Diseases and Disorders of the Upper Gastrointestinal System

Nausa

the unpleasant feeling of needing to vomit, represents awareness of

afferent stimuli (including increased parasympathetic tone) to the medullary vomiting

center

vomiting

is the forceful expulsion of gastric contents caused by involuntary

contraction of the abdominal musculature when the gastric fundus and lower

esophageal sphincter are relaxed

What happens due to n/v

Dehydration

- Electrolyte Imbalance

- Acid Base Disturbances

- Aspiration

- Undernutrition including weight loss and metabolic abnormalities

Warning Signs of n/v

Thirst, dry mouth, no urine output, fatigue

- Headache, stiff neck, confusion, and lethargy

- Constant abdominal pain, abdominal tenderness upon palpation, and distended

abdomen

How does n/v work

• the vomitign cneter with chemorecpotros are triggered

• hearalded by

  • nasue

  • salivation

  • retching

  • dilated pupils

  • outbreak of sweat

  • palness

• abdombal pressure

• fixed repsireation

• duodenal contraction

1. Nausea & Vomiting (N/V) — Enteral Nutrition

N/V with enteral nutrition can result from:

• Delayed gastric emptying

• Rapid infusion of formula

• Formula that is high in fat or fiber

• Formula that is too cold

• Overfeeding

• GI intolerance

Why delayed gastric emptying causes N/V

Slow gastric emptying → formula + gastric secretions accumulate in stomach → gastric distension/pressure → nausea & vomiting → ↑ aspiration risk

Why aspiration risk increases

If the stomach empties slowly, contents remain in the stomach longer. Vomiting/regurgitation can allow formula to enter the airway/lungs.

N/v treatment

• Slow/stop enteral feeding temporarily

• IV fluids if dehydrated

• Antiemetics — use parenteral or sublingual agents when oral medications aren't appropriate

• When symptoms resolve:

  • Start with liquids

  • Progress to solid foods after ~8 hours if tolerated

Stomach Anatomy & Physiology

Mouth → esophagus → lower esophageal sphincter → stomach → pyloric sphincter → duodenum

Main regions

• Cardia — entry from esophagus

• Fundus — upper portion

• Body — major central portion

• Antrum — lower portion

• Pylorus — connects to duodenum

What happens to food?

Food enters stomach → stomach relaxes → contractions mix food with gastric juice → food becomes chyme → pyloric sphincter regulates release into duodenum

How does food move?

The stomach uses smooth-muscle contractions called peristalsis.

As contractions move toward the pylorus:

• Food is pushed toward the pyloric sphincter.

• The pylorus opens intermittently.

• Small amounts of chyme enter the duodenum.

• Most larger particles are pushed backward into the stomach for more mixing.

This backward movement is called retropulsion.

Important concept

Pressure/contractions in the stomach + pyloric sphincter control = gastric emptying

3. Gastroparesis neverse

Gastroparesis = delayed gastric emptying without a physical blockage.

Why are nerves important?

Normal gastric emptying requires coordination between:

• Vagus nerve

• Enteric nervous system

• Gastric smooth muscle

• Hormonal signals

The vagus nerve helps coordinate stomach contractions and pyloric relaxation.

If nerve function is impaired:

↓ nerve signaling → weak/uncoordinated contractions → delayed gastric emptying → food remains in stomach

major risk factors of gastro

Major risk factors

• Diabetes ⭐

• GI surgery

• CNS disorders

• Certain medications

Signs & symptoms

• Nausea/vomiting

• Early fullness

• Abdominal bloating

• Abdominal discomfort

• Reflux/GERD

• Poor appetite

• Weight loss

• Possible dehydration

treeatments of gastro

Diet

• Small, frequent meals

• Low-fat

• Low-fiber

• Semi-solid/liquid foods

• Avoid carbonated beverages

• Avoid lying down immediately after meals

Medications

• Prokinetic agents → increase GI motility

  • Metoclopramide

  • Erythromycin

• Antiemetics → control N/V

Hydration

• ORT/oral fluids if able to tolerate them

• IV fluids if significant dehydration occurs

Big connection

Diabetes → nerve damage → impaired stomach motility → gastroparesis → delayed emptying → N/V + bloating + early satiety

4. Peptic Ulcer Disease (PUD)

Major complications

Think:

B-A-O-B-C

• Bleeding

• Abscess/infection

• Obstruction

• Bowel/stomach perforation

• Cancer risk/associated gastric malignancy

Refractory PUD

An ulcer that doesn't heal despite appropriate medical treatment.

5. Gastric Cancer

Risk factors

• H. pylori infection ⭐

• Smoking

• High intake of certain nitrates/nitrites

• Family/genetic factors

• Certain occupational exposures

Important mechanism

H. pylori → chronic gastric inflammation → cellular damage → increased risk of gastric cancer

Total Gastrectomy

Entire stomach removed

Food:

Esophagus → small intestine

Major nutrition consequences

• ↓ stomach capacity

• Rapid food delivery to intestine

• Vitamin B12 deficiency because stomach produces intrinsic factor

• Iron/calcium/vitamin deficiencies

• Weight loss

• Dumping syndrome (Dumping syndrome is a condition where food moves from your stomach into your small intestine much too fast after you eat

Billroth I

Gastroduodenostomy

Stomach → duodenum

Part of stomach is removed and the remaining stomach is connected directly to the duodenum.

Nutrition issues

• Reduced stomach capacity

• Possible dumping

• Reduced intake

• Iron/B12 and other nutrient deficiencies depending on extent of surgery

Billroth II

Gastrojejunostom

Stomach → jejunum

The duodenum is bypassed.

Nutrition issues

• ↓ nutrient absorption

• Iron deficiency

• B12 deficiency

• Dumping syndrome

• Possible fat malabsorption

Bariatric Surgery who qualifry

Traditional criteria:

• BMI ≥40 kg/m², OR

• BMI ≥35 kg/m² + serious obesity-related complication

  • Type 2 diabetes

  • Hypertension

  • Obstructive sleep apnea

  • Dyslipidemia

Also requires appropriate operative risk and informed/motivated participation.

Note: Modern bariatric guidelines have expanded eligibility in some circumstances, so if your professor gave you the criteria above, memorize those for the exam.

Roux-en-Y Gastric Bypass (RYGB)

Creates a small stomach pouch and connects it to the small intestine.

Mechanism

Small pouch + bypassed intestine → ↓ food intake + some malabsorption

Nutrition complications

• Protein-energy undernutrition

• Iron deficiency

• Vitamin B12 deficiency

• Other vitamin/mineral deficiencies

• Dumping syndrome

• Thiamin deficiency if prolonged vomiting occurs

Gastric Sleeve

Most of the stomach is removed, leaving a narrow sleeve.

Mechanism

Smaller stomach → ↓ food capacity

It is primarily restrictive rather than intestinally malabsorptive.

Nutrition complications

• Reduced food intake

• Vitamin/mineral deficiencies

• Protein deficiency if intake is inadequate

• Possible B12/iron deficiencies

• Dumping-like symptoms can occu

9. Eating Progression After Bariatric Surgery

Typically progresses:

Liquids → puréed foods → soft foods → regular foods

The exact timeline varies by procedure and clinical protocol, but your notes say:

Normal foods are trialed after ~6 weeks.

Dumping Syndrom

apid gastric emptying → large amount of hyperosmolar chyme enters jejunum

This causes water to move into the intestine.

Early dumping

Rapid emptying → hyperosmolar chyme in jejunum → water shifts into intestine → ↓ blood volume + intestinal symptoms

Symptoms:

• Abdominal cramps

• Diarrhea

• Bloating

• Tachycardia

• Weakness/dizziness

Late dumping

Rapid glucose absorption → ↑ blood glucose → excessive insulin release → hypoglycemia

So memorize:

Early = fluid shift
Late = insulin → hypoglycemia

11. Nutritional Complications After Bariatric Surgery

Why deficiencies happen

Inadequate intake + inadequate supplementation + malabsorption

Common deficiencies:

• Protein

• Vitamin B12

• Iron

• Other vitamins/minerals

Thiamin

Prolonged vomiting → thiamin deficiency

This is particularly important because vomiting can rapidly worsen nutritional status.

Malabsorptive procedures

Can cause:

Malabsorption → malodorous flatulence + diarrhea

12. Other Possible Post-Bariatric Issues

Your notes mention increased incidence of:

• Depression/psychological difficulties

• Alcohol use

• Disordered eating

These are possible complications/associations, not inevitable outcomes for people who undergo surgery.

13. Outcomes of Bariatric Surgery

Potential benefits include:

• Significant sustained weight loss

• Improved type 2 diabetes

• Improved lipid metabolism

• Improved cardiovascular risk factors

• Improved obstructive sleep apnea

• Improvement in osteoarthritis

• Other obesity-related conditions may improve or resolve

Your notes specifically state:

~50–65% weight loss after 2 years, with weight loss maintained in some patients at 10 years.