Egyptian Board Gastroenterology & Hepatology cheat sheet

Achalasia: absent peristalsis plus failure of lower esophageal sphincter relaxation; Chicago Classification v4.0 diagnoses esophagogastric junction outflow obstruction from elevated integrated relaxation pressure.

High-resolution manometry types: type I achalasia (no pressurization), type II (pan-esophageal pressurization, best treatment response), type III (premature spastic contractions).

Eosinophilic esophagitis: ≥15 eosinophils per high-power field; first-line therapy is proton pump inhibitor trial, topical swallowed corticosteroids, or food elimination diet.

Los Angeles classification grades esophagitis A-D by mucosal break extent; grade C is ≥2 breaks involving <75% circumference, grade D ≥75%.

Barrett esophagus requires ≥1 cm of salmon-colored mucosa above the gastroesophageal junction with intestinal metaplasia; surveillance interval depends on dysplasia grade.

Zenker diverticulum arises in Killian triangle; rigid or flexible diverticulotomy is preferred over simple dilation because of perforation risk.

Nutcracker esophagus and jackhammer esophagus are hypercontractile peristaltic disorders defined by distal contractile integral thresholds in Chicago Classification v4.0.

Esophageal varices are managed with nonselective beta-blockers or endoscopic band ligation for primary prophylaxis; sclerotherapy is not preferred for esophageal varices.

H. pylori test-and-treat: urea breath test or stool antigen for active infection; serology cannot confirm eradication and should not be used for post-treatment testing.

Eradication confirmation is performed ≥4 weeks after antibiotic completion and ≥2 weeks after stopping proton pump inhibitors.

Peptic ulcer bleeding: Forrest Ia spurting and Ib oozing require endoscopic hemostasis; Forrest IIc flat pigmented spot and III clean base carry low rebleeding risk.

Duodenal ulcer is more common than gastric ulcer; gastric ulcers require biopsy and follow-up endoscopy to exclude malignancy.

Bismuth quadruple therapy is preferred where clarithromycin resistance exceeds 15% or in prior macrolide exposure.

Gastric adenocarcinoma: intestinal type arises via Correa cascade (chronic gastritis, atrophy, intestinal metaplasia, dysplasia); diffuse type is linked to CDH1 mutations.

Gastric MALT lymphoma with H. pylori infection: eradication therapy alone achieves remission in most localized low-grade cases.

Zollinger-Ellison syndrome: fasting gastrin >1000 pg/mL with gastric pH <2 and secretin stimulation test showing paradoxical gastrin rise.

Celiac disease serology: tissue transglutaminase IgA with total IgA level; IgA deficiency affects 2-3% of celiac patients and causes false-negative serology.

Celiac histology: villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis; Marsh-Oberhuber grading quantifies severity.

Small intestinal bacterial overgrowth is diagnosed by glucose or lactulose hydrogen breath testing; duodenal aspirate culture >10^3 CFU/mL is the reference standard.

Tropical sprue: malabsorption with small bowel villous atrophy in residents of or travelers to the tropics, responding to tetracycline plus folate.

Whipple disease: Tropheryma whipplei, periodic acid-Schiff-positive macrophages in duodenal biopsy; treat with ceftriaxone induction then trimethoprim-sulfamethoxazole.

Bile acid diarrhea: SeHCAT retention <10% at 7 days or elevated fecal calprotectin-negative chronic diarrhea; responds to bile acid sequestrants.

Short bowel syndrome: remnant <200 cm without colon or <100 cm with colon predicts parenteral nutrition dependence; citrulline <20 micromol/L suggests poor adaptation.

Carbohydrate malabsorption is confirmed by hydrogen breath test rise ≥20 ppm above baseline within 90 minutes.

Ulcerative colitis involves the rectum and extends proximally in continuity; Crohn disease is patchy, transmural, and may spare the rectum.

Acute severe ulcerative colitis: ≥6 bloody stools/day plus systemic toxicity; give intravenous hydrocortisone and assess response at day 3 using Travis criteria (stool frequency >8 or C-reactive protein >45 mg/L predicts colectomy).

Anti-tumor necrosis factor therapy requires exclusion of latent tuberculosis and hepatitis B screening before initiation.

Therapeutic drug monitoring: reactive monitoring for loss of response, proactive monitoring for infliximab trough levels; target trough 3-7 micrograms/mL in maintenance.

Fecal calprotectin <50 micrograms/g suggests mucosal healing; >250 micrograms/g suggests active inflammation.

Primary sclerosing cholangitis coexists with ulcerative colitis in 70-80% of cases; colonoscopy surveillance for colorectal neoplasia starts at 8 years of disease.

Vedolizumab is gut-selective and carries no increased risk of systemic infection or reactivation of tuberculosis.

Tofacitinib and other Janus kinase inhibitors carry boxed warnings for serious infection, malignancy, and thrombosis; avoid in patients over 65 with cardiovascular risk.

Colorectal cancer screening starts at age 45 for average-risk adults; colonoscopy every 10 years, fecal immunochemical test annually, or stool DNA every 3 years.

Adenoma surveillance: 1-2 tubular adenomas <10 mm, repeat in 7-10 years; ≥10 mm, villous histology, or high-grade dysplasia, repeat in 3 years.

Lynch syndrome: Amsterdam II criteria and revised Bethesda guidelines; universal tumor testing with mismatch repair immunohistochemistry or microsatellite instability.

Familial adenomatous polyposis: APC mutation, hundreds of adenomas; prophylactic colectomy typically after puberty or when polyps become numerous.

Acute anal fissure: lateral internal sphincterotomy or topical nifedipine; avoid posterior midline biopsy because of poor healing.

Hemorrhoids: rubber band ligation for grade II-III internal hemorrhoids; grade IV and external hemorrhoids require surgical management.

Fecal incontinence: endoanal ultrasound and anorectal manometry evaluate sphincter defect and function; sacral neuromodulation for refractory cases.

Colorectal cancer molecular testing: KRAS/NRAS and BRAF V600E for anti-EGFR eligibility; microsatellite instability-high tumors respond to immune checkpoint inhibitors.

Hepatitis B: HBsAg positive >6 months defines chronic infection; treatment thresholds use HBV DNA, alanine aminotransferase, and fibrosis stage; first-line tenofovir or entecavir.

Hepatitis C is cured with direct-acting antivirals achieving sustained virologic response at 12 weeks; pan-genotypic regimens are first-line.

Child-Pugh score uses bilirubin, albumin, international normalized ratio, ascites, and encephalopathy; MELD 3.0 incorporates sodium, albumin, and sex.

Ascites: serum-ascites albumin gradient ≥1.1 g/dL indicates portal hypertension; spontaneous bacterial peritonitis is diagnosed at polymorphonuclear cell count ≥250/mm3.

Hepatorenal syndrome: creatinine rise with no response to albumin challenge; terlipressin plus albumin is first-line therapy.

Variceal hemorrhage: octreotide plus prophylactic antibiotics (ceftriaxone) reduce mortality; band ligation within 12 hours.

Hepatocellular carcinoma surveillance: ultrasound with or without alpha-fetoprotein every 6 months in cirrhosis; LI-RADS 5 on multiphasic imaging is diagnostic without biopsy.

Acute liver failure: coagulopathy (international normalized ratio ≥1.5) plus encephalopathy in a patient without cirrhosis; N-acetylcysteine is used for acetaminophen and non-acetaminophen etiologies.

Acute pancreatitis diagnosis requires 2 of 3: characteristic pain, lipase >3 times upper limit of normal, or imaging findings.

Gallstone pancreatitis: early endoscopic retrograde cholangiopancreatography within 24-72 hours if cholangitis or persistent biliary obstruction; cholecystectomy during index admission for mild disease.

Tokyo Guidelines grade acute cholangitis; biliary drainage is emergent in grade III and urgent in grade II.

Primary sclerosing cholangitis: multifocal strictures and beading on magnetic resonance cholangiopancreatography; annual ultrasound and colonoscopy surveillance.

Choledocholithiasis predictors: choledocholithiasis on imaging, bilirubin >4 mg/dL with dilated duct, or ascending cholangitis warrant endoscopic retrograde cholangiopancreatography.

Autoimmune pancreatitis type 1: elevated IgG4, sausage pancreas, responds to corticosteroids; type 2 associated with inflammatory bowel disease.

Pancreatic adenocarcinoma: only 15-20% resectable at diagnosis; CA 19-9 is prognostic, not diagnostic; FOLFIRINOX or gemcitabine-nab-paclitaxel for advanced disease.

Pancreatic enzyme replacement: lipase units 25,000-50,000 per meal; enteric-coated formulations with proton pump inhibitor for persistent steatorrhea.

Upper gastrointestinal bleeding: Glasgow-Blatchford score ≤1 identifies very low-risk patients suitable for outpatient management.

Nonvariceal bleeding: endoscopic clips, thermal therapy, or epinephrine injection; epinephrine alone is insufficient without a second modality.

Proton pump inhibitor infusion (80 mg bolus then 8 mg/hour for 72 hours) after endoscopic hemostasis for high-risk stigmata.

Lower gastrointestinal bleeding: colonoscopy within 24 hours after bowel preparation; tagged red cell scan or computed tomography angiography for brisk bleeding.

Ischemic colitis affects watershed areas (splenic flexure, rectosigmoid); rectum is typically spared because of collateral supply.

Acute mesenteric ischemia: lactate and metabolic acidosis are late findings; computed tomography angiography is the diagnostic test of choice.

Boerhaave syndrome: transmural esophageal rupture with mediastinal air; requires urgent surgical or endoscopic management.

Foreign body ingestion: button batteries in the esophagus require emergent removal; sharp objects and magnets require endoscopic retrieval.

Esophageal adenocarcinoma arises from Barrett esophagus; squamous cell carcinoma is linked to smoking, alcohol, and achalasia.

Endoscopic resection (endoscopic mucosal resection or submucosal dissection) is curative for early gastric cancer limited to mucosa with low lymph node risk.

Endoscopic ultrasound with fine-needle aspiration stages pancreatic cancer and samples subepithelial lesions; elastography and contrast improve characterization.

Colorectal polyp size ≥10 mm, villous histology, and high-grade dysplasia increase advanced neoplasia risk and shorten surveillance.

Post-endoscopic retrograde cholangiopancreatography pancreatitis prophylaxis: rectal indomethacin plus hydration; pancreatic stent in high-risk patients.

Quality metrics: cecal intubation rate ≥90%, adenoma detection rate ≥25% overall, withdrawal time ≥6 minutes.

Cholangioscopy (SpyGlass) aids diagnosis of indeterminate biliary strictures with targeted biopsy.

Neuroendocrine tumors: grade by Ki-67 index; well-differentiated tumors <10% respond to somatostatin analogues.

Body mass index ≥30 kg/m2 defines obesity; ≥27 with comorbidity qualifies for pharmacotherapy; ≥35 with comorbidity or ≥40 qualifies for bariatric surgery.

Refeeding syndrome: hypophosphatemia, hypokalemia, hypomagnesemia after rapid refeeding; start at 10-20 kcal/kg/day in high-risk patients and supplement thiamine.

Percutaneous endoscopic gastrostomy is indicated for enteral access >4 weeks; contraindicated in severe coagulopathy, ascites, and peritoneal dialysis.

Sarcopenia in cirrhosis: assess with handgrip strength and skeletal muscle index; late-evening snack and 1.2-1.5 g/kg protein intake.

Metabolic dysfunction-associated steatotic liver disease: weight loss ≥5% improves steatosis, ≥10% improves steatohepatitis and fibrosis.

Bariatric surgery: Roux-en-Y gastric bypass and sleeve gastrectomy; monitor for micronutrient deficiencies including B12, iron, folate, and fat-soluble vitamins.

Enteral nutrition is preferred over parenteral when the gut works; trophic feeding in acute pancreatitis within 24-48 hours reduces infectious complications.

Obesity pharmacotherapy: glucagon-like peptide-1 receptor agonists produce 10-15% weight loss; semaglutide 2.4 mg weekly is approved for chronic weight management.

Clostridioides difficile testing: enzyme immunoassay for glutamate dehydrogenase plus toxin, or nucleic acid amplification; do not test formed stools.

Fidaxomicin or vancomycin is first-line for initial C. difficile infection; metronidazole is reserved for when neither is available.

Cholera: rice-water stools; treat with oral rehydration and single-dose doxycycline or azithromycin; notify public health authorities.

Typhoid fever: blood culture is positive in the first week; fluoroquinolone resistance is widespread, so ceftriaxone or azithromycin is preferred.

Amebic liver abscess: Entamoeba histolytica serology positive in >90%; metronidazole followed by a luminal agent such as paromomycin.

Strongyloidiasis: hyperinfection syndrome with gram-negative sepsis in patients receiving corticosteroids; screen at-risk patients before immunosuppression.

Hepatitis A and E are transmitted fecally-orally; hepatitis E is dangerous in pregnancy with mortality up to 25%.

Tuberculous peritonitis: ascitic fluid with lymphocytosis and high adenosine deaminase; peritoneal biopsy is the most sensitive test.

Randomized controlled trials minimize confounding through randomization and allocation concealment; intention-to-treat analysis preserves prognostic balance.

Sensitivity is true positives divided by true positives plus false negatives; specificity is true negatives divided by true negatives plus false positives.

Positive predictive value depends on prevalence; likelihood ratios are prevalence-independent and useful for updating probability.

Number needed to treat equals 1 divided by absolute risk reduction; number needed to harm equals 1 divided by absolute risk increase.

Levels of evidence: systematic reviews of randomized trials are highest; case reports and expert opinion are lowest.

Publication bias is detected with funnel plot asymmetry and Egger test; registered trial protocols reduce selective reporting.

Informed consent requires capacity, disclosure, understanding, and voluntariness; a patient with delirium lacks capacity regardless of family preference.

Withdrawal of life-sustaining therapy in end-stage cirrhosis is ethically permissible when consistent with patient values and goals; palliative care should be integrated early.