Gastroenterology I: upper GI disorders

Metaplasia of distal esophageal squamous epithelium → specialized intestinal columnar epithelium with goblet cells.

what is the metaplasia associated with Barrett's esophagus?

Chronic GERD

Male sex

Age >50

White ethnicity

Obesity (especially central)

Smoking

risk factors for Barret's esophagitis

Premalignant → increases risk of esophageal adenocarcinoma.

complication associated with Barrett's esophagitis

H. pylori

most common cause of peptic ulcer disease

Produces urease → neutralizes gastric acid.

Chronic inflammation → mucosal damage.

Alters gastrin and acid secretion.

mechanism by which H. pylori causes peptic ulcer disease

duodenal ulcers

more common ulcers caused by H. pylori

endoscopy with biopsy

-shows salmon colored mucosa extendding from GE junction

-biopsy shows intestinal metaplasia with goblet cells

gold standard to diagnose barrett's esophagus

Urea breath test (most sensitive/specific, detects active infection).

Stool antigen test (good for diagnosis & test of cure).

Serology (IgG antibodies) → cannot distinguish active vs past infection (not preferred).

non invasive tests for H. pylori

Avoid trigger foods (spicy, citrus, tomato, chocolate, caffeine, alcohol, peppermint, fatty foods).

Eat smaller, more frequent meals.

Avoid lying down within 2-3 hours after meals.

dietary chahges recommended for pt's with GERD

Elevate head of bed (6-8 inches).

Weight loss if overweight.

Stop smoking (reduces LES pressure, worsens reflux).

Limit alcohol use.

lifestyle changes recommended to pt's with GERD

Avoid NSAIDs, aspirin if possible (cause gastric mucosal injury).

avoid this OTC med if you have GERD

Block histamine H2 receptors in gastric parietal cells → ↓ acid secretion.

MOA of ranitidine, famotidine, cimetidine

gynecomastia, impotence, galactorrhea (anti-androgen effect), drug interactions (CYP450 inhibitor).

side effects associated with cimetidine

Irreversibly inhibit H+/K+ ATPase in gastric parietal cells → profound acid suppression.

MOA of PPIs

H2 in: Often taken at night (nocturnal acid suppression)

PPI: Take 30-60 min before first meal of day.

administration of H2 inhibitors vs PPI

Vitamin B12 deficiency.

Hypomagnesemia.

Increased risk of C. difficile infection and pneumonia.

Osteoporosis/fractures (with long-term use).

chronic use of PPI risks

Loss of myenteric plexus ganglion cells → impaired LES relaxation.

etiology of achalasia

Rare, associated with Chagas disease.

risk factors of achalasia

achalasia

Presentation: Progressive dysphagia to solids & liquids, regurgitation, weight loss.

Barium swallow (bird-beak), manometry (gold standard).

diagnostics of achalasia

Pneumatic dilation, Heller myotomy, botulinum toxin.

treatment of achalasia

upper 2/3

alcohol, tobacco, achalasia, caustic ingestion.

main causes of squamous cell carcinoma of esophagus

lower 1/3

Barrett's, GERD, obesity.

main causes of adenocarcinoma of the esophagus

Progressive dysphagia (solids → liquids), weight loss, anemia.

presentation to esophageal cancer

H. pylori infection (most common), NSAIDs, alcohol, stress, autoimmune.

most common etiologies of gastritis

gastritis

Presentation: Epigastric pain, nausea, dyspepsia.

Duodenal ulcer: Pain improves with meals.

Gastric ulcer: Pain worsens with meals.

duodenal vs gastric ulcers

Chronic H. pylori gastritis, smoking, dietary nitrates, family history

most common etiologies of gastric cancer

gastric cancer

Presentation: Weight loss, early satiety, anemia, Virchow node, Sister Mary Joseph nodule.

Sister Mary Joseph nodule

hard nodule in umbilicus that occurs with metastatic cancer of stomach, large intestine, ovary, or pancreas

Family history, type 1 diabetes, autoimmune thyroid disease.

strongest risk factors for celiac disease

celiac disease

Presentation: Chronic diarrhea, steatorrhea, bloating, failure to thrive (children), iron deficiency anemia.

Anti-tTG IgA (serology), duodenal biopsy (villous atrophy).

diagnostic findings of Celiac disease

duodenal atresia

Presentation: Bilious vomiting in newborns, “double-bubble” sign on X-ray

Triple therapy: PPI + clarithromycin + amoxicillin (metro if PCN allgery) for 14 days

Quadruple therapy if high resistance or prior macrolide exposure:

PPI

Bismuth subsalicylate

Tetracycline

Metronidazole

Duration: 10–14 days

first line therapy for H. pylori gastritiis

Non-ulcer dyspepsia (functional)

epigastric pain with normal endoscopy

risk factors: stress, anxiety, viscerral hypersensitivity

PPIs, H2 blockers, prokinetics, TCAs, dietary modification, reassurance

treatment of non-ulcer dyspepsia

At least 4 weeks after completion of antibiotics.

At least 2 weeks after stopping PPIs (false negatives).

when do you test for eradication of H. pylori?

Diabetes (neuropathy), postsurgical vagal injury, idiopathic, medications (opioids, anticholinergics).

common etiologies of delayed gastric emptying (gastrroparesis)

Early satiety

Postprandial fullness

Nausea/vomiting (especially undigested food hours later)

symptoms of gastrroparesis

post-gastrectomy, bariatric surgery

etiologies of rapid gastric emptying (dumping syndrome)

>1000 pg/mL fasting serum gastrin level

-paradoxical increase in gastrin after IV secretin

diagnostic findings of ZES

Zollinger-Ellison Syndrome (ZES)

disorder of excess acid secretion in the stomach resulting in peptic ulcer disease

Visceral afferent signals → dorsal horn of spinal cord.

Interneurons cross-talk with somatic motor neurons → increased tone, tenderness, asymmetry in paraspinal musculature.

mechanism of viscerosomatic reflex

T5-9 on the left

segments asssociated with stomach

T5-T11 (right) epigastric/right subcostal pain.

segments associatedd with duodenum/pancreas

T9-T11 periumbilical pain).

segments associated with small intestine

T8-L2

segments associated with colon/rectum

T9-T12 (initial periumbilical pain → migrates to RLQ as somatic peritoneum involved).

segments associated with appenddix

T5-T9 (greater splanchnic → celiac ganglion)

sympathetic innervation of Upper GI (esophagus → stomach → duodenum, pancreas, liver, gallbladder, spleen)

T10-T11 (middle splanchnic → superior mesenteric ganglion)

sympathetic innervation of mid GI (small intestine → proximal 2/3 transverse colon)

T12-L2 (least splanchnic, lumbar splanchnics → inferior mesenteric ganglion).

sympathetic innervation o f lower GI (distal 1/3 transverse colon → rectum)

↓ motility, ↓ secretions, ↑ sphincter tone, vasoconstriction

sympathetic effects on the GI tract

Foregut + midgut (esophagus → transverse colon up to splenic flexure).

what parts of the GI tract doess the Vagus nerve innervate?

Hindgut (distal 1/3 transverse colon → rectum).

what part of GI tract does S2-S4 innervate?

↑ motility, ↑ secretions, relaxed sphincters.

parasympathetic effects on GI tract

celiac nodes → thoracic duct.

lymph drainage of stomach, duodenum, pancreas

mediastinal nodes

lymphatic drainage of esophagus

improves sympathetic balance and lymphatic flow.

what is the purpose of rib raising?

mesenteric lift

enhances venous/lymphatic drainage from intestines.

Rib raising (inhibitory), paraspinal inhibition, collateral ganglion release (celiac, SMG, IMG).

OMM techniques to inhibit GI sympathetics

OA, AA decompression (vagus), sacral rocking (pelvic splanchnics).

OMM techniques to inhibit GI parasympathetics

Evidence-based guidelines for choosing the most appropriate imaging study based on clinical scenario.

purpose of the ACR appropriateness criteria

7–9 = usually appropriate

4–6 = may be appropriate

1–3 = usually not appropriate

scoring system to determine if an imaging is appropriate accordding to ACR

Screening for obstruction, constipation, calcifications

clinical use for abdominal radiograph

Evaluates bowel gas, stones, device placement

indications for KUB XR

upright abdominal radiograph

-Patient standing; detects air-fluid levels & free intraperitoneal air (under diaphragm)

-use: evall for bowel obstruction, perforatioin

Evaluates bowel obstruction, perforation, pneumonia/pleural process mimicking abdominal pain

clinical use of acute abdominal series (chest + 2 abdominal views)

Prior severe/anaphylactic reaction to iodinated contrast.

Uncontrolled hyperthyroidism (risk of thyrotoxic crisis).

Pregnancy (relative—use alternative unless essential).

absolute contraindications to IV contrast

-renal impairment (eGFR <30)

-metformin use (risk of lactic acidosis if renal injury occurs)

relative contraindications to IV contrast use

1. aspiration risk in pts with dysphagia

2. perforation risk into peritoneum causingg pperitonitis

risk of enteric contrast (oral/rectal barium)

Prednisone 50 mg PO at 13 hr, 7 hr, and 1 hr before contrast.

Diphenhydramine 50 mg PO/IV 1 hr before

pre-treatments for pts with prior allergy or high risk allergy to iodine contrast

Oropharyngeal dysphagia, aspiration risk, stroke, neuromuscular disorders

indications for modified barium swallow test

Dysphagia, suspected stricture, achalasia, Zenker's diverticulum, reflux

indications for esophagram barium swallow

-look at a esophagus, stomach, duodenum

-Ulcers, gastritis, hiatal hernia, malrotation, early gastric outlet obstruction

indications for an upper GI series

Crohn's disease, small bowel obstruction, strictures, malabsorption

indications for aa small bowel follow through imaging

Colonic obstruction, volvulus, diverticular disease, colonic stricture, intussusception reduction (pediatric)

indication for barium enema

Modified Barium Swallow

imaging of Oropharynx & proximal esophagus.

Evaluates swallowing mechanism, aspiration risk.

Esophagram (barium swallow)

imaging of Entire esophagus (pharynx → GE junction).

Detects strictures, rings, achalasia, diverticula, reflu

rigler's sign

- When there is air outside and inside the bowel you can see the lumen wall

barium sulfate

Best mucosal coating, inexpensive.

Contraindicated if perforation suspected (causes peritonitis).

most common enteric contrast used

water soluble iodinated contrast (gastrografin)

Safer contrast if perforation suspected (absorbed by peritoneum).

Hyperosmolar → can cause pulmonary edema if aspirated.