Gastroenterology and General Surgery
Astra Clinical Library
Gastroenterology
Practical gastroenterology guides for clinical decisions, with cited evidence, testing strategies, and actionable next steps.
68 guides
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Gastroenterology
Upper Gastrointestinal Bleeding
Acute upper gastrointestinal bleeding requires immediate hemodynamic assessment, restrictive but context-sensitive transfusion, pre-endoscopic risk stratification, and endoscopy within 24 hours after resuscitation. Management diverges early for suspected variceal hemorrhage and must balance hemostasis against thrombotic risk from interrupted antithrombotic therapy.Hepatology
Primary Biliary Cholangitis
Primary biliary cholangitis is usually diagnosed serologically in the setting of cholestatic liver tests. Management centers on prompt ursodeoxycholic acid, biochemical risk reassessment, escalation for inadequate response or intolerance, symptom-directed care, fibrosis assessment, and surveillance for complications.Hepatology
Primary Sclerosing Cholangitis
Primary sclerosing cholangitis requires cholangiographic confirmation, exclusion of secondary causes, systematic evaluation for inflammatory bowel disease, and surveillance for hepatobiliary and colorectal malignancy. No drug has established disease-modifying benefit; management centers on complications, selected biliary intervention, and timely transplant referral.Gastroenterology and Hepatology
Cholangitis
Acute cholangitis is biliary infection with potential for rapid sepsis and organ failure. Management hinges on immediate resuscitation and antibiotics, severity assessment, and timely biliary drainage when obstruction persists or disease is severe.Gastroenterology and Colorectal Surgery
Large Bowel Obstruction
Large bowel obstruction requires rapid distinction between mechanical obstruction, volvulus, and acute colonic pseudo-obstruction, with immediate resuscitation, CT-based anatomic definition, and urgent surgical or endoscopic involvement when ischemia, perforation, or complete obstruction is suspected.Hepatology
Hepatic Cirrhosis
Cirrhosis may remain clinically silent despite normal routine liver tests. Recognize portal-hypertension signals, stage fibrosis noninvasively when appropriate, identify decompensation promptly, treat the underlying etiology, and refer early for complication-directed and transplant-centered care.Gastroenterology
Chronic Pancreatitis
Chronic pancreatitis requires structural confirmation, etiologic assessment, and longitudinal surveillance for pain, ductal complications, exocrine insufficiency, diabetes, malnutrition, bone disease, and malignancy. Imaging should establish disease and actionable obstruction; treatment should target the dominant complication rather than pain alone.Gastroenterology and General Surgery
Adult Intussusception
Adult intussusception is increasingly detected on cross-sectional imaging, but management hinges on distinguishing transient enteric telescoping from obstruction or a lead-point lesion, particularly colonic malignancy requiring oncologic resection.Gastroenterology
Crohn Disease
Crohn disease requires objective confirmation, phenotype-based risk assessment, steroid-sparing treatment, and longitudinal monitoring beyond symptoms. Ileocolonoscopy with biopsy establishes diagnosis and extent; biomarkers and cross-sectional imaging help detect ongoing inflammation, complications, and discordance between symptoms and disease activity.Gastroenterology
Peptic Ulcer Disease
Peptic ulcer disease requires prompt distinction of uncomplicated ulcer from hemorrhage, obstruction, or malignancy. Management centers on removing NSAID exposure when feasible, identifying and eradicating Helicobacter pylori, acid suppression, and timely endoscopic intervention for bleeding or concerning gastric ulcers.Gastroenterology
Gastroesophageal Reflux Disease
Manage GERD by separating unproven reflux from proven reflux with persistent symptoms, selecting ambulatory testing on or off proton pump inhibitors accordingly, and reserving invasive therapy for objectively documented reflux with an appropriate anatomic and physiologic phenotype.Gastroenterology and Nuclear Medicine
Gastrointestinal Bleeding Scan
Technetium-99m–labeled red blood cell scintigraphy can document active or intermittent gastrointestinal bleeding when endoscopy is nondiagnostic or impractical, but its limited anatomic precision means results should guide—not independently determine—angiography, endoscopy, or surgery.Hepatology
Acute-on-Chronic Liver Failure
Acute-on-chronic liver failure requires immediate identification of extrahepatic organ failure, reversal of precipitants, ICU-level organ support, and early transplant-center engagement. Serial assessment of organ dysfunction—not liver tests alone—determines prognosis, treatment intensity, and whether transplantation remains feasible.Gastroenterology and Hepatology
Portal Hypertension
Use portal-pressure thresholds and noninvasive risk stratification to identify clinically significant portal hypertension, prevent first decompensation, and select endoscopic or shunt-based therapy for bleeding and refractory ascites.Gastroenterology
Extraintestinal Manifestations of Inflammatory Bowel Disease
A practical approach to recognizing inflammatory bowel disease–associated musculoskeletal, skin, ocular, hepatobiliary, renal, and systemic disease; separating activity-linked manifestations from independent disease; and coordinating bowel-directed and organ-specific management.Hepatology and Critical Care
Acute Liver Failure
Acute liver failure requires immediate recognition of encephalopathy with INR greater than 1.5, etiologic triage, intensive monitoring for cerebral edema and multiorgan failure, early N-acetylcysteine when appropriate, and urgent coordination with a liver transplant center.Hepatology
Hepatitis B
Use triple-panel serology to identify infection, immunity, and reactivation risk; stage confirmed chronic infection with HBV DNA, liver assessment, and fibrosis testing; then select durable antiviral suppression, pregnancy prevention measures, or surveillance based on cirrhosis and host risk.Hepatology
Hepatitis C
Confirm viremia with HCV RNA, stage fibrosis without delaying therapy, identify cirrhosis and drug interactions, and treat nearly all nonpregnant patients with direct-acting antivirals. Cure is defined by undetectable HCV RNA 12 weeks after treatment completion.Hepatology
Hepatocellular Carcinoma
Manage hepatocellular carcinoma through risk-based surveillance, multiphasic imaging diagnosis in at-risk livers, integrated tumor and hepatic-reserve staging, and multidisciplinary selection among resection, transplantation, ablation, locoregional therapy, radiation, and systemic therapy.Hepatology
Budd-Chiari Syndrome
Budd-Chiari syndrome requires urgent confirmation of hepatic venous outflow obstruction, immediate anticoagulation when feasible, systematic identification of thrombophilia or secondary obstruction, and rapid escalation to endovascular decompression, TIPS, or transplantation when hepatic dysfunction or portal-hypertension complications progress.Gastroenterology
Celiac Disease
Diagnose celiac disease while the patient is consuming gluten, using tTG-IgA plus total IgA first. In adults, confirm positive serology with properly sampled duodenal biopsies, then use a strict gluten-free diet, dietitian-led exposure review, and targeted reassessment for persistent symptoms or villous atrophy.Gastroenterology
Irritable Bowel Syndrome
Use a positive symptom-based diagnosis, screen selectively for inflammatory, celiac, infectious, and structural mimics, then match therapy to bowel pattern and dominant symptom while reassessing alarm features or treatment-resistant change.Gastroenterology
Short Bowel Syndrome
Manage short bowel syndrome by defining residual anatomy and intestinal-failure severity, correcting high-output fluid and electrolyte losses, advancing enteral exposure, minimizing parenteral-support complications, and referring persistent dependence or adverse anatomy to an intestinal rehabilitation program.Hepatology
Wilson Disease
Diagnose Wilson disease by integrating copper studies, ophthalmologic and neurologic findings, and ATP7B testing when results are equivocal; then select lifelong chelation or zinc according to phenotype, hepatic severity, tolerance, and adherence risk.Pediatric Gastroenterology and Pediatric Surgery
Hirschsprung Disease
Suspect Hirschsprung disease in neonatal distal bowel obstruction or refractory constipation with delayed meconium. Stabilize enterocolitis and obstruction first, establish aganglionosis by rectal pathology, define disease extent for pull-through planning, and systematically evaluate postoperative obstruction, soiling, and recurrent enterocolitis.Gastroenterology
Chronic Diarrhea
Use a pattern-based evaluation to identify inflammatory, malabsorptive, infectious, medication-related, postoperative, bile acid, pancreatic, and functional causes while rapidly correcting volume, electrolyte, and nutritional consequences.Gastroenterology and Cancer Genetics
Lynch Syndrome
Use universal colorectal and endometrial tumor mismatch-repair testing to identify candidates for germline evaluation, distinguish sporadic MLH1-deficient tumors, and implement gene-informed colonoscopic surveillance, cascade testing, and gynecologic risk reduction.Gastroenterology
Anticoagulation After Gastrointestinal Bleeding
After gastrointestinal bleeding, restart anticoagulation once hemostasis is secured in most patients, because interruption lowers rebleeding exposure but increases thromboembolism and death. Timing depends on lesion control, bleeding trajectory, anticoagulant pharmacology, and the indication-specific thrombotic risk.Gastroenterology
Acute Pancreatitis
Use lactated Ringer’s–based, goal-directed rather than aggressive early resuscitation, reassess severity and volume status frequently, and restore oral or enteral nutrition early to avoid unnecessary fasting and parenteral nutrition.Gastroenterology
ERCP in Acute Pancreatitis
ERCP is a therapeutic, not routine diagnostic, procedure in acute pancreatitis. Perform urgent biliary drainage for cholangitis, use selective intervention for persistent obstruction, and avoid routine early ERCP when neither is present because it adds procedural risk without demonstrated benefit.Gastroenterology
Acute Cholangitis Biliary Drainage
Biliary drainage timing is determined by physiologic severity and response to initial resuscitation. Perform urgent decompression for organ dysfunction, early drainage for moderate disease, and reserve antibiotics-alone management for improving mild cholangitis without persistent obstruction.Gastroenterology and Hepatology
Variceal Bleeding Initial Management
Treat suspected acute variceal bleeding as a portal-hypertensive emergency: resuscitate without overtransfusion, immediately start vasoactive therapy and antibiotic prophylaxis, then perform therapeutic endoscopy after hemodynamic stabilization, generally within 12 hours. Identify patients needing early or salvage portal decompression.Hepatology
Hepatic Encephalopathy Treatment Escalation
Escalate hepatic encephalopathy care by protecting the airway in severe impairment, correcting reversible precipitants, using lactulose as first-line therapy, and adding rifaximin for recurrent overt episodes. Persistent or recurrent encephalopathy requires reassessment for ongoing triggers, treatment adherence, and portosystemic shunting.Hepatology
Hepatorenal Syndrome
Diagnose HRS-AKI early in decompensated cirrhosis by confirming AKI, correcting reversible precipitants, and excluding structural kidney disease. Use albumin-directed volume assessment and timely vasoconstrictor therapy while urgently pursuing liver-transplant evaluation.Hepatology
Acute Liver Failure Transfer Criteria
Transfer patients with acute liver failure immediately to a liver transplant center when INR is at least 1.5 with encephalopathy, or when severe acute liver injury is rapidly progressing toward these features.Hepatology
Abnormal Liver Test Patterns
Interpret abnormal liver tests by separating hepatocellular, cholestatic, and mixed injury, assessing bilirubin and INR for urgency, then directing serology, imaging, medication review, and selective biopsy toward the most likely competing etiologies.Gastroenterology
Iron Deficiency Anemia Gastrointestinal Evaluation
Confirm iron deficiency before attributing anemia to gastrointestinal blood loss, then use patient sex, menopausal status, symptoms, and initial endoscopic findings to select bidirectional endoscopy, celiac testing, noninvasive infection testing, or small-bowel evaluation.Gastroenterology
IBD Flare Infection Testing
Test symptomatic inflammatory bowel disease flares for enteric infection before attributing symptoms to inflammatory activity. Stool pathogen testing and C. difficile assays direct therapy, while fecal calprotectin, inflammatory markers, endoscopy, and imaging distinguish active mucosal disease from complications or functional symptoms.Hepatology
Cirrhotic Ascites Diuretics
Use sodium restriction and spironolactone-based diuresis for uncomplicated moderate ascites, but stop or de-escalate therapy when renal, neurologic, or electrolyte toxicity emerges. Refractory ascites requires early transition to large-volume paracentesis with albumin, TIPS selection, and transplant evaluation.Gastroenterology and Hepatology
Spontaneous Bacterial Peritonitis
Diagnose SBP with prompt diagnostic paracentesis and ascitic neutrophil count, begin empiric therapy when PMNs reach 250/mm3, prevent renal deterioration with albumin when indicated, and actively exclude secondary peritonitis when the clinical or fluid profile is atypical.Gastroenterology
Upper Gastrointestinal Bleeding Risk Stratification
Use Glasgow-Blatchford scoring at presentation to identify patients suitable for outpatient care, while recognizing that hemodynamic instability, ongoing hemorrhage, comorbidity, and suspected varices override low-complexity disposition pathways and require resuscitation and timely endoscopy.Gastroenterology
Gastrinoma
Suspect gastrinoma in recurrent or refractory ulcer disease, severe reflux, or secretory diarrhea with hypergastrinemia. Confirm inappropriate gastrin secretion in an acidic stomach, protect against acid-related complications immediately, then localize and stage for multidisciplinary curative or disease-control treatment.Gastroenterology
Achalasia
Confirm suspected achalasia with high-resolution manometry after excluding mechanical obstruction, then select pneumatic dilation, laparoscopic Heller myotomy with fundoplication, or POEM by subtype, anatomy, reflux tradeoff, prior therapy, and local expertise.Gastroenterology and Hepatology
Acute Hepatic Porphyria
Suspect acute hepatic porphyria in recurrent unexplained neurovisceral attacks, confirm with a creatinine-normalized random urine precursor panel, treat admitted severe attacks with intravenous hemin, and prevent recurrent attacks through trigger control plus givosiran or prophylactic heme therapy.Gastroenterology and Hepatology
Ascites
New or worsening ascites requires prompt paracentesis, fluid-pattern interpretation, and early detection of spontaneous bacterial peritonitis, renal dysfunction, and portal-hypertensive decompensation. Management is driven by etiology, ascites severity, response to fluid removal, and candidacy for TIPS or liver transplantation.Gastroenterology
Barrett Esophagus
Manage Barrett esophagus by confirming intestinal metaplasia and dysplasia with high-quality endoscopy and expert pathology, then selecting surveillance or eradication therapy according to dysplasia grade, visible lesions, and procedural fitness.Gastroenterology
Biliary Obstruction
Biliary obstruction requires rapid separation of infected obstruction needing decompression from stable stone disease, benign stricture, and malignancy. Ultrasound establishes the initial anatomic assessment; MRCP, EUS, ERCP, tissue sampling, and multidisciplinary review then determine intervention.Gastroenterology and Medical Oncology
Cholangiocarcinoma
Manage cholangiocarcinoma by defining intrahepatic, perihilar, or distal anatomy; obtaining high-quality staging before biliary intervention when feasible; securing diagnosis without compromising curative options; determining resectability in a multidisciplinary setting; relieving clinically consequential obstruction; and profiling unresectable or metastatic disease for biomarker-directed therapy.Gastroenterology
Choledocholithiasis
Manage suspected common bile duct stones by separating patients needing urgent biliary drainage from those needing risk-stratified confirmation, reserving ERCP for therapeutic intent, and ensuring gallbladder-source control after duct clearance when surgery is feasible.Gastroenterology
Constipation
Evaluate constipation by first excluding obstruction, cancer-risk features, fecal impaction, medication effects, and systemic disease; then distinguish defecatory disorder from slow-transit and normal-transit phenotypes before escalating beyond empiric laxatives. Anorectal testing directs biofeedback and prevents inappropriate transit testing or surgery.Gastroenterology
Diverticulosis
Incidentally detected colonic diverticulosis requires no disease-directed treatment in most patients; management changes only with acute pain suggesting diverticulitis, painless hematochezia suggesting diverticular hemorrhage, or rare obstructive and inflammatory complications requiring imaging, endoscopic hemostasis, embolization, or surgery.Gastroenterology
Dysphagia
Triage aspiration risk first, then separate oropharyngeal dysfunction from esophageal obstruction or motility disease. Bedside screening determines immediate oral-intake safety; FEES or videofluoroscopy defines pharyngeal physiology, while endoscopy, barium imaging, and manometry direct esophageal treatment.Gastroenterology and Hepatology
Esophageal Varices
Use noninvasive portal-hypertension assessment to identify patients who need endoscopy or preventive therapy, recognize acute variceal hemorrhage early, and combine vasoactive treatment, antibiotics, endoscopic therapy, and timely TIPS referral to reduce failure and recurrent bleeding.Gastroenterology
Esophagitis
Manage esophagitis by first identifying obstruction, food impaction, bleeding, or malignancy risk, then using upper endoscopy with biopsy to separate reflux, eosinophilic, infectious, pill-related, and motility-associated injury and direct therapy.Gastroenterology
Familial Adenomatous Polyposis
Familial adenomatous polyposis requires early APC-directed family testing, intensive colorectal surveillance, timely risk-reducing colectomy, and lifelong upper gastrointestinal assessment with ampullary visualization to prevent colorectal and duodenal malignancy.Gastroenterology
Fecal Impaction
Diagnose fecal impaction with targeted abdominal and digital rectal examination, exclude obstruction or ischemic complications when suggested clinically, achieve complete clearance, then reassess bowel function and contributors to prevent recurrent loading.Gastroenterology and Colorectal Surgery
Fecal Incontinence
Manage fecal incontinence by first identifying stool-driven, overflow, structural, pelvic floor, and neurologic contributors; correct reversible drivers, reserve anorectal testing for persistent symptoms, and escalate refractory cases to sacral neuromodulation or selected repair strategies.Gastroenterology
Gastritis
Manage suspected gastritis by separating histologically confirmed inflammation from reactive gastropathy, identifying Helicobacter pylori, medication or alcohol injury, and recognizing atrophic or autoimmune patterns that require systematic biopsy staging and cancer-risk surveillance planning.Gastroenterology
Gastroparesis
Confirm delayed solid gastric emptying only after excluding obstruction, then reverse medication and glycemic contributors, protect hydration and nutrition, and escalate from diet and prokinetics to selected pyloric or device therapies for medically refractory nausea and vomiting.Hepatology
Hemochromatosis
Evaluate suspected hemochromatosis with transferrin saturation and ferritin, confirm appropriate HFE genotypes, distinguish secondary hyperferritinemia, stage hepatic risk, and use phlebotomy to deplete demonstrable iron overload while avoiding treatment of genotype alone.Hepatology
Hepatic Encephalopathy
Manage suspected hepatic encephalopathy as a clinical diagnosis of exclusion: stabilize impaired consciousness, grade overt disease, identify reversible precipitants and shunts, initiate bowel-directed therapy, and use recurrence or TIPS risk to drive secondary prevention and transplant-focused planning.Gastroenterology and General Surgery
Ileus
Manage suspected ileus by first excluding mechanical obstruction, ischemia, perforation, and acute colonic pseudo-obstruction. Correct reversible drivers, decompress selectively for vomiting or marked distention, minimize opioids, mobilize early, and escalate predominant colonic dilation to monitored neostigmine or endoscopic decompression.Gastroenterology
Lactose Intolerance
Confirm that dairy-triggered symptoms reflect lactose intolerance rather than broader functional or mucosal disease, then preserve nutritional intake through individualized lactose dosing, fermented or reduced-lactose foods, and treatment of reversible secondary lactase deficiency.Gastroenterology
Pancreatic Pseudocyst
Confirm that a mature, purely fluid pancreatic collection is a pseudocyst rather than walled-off necrosis or a cystic neoplasm; observe uncomplicated asymptomatic lesions, and drain only symptomatic or complicated collections using anatomy- and duct-directed endoscopic strategies.Gastroenterology
Protein-Losing Enteropathy
Protein-losing enteropathy should be confirmed in unexplained hypoalbuminemia after excluding renal, hepatic, and nutritional causes, then localized to inflammatory mucosal disease, lymphatic obstruction, or Fontan-related hemodynamic dysfunction to direct treatment.Gastroenterology
Toxic Megacolon
Toxic megacolon requires immediate recognition of nonobstructive colonic dilation with systemic toxicity, exclusion of mechanical obstruction and superimposed infection, serial reassessment, and early colorectal surgical involvement before perforation, shock, or prolonged unsuccessful medical treatment markedly worsens outcomes.Hepatology