Essential Multiorgan Pathophysiology of COVID-19

Typical manifestations of coronavirus disease-2019 (COVID-19) include mild-to-moderate "flu-like” symptoms, although more severe manifestations have been reported. The pathophysiology of COVID-19 is complex, and its clinical spectrum might not be limited to local pneumonia, but rather may represent a multisystem illness with potential for severe acute respiratory distress syndrome (ARDS) and multiorgan impairment. In this context, the aim of the present handbook is to provide an overview of possible multisystemic manifestations and therapeutic strategies, in order to guide the clinician to deal with COVID-19 critical illness and to prevent potential systemic consequences. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Gastrointestinal Manifestations of COVID-19

Gastrointestinal manifestations of SARS-CoV-2 are reported in 10-50% of patients, being diarrhea, nausea, vomiting, and abdominal pain the most frequent ones. Gastrointestinal manifestations could be present without respiratory symptoms, leading to delayed diagnosis. In addition, COVID-19 is commonly associated with hepatic dysfunction manifesting with elevation of hepatic enzymes and total bilirubin levels, observed in up to 50% of the COVID-19 patients. Other less common gastrointestinal manifestations include acute cholecystitis, pancreatitis, and oral lesions. Clinicians should be also aware that the gastrointestinal tract is also frequently involved in COVID-19-related complications. As a matter of fact, several studies reported ileus, intestinal ischemia, perforation, and gastrointestinal bleeding during the course of COVID-19 disease. Lastly, the inappropriate and excessive use of antibiotics has led to an increase in Clostridioides difficile infection with consequent prolonged hospitalization and higher mortality. Although, the exact pathogenesis of gastrointestinal involvement is not completed understood, four main mechanisms have been advocated: the direct angiotensin converting enzyme 2 mediated viral cytotoxicity, cytokine-induced inflammation, gut dysbiosis, and vascular abnormalities. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.

Gastrointestinal Endoscopy in Patients with Coronavirus Disease 2019: Indications, Findings, and Safety.

The coronavirus disease 2019 (COVID-19) pandemic has changed the practice of gastroenterology and how we perform endoscopy. As with any new or emerging pathogen, early in the pandemic, there was limited evidence and understanding of disease transmission, limited testing capability, and resource constraints, especially availability of personal protective equipment (PPE). As the COVID-19 pandemic progressed, enhanced protocols with particular emphasis on assessing the risk status of patients and proper use of PPE have been incorporated into routine patient care. The COVID-19 pandemic has taught us important lessons for the future of gastroenterology and endoscopy.

Assessment of Gastrointestinal Symptoms and Dyspnea in Patients Hospitalized due to COVID-19: Contribution to Clinical Course and Mortality.

Gastrointestinal manifestations may accompany the respiratory symptoms of COVID-19. Abdominal pain (AP) without nausea and vomiting is one of the most common. To date, its role and prognostic value in patients with COVID-19 is still debated. Therefore, we performed a retrospective analysis of 2184 individuals admitted to hospital due to COVID-19. We divided the patients into four groups according to presented symptoms: dyspnea, n = 871 (39.9%); AP, n = 97 (4.4%); AP with dyspnea together, n = 50 (2.3%); and patients without dyspnea and AP, n = 1166 (53.4%). The patients with AP showed tendency to be younger than these with dyspnea, but without AP (63.0 [38.0-70.0] vs. 65.0 [52.0-74.0] years, p = 0.061), and they were more often females as compared to patients with dyspnea (57.7% vs. 44.6%, p = 0.013, for females). Patients with AP as a separate sign of COVID-19 significantly less often developed pneumonia as compared to individuals with dyspnea or with dyspnea and AP together (p < 0.0001). Patients with AP or AP with dyspnea were significantly less frequently intubated or transferred to the intensive care unit (p = 0.003 and p = 0.031, respectively). Individuals with AP alone or with dyspnea had significantly lower rate of mortality as compared to patients with dyspnea (p = 0.003). AP as a separate symptom and also as a coexisting sign with dyspnea does not predispose the patients with COVID-19 to the worse clinical course and higher mortality.

COVID in children and the digestive system: сlinical and pathogenetic correlation

Coronaviruses, seven of which are known to infect humans, can range from asymptomatic infection to malnutrition and death. Russia has over 12.4 million confirmed cases of COVID-19 at the time of writing, with nearly 334, 000 deaths. While all other coronaviruses affect cardiovascular disease, the SARS-CoV-2 virus also has a tropism for the cardiovascular system, gastrointestinal tract, liver, pancreas, kidneys, and nervous system. In this review, we describe the important gastrointestinal manifestations of COVID-19 in children and discuss possible underlying pathophysiological mechanisms for their occurrence. © 2022 Global Media Technologies. All rights reserved.

Early detection of COVID-19 cholangiopathy using cholangioscopy-a case report of two critically ill patients.

Background: The coronavirus disease 2019 (COVID-19) crisis caused by the severe respiratory distress syndrome coronavirus 2 (SARS-CoV-2) rapidly led to a pandemic. While the majority of SARS-CoV-2-infected patients present with fever and respiratory symptoms, gastrointestinal symptoms may also occur. In addition, serious hepatic manifestations like cholangiopathy and liver failure have been described. Patients and methods: We identified two critically ill patients suffering from SARS-CoV­2 infection in our intensive care unit (ICU). In both patients, laboratory testing revealed elevated liver chemistries weeks after initial diagnosis with COVID-19. Results: During repeated endoscopic retrograde cholangiopancreatography (ERCP) with cholangioscopy, a severely destructed biliary mucosa with ischemia and epithelial roughness was seen in both patients. Due to the prolonged course of COVID-19 and chronic liver damage with ongoing sepsis, both patients succumbed to the disease. Conclusion: In our opinion, a COVID-19 infection can lead to development of cholangiopathy in critically ill patients. Cholangioscopy performed early can confirm the diagnosis of COVID-19-associated cholangioscopy.

Risk of pediatric inflammatory multi-system syndrome (PIMS or MIS-C) in pediatric patients with COVID-19 presenting with gastrointestinal symptoms.

Introduction and objectives: Pediatric inflammatory multisystem syndrome (PIMS) is a life-threatening complication in pediatric patients with SARS-CoV-2 infection. An increase in the association of gastrointestinal symptoms and the presence of PIMS has been observed. The objective of this study was to analyze whether pediatric patients with COVID-19, who debut with gastrointestinal symptoms, have a higher risk of developing PIMS. Material and methods: An observational, analytical and retrolective study was carried out with a review of the records of patients diagnosed with COVID-19. Demographic, clinical and laboratory variables were recorded. Results: A total of 248 patients who met the selection criteria were included. Of Those 40% were female, with a mean age of 7 +/- 5.8 years. Gastrointestinal symptoms were the initial presentation in 103 patients, with vomiting being the most frequent symptom, followed by abdominal pain and diarrhea. In total 52 patients developed PIMS, 30 of whom presented with gastrointestinal symptoms. A RR of 1.57 (97% CI of 1.17-2.11) was found for the presentation of PIMS in patients positive for SARS-CoV-2 who present with gastrointestinal symptoms. Conclusions: There is an increased risk of developing pediatric multisystem inflammatory syndrome when there are gastrointestinal symptoms in pediatric patients with COVID-19.

Gastrointestinal manifestations in patients with coronavirus disease-2019 (COVID-19): Impact on clinical outcomes.

Background: In this study, we summarized the data on gastrointestinal (GI) involvement and the potential association with clinical outcomes among the patients admitted to Khorshid Hospital. Materials and Methods: We investigated 1113 inpatients (≥18 years old) diagnosed with coronavirus disease-2019 (COVID-19) from March to June 2020 in Khorshid Hospital. We collected demographic details, clinical information, vital signs, laboratory data, treatment type, and clinical outcomes from patients' medical records. The data of patients with GI symptoms were compared with those without GI symptoms. Results: A total of 1113 patients were recruited (male = 648). GI symptoms were observed in 612 (56.8%) patients (male = 329), the most common of which were nausea 387 (34.7%), followed by diarrhea 286 (25.7%), vomiting 260 (23.4%), and abdominal pain 168 (15.0%). The most prominent non-GI symptoms were cough 796 (71.5%), fever 792 (71.2%), shortness of breath 653 (58.7%), and body pain 591 (53.1%). The number of patients who were discharged, died, and were admitted to intensive care unit was significantly different in groups on the basis of GI and non-GI symptoms (P = 0.002, 0.009, 0.003). Conclusion: While COVID-19 was predominantly diagnosed in males, GI symptoms were more commonly reported by females. The results indicated that GI symptoms in COVID-19 patients are common, and the symptoms are not correlated with the severity of the disease. Moreover, the presence of GI symptoms was positively related to milder disease. Among COVID-19 positive patients, the clinical outcomes of the GI group were promising, compared to those of non-GI group.

Hepatic and gastrointestinal manifestations in patients with COVID-19 and relationship with disease severity: a single-centre experience.

Background and aims: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged in late 2019. While the infection is commonly perceived as a respiratory disease, gastrointestinal complaints have been described in a significant number of patients since the beginning of the pandemic. This study investigated the prevalence of hepatic and gastrointestinal manifestations among patients with COVID-19 in terms of symptoms and biochemical findings, and the relationship with disease severity and outcomes. Methods: Patients admitted to a tertiary medical centre in Dubai, United Arab Emirates, between March and June 2020, with COVID-19 were analysed retrospectively. Patients were stratified into two main groups based on the presence or absence of hepatic and gastrointestinal manifestations. Results: Among 521 eligible patients, 119 patients (22.8%) had gastrointestinal manifestations, and the majority of patients were middle-aged males (90%). The most common symptom was diarrhoea, followed by vomiting and abdominal pain. The most commonly observed biochemical abnormality was raised alanine transferase. No differences in the severity of COVID-19 pneumonia or overall mortality rate were found between the two groups. However, patients with COVID-19 pneumonia, even those without hepatic or gastrointestinal manifestations, had longer hospital stays (P<0.05) and other infection-related complications. Conclusion: This paper adds to the literature on the extrapulmonary manifestations of SARS-CoV- 2 with a focus on the hepatic and gastrointestinal systems. The presence of hepatic and gastrointestinal manifestations in patients with COVID-19 at hospital admission was not associated with increased severity of COVID-19 pneumonia or overall mortality.

Gastrointestinal Manifestations of COVID-19 Infection: Clinicopathologic Findings in Intestinal Resections Performed at Single Institution.

It is now known that COVID-19 not only involves the lungs, but other organs as well including the gastrointestinal tract. Although clinic-pathological features are well-described in lungs, the histopathologic features of gastrointestinal involvement in resection specimens are not well characterized. Herein, we describe in detail the clinicopathologic features of intestinal resection specimens in four patients with COVID-19 infection. COVID-19 viral particles by in situ hybridization and immunofluorescence studies are also demonstrated. All four patients were males, aged 28-46 years, with comorbidities. They initially presented with a severe form of pulmonary COVID-19 and showed gastrointestinal symptoms, requiring surgical intervention. Histopathologic examination of resected GI specimens, mostly right colectomies, revealed a spectrum of disease, from superficial mucosal ischemic colitis to frank transmural ischemic colitis and associated changes consistent with pneumatosis cystoides intestinalis. Three patients were African American (75%), and one was Caucasian (25%); three patients died due to complications of their COVID-19 infection (75%), while one ultimately recovered from their GI complications (25%), but experienced prolonged sequela of COVID-19 infection including erectile dysfunction. In conclusion, COVID-19 infection, directly or indirectly, can cause ischemic gastrointestinal complications, with predilection for the right colon.

COVID-19: Gastrointestinal manifestations, liver injury and recommendations.

Coronavirus disease 2019 (COVID-19) has caused a pandemic that affected all countries with nearly 270 million patients and 5 million deaths, as of as of December, 2021. The severe acute respiratory syndrome coronavirus 2 virus targets the receptor, angiotensin-converting enzyme 2, which is frequently found in human intestinal epithelial cells, bile duct epithelial cells, and liver cells, and all gastrointestinal system organs are affected by COVID-19 infection. The aim of this study is to review the gastrointestinal manifestations and liver damage of COVID-19 infection and investigate the severe COVID-19 infection risk in patients that have chronic gastrointestinal disease, along with current treatment guidelines. A literature search was conducted on electronic databases of PubMed, Scopus, and Cochran Library, consisting of COVID-19, liver injury, gastrointestinal system findings, and treatment. Liver and intestinal involvements are the most common manifestations. Diarrhea, anorexia, nausea/vomiting, abdominal pain are the most frequent symptoms seen in intestinal involvement. Mild hepatitis occurs with elevated levels of transaminases. Gastrointestinal involvement is associated with long hospital stay, severity of the disease, and intensive care unit necessity. Treatments and follow-up of patients with inflammatory bowel diseases, cirrhosis, hepatocellular carcinoma, or liver transplant have been negatively affected during the pandemic. Patients with cirrhosis, hepatocellular carcinoma, auto-immune diseases, or liver transplantation may have a greater risk for severe COVID-19. Diagnostic or therapeutic procedures should be restricted with specific conditions. Telemedicine should be used in non-urgent periodic patient follow up. COVID-19 treatment should not be delayed in patients at the risk group. COVID-19 vaccination should be prioritized in this group.

Gastrointestinal manifestations of COVID-19 in a single center in the Eastern Province of Saudi Arabia.

Background: Several gastrointestinal (GI) symptoms have been associated with novel coronavirus disease-2019 (COVID-19). Their prevalence and relation to the severity and hospital outcome of COVID-19 have not been well reported in the Middle East and Saudi Arabia. We aimed to examine the GI manifestations of COVID-19 and their association with the severity and hospital outcome of COVID-19 infection. Methods: We conducted a retrospective observational study of hospitalized COVID-19 patients who had a positive SARS-COV2 PCR test and were admitted at a university hospital in Saudi Arabia, from March to September 2020. The primary objective of the study was to describe the GI manifestations of COVID-19. The secondary objective was to investigate the association of GI manifestations with severity and outcome of COVID-19 infection. Results: We included 390 patients, of which 111 (28.5%) presented with GI manifestations. The most common presentation was diarrhea followed by nausea, vomiting, and abdominal pain. Patients without GI manifestations had a higher risk of severe-critical COVID-19 infection evident by the development of lung infiltration in more than 50% of lung fields within 24-48 h, acute respiratory distress syndrome, altered mental status, multiorgan failure, and cytokine storm syndrome (P < 0.05). These patients had a higher mortality rate compared to patients with GI manifestations (P = 0.01). A lower odds of death was seen among patients with GI symptoms (AOR 0.36; 95% CI, 0.158-0.82; P = 0.01). Conclusion: COVID-19 infection presents commonly with GI manifestations. Patients with GI manifestations have less severe COVID-19 disease and lower mortality rates.

COVID-19 status quo: Emphasis on gastrointestinal and liver manifestations.

The coronavirus disease 2019 (COVID-19) has caused one of the worst public health crises in modern history. Even though severe acute respiratory syndrome coronavirus 2 primarily affects the respiratory tract, gastrointestinal manifestations are well described in literature. This review will discuss the epidemiology, virology, manifestations, immunosuppressant states, and lessons learned from COVID-19. Observations: At the time of writing, COVID-19 had infected more than 111 million people and caused over 2.5 million deaths worldwide. Multiple medical comorbidities including obesity, pre-existing liver condition and the use of proton pump inhibitor have been described as risk factor for severe COVID-19. COVID-19 most frequently causes diarrhea (12.4%), nausea/vomiting (9%) and elevation in liver enzymes (15%-20%). The current data does not suggest that patients on immunomodulators have a significantly increased risk of mortality from COVID-19. The current guidelines from American Gastroenterological Association and American Association for the Study of Liver Diseases do not recommend pre-emptive changes in patients on immunosuppression if the patients have not been infected with COVID-19. Conclusions and relevance: The COVID-19 pandemic has prompted a change in structure and shape of gastroenterology departmental activities. Endoscopy should be performed only when necessary and with strict protective measures. Online consultations in the form of telehealth services and home drug deliveries have revolutionized the field.

Digestive system involvement and clinical outcomes among COVID-19 patients: A retrospective cohort study from Qatar.

BACKGROUND: Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 virus most commonly presents with respiratory symptoms. While gastrointestinal (GI) manifestations either at presentation or during hospitalization are also common, their impact on clinical outcomes is controversial. Some studies have described worse outcomes in COVID-19 patients with GI symptoms, while others have shown either no association or a protective effect. There is a need for consistent standards to describe GI symptoms in COVID-19 patients and to assess their effect on clinical outcomes, including mortality and disease severity. AIM: To investigate the prevalence of GI symptoms in hospitalized COVID-19 patients and their correlation with disease severity and clinical outcomes. METHODS: We retrospectively reviewed 601 consecutive adult COVID-19 patients requiring hospitalization between May 1-15, 2020. GI symptoms were recorded at admission and during hospitalization. Demographic, clinical, laboratory, and treatment data were retrieved. Clinical outcomes included all-cause mortality, disease severity at presentation, need for intensive care unit (ICU) admission, development of acute respiratory distress syndrome, and need for mechanical ventilation. Multivariate logistic regression model was used to identify independent predictors of the adverse outcomes. RESULTS: The prevalence of any GI symptom at admission was 27.1% and during hospitalization was 19.8%. The most common symptoms were nausea (98 patients), diarrhea (76 patients), vomiting (73 patients), and epigastric pain or discomfort (69 patients). There was no difference in the mortality between the two groups (6.21% vs 5.5%, P = 0.7). Patients with GI symptoms were more likely to have severe disease at presentation (33.13% vs 22.5%, P < 0.001) and prolonged hospital stay (15 d vs 14 d, P = 0.04). There was no difference in other clinical outcomes, including ICU admission, development of acute respiratory distress syndrome, or need for mechanical ventilation. Drugs associated with the development of GI symptoms during hospitalization were ribavirin (diarrhea 26.37% P < 0.001, anorexia 17.58%, P = 0.02), hydroxychloroquine (vomiting 28.52%, P = 0.009) and lopinavir/ritonavir (nausea 32.65% P = 0.049, vomiting 31.47% P = 0.004, and epigastric pain 12.65% P = 0.048). In the multivariate regression analysis, age > 65 years was associated with increased mortality risk [odds ratio (OR) 7.53, confidence interval (CI): 3.09-18.29, P < 0.001], ICU admission (OR: 1.79, CI: 1.13-2.83, P = 0.012), and need for mechanical ventilation (OR: 1.89, CI:1.94-2.99, P = 0.007). Hypertension was an independent risk factor for ICU admission (OR: 1.82, CI:1.17-2.84, P = 0.008) and need for mechanical ventilation (OR: 1.66, CI: 1.05-2.62, P = 0.028). CONCLUSION: Patients with GI symptoms are more likely to have severe disease at presentation; however, mortality and disease progression is not different between the two groups.

Gastrointestinal manifestations in American minority population with COVID-19.

BACKGROUND: The spectrum of gastrointestinal (GI) injuries by the SARS-CoV-2 remain largely unknown. Ethnicity data is missing or unspecified. We analyzed GI involvement in American minority patients with COVID-19 infection. METHODS: Retrospective study of hospitalized patients with confirmed COVID-19 in March-April 2020. RESULTS: 183 patients included: 114 (62.30%) African-Americans, 58 (31.69%) Hispanics and 11 (6.01%) Asians. 73 females, 110 males; mean age 64.77, mean BMI 29.03 (50.82%); GI manifestations upon presentation: anorexia (29.51%), diarrhea (22.40%), nausea/vomiting (18.03%), abdominal pain (9.84%). No difference observed between three ethnical groups for GI symptoms and liver function tests. C Reactive Protein (CPR) (P=0.008), Lactate (P=0.03) and Prothrombin Time (PT) (P=0.03) were significantly elevated in patients without GI symptoms. No difference was observed for other laboratory tests. Patients with severe disease course/intubated had higher levels of Aspartate Transaminase (AST) (109.17 vs 53.97, P=0.018), Alanine Transaminase (ALT) (79.53 vs 40.03, P=0.02) and total bilirubin (0.82 vs 0.60, P=0.03) vs non-intubated patents as well as body temperature (101.38 vs 100.70, p=0.0006), CRP (24.06 v 15.96, P=0.019) and lactate (3.28 vs 2.13, P=0.009). There was no correlation between severity of the disease and GI symptoms, PT, platelets and albumin. However, CRP and lactate were markedly elevated in deceased vs survived patients: (27.09 vs 16.39, P=0.008) and (3.33 vs 2.10 P=0.005) respectively. CONCLUSIONS: ~ 50% of patients presented with GI symptoms and they had lower levels of inflammatory markers, better liver synthetic function, indicating less overall inflammatory response and direct viral damage. Our results suggest that SARS-CoV-2 virus targets GI tract along with the lung tissue, and the degree of hepatocyte damage correlated well with more severe disease.

Gastrointestinal manifestations with COVID-19 virus infection: A Moroccan prospective study.

BACKGROUND AND STUDY AIMS: Gastrointestinal manifestations are common during coronavirus disease (COVID-19) infection. They can occur before respiratory symptoms, resulting in a diagnostic delay and an increased risk of disease transmission. The current study reports major gastrointestinal manifestations as initial symptoms of COVID-19. PATIENTS AND METHODS: This prospective, descriptive, cross-sectional, and single-center study of 713 cases was conducted in a field hospital in Morocco over a 5-week period from June 21 to July 25, 2020. RESULTS: The average age of our patients was 31.95 years. Clinically, on admission, anorexia was the main symptom, present in 32.3% of patients. Gastrointestinal manifestations were present in 14.9% of patients, including watery diarrhea in 8.6% of cases, nausea and/or vomiting in 4.6% of cases, and abdominal pain in 1.6% of cases. Six hundred thirty-two patients were treated in accordance with one of the two therapeutic protocols recommended by the National Ministry of Health. The treatment-related effects that occurred in 61.4% of patients were primarily digestive in 55.3% of cases. In multivariate analysis, following adjustment of the studied parameters, only the presence of gastrointestinal manifestations (odds ratio [OR]: 1.478 confidence interval [CI]: 1.286-1.698; p < 0.001) and treatment side effects (OR = 1.069, CI: 1.020-1.119, p = 0.005) altered the rate of negative polymerase chain reaction (PCR) tests on day 10. CONCLUSION: Gastrointestinal manifestations are common during COVID-19 and seem to be linked to a longer duration of disease. SARS-CoV-2 (the causative virus of COVID-19) can persist in the digestive tract, with the possibility of fecal-oral transmission. Therefore, hygiene is extremely important, especially handwashing and strict precautions when performing gastrointestinal endoscopy and handling stools from infected patients.

Impact of COVID-19 on the Intestinal Microbiome.

PURPOSE OF REVIEW: This review article aims to explore the GI changes induced by SARS-CoV-2 and how gut microbial homeostasis can influence these changes and affect the lung-gut axis and its relationship with the induction of the cytokine release syndrome in severe COVID-19 patients. RECENT FINDINGS: Coronavirus disease 2019 (COVID-19) affects not only the respiratory system but can produce multi-systemic damage. The expression of angiotensin-converting enzyme 2 (ACE-2) receptors in the gastrointestinal (GI) tract, the high prevalence of GI symptoms in severely ill COVID-19 patients, and the abnormalities described in the gut microbiome in these patients have raised concerns about the influence of GI tract as a risk factor or as a potential modulator to reduce the severity of COVID-19. Understanding the mechanisms by which gut dysbiosis may influence viral transmission and disease progression in COVID-19 may help in shaping how accessible therapies, like diet modulation, can potentially help beat the devastating consequences of COVID-19.

Clinical Features and Pathophysiological Mechanisms of COVID-19-associated Gastrointestinal Manifestations.

AIM AND OBJECTIVE: According to the literature, gastrointestinal (GI) involvement may have a remarkable influence on the course of coronavirus disease-2019 (COVID-19). Our aim with this article is to appraise clinical characteristics and presumptive biological mechanisms of digestive tract involvement of COVID-19. BACKGROUND: In this review article, the English language literature was reviewed by using PubMed and MEDLINE databases, up to February 2021. REVIEW RESULTS: The patients with GI involvement are generally presented with diarrhea, nausea/vomiting, anorexia, abdominal pain, and rarely GI bleeding. However, frequencies of these manifestations are diverse in studies published so far, depending on the countries where the studies were conducted, characteristics of the study populations, and methodological differences. Several studies proved that this novel coronavirus gets into the enterocytes by attaching to angiotensin-converting enzyme 2 receptor. Some of them have shown a direct viral invasion and replication of the virus within enterocytes. Along with detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients' fecal materials, all these results explicitly indicate that the virus has the capability to invade the GI system. These findings may represent a potential risk indicator for fecal-oral spread of the virus. Although pathophysiology of COVID-19 associated GI manifestations remains elusive, direct viral damage, dysfunction in renin-angiotensin-aldosterone system, effects of gut-lung axis, and GI tract microbiome dysbiosis have been proposed as culprit mechanisms of the GI symptoms and inflammatory response. CONCLUSION: The patients with COVID-19 can be presented with diverse clinical manifestations including the GI symptoms. Understanding the actual impact of the virus on the GI tract depends on uncovering the pathophysiology of COVID-19. CLINICAL SIGNIFICANCE: GI involvement of COVID-19 appears to be crucial not only for its clinical consequences but also for its impacts on public health and prevention. HOW TO CITE THIS ARTICLE: Aslan AT, Simsek H. Clinical Features and Pathophysiological Mechanisms of COVID-19-associated Gastrointestinal Manifestations. Euroasian J Hepato-Gastroenterol 2021;11(2):81-86.

Gastrointestinal manifestations of human immunodeficiency virus and coronavirus disease 2019: Understanding the intersecting regions between the two epidemics.

In March 2020, the World Health Organization declared coronavirus disease (COVID-19) a pandemic. As of February 2021, there were 107 million COVID-19 cases worldwide. As a comparison, there are approximately 38 million people living with human immunodeficiency virus (PLHIV) worldwide. The coexistence of both epidemics, and the syndemic effect of both viruses could lead to a delirious impact both at individual and community levels. Many intersecting points were found between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19, and HIV; among which, gastrointestinal (GI) manifestations are the most notable. GI manifestations represent a common clinical presentation in both HIV and SARS-CoV-2. The emergence of GI symptoms as a result of SARS-CoV-2 infection provides a new dynamic to COVID-19 diagnosis, management, and infection control measures, and adds an additional diagnostic challenge in case of coinfection with HIV. The presence of GI manifestations in PLHIV during the COVID-19 pandemic could be referred to HIV enteropathy, presence of opportunistic infection, adverse effect of antiretrovirals, or coinfection with COVID-19. Thus, it is important to exclude SARS-CoV-2 in patients who present with new-onset GI manifestations, especially in PLHIV, to avoid the risk of disease transmission during endoscopic interventions. Structural similarities between both viruses adds a valuable intersecting point, which has mutual benefits in the management of both viruses. These similarities led to the hypothesis that antiretrovirals such as lopinavir/Rironavir have a role in the management of COVID-19, which was the target of our search strategy using the available evidence. These similarities may also facilitate the development of an efficient HIV vaccine in the future using the advances in COVID-19 vaccine development.