáneas (FCC) es una rara complicación de la patología biliar no tratada, habiendo menos de 100 casos documentados en la literatura. La mayoría son secundarias a infección bacteriana, aunque también fue descripta en el adenocarcinoma de vesícula y posterior a traumatismo. Su presentación clínica es variable, pudiendo presentar afección sistémica, y su sitio más frecuente de drenaje externo es en hipocondrio derecho. Debido a la baja incidencia de esta afección, y a la variedad de formas de presentación, su manejo no tiene hasta el momento bases estandarizadas. Presentamos dos casos de pacientes que consultaron por guardia de urgencias en el Hospital Nacional de Clínicas por presentar fistula colecisto-cutánea. El tratamiento de ambos fue quirúrgico.

Hepatic Abscess in Inflammatory Bowel Disease: A Systematic Scoping Review of an Overlooked Entity.

Background: Liver abscess is one of the hepatobiliary manifestations of inflammatory bowel disease (IBD) that has been scarcely described in the literature. Objectives: To conduct a scoping review to provide a detailed description of the occurrence of hepatic abscess in patients with IBD and summarize the observed clinical features. Methodology: Searches were carried out using relevant keywords in Medline (via PubMed) and Web of Science from inception until June 13, 2022. Only articles that reported the occurrence of hepatic abscess in patients with IBD were included. Results: Forty-eight publications (40 case reports and 8 case series) were included, representing 73 patients with IBD who were radiologically or intraoperatively diagnosed with hepatic abscess. Patients with Crohn's disease were more predisposed to developing hepatic abscess than patients with ulcerative colitis (79.5% vs. 20.5%, respectively). Furthermore, pyogenic liver abscess was found to be more prevalent (57.9%) compared with aseptic (38.7%) and amebic (3.2%) abscesses. No clear relation was found between death or prolonged hospital stay in terms of the clinical presentation or management plan, as mortality was reported in different age groups with different managements. Conclusion: To date, there is no consensus regarding the appropriate management of hepatic abscess as an extraintestinal manifestation of IBD. However, the condition shares several features with liver abscess diagnosed among the general population.

Intra-Abdominal Abscess and Bacteremia Due to Stenotrophomonas maltophilia After Total Gastrectomy: A Case Report and Literature Review.

Stenotrophomonas maltophilia (S. maltophilia) is increasingly recognized as a pathogen responsible for nosocomial infections, particularly in immunocompromised patients. The most common types of S. maltophilia infections are pneumonia and catheter-related bloodstream infection, and clinical cases of intra-abdominal abscesses due to S. maltophilia are rare. We present a rare case of intra-abdominal abscess and bacteremia as a surgical site infection (SSI) caused by S. maltophilia in a patient following total gastrectomy. We also reviewed previous literature to elucidate the clinical characteristics of intra-abdominal abscess due to S. maltophilia. The patient, a 75-year-old man with diabetes and polymyositis (treated with prednisolone), developed a fever 17 days after undergoing a total gastrectomy for gastric cancer. Abdominal computed tomography revealed a hypodense solid mass at the esophagojejunostomy site, which appeared to be an intra-abdominal abscess. The culture of both blood and drained abscess pus confirmed only S. maltophilia. Treatment with intravenous trimethoprim-sulfamethoxazole and abscess drainage led to complete resolution. The patient recovered and was discharged and did not experience a recurrence. We reviewed the English literature and found only two additional case reports of intra-abdominal abscesses caused by S. maltophilia. As in our case, the intra-abdominal abscess occurred after abdominal surgery and the source was suspected to be deep SSI. This case highlights the importance of considering S. maltophilia as a potential pathogen in patients with atypical post-surgical abdominal infections. Physicians should be aware that S. maltophilia has the potential to cause intra-abdominal abscesses secondary to SSI, in addition to Enterobacteriaceae, a major causative pathogen of SSI. Further studies are required to elucidate the etiology, epidemiology, and risk factors for SSI caused by S. maltophilia.

Preliminary measurements of optical properties in human abscess cavities prior to methylene blue photodynamic therapy.

As part of our ongoing Phase 1 clinical trial to establish the safety and feasibility of methylene blue photodynamic therapy (MB-PDT) for human deep tissue abscess cavities, we have shown that determination of abscess wall optical properties is vital for the design of personalized treatment plans aiming to optimize light dose. To that end, we have developed and validated an optical spectroscopy system for the assessment of optical properties at the cavity wall, including a compact fiber-optic probe that can be inserted through the catheter used for the standard of care abscess drainage. Here we report preliminary findings from the first three human subjects to receive these optical spectroscopy measurements. We observed wide variability in concentrations of oxy- and deoxy-hemoglobin prior to MB administration, ranging from 7.3-213 µM and 0.1-47.2 µM, respectively. Reduced scattering coefficients also showed inter-patient variability, but recovered values were more similar between subjects (5.5-10.9 cm-1 at 665 nm). Further, methylene blue uptake was found to vary between subjects, and was associated with a reduction in oxygen saturation. These measured optical properties, along with pre-procedure computed tomography (CT) images, will be used with our previously developed Monte Carlo simulation framework to generate personalized treatment plans for individual patients, which could significantly improve the efficacy of MB-PDT while ensuring safety.

Antibiotic treatment of post-appendectomy abscesses in children, regardless of size: a twelve years' experience.

Intra-abdominal abscesses are a common issue after appendectomy. Antibiotics have shown efficacy in treating smaller abscesses, while larger ones have traditionally been treated with drainage. This study assesses the efficacy of antibiotics for post-appendectomy intra-abdominal abscess (PAA) in children regardless of size. Case-control study of children with PAA admitted at our hospital from 2010 to 2022. The efficacy of antibiotics was compared between abscesses less and more than 6 cm in diameter. The Institutional Review Board has approved this study. A total of 1766 appendectomies were performed from 2010 to 2022 with an incidence of PAA of 5% (n = 89): age 9.3 IQR 5.8, 63% male (n = 56). Sixty-seven patients presented with a ≤ 6 cm abscess (controls) and 22 children had a > 6 cm PAA (cases). Length of intravenous antibiotics were higher in cases (15 IQR 7 days) than controls (12 IQR 4 days), p = 0.003. The efficacy of antibiotics in controls was 97% whereas 86.4% in cases (p = 0.094), reoperation was needed in 2/67 controls and 3/22 cases, with no differences in complications or readmission. The length of stay was longer in cases (15 IQR 6 days) than controls (13 IQR 5 days), p = 0.042. Antibiotics seem a safe treatment for PAA in children regardless of the size. However, this approach is associated with a longer period of intravenous antibiotics and hospital stay, although not with a higher rate of therapeutic failure, complications or reoperations.