Pathophysiology GI

Oral cancer can occur where?

Lips, gums, inside structures of the mouth

Risk factors for oral cancer

Smoking, chewing tobacco, HPV infection

Pathophysiology of Oral Cancer

Leukoplakia (white plaque under tongue or on cheek, often precancerous lesion)
Malignant transformation (in about 20%)
Erythroplasia (red mucousal plaque, no signs of inflammation)

Cleft Lip and Palate

Congenital splitting or defect in integrity of lip; with or without splitting of the plane

Pathophysiology of Cleft Lip

Disfigurement causes varying degrees of impairment
Risk of aspiration increased

Clinical Manifestations of Cleft Lip

Facial deformity, difficult feeding
Delayed development of teeth and speech

Types of Esophageal Alterations

GERD
Esophageal cancer
Achalasia
Esophageal Atresia

GERD

Gastroesophageal Reflux Disease:
Regurgitation of gastric contents into the esophagus

Pathophysiology of GERD?

Incompetent lower esophageal sphincter (cardiac) causes Hiatal hernia (stomach protrudes back into esophagus)
Esophageal mucosa injury

Risk Factors for Esophageal Cancer

Alcohol, tobacco, males over age 50

Barrett esophagus

Esophageal adenocarcinoma
Normal esophageal lining replaced by abnormal epithelium

Clinical Manifestations of Esophageal Cancer

Dysphagia
Weight loss, pain, fatigue

Achalasia

Inability of the cardiac sphincter to relax
Abscence of esphageal peristalsis
Food is retained
Hypertrophy and dilation of lower esophagus

Symptoms of Achalasia

Dysphagia
Vomiting
Pain

Esophageal Atresia

Congenital concurrent abnormality of trachea
Esophagus ends in blind pouch or fistula from trachea to stomach

Clinical Manifestations of Esophageal Atresia

Aspiration of gastric contents into respiratory system
Abdominal distension
Coughing and cyanosis with feeding
Recurrent pneumonia

Alterations in the Stomach and Duodenum

Gastritis
Peptic Ulcer Disease
Stomach Cancer
Hypertrophic pyloric stenosis

Gastritis

Inflammation of gastric mucosa

Risk Factors for Gastritis

Cigarettes, alcohol, spicy foods, caffeine, aspiring, NSAIDs

Pathophysiology of Gastritis

Increased acid and pepsinogen
Superficial erosion of surface epithelium (usually regenerates)

Manifestations of Gastritis

Heart burn, hematemesis (blood in vomit), scarring (risk for cancer)

Peptic Ulcer Disease

Chronic inflammatory disorder causes by erosion by acid and pepsin

Risk Factors for Peptic Ulcer Disease

Helicobacter pylori (H. pylori)
Chronic use of aspirin or NSAIDS
Zollinger-Ellison syndrome

Effects of H. pylori

Increases gastric acid production and produces cellular injury
Ulcerative lesions
Blood vessel erosion

Pathophysiology of Peptic Ulcer Disease

Inflammatory damage to mucosa
May cause peritonitis

What is peritonitis?

Perforation of the bowel, bacteria enter abdominal cavity

Stomach Cancer Risk Factors

Dietary preservatives, recurrent gastritis, genetics

Hypertrophic pyloric stenosis

Genetic in infants
Obstruction of gastric outlet resulting from hypertrophy of musculature surrounding pylorus

Symptoms of Hypertrophic pyloric stenosis

Projectile vomiting within 3-10 weeks of birth
No bile in emesis

Inflammation Disorders of SI and LI

Gastroenteritis
Inflammatory Bowel Disease
Ulcerative colitis
Irritable Bowel Syndrome
Diverticular Disease

Gastroenteritis (Infectious Enterocolitis) is also known as...

The "stomach flu

Gastroenteritis is caused by...

Bacterial toxins or irritants in food

Clostridium difficile

Loss of normal flora due to antibiotic therapy. C. diff flourishes and overtakes GI

Inflammatory Bowel Disease

Crohn's diease
Cobblestone appearance

Ulcerative colitis

Starts lower in rectum, ascends to colon
Inflammatory lesions become necrotic and fill with exudate

Irritable Bowel Syndrome

Combination of chronic and recurrent intestinal symptoms not explained by structural or chemical problems

Clinical Manifestations of Irritable Bowel Syndrome

Increased motility and intestinal contractions cause uncontrollable diarrhea
Persistent and recurrent abdominal pain relieved by defecation

2 types of Diverticular disease

Diverticula: out-pouching or ballooned segments of colon, caused by pressure of bowel movement
Diverticulitis: inflamed pouches

Hemorrhoids

Dilations of venous plexus, varicose veins of rectum

Types of Obstructive Disorders

Paralytic Ileus
Hirschprung's Disease
Mechanical Obstruction
Intestinal Ischemia or Infarction

Paralytic ileus

Functional bowel obstruction
Lack of neural stimuli (d/t anesthesia) leads to mechanical obstruction (stool build-up)

Hirschprung's Disease

Congenital lack of colonical innervations

2 Types of Mechanical Obstruction

Intussesception: bowel folds over on itself
Volvulus: bowel twists around itself, cuts of blood supply

Intestinal Ischemia or Infarction

Lack of oxygen supply to intestine d/t clot, obstruction

Hernia

Abdominal wall defect, protrusion of stomach or intestinal wall through defect/weakened area

2 types of hernias

Intermittent: can be reduced by pushing back in
Strangulated: tight section of bowel can't be pushed back in

Disorders of Intestinal Absorption

Celiac Disease
Malabsorption Syndromes

Celiac Disease

Inappropriate T-cell response against gluten (wheat, rye, barley)
Intense inflammatory reaction results in loss of absorptive villi
Impaired nutrient absorption

Main type of malabsorption syndrome

Lactose Intolerance (congenital or secondary)

Pathophysiology of lactose intolerance

-Carbs malabsorption results in lack of carbs in blood
-Carbs accumulate in lumen of bowel
-Excess carbs act as osmotic gradient to pull water into bowel
-Watery Diarrhea results

Colorectal Cancer

Dietary: High fat, low fiber intake
Polyps: growth protruding into intestine

Hormone effects of Anorexia nervosa

Female: decreased estrogen (d/t depleted fat stores) may lead to absence of menstruation
Male: fluctuating testosterone levels

Other manifestations of Anorexia nervosa

-Reduced thyroid function causes dry skin and hair
-Electrolyte imbalances (low potassium) causes cardiac rhythm problems
-Ketoacidosis from increased breakdown of fat as fuel
-Renal failure due to BUN elevation
-Anemia

Complications of Bulimia nervosa

Dental Disorders
Esophagitis
Hypokalemia
Metabolic Alkalosis

Pancreatitis

Acute or chronic inflammation of pancreas

Causes of Pancreatitis

Obstruction of pancreatic ducts
Often alcohol related