Step 3 · 6–8%

Gastrointestinal System

Bleeding, liver, gallbladder and pancreas, bowel disease, screening and the acute abdomen.

GI bleeding

Resuscitate first, then sort upper from lower and time the scope. Questions turn on who needs octreotide and antibiotics, who can go home, and when radiology takes over.

Rules to know

Hematemesis or melena with tachycardia or low pressure → two large-bore IVs, crystalloid, type and crossmatch; endoscopy once resuscitated
Upper GI bleed, no cardiac disease → transfuse red cells only below hemoglobin 7 g/dL; use 8 g/dL with cardiovascular disease
Suspected ulcer bleed awaiting endoscopy → IV proton pump inhibitor; upper endoscopy within 24 hours of arrival
Ulcer with active spurting or a visible vessel → endoscopic hemostasis, high-dose PPI for 3 days, then oral PPI twice daily to day 14
Clean-based ulcer on endoscopy → oral PPI, resume eating, discharge soon; rebleeding risk is low
Glasgow-Blatchford score 0–1 → outpatient care with early outpatient endoscopy instead of admission
Cirrhosis with hematemesis → IV octreotide, IV ceftriaxone, careful transfusion to about 7 g/dL, band ligation within 12 hours
Variceal bleeding not stopped by banding → balloon tamponade as a short bridge, then TIPS
Child-Pugh C (10–13) variceal bleed controlled at endoscopy → early TIPS within 72 hours lowers rebleeding and death
Survivor of a variceal bleed → nonselective beta-blocker plus repeat banding every few weeks until varices are gone
Isolated gastric varices in chronic pancreatitis → splenic vein thrombosis; splenectomy is curative
Hematemesis after repeated retching in a heavy drinker → Mallory-Weiss tear; most stop alone, endoscopic therapy if still bleeding
Brisk hematochezia with shock → upper endoscopy first, since roughly one in ten such bleeds comes from above the ligament of Treitz
Stable hospitalized lower GI bleed → bowel preparation, then colonoscopy; diverticula and angioectasias are the usual sources
Lower GI bleed with Oakland score ≤8 → discharge for outpatient colonoscopy
Ongoing hematochezia, unstable, upper source excluded → CT angiography, then catheter angiography and embolization
Painless, large-volume maroon or red stool in an older adult → diverticular bleeding; usually stops spontaneously, may recur
Recurrent occult bleeding with aortic stenosis → angioectasias (Heyde syndrome); endoscopic ablation, and valve replacement often helps
Bleeding persists with normal upper endoscopy and colonoscopy → video capsule study of the small bowel
Prior aortic graft and a small self-limited bleed → herald bleed of aortoenteric fistula; urgent CT angiography and vascular surgery
GI bleed on warfarin or a DOAC → hold it; reverse only for life-threatening bleeding; do not delay endoscopy to fix the INR
Ulcer bleed on aspirin for coronary or stroke prevention → restart aspirin as soon as hemostasis is secure; stop aspirin used only for primary prevention
Bleeding ulcer → test for H. pylori by biopsy; a negative result during acute bleeding should be repeated later
Brisk upper bleeding with blood in the stomach → IV erythromycin 30–120 minutes before endoscopy improves the view
Ulcer rebleeds after endoscopic therapy → second endoscopy; if that fails, transcatheter embolization, then surgery
ICU patient ventilated over 48 hours or coagulopathic → stress-ulcer prophylaxis with PPI or H2 blocker; not for routine ward patients

Traps that cost points

Transfusing a variceal bleeder up to a hemoglobin of 10→ Extra volume raises portal pressure and rebleeding. Use a restrictive threshold near 7 g/dL unless the patient is exsanguinating or has active coronary ischemia.
Sending a cirrhotic patient with a GI bleed to endoscopy without antibiotics→ Start ceftriaxone on arrival and continue up to 7 days; it reduces infection, rebleeding and death in cirrhosis.
Ordering colonoscopy first for hematochezia with hypotension→ A fast upper source can present as red blood per rectum. Resuscitate and do upper endoscopy first when the patient is unstable.
Postponing endoscopy until a mildly raised INR is fully corrected→ Endoscopy is safe with modest INR elevation; reversal is for life-threatening bleeding and should not delay the scope.
Stopping a coronary patient's aspirin for weeks after an ulcer bleed→ Restart secondary-prevention aspirin once bleeding is controlled, usually within days, with a PPI; prolonged interruption raises cardiovascular death.
Starting propranolol during the acute variceal bleed→ Beta-blockers worsen hypotension during active bleeding. Use octreotide acutely and begin the beta-blocker after the bleed is controlled, before discharge.
Treating a variceal bleed with PPI alone→ Variceal bleeding needs octreotide, antibiotics and band ligation; a PPI does not lower portal pressure.
Accepting a negative H. pylori biopsy taken during an active bleed→ Bleeding and PPI use cause false negatives. Retest later with breath test, stool antigen or biopsy before ruling the organism out.

Liver tests, hepatitis & acute liver injury

In the Brain

Read the enzyme pattern, then order the single test that names the cause. Know which viral, alcohol, drug and autoimmune injuries need treatment, and who goes to a transplant center.

Rules to know

Aminotransferases in the thousands → acute viral, ischemic or toxin injury; send an acetaminophen level even without a reported overdose
ALT and AST above 1,000 after hypotension, high LDH, falling within days → ischemic hepatitis; treat the circulation
AST about twice ALT, both under 300, with high GGT → alcohol-related liver disease
Isolated high alkaline phosphatase → GGT to confirm a liver source, then right upper quadrant ultrasound
Cholestatic labs, normal ducts on ultrasound, middle-aged woman with itch → antimitochondrial antibody; positive means primary biliary cholangitis, start ursodiol
PBC with alkaline phosphatase still high after a year of ursodiol → add a second-line agent such as a PPAR agonist; check bone density
Ulcerative colitis with cholestatic labs → MRCP; beaded strictures mean primary sclerosing cholangitis, needing yearly colonoscopy and cholangiocarcinoma surveillance
Mild unconjugated hyperbilirubinemia during fasting or illness, normal blood count and enzymes → Gilbert syndrome; reassure
Young woman, ALT in hundreds, high IgG, ANA or anti-smooth muscle antibody → autoimmune hepatitis; biopsy, then prednisone plus azathioprine after TPMT check
Transferrin saturation ≥45% with high ferritin → HFE genotype; C282Y homozygotes get phlebotomy to ferritin 50–100
Hemochromatosis with ferritin over 1,000 or raised ALT → stage fibrosis by elastography, MRI or biopsy; screen first-degree relatives
Liver disease under 40 with tremor, psychiatric change or hemolysis → Wilson disease; ceruloplasmin, 24-hour urine copper, slit-lamp exam
Wilson disease confirmed → chelation with penicillamine or trientine, zinc for maintenance, test siblings
Acute hepatitis workup → IgM anti-HAV, HBsAg, IgM anti-HBc, and HCV antibody with HCV RNA
Anti-HBs alone → vaccinated; anti-HBs with anti-HBc → past infection; HBsAg beyond 6 months → chronic hepatitis B
Chronic hepatitis B with cirrhosis, or high DNA plus raised ALT → tenofovir or entecavir long term; in cirrhosis any detectable DNA qualifies
Before rituximab, chemotherapy or strong immunosuppression → check HBsAg and anti-HBc; prophylactic antiviral if HBsAg positive, often if core positive
Positive HCV antibody → HCV RNA; antibody alone may mean cleared infection
Chronic hepatitis C → pangenotypic direct-acting antiviral for 8–12 weeks after checking HBV status, since HBV can flare
Undetectable HCV RNA 12 weeks after therapy → cure; patients with cirrhosis still need liver cancer surveillance
Hepatitis B carrier with abrupt worsening → test for hepatitis D (anti-HDV)
Pregnant traveler with acute hepatitis after untreated water → hepatitis E; high risk of fulminant failure
Household or sexual contact of hepatitis A within 2 weeks → vaccine; immune globulin instead under age 1, and added for immunocompromise or chronic liver disease
Heavy drinker with jaundice, fever, tender liver, AST below 400 → alcohol-associated hepatitis; exclude infection and GI bleeding
Alcohol-associated hepatitis with MELD above 20 → prednisolone 40 mg daily for 28 days if no active infection
Lille score above 0.45 on day 7 of prednisolone → stop steroids; discuss early transplant where offered
Hepatic steatosis plus obesity, diabetes, hypertension or dyslipidemia → MASLD (the old NAFLD); calculate FIB-4
MASLD with FIB-4 ≥1.3 → elastography; below 1.3 is low risk, repeat every 1–3 years
MASH with stage F2–F3 fibrosis → weight loss plus resmetirom or semaglutide; statins are safe and should continue
Acetaminophen liver injury → ALT peaks on day 3–4; acidosis, rising INR or encephalopathy → early transfer to a transplant center
INR ≥1.5 with encephalopathy and no prior cirrhosis → acute liver failure; ICU at a transplant center, acetylcysteine regardless of cause
Fever, RUQ pain and liver lesion after biliary infection → pyogenic abscess; percutaneous drainage plus antibiotics

Traps that cost points

Ordering hepatitis B surface antibody alone to judge infection status→ Use HBsAg, anti-HBc and anti-HBs together; core antibody separates past infection from vaccination.
Draining a suspected amebic liver abscess in a young traveler→ Amebic abscess responds to metronidazole followed by a luminal agent; drainage is reserved for rupture risk or failure to improve.
Starting prednisolone for alcohol-associated hepatitis with an untreated infection→ Screen with cultures, chest film and paracentesis if ascites. Treat infection first; steroids raise infection deaths.
Giving DAA therapy for hepatitis C without checking hepatitis B→ HBV can reactivate as HCV clears. Test HBsAg and anti-HBc first and monitor or give prophylaxis as needed.
Stopping statins because of mild enzyme rise in MASLD→ Statins are safe in fatty liver and lower cardiovascular death, the leading cause of mortality in these patients.
Working up Gilbert syndrome with imaging and biopsy→ Isolated indirect bilirubin with normal blood count and enzymes needs no further testing; reassure.
Keeping an acetaminophen liver failure patient at a small hospital until labs worsen→ Call the transplant center early when INR, lactate, pH or mental status turn; transfer windows close fast.
Using HCV antibody to confirm cure or reinfection→ Antibody stays positive for life; use HCV RNA to diagnose active infection, cure and reinfection.

Cirrhosis & its complications

In the Brain

Each decompensation has a fixed first move: tap new ascites, look for the trigger behind confusion, protect the kidneys, screen for varices and cancer, and refer for transplant early.

Rules to know

New ascites, or any admitted patient with cirrhotic ascites → diagnostic paracentesis: cell count, albumin, protein, culture in blood-culture bottles
Serum-ascites albumin gradient ≥1.1 g/dL → portal hypertension; below 1.1 → carcinomatosis, tuberculosis, pancreatic or nephrotic causes
Ascitic neutrophil count ≥250 per microliter → spontaneous bacterial peritonitis; IV cefotaxime or ceftriaxone without waiting for culture
SBP with creatinine above 1, BUN above 30 or bilirubin above 4 → IV albumin 1.5 g/kg on day 1 and 1 g/kg on day 3
Ascitic fluid with several organisms, high protein, low glucose → secondary peritonitis from perforation; CT and surgical consult
After a first SBP episode → long-term prophylaxis with ciprofloxacin or trimethoprim-sulfamethoxazole
Cirrhotic ascites → spironolactone with furosemide at about 100:40; avoid NSAIDs and ACE inhibitors
Tense or diuretic-resistant ascites → large-volume paracentesis with 6–8 g albumin per liter if over 5 L removed; TIPS if frequent
Right pleural effusion in cirrhosis without lung or heart disease → hepatic hydrothorax; control ascites, avoid a chest tube
Confusion with asterixis in cirrhosis → look for infection, bleeding, constipation, low potassium or sedatives, start lactulose; ammonia level adds little
Lactulose titrated to 2–3 soft stools daily; encephalopathy recurring despite it → add rifaximin
Rising creatinine in cirrhosis → stop diuretics and nephrotoxins, give IV albumin 1 g/kg for 2 days, look for infection
Kidney injury persisting after albumin, no shock or toxin → hepatorenal syndrome; terlipressin plus albumin (not if hypoxic) or norepinephrine
Breathlessness and lower saturation when upright in cirrhosis → hepatopulmonary syndrome; bubble echo shows late shunting; transplant evaluation
Newly diagnosed cirrhosis → endoscopy for varices unless liver stiffness <20 kPa with platelets >150,000
Medium or large varices that have never bled → carvedilol or propranolol, or band ligation if beta-blockers are not tolerated
Cirrhosis of any cause → ultrasound with or without AFP every 6 months for hepatocellular carcinoma
Hepatitis B without cirrhosis → still survey for liver cancer in Asian men over 40, Asian women over 50, African-born adults, family history
Liver nodule ≥1 cm in cirrhosis → multiphase CT or MRI; arterial enhancement with washout is diagnostic, no biopsy
HCC within Milan criteria → transplant evaluation (one tumor ≤5 cm, or up to three ≤3 cm); small single tumors may be resected or ablated
MELD ≥15 or a first decompensation (ascites, variceal bleed, encephalopathy, jaundice) → refer for transplant evaluation
Child-Pugh class C → poor surgical survival; avoid elective operations
Pain control in cirrhosis → acetaminophen up to 2 g daily; avoid NSAIDs, minimize opioids and benzodiazepines
Sodium below 125 in cirrhosis → hold diuretics and restrict free water
Hospitalized patient with cirrhosis and high INR → still give VTE prophylaxis; a prolonged INR does not protect against clots
Cirrhosis maintenance → hepatitis A and B vaccines if not immune, plus pneumococcal and influenza vaccines; avoid alcohol completely

Traps that cost points

Holding paracentesis or giving plasma because the INR is 2→ Paracentesis bleeding is rare even with abnormal INR or platelets; tap without routine correction.
Measuring serial ammonia levels to diagnose or track encephalopathy→ The diagnosis is clinical. Find the precipitant and titrate lactulose to stool output, not to a lab value.
Treating SBP with antibiotics but skipping albumin→ Albumin on days 1 and 3 cuts kidney failure and death in patients with raised creatinine, BUN or bilirubin.
Using furosemide alone for cirrhotic ascites→ Spironolactone is the backbone because secondary hyperaldosteronism drives sodium retention; add furosemide for balance and potassium.
Biopsying a nodule with classic arterial enhancement and washout→ In cirrhosis that imaging pattern establishes HCC; biopsy adds bleeding and seeding risk without changing care.
Stopping liver cancer surveillance after hepatitis C cure→ Established cirrhosis keeps its cancer risk; continue 6-monthly ultrasound.
Placing a chest tube for hepatic hydrothorax→ Tubes cause massive protein and fluid loss and infection. Treat ascites, use thoracentesis for symptoms, and consider TIPS.
Ordering a large-volume tap without albumin→ Removing more than 5 L without albumin risks circulatory dysfunction and kidney injury; give 6–8 g per liter removed.

Gallbladder, bile ducts & pancreas

In the Brain

Ultrasound first for right upper pain, then match the stone's location to the procedure. In pancreatitis give moderate fluids, feed early, and save the CT for patients who are not improving.

Rules to know

Meal-related RUQ pain lasting under 6 hours, normal labs → biliary colic; ultrasound, then elective laparoscopic cholecystectomy
Gallstones found incidentally, no symptoms → no surgery; explain which symptoms should bring them back
RUQ pain over 6 hours, fever, Murphy sign, thick wall on ultrasound → acute cholecystitis; NPO, fluids, antibiotics, cholecystectomy within 72 hours
Suspected cholecystitis, equivocal ultrasound → HIDA scan; gallbladder that never fills confirms cystic duct obstruction
Cholecystitis in a patient too ill for surgery → percutaneous cholecystostomy, interval cholecystectomy if they recover
ICU, burn or TPN patient with fever and RUQ tenderness, no stones → acalculous cholecystitis; antibiotics and percutaneous drainage
Diabetic with cholecystitis and gas in the gallbladder wall → emphysematous cholecystitis; urgent cholecystectomy, broad antibiotics
Fever, jaundice and RUQ pain → ascending cholangitis; blood cultures, piperacillin-tazobactam, ERCP within 24–48 hours, sooner with shock
Stone seen in the common bile duct → ERCP with sphincterotomy and extraction, then cholecystectomy
Gallstones with dilated duct or high bilirubin but no duct stone seen → MRCP or endoscopic ultrasound before deciding on ERCP
Mild gallstone pancreatitis → cholecystectomy during the same admission
Older woman with small bowel obstruction and air in the bile ducts → gallstone ileus; surgical removal of the stone
Epigastric pain to the back with lipase over 3 times normal → acute pancreatitis; two of pain, enzyme, imaging suffice
Clear-cut acute pancreatitis on arrival → no CT; contrast CT only if the diagnosis is uncertain or no improvement after 48–72 hours
First episode of pancreatitis → right upper quadrant ultrasound, triglycerides and calcium
Acute pancreatitis fluids → moderate, goal-directed lactated Ringer's; aggressive large volumes add harm without benefit
Mild pancreatitis → oral diet within 24 hours as tolerated; severe → nasogastric or nasojejunal tube feeding rather than TPN
Organ failure lasting beyond 48 hours → severe acute pancreatitis; ICU-level care
Necrotizing pancreatitis → no prophylactic antibiotics; carbapenem only for suspected infected necrosis (gas on CT, worsening after a week)
Infected or symptomatic walled-off necrosis → wait about 4 weeks, then stepwise endoscopic or percutaneous drainage
Fluid collection persisting past 4 weeks → pseudocyst; watch if asymptomatic, drain endoscopically if it causes pain, obstruction or infection
Pancreatitis with triglycerides over 1,000 → IV insulin infusion with dextrose; plasmapheresis for severe cases; then long-term lipid control
Unexplained pancreatitis after 40, no stones or alcohol → endoscopic ultrasound to look for a tumor
Recurrent pain, oily stools, diabetes, calcifications on CT → chronic pancreatitis; fecal elastase confirms exocrine insufficiency
Chronic pancreatitis care → stop alcohol and tobacco, enzyme replacement with meals, yearly glucose screening
Older adult with painless jaundice, weight loss and palpable gallbladder → pancreatic head cancer; pancreas-protocol CT
Pancreatic cancer suspected but no mass on CT → endoscopic ultrasound with fine-needle aspiration
CA 19-9 → follows known pancreatic cancer; not for screening or diagnosis
Pancreatic adenocarcinoma → germline genetic testing for every patient
Pancreatic cyst with main-duct dilation, mural nodule or jaundice → endoscopic ultrasound and surgical referral
Sausage-shaped pancreas with high IgG4 → autoimmune pancreatitis; glucocorticoids
PSC with new jaundice and a dominant stricture → cholangiocarcinoma until proven otherwise; ERCP brushings, CA 19-9

Traps that cost points

Ordering abdominal CT on admission for straightforward pancreatitis→ Early CT underestimates necrosis and rarely changes care. Reserve it for diagnostic doubt or failure to improve after 48–72 hours.
Giving prophylactic imipenem for sterile necrosis→ Prophylactic antibiotics do not lower infection or death; start them only for suspected infected necrosis or another documented infection.
Keeping pancreatitis patients NPO until lipase normalizes→ Feed by mouth as soon as tolerated; early feeding protects the gut barrier and lipase level does not guide timing.
Discharging gallstone pancreatitis to an outpatient surgery referral→ Recurrence in the following weeks is common; remove the gallbladder during the same admission for mild disease.
Sending every gallstone pancreatitis for urgent ERCP→ ERCP helps only with cholangitis or persistent bile duct obstruction; otherwise it adds risk.
Running lactated Ringer's at 20 mL/kg per hour for a day→ Aggressive fluids cause overload without better outcomes; use moderate, goal-directed resuscitation with frequent reassessment.
Removing asymptomatic gallstones found on imaging→ Most never cause symptoms; operate when biliary pain or a complication appears.
Draining an early pancreatic necrosis collection in week one→ Early intervention raises death; let the collection wall off for about 4 weeks unless the patient is unstable.

Esophagus & stomach

In the Brain

Treat reflux without alarm signs empirically and scope anyone with alarm signs. Test for H. pylori with tests that detect active infection, treat with a regimen that works, and prove eradication.

Rules to know

Heartburn and regurgitation without alarm features → daily PPI 30–60 minutes before breakfast for 8 weeks, then step down to the lowest dose that works
Reflux or dyspepsia plus dysphagia, weight loss, bleeding, anemia or persistent vomiting → upper endoscopy
Heartburn persisting on twice-daily PPI → check adherence and timing, then endoscopy and pH monitoring off PPI
Chronic reflux plus three Barrett risk factors → screening endoscopy; risks are male sex, age over 50, white race, smoking, obesity, family history
Barrett esophagus without dysplasia → daily PPI and surveillance endoscopy every 3–5 years by segment length
Barrett with confirmed dysplasia → endoscopic eradication: resect visible nodules, then ablate
Coughing, choking or nasal regurgitation with swallowing after a stroke → oropharyngeal dysphagia; videofluoroscopic swallow study
Solid food sticking behind the sternum → upper endoscopy first
Dysphagia to solids and liquids from onset, regurgitation, bird-beak narrowing → achalasia; high-resolution manometry confirms
Achalasia confirmed → endoscopy to exclude junction cancer, then pneumatic dilation, Heller myotomy or POEM; botulinum injection for frail patients
Older adult with bad breath and regurgitated old food → Zenker diverticulum; barium swallow before any endoscopy
Young atopic man with food impaction or recurrent solid dysphagia → eosinophilic esophagitis; endoscopy with at least 6 biopsies
Eosinophilic esophagitis → PPI or swallowed topical steroid (budesonide or fluticasone); dupilumab for refractory disease
Food stuck with drooling and inability to handle saliva → emergency endoscopy within hours; partial obstruction within 24 hours
Painful swallowing after doxycycline, bisphosphonate, potassium or NSAID tablet → pill esophagitis; stop the drug, take pills upright with water
Odynophagia plus thrush in HIV or immunosuppression → empiric fluconazole; endoscopy if no better in 3–5 days (CMV, HSV)
Chest pain and neck crepitus after violent vomiting → Boerhaave perforation; water-soluble contrast study or CT, NPO, antibiotics, surgery
Dyspepsia under 60 without alarm features → noninvasive H. pylori test-and-treat; PPI trial if negative
Dyspepsia starting at 60 or older → upper endoscopy
H. pylori testing → urea breath test or stool antigen after 2 weeks off PPI and 4 weeks off antibiotics or bismuth; not serology
H. pylori with unknown resistance → bismuth quadruple therapy (PPI, bismuth, tetracycline, metronidazole) for 14 days
H. pylori alternatives → vonoprazan with amoxicillin, or rifabutin triple; clarithromycin triple only for proven susceptible strains
Treated H. pylori → test of cure by breath test or stool antigen at least 4 weeks after therapy
Gastric ulcer seen at endoscopy → biopsy; repeat endoscopy at 8–12 weeks if it looked suspicious or was not sampled
High-risk patient who must stay on an NSAID or aspirin → add a PPI (prior ulcer, age over 65, anticoagulant, steroid); test and treat H. pylori
Multiple or jejunal ulcers, diarrhea, PPI-refractory → Zollinger-Ellison; fasting gastrin off PPI, check calcium for MEN1
Vomiting undigested food, succussion splash, low chloride and potassium → gastric outlet obstruction; NG decompression, fluids, then endoscopy
Diabetic with early satiety and vomiting, normal endoscopy → 4-hour gastric emptying scan off opioids and GLP-1 agonists
Gastroparesis → glucose control and drug review; metoclopramide no longer than 12 weeks because of tardive dyskinesia
Daily cannabis use with cyclic vomiting eased by hot showers → cannabinoid hyperemesis; stop cannabis; haloperidol or topical capsaicin acutely
Cramps, flushing and diarrhea within 30 minutes of eating after gastric surgery → early dumping; meal changes first, octreotide if refractory
Symptomatic paraesophageal hiatal hernia → surgical repair; risk of volvulus and strangulation

Traps that cost points

Ordering H. pylori serology to diagnose or confirm cure→ Antibodies persist after cure and cannot show active infection; use breath test, stool antigen or biopsy.
Testing for H. pylori while the patient keeps taking a PPI→ PPIs suppress the organism and cause false negatives; stop them 2 weeks before breath or stool testing.
Choosing clarithromycin triple therapy by default→ Clarithromycin resistance is common in the US; use bismuth quadruple or another regimen unless susceptibility is known.
Skipping the test of cure after H. pylori therapy→ Every treated patient should have eradication confirmed, at least 4 weeks after antibiotics and off PPI.
Scoping first for suspected Zenker diverticulum→ Blind intubation can perforate the pouch; a barium swallow defines the anatomy first.
Labeling achalasia in an older adult with rapid weight loss without endoscopy→ Cancer at the gastroesophageal junction can mimic achalasia; endoscopy excludes pseudoachalasia before treatment.
Keeping metoclopramide going for months→ Tardive dyskinesia risk rises with duration; limit to 12 weeks and stop if movement symptoms appear.
Leaving uncomplicated reflux on twice-daily PPI indefinitely→ Once symptoms settle, step down to the lowest effective dose or on-demand use; keep long-term PPI for Barrett, severe esophagitis or ongoing NSAID risk.

Diarrhea & enteric infections

In the Brain

Most acute diarrhea needs fluids rather than tests. Questions hinge on which exposure or host needs a stool test or antibiotic, how to treat C. difficile, and how to sort chronic diarrhea.

Rules to know

Watery diarrhea under a week, no fever or blood, drinking well → oral fluids, no stool test; loperamide is acceptable
Diarrhea with fever, blood, severe dehydration, over 7 days, immunosuppression or outbreak → stool multiplex PCR or culture
Vomiting within 1–6 hours of a shared meal → preformed toxin (S aureus, B cereus); supportive care
Bloody diarrhea with little fever after undercooked beef or a petting zoo → Shiga toxin E coli; no antibiotics or antimotility drugs, watch for HUS
Traveler's diarrhea, mild → fluids and loperamide; disabling or bloody → single-dose azithromycin, given fluoroquinolone resistance in Asia
Campylobacter enteritis → usually self-limited; azithromycin if severe; Guillain-Barré or reactive arthritis may follow
Nontyphoidal Salmonella in a healthy adult → no antibiotics; treat infants, adults over 50 with vascular disease, prosthetics, sickle cell, immunosuppression
Shigella dysentery → antibiotic guided by susceptibility (azithromycin or ciprofloxacin); keep food handlers and daycare workers out until cleared
Raw oysters, then bullae and shock in someone with cirrhosis → Vibrio vulnificus; doxycycline plus ceftriaxone, surgical debridement
Fever and RLQ pain mimicking appendicitis after pork products → Yersinia enterocolitica
Weeks of foul greasy diarrhea and bloating after camping or well water → Giardia; stool antigen or PCR, tinidazole or metronidazole
Recurrent or refractory giardiasis → look for IgA deficiency or common variable immunodeficiency
Advanced HIV with chronic watery diarrhea → Cryptosporidium; start or optimize antiretroviral therapy
Bloody diarrhea after travel, or a liver abscess in a migrant → Entamoeba histolytica; metronidazole then paromomycin
Eosinophilia in someone from the tropics before steroids or transplant → Strongyloides serology and ivermectin to prevent hyperinfection
New diarrhea after antibiotics, 3 or more unformed stools a day → C difficile testing on unformed stool only
First C difficile episode → oral fidaxomicin or oral vancomycin for 10 days; metronidazole only when neither is available
C difficile with hypotension, ileus or megacolon → high-dose oral vancomycin plus IV metronidazole, rectal vancomycin if ileus; surgical consult
First C difficile recurrence → fidaxomicin, or a tapered and pulsed oral vancomycin course
Two or more C difficile recurrences → fecal microbiota-based therapy after a course of anti-C difficile antibiotics
C difficile on a hospital ward → contact precautions and soap-and-water handwashing; stop needless antibiotics and PPIs
Diarrhea lasting over 4 weeks → CBC, metabolic panel, celiac serology, fecal calprotectin, Giardia test; colonoscopy with biopsies if unexplained
Stool osmotic gap above 100 that stops with fasting → osmotic diarrhea (lactose, magnesium, sugar alcohols)
Low stool osmotic gap, persisting while fasting → secretory diarrhea (stimulant laxatives, hormone-secreting tumors, bile acids)
Low potassium, watery diarrhea and dark-pigmented colon lining → covert stimulant laxative use; stool or urine laxative screen
Bloating and loose stools after dairy → lactose malabsorption; avoidance trial or hydrogen breath test
Prior bowel surgery or scleroderma, bloating, low B12 with high folate → bacterial overgrowth; breath test or empiric rifaximin
Watery diarrhea after ileal resection or gallbladder removal → bile acid diarrhea; trial of cholestyramine
Middle-aged man with diarrhea, weight loss, migratory arthritis and confusion → Whipple disease; PAS-positive macrophages, ceftriaxone then a year of TMP-SMX

Traps that cost points

Sending stool cultures on every short watery illness→ Uncomplicated acute diarrhea resolves with fluids; test when fever, blood, dehydration, duration over a week, immunosuppression or outbreak is present.
Treating bloody diarrhea after a hamburger with ciprofloxacin→ Antibiotics may raise Shiga toxin release and HUS risk; give fluids and monitor counts and creatinine.
Choosing metronidazole first for C difficile→ Fidaxomicin or oral vancomycin cure more reliably; metronidazole is a fallback when neither is available.
Sending a test of cure after C difficile therapy→ Toxin and PCR can stay positive in recovered patients; judge cure clinically and do not retest formed stool.
Relying on alcohol hand rub after a C difficile room→ Alcohol does not kill spores; wash with soap and water and use contact precautions.
Prescribing antibiotics for Salmonella gastroenteritis in a healthy 30-year-old→ Antibiotics do not shorten mild disease and prolong carriage; reserve them for high-risk hosts or invasive infection.
Starting high-dose steroids in a patient from the tropics with eosinophilia→ Check Strongyloides serology and treat with ivermectin first; steroids can trigger fatal hyperinfection.
Giving loperamide for fever with bloody diarrhea→ Antimotility drugs can worsen invasive infection and toxic dilation; avoid them with fever or dysentery.

IBD, IBS, celiac & microscopic colitis

In the Brain

Separate inflammatory from functional disease with calprotectin and a scope, know which IBD patient needs admission or a biologic, and test for celiac while the patient still eats gluten.

Rules to know

Bloody diarrhea, urgency and continuous inflammation from the rectum → ulcerative colitis; exclude infection and C difficile, then colonoscopy with biopsies
Skip lesions, terminal ileitis, perianal fistulas or strictures → Crohn disease; ileocolonoscopy plus CT or MR enterography
Mild-to-moderate ulcerative colitis → oral plus rectal mesalamine; proctitis alone → mesalamine suppository
Moderate-to-severe IBD → biologic or small molecule (anti-TNF, vedolizumab, ustekinumab, IL-23 blocker, JAK inhibitor); steroids only as a bridge
Crohn disease maintenance → mesalamine does not work; use biologic therapy, with or without an immunomodulator
Before anti-TNF or JAK inhibitor → screen for latent TB and hepatitis B; update inactivated vaccines, avoid live vaccines once immunosuppressed
Before azathioprine or mercaptopurine → TPMT (and NUDT15) testing; monitor blood counts and liver tests
Six or more bloody stools daily with fever, tachycardia or anemia → acute severe colitis; admit, IV steroids, VTE prophylaxis, C difficile test
Acute severe colitis not responding by day 3 of IV steroids → infliximab or cyclosporine rescue, or colectomy
Colon wider than 6 cm with systemic toxicity → toxic megacolon; NPO, NG tube, IV steroids and antibiotics, stop opioids; surgery if no quick response
Crohn with perianal pain and fluctuance → pelvic MRI or exam under anesthesia, drain the abscess, then anti-TNF
Crohn with ileal disease or resection → watch for oxalate kidney stones, gallstones and B12 deficiency
Smoker with Crohn disease → stop smoking; it worsens disease course and recurrence after surgery
Colitis beyond the rectum for 8 years → surveillance colonoscopy every 1–3 years; with PSC, yearly from diagnosis
IBD with erythema nodosum or peripheral arthritis → these track bowel activity; uveitis, axial spondyloarthritis and PSC do not
Recurrent abdominal pain tied to defecation at least weekly for 3 months → irritable bowel syndrome if no alarm features
IBS-type symptoms with alarm features → colonoscopy, not an IBS label; alarms are onset after 50, bleeding, weight loss, night symptoms, iron deficiency, family CRC or IBD
Suspected diarrhea-predominant IBS → CBC, celiac serology and fecal calprotectin or CRP; colonoscopy not routine under 45
IBS with constipation → soluble fiber (psyllium) and PEG, then linaclotide or plecanatide
IBS with diarrhea → loperamide, a rifaximin course or eluxadoline (not after cholecystectomy); low-dose tricyclic for pain
Refractory iron deficiency, early osteoporosis or unexplained raised ALT → test for celiac disease
Celiac testing → tissue transglutaminase IgA plus total IgA while eating gluten; IgA deficient → IgG-based tests
Positive celiac serology in an adult → upper endoscopy with duodenal biopsies to confirm
Treated celiac disease → tTG-IgA at 6–12 months; persistent positivity usually means ongoing gluten exposure
Celiac symptoms returning despite strict avoidance → evaluate for refractory celiac disease and T-cell lymphoma
Itchy grouped vesicles on elbows and knees → dermatitis herpetiformis; celiac workup, dapsone after G6PD check
Type 1 diabetes, Down or Turner syndrome, or a celiac first-degree relative → screen with tTG-IgA
Older woman with watery diarrhea, normal colonoscopy, taking NSAID/PPI/SSRI → microscopic colitis; random colon biopsies
Microscopic colitis → stop the suspect drug and give oral budesonide

Traps that cost points

Escalating IBD therapy for a flare without stool testing→ C difficile and other infections mimic flares and worsen with more immunosuppression; test stool first, and biopsy for CMV in steroid-refractory colitis.
Keeping an IBD patient on prednisone to maintain remission→ Steroids induce but do not maintain remission and cause cumulative harm; plan a steroid-sparing maintenance drug at the start.
Using mesalamine to maintain Crohn disease→ Mesalamine has little effect in Crohn disease; maintenance relies on biologics with or without an immunomodulator.
Withholding heparin prophylaxis in severe colitis because of rectal bleeding→ IBD flares are strongly prothrombotic; give pharmacologic VTE prophylaxis unless bleeding is massive.
Starting a gluten-free diet before celiac testing→ Serology and biopsy normalize off gluten; test while the patient still eats it.
Ordering colonoscopy for every young adult with IBS symptoms→ Without alarm features or an age-based screening indication, limited labs and a positive diagnosis are enough.
Giving a live zoster or MMR vaccine to a patient on infliximab→ Live vaccines are contraindicated during biologic therapy; vaccinate before starting or use inactivated options.
Using loperamide or opioids in acute severe colitis→ These can precipitate toxic megacolon; avoid them and treat the inflammation.

Constipation & anorectal problems

In the Brain

Most constipation responds to fiber and osmotic laxatives once alarm features are excluded. Anorectal pain is sorted by examination into fissure, thrombosed hemorrhoid or abscess.

Rules to know

Chronic constipation without alarm features → fiber and fluids, then polyethylene glycol; stimulant laxatives are safe add-ons
New constipation from age 45, or with alarm features → colonoscopy; check calcium and TSH, review drugs (alarms: bleeding, anemia, weight loss)
Constipation failing standard laxatives → prucalopride, linaclotide, plecanatide or lubiprostone
Excess straining, sense of blockage, manual maneuvers → dyssynergic defecation; anorectal manometry and balloon expulsion, then biofeedback
Starting a scheduled opioid → prescribe a stimulant or osmotic laxative at the same time
Opioid constipation despite laxatives → peripherally acting opioid antagonist (methylnaltrexone, naloxegol); never with suspected obstruction
Nursing-home resident with liquid stool leakage and hard stool in the rectum → impaction with overflow; disimpaction and enemas
Painless bright red blood on the paper → internal hemorrhoids; fiber, fluids, topical care; rubber band ligation if persistent
Rectal bleeding blamed on hemorrhoids at 45 or older, or with anemia → colonoscopy anyway
Severely painful bluish perianal lump under 72 hours old → thrombosed external hemorrhoid; excision; after 72 hours, sitz baths
Tearing pain with defecation and a posterior midline split → anal fissure; fiber, sitz baths, topical nifedipine or nitroglycerin
Chronic fissure after 6–8 weeks of topical treatment → botulinum toxin injection or lateral internal sphincterotomy
Lateral, multiple or painless fissures → think Crohn disease, HIV, syphilis, tuberculosis or cancer
Throbbing perianal pain with a tender fluctuant mass → anorectal abscess; incision and drainage; antibiotics only with cellulitis, diabetes or immunosuppression
Persistent drainage from a skin opening after an abscess → fistula-in-ano; fistulotomy or seton; consider Crohn disease
Older woman with tissue prolapsing in concentric rings on straining → full-thickness rectal prolapse; surgical repair
Fecal incontinence after an obstetric tear → endoanal ultrasound for sphincter defect; fiber, pelvic floor therapy, repair if needed
Painful swelling in the sacrococcygeal cleft → pilonidal abscess; drainage now, definitive excision later
Rectal pain and discharge in men who have sex with men → proctitis; test gonorrhea, chlamydia including LGV, syphilis and HSV
Rectal bleeding months after pelvic radiation → radiation proctitis; colonoscopy, then topical or endoscopic argon therapy

Traps that cost points

Attributing rectal bleeding in a 60-year-old to visible hemorrhoids→ Hemorrhoids are common and can coexist with cancer; do colonoscopy at 45 or older or with anemia or bowel-habit change.
Excising a thrombosed external hemorrhoid on day 6→ After 72 hours the clot is organizing and pain is easing; conservative care works better than surgery.
Treating a perianal abscess with antibiotics alone→ Pus needs drainage; antibiotics are an adjunct only for cellulitis, diabetes, immunosuppression or prosthetic hardware.
Relying on docusate as the main laxative→ Stool softeners have weak evidence; polyethylene glycol and stimulants work better.
Giving methylnaltrexone with vomiting and distension→ Peripheral opioid antagonists can perforate an obstructed bowel; image first when obstruction is possible.
Labeling overflow leakage as diarrhea and giving loperamide→ A rectal exam finds the impaction; disimpact and start a bowel regimen.
Going straight to sphincterotomy for a new fissure→ Most acute fissures heal with fiber, sitz baths and topical relaxants; surgery is for chronic fissures that fail them.

GI cancer screening, polyps & tumors

In the Brain

Start average-risk colorectal screening at 45, set the next colonoscopy by what was removed, intensify for families and syndromes, and scope iron deficiency in men and postmenopausal women.

Rules to know

Average-risk adult 45–75 → colonoscopy every 10 years, yearly FIT, stool DNA-FIT every 3 years, or CT colonography every 5 years
Adults 76–85 → screen selectively by health, life expectancy and past screening; stop after 85
Positive FIT, stool DNA or CT colonography → follow-up colonoscopy within months; never repeat the stool test
Parent or sibling with colorectal cancer before 60 → colonoscopy every 5 years from 40, or 10 years before their diagnosis age; same for advanced adenoma or two affected relatives
One first-degree relative diagnosed at 60 or older → start at 40, average-risk methods and intervals
One or two tubular adenomas under 10 mm → next colonoscopy in 7–10 years
Three or four small adenomas → repeat in 3–5 years
5–10 adenomas, or one ≥10 mm, villous or high-grade → repeat colonoscopy in 3 years
Polyp ≥20 mm removed piecemeal → check the site in 6 months
Small hyperplastic polyps in the rectosigmoid → treat as normal; 10-year interval
Sessile serrated lesion ≥10 mm or with dysplasia → repeat in 3 years
Inadequate bowel preparation → repeat colonoscopy within a year
Every new colorectal cancer → tumor mismatch-repair or microsatellite testing to find Lynch syndrome
Lynch syndrome → colonoscopy every 1–2 years from 20–25 (later for some genes); discuss hysterectomy and oophorectomy after childbearing
Hundreds of colon adenomas in a teenager → familial adenomatous polyposis; yearly colonoscopy from 10–12, planned colectomy, duodenal surveillance
Polyposis with osteomas, desmoid tumors or extra teeth → Gardner variant; with brain tumors → Turcot
Ten to one hundred adenomas, affected siblings, unaffected parents → MUTYH-associated polyposis; germline testing
Hamartomatous polyps with dark spots on lips and buccal mucosa → Peutz-Jeghers; intussusception risk, surveillance for GI, breast and pancreatic cancer
Streptococcus gallolyticus bacteremia or endocarditis → colonoscopy for colorectal neoplasia
Iron deficiency anemia in a man or postmenopausal woman → upper endoscopy and colonoscopy, plus celiac serology
Right colon cancer → fatigue and iron deficiency; left colon cancer → obstruction, narrower stools, visible blood
Newly diagnosed colorectal cancer → CT chest, abdomen and pelvis, CEA; pelvic MRI for rectal tumors
After curative colon cancer surgery → CEA and CT surveillance, colonoscopy one year after resection
Progressive dysphagia to solids then liquids with weight loss → esophageal cancer; endoscopic biopsy, then CT/PET and endoscopic ultrasound
Esophageal squamous cancer → smoking, alcohol, achalasia, caustic injury; adenocarcinoma → Barrett, reflux, obesity
Early satiety, weight loss, left supraclavicular node or umbilical nodule → gastric cancer; endoscopy with biopsy
Localized gastric MALT lymphoma with H. pylori → eradication therapy first
Submucosal gastric mass staining for KIT (CD117) → gastrointestinal stromal tumor; resection, imatinib for high risk or metastases
Flushing, diarrhea and wheeze with liver metastases → carcinoid syndrome; 24-hour urine 5-HIAA, somatostatin analog
People with HIV → anal cancer screening by cytology or HPV test (from 35 in MSM and transgender women, 45 for others)
Anal squamous cell cancer → chemoradiation, not surgery first
Oral white or red patch lasting over 2–3 weeks → biopsy, especially in smokers and drinkers; red patches carry the higher cancer risk

Traps that cost points

Starting average-risk colorectal screening at 50→ Current US guidance starts at 45 for average-risk adults.
Repeating a positive FIT to see if it was real→ Any positive stool-based or CT test needs colonoscopy; the screening is incomplete until it is done.
Booking colonoscopy in 5 years after one small tubular adenoma→ One or two adenomas under 10 mm carry low risk; 7–10 years is enough.
Giving iron alone to a 65-year-old man with iron deficiency→ GI blood loss, often cancer, must be excluded with upper endoscopy and colonoscopy before attributing it to diet.
Using CEA to screen for colon cancer→ CEA lacks sensitivity for early disease; it serves for baseline and surveillance after diagnosis.
Sending anal squamous cancer straight to abdominoperineal resection→ Chemoradiation cures most and preserves the sphincter; surgery is for persistent or recurrent disease.
Stopping all screening at 70 in a healthy adult with no prior tests→ Screening runs through 75; an unscreened healthy adult up to 85 may still benefit.
Missing Lynch syndrome in a 45-year-old with colon cancer→ Universal tumor testing for mismatch repair identifies families who need intensified screening and gynecologic risk reduction.

Acute abdomen & surgical GI

In the Brain

Decide who needs the operating room now and who needs imaging, antibiotics and observation. The pregnancy test, the right CT and the timing of the surgical call are what get tested.

Rules to know

Abdominal pain in a woman of reproductive age → pregnancy test before imaging or treatment
Periumbilical pain shifting to the RLQ, anorexia, fever → appendicitis; adults with an unclear picture get CT with IV contrast
Suspected appendicitis in a child or pregnant patient → ultrasound first; MRI in pregnancy if ultrasound is nondiagnostic
Confirmed appendicitis → IV antibiotics and laparoscopic appendectomy; antibiotics alone is an option for uncomplicated cases without appendicolith
Appendicitis with 5 or more days of pain and a contained abscess → IV antibiotics and percutaneous drainage; delay surgery
Prior surgery, crampy pain, vomiting, distension, no flatus → small bowel obstruction; CT with IV contrast
Adhesive bowel obstruction without ischemia → NPO, NG decompression, IV fluids and electrolytes; water-soluble contrast predicts resolution
Bowel obstruction with signs of strangulation → emergency surgery; clues are fever, constant pain, peritonitis, rising lactate, closed loop on CT
Adhesive obstruction not resolving after 48–72 hours of decompression → operate
Bowel obstruction with no previous surgery → hernia or tumor likely; early surgical evaluation
Tender irreducible groin bulge with red skin and fever → strangulated hernia; emergency repair, no attempt at reduction
Femoral hernia → repair even if mild, given high strangulation risk; minimally symptomatic inguinal hernia in men may be watched
Pain out of proportion to exam with AF or recent MI → acute mesenteric ischemia; CT angiography, heparin, fluids, antibiotics, revascularization
Pain after meals, fear of eating and weight loss in a vasculopath → chronic mesenteric ischemia; CT angiography, then stenting
Crampy pain then bloody diarrhea after hypotension or aortic surgery → ischemic colitis; bowel rest, fluids, colonoscopy; surgery if gangrene
LLQ pain, fever and tenderness → diverticulitis; CT with contrast for a first episode, severe symptoms or uncertain diagnosis
Uncomplicated diverticulitis in an immunocompetent patient drinking fluids → outpatient care; antibiotics are selective, not mandatory
Diverticulitis needing admission → unable to drink, sepsis, immunosuppression, severe pain or major comorbidity
Diverticular abscess about 4 cm or larger → IV antibiotics plus CT-guided percutaneous drainage
Diverticulitis with free air and generalized peritonitis → emergency colectomy, often with end colostomy
After complicated diverticulitis, or no recent colonoscopy → colonoscopy 6–8 weeks later to exclude cancer
Nursing-home resident with massive distension, bent-inner-tube loop on film → sigmoid volvulus; endoscopic detorsion, then sigmoid resection that admission
Cecal volvulus → right colectomy; endoscopic detorsion rarely succeeds
Massive colonic dilation without blockage after surgery or illness → Ogilvie syndrome; fix electrolytes, stop opioids; neostigmine if cecum exceeds 12 cm
Sudden severe epigastric pain and rigid abdomen in an NSAID user → perforated ulcer; upright chest film or CT for free air, surgery
Blunt abdominal trauma, unstable with positive FAST → laparotomy; stable → CT with IV contrast
Seat-belt bruise across the abdomen → hollow viscus, mesenteric or pancreatic injury and Chance fracture; CT and serial exams
Stable spleen or liver laceration on CT → nonoperative care with monitoring; angioembolization for active contrast blush
Fever, tachycardia and abdominal pain 5–7 days after a bowel anastomosis → anastomotic leak; CT, antibiotics, drainage or reoperation
Epigastric pain in an older diabetic → ECG and troponin before blaming the abdomen
Tense abdomen, bladder pressure over 20, new organ failure → abdominal compartment syndrome after big resuscitation; decompressive laparotomy
Older or steroid-treated patient with mild abdominal findings → the exam understates disease; low threshold for CT

Traps that cost points

Withholding pain medicine until the surgeon examines the patient→ Early opioid analgesia does not hide the diagnosis or delay surgery; treat pain promptly.
Ordering a barium study when perforation is possible→ Barium in the peritoneum causes severe peritonitis; use water-soluble contrast or CT.
Waiting for lactate to rise before imaging suspected mesenteric ischemia→ Lactate rises late, after infarction. Get CT angiography as soon as the history fits.
Admitting every patient with mild diverticulitis for IV antibiotics→ Uncomplicated cases who can drink and are immunocompetent do well at home, often without antibiotics.
Scheduling colonoscopy during an acute diverticulitis attack→ Insufflation risks perforation; wait 6–8 weeks after recovery.
Attempting endoscopic detorsion of a cecal volvulus→ It rarely works and delays care; cecal volvulus needs operative resection.
Manually reducing a hernia with skin changes and fever→ Pushing dead bowel back into the abdomen hides gangrene; strangulation needs emergency surgery.
Ordering CT before a pregnancy test in a young woman with pain→ Check hCG first; pregnancy changes the diagnosis, the imaging choice and the drugs.

Pediatric GI

In the Brain

Age and the color of the vomit point to the diagnosis. Know the one test and the urgent fix for each surgical cause, and rehydrate most children by mouth.

Rules to know

Bilious vomiting in a newborn or infant → malrotation with volvulus until excluded; emergency upper GI contrast study, then Ladd procedure
Bilious vomiting with peritonitis or shock in an infant → straight to the operating room without imaging
Hungry infant at 3–6 weeks with projectile nonbilious vomiting, olive mass → pyloric stenosis; ultrasound
Pyloric stenosis with hypochloremic hypokalemic metabolic alkalosis → correct fluids and electrolytes before pyloromyotomy
Bilious vomiting on day 1, double bubble on x-ray, Down syndrome → duodenal atresia; NG decompression, echo, surgical repair
Choking at first feed, NG tube coiled in the chest → esophageal atresia with fistula; look for VACTERL anomalies
Infant or toddler with episodic colicky pain, legs drawn up, lethargy → intussusception (peak 6–36 months; red jelly stool comes late); ultrasound target sign
Intussusception without peritonitis → air or contrast enema reduction; surgery for perforation, shock or failed enema
Intussusception after age 5 → search for a lead point (Meckel diverticulum, lymphoma, IgA vasculitis)
No meconium by 48 hours and explosive stool after rectal exam → Hirschsprung disease; rectal suction biopsy shows absent ganglion cells
Meconium ileus in a newborn → test for cystic fibrosis
Preterm infant with feeding intolerance, distension, bloody stool and pneumatosis → necrotizing enterocolitis; NPO, decompression, IV antibiotics; surgery for free air
Painless brisk rectal bleeding in a toddler → Meckel diverticulum; technetium-99m pertechnetate scan
Jaundice beyond 2 weeks of age → fractionated bilirubin; a raised direct fraction is never physiologic
Conjugated hyperbilirubinemia, pale stools and dark urine in an infant → biliary atresia; ultrasound, operative cholangiogram, Kasai before about 60 days
Spitting-up infant who is content and gaining weight → physiologic reflux; reassure, avoid overfeeding, hold upright; no acid suppression
Infant reflux with poor weight gain or marked irritability → thickened feeds and a 2–4 week trial without cow's milk protein; PPI only for proven esophagitis
Thriving breastfed infant with blood-streaked stools → cow's milk protein proctocolitis; mother eliminates dairy
Mild or moderate dehydration from gastroenteritis → oral rehydration solution in small frequent amounts; one dose of ondansetron if vomiting
Severe dehydration with lethargy and poor perfusion → 20 mL/kg isotonic bolus, reassess, repeat as needed
After rehydration → resume a normal diet for age; avoid juice and sports drinks; no antidiarrheal drugs in young children
Bloody diarrhea, then pallor, petechiae and little urine in a child → hemolytic uremic syndrome; CBC, smear, creatinine, supportive care, no antibiotics
Button battery in the esophagus (double-ring halo on x-ray) → emergency endoscopic removal; honey en route if over 1 year and within 12 hours
Asymptomatic coin in the esophagus → may observe up to 24 hours, remove if still there; coins in the stomach usually pass
Two or more magnets swallowed, or a magnet plus metal → urgent removal; attracted loops can necrose and perforate
Bowel protruding right of the umbilicus without a sac → gastroschisis; cover in sterile wrap, NG tube, surgical closure
Midline defect covered by a membrane sac → omphalocele; look for trisomy, Beckwith-Wiedemann and heart defects
Infant umbilical hernia → most close by 4–5 years; repair if still present or very large
Inguinal hernia in an infant → prompt elective repair; incarceration risk is high
Child with withholding and hard stools → functional constipation; clear impaction, then daily PEG and scheduled toilet sitting for months

Traps that cost points

Relying on a plain film to rule out malrotation→ Plain films can look normal; the upper GI contrast study is the test, and surgery should not wait if the infant is ill.
Rushing a pyloric stenosis infant to surgery with a bicarbonate of 34→ Alkalosis raises anesthesia apnea risk; rehydrate and replace chloride and potassium first.
Starting a PPI for a thriving infant who spits up→ Physiologic reflux resolves with time; acid suppression adds infection risk without benefit.
Placing an IV for mild dehydration in a child who can drink→ Oral rehydration works as well and is less invasive; use ondansetron to make it possible.
Watching an esophageal button battery to see if it passes→ Batteries burn through the esophagus within hours; remove emergently.
Reassuring parents about jaundice persisting at 4 weeks→ Check direct bilirubin; biliary atresia outcomes depend on surgery before about 60 days.
Prescribing antibiotics for bloody diarrhea that may be Shiga toxin E coli→ Antibiotics may raise HUS risk; give fluids and monitor counts and kidney function.
Ignoring a second magnet on an abdominal film→ Multiple magnets attract across bowel walls; arrange urgent removal even if the child looks well.