Cholelithiasis

Acute cholecystitis is inflammation of the gallbladder from cystic duct obstruction, most often by a gallstone, presenting with RUQ pain lasting more than 6 hours, fever, and a positive Murphy sign. Diagnosis follows the Tokyo Guidelines TG18 criteria and severity grade, and treatment combines IV antibiotics with early laparoscopic cholecystectomy, or cholecystostomy in patients too unstable for surgery.

Choledocholithiasis is a gallstone that has migrated into the common bile duct, causing obstructive jaundice and cholestatic liver chemistries and predisposing to acute cholangitis and gallstone pancreatitis. Risk is stratified by ASGE criteria and confirmed by MRCP, endoscopic ultrasound, or therapeutic ERCP, which clears the duct before same-admission cholecystectomy.

Acute cholangitis is a bacterial infection of an obstructed biliary tree, classically presenting as Charcot triad of fever, right upper quadrant pain, and jaundice and progressing to septic shock when drainage is delayed. Diagnosis follows the Tokyo Guidelines and severity grade, and treatment combines prompt broad-spectrum antibiotics with biliary drainage, most often by ERCP.

Acute pancreatitis is acinar-cell autodigestion and inflammation of the pancreas, most often from gallstones or alcohol, diagnosed by the revised Atlanta criteria and graded mild, moderately severe, or severe by organ failure. Management centers on early goal-directed lactated Ringer's resuscitation, analgesia, early enteral feeding, and timed ERCP for gallstone pancreatitis with cholangitis, reserving antibiotics for confirmed infected necrosis.

Peptic ulcer disease is a mucosal break in the stomach or duodenum caused chiefly by Helicobacter pylori infection or NSAID use, diagnosed by upper endoscopy with biopsy of gastric ulcers to exclude malignancy. Treatment eradicates H. pylori when present, stops the ulcerogenic drug, and heals the ulcer with a proton pump inhibitor, while its complications of bleeding, perforation, and obstruction drive most of its morbidity.

GERD is retrograde reflux of gastric contents into the esophagus causing heartburn and regurgitation, diagnosed clinically and confirmed by response to an empiric PPI trial, with endoscopy reserved for alarm features or refractory symptoms. Management proceeds from lifestyle measures through an 8-week once-daily PPI trial, dose escalation or agent switch for partial response, and fundoplication for medication-refractory or regurgitation-predominant disease.

ST-elevation myocardial infarction is acute transmural myocardial ischemia from complete coronary occlusion, diagnosed by ischemic symptoms with diagnostic ST-segment elevation and a rising troponin. It is a time-critical emergency in which immediate reperfusion, primary PCI within 90 minutes or fibrinolysis when PCI is unavailable, plus antiplatelet and anticoagulant therapy, determines survival.

Irritable bowel syndrome is a functional disorder of gut-brain interaction diagnosed clinically by Rome IV criteria, recurrent abdominal pain related to defecation, stool frequency, or stool form, without alarm features. Management is subtyped by stool pattern, with fiber and dietary change first, then IBS-C secretagogues or IBS-D antidiarrheals and antibiotics, and low-dose tricyclics or antispasmodics for pain.

Acute appendicitis is luminal obstruction and infection of the vermiform appendix presenting as migratory periumbilical-to-right-lower-quadrant pain, diagnosed by the classic history and exam plus confirmatory imaging (CT in adults, ultrasound or MRI in children and pregnancy), and treated with prompt appendectomy or, in selected uncomplicated cases, antibiotics alone.