Digestive System Disorders

Gastroesophageal Reflux Disease (GERD)

  • Definition: Gastroesophageal reflux disease (GERD) is characterized by the repeated backward movement of stomach contents into the esophagus.

  • Etiology and Mechanism:

    • The condition occurs because the lower esophageal sphincter (LES) becomes weak or relaxes at inappropriate times.

    • This allows stomach acid and digestive contents to move upward, which irritates the esophageal lining.

  • Contributing Factors:

    • Hiatal hernia

    • Obesity

    • Pregnancy

    • Delayed stomach emptying

    • Smoking

    • Alcohol consumption

    • Consumption of fatty meals

    • Chocolate, caffeine, or peppermint

    • Certain medications

    • Increased abdominal pressure

  • Potential Complications of Repeated Acid Exposure:

    • Esophagitis

    • Ulcers

    • Strictures

    • Barrett's esophagus

Peptic Ulcer Disease: Pathophysiology and Complications

  • Pathophysiology of Peptic Ulcers:

    • A peptic ulcer develops when damaging factors overpower the protective mechanisms of the stomach or duodenum.

    • When the protective barrier is weakened, acid and pepsin erode the mucosal lining. This erosion deepens to form an ulcer.

  • Damaging Factors:

    • Hydrochloric acid (HClHCl)

    • Pepsin

    • H.pyloriH. pylori (Helicobacter pylori)

    • NSAIDs (Nonsteroidal anti-inflammatory drugs)

    • Smoking and alcohol

  • Protective Factors:

    • Mucus

    • Bicarbonate

    • Adequate blood flow

    • Intact epithelial cells

    • Prostaglandins

  • Potential Complications:

    • Hemorrhage: Caused by the erosion of blood vessels; clinical signs include hematemesis (vomiting blood), melena (dark, tarry stools), anemia, or shock.

    • Perforation: The ulcer creates a complete hole through the wall of the stomach or duodenum.

    • Peritonitis: This occurs when gastric or intestinal contents leak through a perforation and enter the abdominal cavity.

    • Penetration: The ulcer extends directly into a nearby organ, such as the pancreas.

    • Gastric-outlet obstruction: The passage of food is blocked due to edema or the development of scar tissue.

    • Hypovolemic shock: A potential result of major bleeding (hemorrhage).

Signs and Symptoms of Peptic Ulcers

  • General Clinical Manifestations:

    • Burning or gnawing epigastric pain

    • Indigestion

    • Bloating

    • Belching

    • Nausea

    • Heartburn

    • Early fullness

    • Possible weight loss

    • Hematemesis or melena (if bleeding is present)

  • Gastric Ulcer Specifics:

    • Pain often worsens shortly after eating.

    • Food intake may increase acid contact with the ulcerated area.

    • Patients may avoid food, leading to weight loss.

  • Duodenal Ulcer Specifics:

    • Pain often improves temporarily after eating.

    • Pain typically returns 2−32-3 hours after a meal or during the night.

    • Food or antacids may provide relief.

Gallstones: Signs and Symptoms

  • Sudden pain in the right upper quadrant (RUQRUQ) or epigastric region.

  • Pain commonly occurs after consuming a fatty meal.

  • Pain may radiate to the right shoulder or the back.

  • Nausea and vomiting.

  • Abdominal tenderness.

  • Bloating or indigestion.

  • Cholecystitis indicators: Fever and leukocytosis (elevated white blood cell count) if the gallbladder becomes inflamed.

  • Common bile duct obstruction indicators: Jaundice (yellowing of skin/eyes), dark urine, and pale stools.

Pathophysiology of Cirrhosis

  • The Cirrhotic Process:

    1. Chronic liver injury triggers hepatocyte inflammation and death.

    2. The body attempts to repair this damage.

    3. Fibrous scar tissue forms in place of healthy tissue.

    4. Regenerating liver cells form abnormal nodules.

    5. The combination of scar tissue and nodules distorts blood vessels and bile channels.

    6. Blood flow through the liver is significantly impeded.

    7. Portal hypertension develops.

    8. The mass of functioning liver cells decreases.

    9. Impairment occurs in detoxification, protein production, metabolism, and bile excretion.

  • Simplified Summary: Repeated liver injury replaces flexible, working tissue with stiff scar tissue. This prevents normal blood flow and stops the liver from performing its essential biological jobs.

Impact of Cirrhosis on Liver Function and Clinical Symptoms

  • Lost or Impaired Liver Functions:

    • Albumin production

    • Clotting-factor production

    • Bilirubin conjugation and excretion

    • Ammonia conversion to urea

    • Detoxification of medications and toxins

    • Glucose storage and regulation

    • Protein and fat metabolism

    • Bile production

    • Storage of vitamins and minerals

    • Breakdown of hormones

    • Immune filtration of bacteria from portal blood

  • Symptomatic Manifestations of Impaired Function:

    • Low albumin production: Leads to edema and ascites (fluid in the abdominal cavity).

    • Low clotting-factor production: Leads to easy bruising, petechiae, and bleeding.

    • Poor bilirubin processing: Leads to jaundice, dark urine, pale stools, and itching.

    • Poor ammonia detoxification: Leads to confusion, asterixis (flapping tremor), and hepatic encephalopathy.

    • Poor nutrient metabolism: Leads to weight loss, weakness, and malnutrition.

    • Poor glucose regulation: Leads to hypoglycemia.

    • Poor hormone breakdown: Leads to gynecomastia (breast tissue growth in males), testicular atrophy, and menstrual changes.

    • Reduced immune function: Results in an increased risk of infection.

    • Reduced bile secretion: Results in fat malabsorption and vitamin deficiencies.

Portal Hypertension

  • Definition: Abnormally high blood pressure within the portal venous system.

  • Development: Cirrhotic scar tissue and regenerative nodules increase the resistance against blood flowing through the liver. This causes blood to back up into the portal vein and its tributaries.

  • Complications of Portal Hypertension:

    • Ascites: Collection of fluid in the abdominal cavity.

    • Splenomegaly: Enlargement of the spleen due to blood backup.

    • Hypersplenism: The enlarged spleen prematurely destroys platelets and blood cells.

    • Esophageal and gastric varices: Development of enlarged, fragile veins that are prone to rupture and life-threatening hemorrhage.

    • Caput medusae: Visible enlarged veins appearing around the umbilicus (navel).

    • Hemorrhoidal or rectal varices: Enlargement of veins in the rectal area.

    • Portal-systemic shunting: Blood bypasses the liver entirely.

    • Hepatic encephalopathy: Toxins like ammonia reach systemic circulation because they are not filtered by the liver.

    • Hepatorenal syndrome: Severe liver disease contributing to the development of kidney failure.

Comparison of Crohn's Disease and Ulcerative Colitis (UC)

  • High-Risk Individuals:

    • Crohn's: Young adults; people with a family history; smokers; those of Northern European or Jewish ancestry.

    • UC: Young adults; people with a family history; notably more common in nonsmokers or former smokers.

  • Etiology: For both conditions, the exact cause is unknown; it involves a combination of genetic, immune, environmental, and microbiome factors.

  • Location of Disease:

    • Crohn's: May affect any part of the gastrointestinal tract from the mouth to the anus; most commonly found in the terminal ileum and colon.

    • UC: Limited strictly to the colon and the rectum.

  • Distribution of Lesions:

    • Crohn's: Identified by "skip lesions," which are diseased sections separated by areas of normal tissue.

    • UC: Characterized by continuous inflammation that typically begins in the rectum.

  • Depth of Involvement:

    • Crohn's: Transmural, meaning it involves all layers of the bowel wall.

    • UC: Primarily involves the mucosa and submucosa layers.

  • Physical Appearance:

    • Crohn's: Features a "cobblestone" mucosa, deep fissures, and a thickened bowel wall.

    • UC: Mucosa appears red and friable (easily crumbled/bleeding) with superficial ulcers.

  • Common Complications:

    • Crohn's: Fistulas, abscesses, strictures, bowel obstruction, malnutrition, and Vitamin B12B_{12} deficiency.

    • UC: Toxic megacolon, severe bleeding, perforation, and an increased risk of colorectal cancer.

  • Stool Characteristics:

    • Crohn's: Chronic diarrhea; may sometimes be nonbloody.

    • UC: Frequent, bloody diarrhea that often contains mucus.

  • Pain Patterns:

    • Crohn's: Often involves cramping in the right lower quadrant (RLQRLQ).

    • UC: Often involves cramping in the left lower quadrant (LLQLLQ).

  • Weight Impact:

    • Crohn's: Weight loss and malnutrition are very common.

    • UC: Weight loss typically occurs only during severe flare-ups.

  • Surgical Options:

    • Crohn's: Surgery is not curative; the disease often recurs in other areas of the GI tract.

    • UC: The removal of the colon and rectum (total proctocolectomy) is considered curative.