Clin Med GI Unit FAST DIFFERENTIATORS

Dyspepsia

Age >60 with new dyspepsia -> EGD. Age

Erosive / hemorrhagic gastritis (gastropathy)

Superficial erosions + bleeding risk; technically gastropathy because inflammation may be minimal.

Acute stress gastritis

Think ICU patient + stress-related mucosal disease.

NSAID / alcoholic gastritis

Medication/alcohol exposure is the separator.

Nonerosive nonspecific gastritis

Histologic inflammation WITHOUT erosive gastropathy pattern.

H. pylori gastritis / infection

Chronic infection: asymptomatic or development of duodenal or gastric ulcers, gastric cancer

Autoimmune (pernicious anemia) gastritis

Autoimmune disorder involving the fundic glands with resultant achlorhydria and decreased intrinsic factor secretion, can’t bind B12

Zollinger-Ellison syndrome

Rare cause of PUD

Gastric adenocarcinoma

★ Risk factors: increasing age, male sex, smoking, H pylori infection

Acute infectious gastritis

Acute gastritis caused by infection

Duodenal ulcer

Younger patient + pain relieved by food/antacid favors duodenal ulcer in this lecture.

Gastric ulcer

Older patient + early satiety/anorexia; biopsy gastric ulcers because malignancy is a concern.

Infectious esophagitis

Biopsy and brushing for microbiologic (sending for cultures) and histopathologic (pathology, looking for cancerous/abnormal cells) analysis provides high diagnostic accuracy • Candida: diffuse, linear, yellow-…

Pill-induced esophagitis

Most common culprits are NSAIDs, iron, vitamin C, antibiotics, potassium, bisphosphonates

Caustic esophageal injury

Perform upper endoscopy within 12-24 hours to determine extent of injury/treatment pathway – severe injury poses highest risk for short-term and long-term complications

Eosinophilic esophagitis

Edema • Concentric Rings

Esophageal stricture

Gradual and progressive dysphagia to solids over months to years

Esophageal web

Thin diaphragm-like membrane in MID/UPPER esophagus; may be multiple.

Schatzki ring

Smooth circumferential ring at DISTAL esophagus/squamocolumnar junction.

Zenker diverticulum

Diagnose with video esophagography • Small, asymptomatic diverticula can be observed

GERD

Retrosternal burning/regurgitation; alarm symptoms or refractory disease -> EGD. Barrett is a major chronic complication.

Barrett esophagus

With chronic damage, squamous epithelium is replaced by metaplastic columnar epithelium over time

Achalasia

Dysphagia to BOTH solids + liquids; bird-beak on barium; manometry confirms impaired LES relaxation.

Mallory-Weiss syndrome

Mucosal tear after forceful retching/vomiting -> hematemesis; usually self-limited.

Boerhaave syndrome

TRANSMURAL rupture after forceful emesis -> severe chest pain/systemic toxicity; surgical emergency.

Esophageal varices

Portal HTN + painless massive hematemesis. Acute: resuscitate + octreotide + urgent banding; prevention: nonselective β-blocker.

Odynophagia

Pain with swallowing = odynophagia; difficulty/food sticking = dysphagia.

Dysphagia

Solids only/progressive = think mechanical obstruction; solids + liquids = think motility disorder.

Hiatal hernia

Found in about 1/4 of patients with nonerosive GERD, 3/4 with severe erosive esophagitis, and 90% with Barrett esophagus (lecture figures).

Esophageal SCC

Most often upper/middle third of esophagus in the lecture comparison.

Esophageal adenocarcinoma

Most often distal esophagus/GE junction; Barrett esophagus is the key precursor emphasized in lecture.

Osmotic diarrhea

Stops/decreases with fasting; positive/high osmotic gap; typically <1 L/day.

Secretory diarrhea

Persists despite fasting; high-volume watery stool; infectious toxins are classic causes.

Acute inflammatory / infectious diarrhea

MCC bacterial enteritis in US Classically caused from undercooked poultry C jejuni infection also has been associated with reactive arthritis and Guillain-Barré syndrome Reactive arthritis is 1-2 months after…

Parasitic diarrhea

Giardia lamblia

Chronic diarrhea

IBS is MCC of chronic diarrhea in young adults

Constipation

Chronic difficult stool passage without an obstructing stool mass.

Fecal impaction

Hard stool mass in rectum; overflow diarrhea can mimic true diarrhea.

Nausea and vomiting

Bulk-forming laxatives (ex: psyllium, methylcellulose) Osmotic laxatives (ex: magnesium hydroxide, magnesium citrate, lactulose) Stimulant laxatives (ex: senna) Emollients (stool surfactant) (ex: docusate) Opi…

Viral gastroenteritis

Full recovery occurs, but long-lasting immunity does not develop.

Cholera (Vibrio cholerae)

Rice-water stool + very large volume + dehydration.

ETEC / traveler’s diarrhea

Traveler’s diarrhea also can be caused by Campylobacter, Shigella, Salmonella, norovirus, rotavirus, and Giardia.

Campylobacter jejuni enteritis

Associated with reactive arthritis and Guillain-Barré syndrome.

Shigella infection

Can be associated with hemolytic uremic syndrome (HUS).

Nontyphoidal Salmonella

Think eggs/poultry and reptile exposure.

EHEC (incl. O157:H7)

Major complication: HUS (hemolytic anemia, thrombocytopenia, AKI).

Yersinia enterocolitica

Undercooked pork + RLQ pain + pharyngitis.

Acute hemorrhagic colitis

EHEC treatment warning is high yield because antibiotics can increase HUS risk.

Giardiasis

Fat malabsorption -> greasy/floating stool.

Entamoeba histolytica infection

Amebic liver abscess is the key complication emphasized.

Malabsorption overview

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Fat / bile-salt malabsorption

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Specific nutrient malabsorption

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Celiac disease

Gluten-triggered proximal small-bowel villous destruction; dermatitis herpetiformis is a major clue.

Whipple disease

Malabsorption + weight loss + diarrhea PLUS migratory arthralgias/systemic findings; rare Tropheryma whipplei disease.

Carbohydrate intolerance

A malabsorption syndrome caused by the inability to digest certain dietary carbohydrates due to the lack of one or more intestinal enzymes

Lactose intolerance

Symptoms follow lactose exposure; classic osmotic diarrhea pattern that improves when lactose is removed.

Short bowel syndrome

MCC are resection to treat Crohn disease, mesenteric ischemia/infarction, radiation enteritis, cancer/tumor resection, volvulus, congenital anomalies, and trauma

Small intestinal bacterial overgrowth (SIBO)

Under normal conditions, the proximal small bowel contains < 105 bacteria/mL, mainly gram-positive aerobic bacteria

Internal hemorrhoids

ABOVE dentate line + usually painless bleeding/prolapse.

External / thrombosed external hemorrhoids

BELOW dentate line; thrombosis = severe pain.

Proctitis

Tenesmus + urgency + mucus/bloody discharge

Anal fissure

Severe tearing pain WITH/after defecation + small bright-red blood; usually posterior midline.

Perianal abscess

Constant throbbing perianal pain + tender/fluctuant mass; needs incision & drainage.

Anorectal fistula

Chronic/recurrent drainage after abscess; external opening/tract; usually surgical management.

Pilonidal disease

Occurs within or above gluteal cleft

Hidradenitis suppurativa

Chronic inflammatory condition involving the follicle

Acute pancreatitis

Severe epigastric pain radiating to back + lipase ≥3× ULN; gallstones/alcohol are major causes. Treat with aggressive fluids, analgesia, early enteral feeding.

Chronic pancreatitis

Chronic/recurrent epigastric pain + calcifications -> later steatorrhea, weight loss, diabetes; enzymes may be normal.

Pancreatic pseudocyst

Complication of pancreatitis (usually chronic) or trauma

Pancreatic insufficiency

MCC is chronic pancreatitis; steatorrhea appears after about 90% function is lost; low fecal elastase in pt w/chronic pancreatic disease

Pancreatic cancer

Painless jaundice + weight loss (head lesion); Courvoisier sign. CT pancreas protocol is key imaging.

Autoimmune pancreatitis

Remember the HISTORt mnemonic exactly as emphasized in lecture.

Cholelithiasis

Episodic postprandial RUQ/epigastric biliary colic; NO fever, leukocytosis, or persistent obstruction; labs often normal.

Acute cholecystitis

Persistent RUQ pain + fever/leukocytosis + Murphy sign. US first; HIDA if equivocal.

Chronic cholecystitis

Repeated episodes of acute cholecystitis or chronic irritation of the gallbladder wall by stones

Biliary dyskinesia

Also called chronic acalculous cholecystitis (no stones)

Postcholecystectomy syndrome

Continued RUQ pain, flatulence, and fatty food intolerance after cholecystectomy sx suggests the possibility of an incorrect diagnosis

Biliary stricture

Cholangitis is most common complication of stricture Pain, fever, chills, and jaundice develop within a few weeks to months after cholecystectomy • ERCP permits sphincterotomy, biopsy, dilation, or stent place…

Primary sclerosing cholangitis (PSC)

Up to 20% of patients will develop cholangiocarcinoma (#1 complication) • Tumor marker for this and pancreatic cancer

Primary biliary cholangitis (PBC)

Cholestasis: elevated alk phos, cholesterol, and bilirubin • Antimitochondrial antibodies are present in 90% of patients, can confirm dx

Choledocholithiasis

CBD stone -> jaundice/obstructive labs ± RUQ pain; MRCP/EUS detects, ERCP removes.

Acute cholangitis

Charcot triad = fever + jaundice + RUQ pain; urgent IV antibiotics + ERCP drainage.

Gallbladder carcinoma

Gallbladder cancer pain tends to occur earlier; diagnosis is often incidental.

Cholangiocarcinoma

~50% perihilar, ~40% distal extrahepatic, ~10% intrahepatic in lecture; intrahepatic tumors may lack obstructive findings.

Ileus

Diffuse bowel dilation with NO mechanical obstruction; hypoactive/absent bowel sounds; common post-op/opioid/electrolyte causes.

Ogilvie syndrome

Acute COLONIC pseudo-obstruction in ill/hospitalized patient; no mechanical blockage; neostigmine or decompression if needed.

Small bowel obstruction (SBO)

Mechanical obstruction: colicky pain + vomiting + distention + obstipation; transition point on CT; prior surgery/adhesions common.

Appendicitis

Periumbilical pain migrating to RLQ + anorexia/N/V; McBurney tenderness; CT in adults, US often first in pregnancy/children.

Meckel diverticulum

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Intussusception

Most common in children, particularly 6 mo to 3 yo

Duodenal intestinal atresia

Occurs in 1:10K live births

Acute mesenteric ischemia

Severe abdominal pain OUT OF PROPORTION to exam; embolic/thrombotic risk; CTA urgently.

Chronic mesenteric ischemia

Postprandial pain + food fear + weight loss; atherosclerotic vascular disease.

Ischemic colitis

Older/vascular-risk patient with crampy LLQ pain + hematochezia; watershed colon involvement.

Incisional hernia

Prior abdominal incision is the key clue.

Femoral hernia

Less common than inguinal hernias but HIGHER risk of strangulation.

Direct inguinal hernia

MEDIAL to inferior epigastric vessels; lower strangulation risk.

Indirect inguinal hernia

Most common hernia overall; LATERAL/superior to inferior epigastric vessels; higher incarceration/strangulation risk.

Umbilical hernia

Location at navel is the main distinguishing feature.