Mathematical analysis of a generalized epidemic model with nonlinear incidence function

Background

Though different forms of control measures have been deployed to curtail disease transmission, which are mostly through vaccination, treatment, isolation, etc., using mathematical models. Therefore, there is a need to consider the strict compliance or attendance of human individuals to medical awareness program through media outlets like radio, television, etc. In this work, a generalized mathematical model of two groups of infectious individuals who are compliant and non-compliant to medical awareness program is studied.

Results

A generalized Susceptible-Exposed-Infected-Recovered (SEIR) model with two groups of infectious individuals who attend or are compliant and those who do not attend or are non-compliant to medical awareness program is established. The analytical results of the model shows that the model is positive, well-posed, and epidemiologically reasonable. The two equilibria and the basic reproduction number Rr of the model is computed and analyzed and it is shown that the disease-free equilibrium is locally and globally asymptotically stable when Rr < 1 and the endemic equilibrium is globally stable when Rr > 1. Simulations are carried out by varying some parameters when Rr is less and above unity. The simulations suggest that control interventions are to be implemented and medical awareness program scaled up to mitigate the spread of diseases. Furthermore, two numerical methods of Runge-Kutta and Differential Transform Method (DTM) are employed to obtain the approximate solutions of the model system equations, and it is observed that the results of the two methods agreeably compare with each other in terms of efficiency and convergence.

Conclusion

This work should be taken into consideration by health policy makers and bio-mathematicians, because existing literature only take into consideration, how diseases spread and its management without considering the impact of strict compliance to consistent awareness program to mitigate the spread of diseases, which has been considered in this work. The limitation of this work is the unavailability of data on individuals in disease endemic regions who always and who do not comply with medical awareness programs.

Extrapulmonary Sarcoidosis Manifested as Cirrhosis with Portal Hypertension

Hepatic involvement has been reported in 20-30% of patients with systemic sarcoidosis. However, isolated liver involvement is rare. We report a case of cirrhosis with portal hypertension, diagnosed as hepatic sarcoidosis based on high angiotensin-converting enzyme level and presence of multiple non-caseating granulomas in liver histopathology. She improved clinically after treatment with steroid and ursodeoxycholic acid.

Prevalence and determinants of hepatopulmonary syndrome in decompensated chronic liver disease

BACKGROUND

One of the severe complications of liver disease is hepatopulmonary syndrome (HPS). There is paucity in literature regarding the various factors associated with the development of HPS. This study was conducted to analyze the prevalence and determinants of HPS among patients with decompensated chronic liver disease (CLD).

METHODS

This study was a cross-sectional-observational study conducted in a tertiary care center. Decompensated CLD patients admitted for pre-liver transplant workup were included in the study. Demographic data, clinical findings, and biochemical and hematologic parameters were collected. Pulse oximetry, arterial blood gas analysis, bubble contrast echocardiogram, diffusion capacity of the lungs for carbon monoxide (DLCO), and spirometry were done to get the needed parameters. All data were entered into a Microsoft Excel sheet and analyzed using the statistical software SPSS for Windows, version 22.0.

RESULTS

Among 64 subjects, 58 were men (90.6%). Mean age was 54.5 years. HPS was present in 26 (40.6%) patients. Platypnea and orthodeoxia were present more often in HPS patients. DLCO was significantly impaired among patients with HPS. Portopulmonary hypertension was seen in 8 (12.5%) subjects with no difference between HPS and non-HPS patients. Subjects with HPS had more severe liver disease. A model for end-stage liver disease (MELD)-Na score > 19 was associated with HPS (sensitivity 73.08%, specificity 65.79%, PPV 59.4%, and NPV 78.1%). Multivariate analysis (binary logistic regression) revealed that a higher MELD-Na score, hepatic encephalopathy, and impaired DLCO were independently associated with HPS.

CONCLUSIONS

HPS is associated with more severe liver disease (as per Child-Turcotte-Pugh [CTP] stage and MELD-Na score). There was no relation between HPS and causes of CLD. Higher MELD-Na score, hepatic encephalopathy, impaired DLCO, clubbing, and spider naevi were independently associated with HPS.

Small Bowel Angiodysplasia Managed with Novel Motorized Spiral Enteroscope: A Case Report

We report a case of 72-year-old woman, who presented with complaints of melena associated with shortness of breath on exertion for more than 2 weeks. On evaluation, she was diagnosed to have severe anemia with evidence of occult blood in stool. After initial management, further workup was done to find out the source of bleeding. Upper and lower gastrointestinal endoscopy were normal. Computerized tomography enteroclysis showed no significant abnormality. Later small bowel enteroscopy was performed with the help of Novel Motorized Spiral Enteroscope in antegrade approach and scope passed through oral cavity up to cecum. Multiple angiodysplasia lesions seen in ileum. All the lesions were managed with argon plasma coagulation (APC). Postprocedure, patient improved well and hemoglobin also remained stable. Small bowel diseases always remain a diagnostic and therapeutic challenge, despite the introduction of various modalities for deep enteroscopy. Spiral enteroscopy is a recent advance which uses an overtube with a raised spiral at the distal end to pleat the small intestine. It consumes less time and suits for both diagnostic and therapeutic needs of small bowel diseases.

Effect of Donor Hepatic Steatosis on Ischemia Reperfusion Injury in Liver Transplant Recipient

INTRODUCTION

Ischemia reperfusion injury (IRI) is an important complication of liver transplant (LT). The donor risk index, which does not incorporate steatosis, includes several variables known to impact on allograft survival. The purpose of this study was to report on donor liver allograft steatosis and its association with severity of IRI.

AIM

The aim of this study was to determine the effect of type and grade of donor liver steatosis on the occurrence and severity of IRI in LT recipients.

METHODS

This was an observational study conducted at a single center over a period of 37 months from July 2013 to August 2016. Liver biopsy was performed twice, initially at the time of procurement before graft perfusion for steatosis assessment. Steatosis was classified as microsteatosis (MiS) or macrosteatosis (MaS) with mild, moderate, or severe grade. Second biopsy for IRI assessment was taken before skin closure in death donor LT (DDLT) and at the time of transaminitis in postoperative period (<72 hrs) in living donor LT (LDLT). IRI was graded as per neutrophil infiltrate, apoptosis, and hepatocyte cell dropout. Prevalence of IRI and association steatosis was studied along with other factors.

RESULTS

Among 53 subjects, 35 were DDLTs and 18 were LDLTs. All live donor grafts were restricted to <15% MaS and the deceased liver grafts had different type and degree of steatosis. In DDLTs, the association between occurrence of IRI and MaS was not statistically significant (P = 0.201). In DDLTs, the mild steatosis was not significantly associated with IRI. Death donor and ischemic time were significantly associated with IRI. Child's stage and MELD scores, gender, and age were not associated with risk of IRI. Severity of IRI is significantly associated with 3-month mortality (P = 0.001).

CONCLUSION

In patients with mild steatosis, IRI does not correlate with steatosis. However, more patients with moderate and severe steatosis are needed to define the relationship of the two in this group of patients.

Hepatitis B Reactivation in Liver Transplant Recipients With Hepatitis B Virus Core Antibody Positive Grafts: a Retrospective Study

BACKGROUND

Liver grafts from hepatitis B core antibody (anti-HBc) positive donors increase the risk of hepatitis B virus (HBV) reactivation in recipients due to posttransplant immunosuppressive therapy.

AIM AND OBJECTIVE

to study the HBV reactivation in liver transplant recipients with anti-HBc-positive donors.

METHODS

This was a retrospective study. Liver transplant recipients who received grafts from anti-HBc-positive donors between January 2013 and December 2017 were included in analysis. Hospital records of all subjects for a 2-year posttransplantation period were studied to observe reactivation of hepatitis B. As per our institute protocol, prophylaxis for HBV was given to subjects with either positive hepatitis B surface antigens or hepatitis B surface antibody (anti-HBs) titre <100 mIU/ml, after transplantation with anti-HBc-positive donor grafts. Recipients with anti-HBs titre >100 mIU/mL were exempted from prophylaxis and kept on regular monitoring for HBV markers.

RESULTS

Of 85 liver transplant recipients, 20 subjects who received anti-HBc-positive grafts were included in analysis. The mean age of the study population was 46 years (range 2-68 years). The most common aetiology of cirrhosis in our study population was cryptogenic followed by ethanol. Among the study population, 16 (80%) transplant recipients had anti-HBs titre less than 100 mu/ml and 4 (20%) subjects had anti-HBs > 100 miu/ml. HBV reactivation occurred in 6 (30%) subjects. Reactivation was seen even in those who received HBV prophylaxis, while none of the subjects with anti-HBs titre >100 miu/ml developed HBV reactivation despite absence of prophylaxis.

CONCLUSION

HBV reactivation can occur even in the presence of target anti-HBs titre (i.e. >10 miu/ml) and HBV prophylaxis during postliver transplantation. However, HBV reactivation is not seen in recipients with anti-HBs titre of >100 miu/ml.

Perforated appendicitis presenting with ileo-caecal ulceration and mechanical intestinal obstruction

A 30-year-old lady presented with a 6-month history of recurrent partial intestinal obstruction associated with intermittent fever, anorexia and weight loss. Barium meal follow-through and colonoscopic evaluation suggested ulceration of the ileum and caecum with small bowel obstruction. Histology of the lesions showed marked acute and chronic inflammation consistent with ulceration and granulation tissue. Abdominal CT revealed circumferential thickening of the ascending colon, caecum and terminal ileum with extraluminal air pockets. Surgical exploration revealed a large conglomerate mass involving the terminal ileum, caecum and ascending colon. Histopathology of the resected specimen revealed perforated appendix with nonspecific ulceration of the surrounding bowel. She recovered completely after surgery and did not suffer from gastrointestinal symptoms in the 14 months of follow-up.