Introduction In vitro fertilization (IVF) is one of the most advanced and widely used assisted reproductive technologies (ARTs) to help individuals and couples conceive when natural conception is not possible.…
Pathophysiology & Diagnostic Criteria Achalasia is a primary esophageal motility disorder rooted in neurodegenerative loss of inhibitory neurons (primarily nitric oxide– and VIP-producing) in the myenteric plexus of the lower…
Pathophysiology & Clinical Context Acute cholangitis is an acute bacterial infection of the biliary tree secondary to biliary obstruction (most commonly choledocholithiasis), leading to stasis, ascending infection, and systemic inflammation.…
Definition & Pathophysiology Acute pancreatitis (AP) is an acute inflammatory process of the pancreas, characterized by autodigestion of pancreatic tissue due to premature activation of pancreatic enzymes (e.g., trypsinogen →…
Pathophysiology Overview Chronic pancreatitis (CP) is a progressive, irreversible inflammatory pancreatic disorder characterized histopathologically by: Fibrotic replacement of parenchyma Calcification (in ~75% of alcoholic CP) Ductal distortion (strictures, dilatation, stones)…
Definition & Pathophysiology GERD is a chronic, often relapsing disorder characterized by the reflux of gastric (and duodenal) contents—acid, bile, pepsin, and pancreatic enzymes—into the esophagus, pharynx, or larynx, resulting…
I. Definition & Pathophysiology Peptic ulcer disease (PUD) is characterized by localized defects in the gastroduodenal mucosa that extend through the muscularis mucosae, resulting from an imbalance between aggressive factors…
I. Definition & Epidemiologic Context Splenomegaly is defined as a spleen that exceeds the 95th percentile for age- and sex-matched controls—typically: Transverse diameter >12 cm in adolescents Length >7.3 cm +…
Epidemiology and Pathophysiology Insulinomas are rare, typically benign (85–90%), functioning pancreatic neuroendocrine tumors (pNETs) arising from β-cells of the islets of Langerhans. Incidence is ~1–2 cases per million person-years, with…
Epidemiology and Burden of Disease Hepatitis A virus (HAV), a non-enveloped, positive-sense single-stranded RNA virus belonging to the Picornaviridae family (genus Orthohepatovirus), remains one of the most prevalent causes of…
Epidemiology and Global Burden Hepatitis E virus (HEV), a non-enveloped, positive-sense, single-stranded RNA virus belonging to the Hepeviridae family (genus Orthohepevirus, species HEV-A), is a globally significant cause of acute…
Authored for clinicians with emphasis on evidence-based practice, updated guidelines (AASLD 2018, EASL 2017/2024 updates), and practical decision-making tools. Epidemiology & Virology Primer (Clinician Refresher) HBV is a Hepadnaviridae family,…
Epidemiology and Clinical Significance Chronic functional constipation (CFC) affects approximately 12–27% of the general adult population, with prevalence rising sharply with age—up to 30–40% in individuals ≥65 years. It is…
Epidemiology & Pathogenesis Giardia lamblia (syn. G. duodenalis, G. intestinalis) is a flagellated protozoan parasite and a leading cause of protozoal gastroenteritis worldwide. The CDC estimates over 280 million cases…
Definition and Pathophysiology Lactose intolerance (LI) is a clinical syndrome characterized by the development of digestive symptoms following ingestion of lactose—the primary carbohydrate in mammalian milk. It results from lactose…
