Ivan Lerotić

Overview and developments in noninvasive diagnosis of nonalcoholic fatty liver disease

High prevalence of non-alcoholic fatty liver disease (NAFLD) and very diverse outcomes that are related to disease form and severity at presentation have made the search for noninvasive diagnostic tools in NAFLD one of the areas with most intense development in hepatology today. Various methods have been investigated in the recent years, including imaging methods like ultrasound and magnetic resonance imaging, different forms of liver stiffness measurement, various biomarkers of necroinflammatory processes (acute phase reactants, cytokines, markers of apoptosis), hyaluronic acid and other biomarkers of liver fibrosis. Multicomponent tests, scoring systems and diagnostic panels were also developed with the purposes of differentiating non-alcoholic steatohepatitis from simple steatosis or discriminating between various fibrosis stages. In all of the cases, performance of noninvasive methods was compared with liver biopsy, which is still considered to be a gold standard in diagnosis, but is by itself far from a perfect comparative measure. We present here the overview of the published data on various noninvasive diagnostic tools, some of which appear to be very promising, and we address as well some of still unresolved issues in this interesting field.

Acid Inhibition and the Acid Rebound Effect

Acid secretion from gastric parietal cells is a result of a complex interaction between different stimulatory and inhibitory mediators. One of the most important mediators is gastrin, which stimulates gastric acid secretion from parietal cells mostly indirectly, by the release of histamine from enterochromaffin-like (ECL) cells. Therapy with antisecretory agents leads to hypergastrinemia, mucosal hyperplasia and increased ECL cell mass, which results in increase of gastric acid secretion capacity. This increased secretion capacity has been shown to manifest itself after antisecretory therapy withdrawal as rebound acid hypersecretion (RAH). Various studies have quantified acid hypersecretion after the cessation of therapy with H2 antagonists and proton-pump inhibitors (PPIs). While most of those studies had small patient numbers, the findings generally demonstrate that RAH after H2 antagonist therapy is of low magnitude, short duration, and has questionable clinical significance. On the contrary, acid hypersecretion after PPI therapy is more pronounced, lasts longer, and could possibly be the cause of acid-related symptoms. Potential for causing symptoms has recently been confirmed in two randomized placebo-controlled studies, and while we witness the increasing use of PPIs, RAH could become a proven cause of failure to withdraw therapy in a proportion of patients with reflux or dyspeptic symptoms.

Management of Helicobacter pylori Infection

The discovery of Helicobacter pylori (H. pylori) in 1982 by Barry Marshall and Robin Warren was the starting point of a new era in understanding and management of gastroduodenal diseases. H. pylori is a spiral-shaped, gram-negative, microaerophilic, urease-producing bacterium. It is one of the most common human infections worldwide, and it is estimated that about one half of the world’s population is infected [1]. The risk of acquiring H. pylori infection is related to socioeconomic status, living conditions, and habits that we acquire from early childhood. Person-to-person transmission through either fecal-to-oral or oral-to-oral exposure seems to be the most probable way of acquiring the infection. In developing nations, where the majority of children are infected before the age of 10, the prevalence in adults exceeds 80% [1]. In developed countries, detection of the infection in children is unusual but becomes more common during adulthood, and the prevalence increases up to 50% in the elderly population [1]. Approximately 30% to 40% of the United States (US) population is infected with H. pylori [2]. In North America, the prevalence of H. pylori among Asian Americans, African Americans, and Hispanics is similar to the one found in developing countries [3]. Once acquired, infection persists in the stomach for years and may or may not produce a gastroduodenal disease. Over 80% of individuals infected with the bacterium are asymptomatic. However, H. pylori infection is the main risk factor for a broad variety of chronic gastrointestinal diseases such as chronic gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

Candidemia after endoscopic therapy with lumen-apposing metal stent for pancreatic walled-off necrosis

Necrotizing pancreatitis remains a challenging and unpredictable condition accompanied by various complications. Endoscopic ultrasound-guided transmural drainage and necrosectomy have become the standard treatment for patients with walled-off necrosis (WON). Endoscopic therapy via lumen-apposing metal stents (LAMS) with large diameters has shown success in the management of pancreatic fluid collections, but there are few data on specific complications of that therapy. We report a case of infected WON and concomitant fungemia following LAMS placement and necrosectomy. In addition, a systematic literature review of current related studies has been provided.