COVID-19 Rapid Antigen Test: Role in Screening Prior to Gastrointestinal Endoscopy

Background/Aims The severe acute respiratory syndrome coronavirus 2 pandemic has affected the gastrointestinal (GI) endoscopy units globally owing to the risk of transmission. We present our data on the use of rapid antigen test (RAT) as a screening tool prior to endoscopy to prevent the transmission of coronavirus disease (COVID-19). Methods This study was a retrospective analysis of patients who underwent any GI endoscopic procedure from July 2020 to October 2020 at a tertiary referral center in New Delhi, India. All patients underwent screening for COVID-19 using RAT, and endoscopy was performed only when the RAT was negative. The data are presented as numbers and percentages. Results A total of 3,002 endoscopic procedures were performed during the study period. Only one endoscopic procedure was performed in a COVID-19 positive patient. A total of 53 healthcare workers were involved in conducting these procedures. Only 2 healthcare workers (3.8%) were diagnosed COVID-19 positive, presumably due to community-acquired infection, during this period. Conclusions The COVID-19 RAT is easily usable as a simple screening tool prior to GI endoscopy during the COVID-19 pandemic

Anomaly detection in network traffic based on connection-specific profiling

Recent studies have shown that a number of network attacks that were used to target mainframes and personal computers are now being directed towards mobile devices. The ever-evolving nature of mobile attacks, coupled with the growing number of new vulnerabilities in mobile platforms poses a challenge to the security of mobile networks and devices. The intrusion detection systems based on attack signature fail to detect novel attacks or anomalies. In such scenarios, an anomaly-based detection approach is a necessary security measure against previously unknown attacks. Machine learning methods have been widely used in anomaly detection in various domains including network intrusion detection, credit card fraud detection, etc. In this work, we utilise machine learning algorithms for anomaly detection in mobile network traffic. We choose an unsupervised algorithm that does not require a labelled dataset. We define a connection as the flow instance using a particular combination of protocol type and network port. We observe that the network data comprises a variety of connections, each of which follows a different profile. We illustrate an anomaly detection approach, which is based on connection-specific profiling of network data. We develop the profile of each connection using the isolation forest model. We provide the evaluation of our approach using two use-cases of mobile traffic data with identified anomalies. The result illustrates that our approach works best when the distribution of anomalies in the incoming network traffic is similar to the distribution of anomalies in the learned profile. Our model achieves more than 95% F-1 measure in both use-cases. Even though our model is sensitive to the model parameters, it performs very well with the same distribution of anomalies in the new network traffic

Indian tubercular belly: A prospective study of 140 patients of abdominal tuberculosis and their outcomes

Background: Abdominal tuberculosis is an important yet ignored entity in the spectrum of tuberculosis which has been dominated by pulmonary tuberculosis. Diagnosis and treatment are often delayed due to nonspecific symptoms. In this study, we aimed to highlight the clinical features, diagnostic methods and outcomes of abdominal tuberculosis. Methods: A prospective study was conducted in tertiary referral centre where all patients referred to drug distribution centres (DOTS centre) for abdominal tuberculosis were identified. Their demographic clinical and radiological profile was evaluated. These patients were followed-up for their treatment course for complications and outcomes. Results: A total of 140 patients who were labelled abdominal tuberculosis over a period of 2 years were reviewed at tuberculosis drug distribution centre (DOTS). Mean age of study population was 35.42 ± 12.53 years and majority of the population were males, 58.6% (82). The most common presenting symptom was abdominal pain which was seen in 82.8% (n = 116) of the patients, followed by feverin 65.6% (n = 92); 22.8% (n = 32) were seropositive for HIV and 44.2% (n = 62) had luminal tuberculosis of which ileocecal was the most common site. Peritoneum was second most common site which was involved in 26.4% (n = 37) of the patients followed by mixed tuberculosis involving more than one type. Confirmed diagnosis was achieved in 74 patients (52.8%), while the remaining 66 patients (47.14%) were diagnosed clinically. During follow-up, 12 patients were lost to follow-up; 113 (80.7%) had complete response, while 3 (2.14%) patients died during treatment. Conclusion: Abdominal tuberculosis usually presents with nonspecific complaints which require high index of suspicion. Most patients require only medical therapy which has good results

Predictive factors for malignancy in undiagnosed isolated small bowel strictures

Background/Aims: Patients with small bowel strictures have varied etiologies, including malignancy. Little data are available on the demographic profiles and etiologies of small bowel strictures in patients who undergo surgery because of intestinal obstruction but do not have a definitive pre-operative diagnosis.Methods: Retrospective data were analyzed for all patients operated between January 2000 and October 2014 for small bowel strictures without mass lesions and a definite diagnosis after imaging and endoscopic examinations. Demographic parameters, imaging, endoscopic, and histological data were extracted from the medical records. Univariate and multivariate analyses were conducted to identify factors that could differentiate between intestinal tuberculosis (ITB) and Crohn's disease (CD) and between malignant and benign strictures.Results: Of the 7,425 reviewed medical records, 89 met the inclusion criteria. The most common site of strictures was the proximal small intestine (41.5%). The most common histological diagnoses in patients with small bowel strictures were ITB (26.9%), CD (23.5%), non-specific strictures (20.2%), malignancy (15.5%), ischemia (10.1%), and other complications (3.4%). Patients with malignant strictures were older than patients with benign etiologies (47.6±15.9 years vs. 37.4±16.4 years, P=0.03) and age >50 years had a specificity for malignant etiology of 80%. Only 7.1% of the patients with malignant strictures had more than 1 stricture and 64% had proximally located strictures. Diarrhea was the only factor that predicted the diagnosis of CD 6.5 (95% confidence interval, 1.10–38.25; P=0.038) compared with the diagnosis of ITB.Conclusions: Malignancy was the cause of small bowel strictures in approximately 16% patients, especially among older patients with a single stricture in the proximal location. Empirical therapy should be avoided and the threshold for surgical resection is low in these patients

Predictors of infection in viral-hepatitis related acute liver failure

<p><b>Objective:</b> Infections are common and associated with complications and mortality in acute liver failure (ALF). The temporal relationship between ammonia and infection in ALF patients is unclear. We aimed to evaluate the predictors of infection and its relationship with arterial ammonia levels.</p> <p><b>Materials and methods:</b> Consecutive ALF patients hospitalized between January 2004 and December 2015, without signs of infection at/within 48 h of admission, were included. Occurrence of infection after 48 h was documented and ammonia levels were estimated for five consecutive days. Multivariate logistic regression analysis was used to assess factors associated with development of infection. Generalized estimating equations (GEE) were used to evaluate five-day time trend of ammonia in patients with and without infection.</p> <p><b>Results:</b> Of 540 consecutive patients, 120 were infected at admission/within 48 h and were excluded. Of the rest 420 patients, 144 (34.3%) developed infection after 48 h and 276 (65.7%) remained non-infected. Infected patients had higher mortality than non-infected patients (61.8% vs 40.0%, <i>p</i> < .001). On multivariate analysis, presence of cerebral edema(HR 2.049; 95%CI, 1.30–3.23), ammonia level on day 3 of admission (HR 1.006; 95%CI, 1.003–1.008), and model for end stage liver disease (MELD) score (HR 1.051; 95%CI, 1.026–1.078) were associated with development of infection. GEE showed group difference in serial ammonia values between infected and non-infected patients indicating lack of ammonia decline in infected patients.</p> <p><b>Conclusions:</b> Cerebral edema, elevated ammonia on day 3, and higher MELD score predict the development of infection in ALF. Ammonia persists at high levels in infected patients, and elevated ammonia on day 3 is associated with complications and death.</p

Comparison of Dynamic Changes Among Various Prognostic Scores in Viral Hepatitis-Related Acute Liver Failure

Introduction and aim. Multiple prognostic scores are available for acute liver failure (ALF). Our objective was to compare the dynamicity of model for end stage liver disease (MELD), MELD-sodium, acute liver failure early dynamic model (ALFED), chronic liver failure (CLIF)-consortium ACLF score and King’s College Hospital Criteria (KCH) for predicting outcome in ALF.Materials and methods. All consecutive patients with ALF at a tertiary care centre in India were included. MELD, MELD-Na, ALFED, CLIF-C ACLF scores and KCH criteria were calculated at admission and day 3 of admission. Area under receiver operator characteristic curves (AUROC) were compared with DeLong method. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) and diagnostic accuracy (DA) were reported.Results. Of the 115 patients included in the study, 73 (63.5%) died. The discrimination of mortality with baseline values of prognostic scores (MELD, MELD-Na, ALFED, CLIF-C ACLF and KCH) was modest (AUROC: 0.65-0.77). The AUROC increased on day 3 for all scores, except KCH criteria. On day 3 of admission, ALFED score had the highest AUROC 0.95, followed by CLIF-C ACLF 0.88, MELD 0.81, MELD-Na 0.77 and KCH 0.52. The AUROC for ALFED was significantly higher than MELD, MELD-Na and KCH (P 4 on day 3 had the best sensitivity (87.1%), specificity (89.5%), PPV (93.8%), NPV (79.1%), LR positive (8.3) and DA (87.9%) for predicting mortality.Conclusions. Dynamic assessment of prognostic scores better predicts outcome. ALFED model performs better than MELD, MELD, MELD-Na, CLIF-C ACLF scores and KCH criteria for predicting outcome in viral hepatitis-related ALF