MSP Unit 5 Intro to GI system

To provide a broad overview of the GI system structures and their associated disorders

Esophagus (function. Primary Disorder and Secondary Disorder)

Function: Peristalsis moves food toward stomach

Primary Disorder: Bleeding, reflux, inflammation

Secondary Disorders: Obstruction (Malignancies, restrictions)

Stomach (Primary Disorders & Secondary Disorders)

• Primary Disorders: Bleeding, inflammation.

• Secondary Disorders: Herniation (protrusion into the diaphragm)

Intestines (Small & Large)

Primary Disorders: Bleeding, malabsorption, infectious disorders, obstructions

Hernias: Intestines can protrude and become entangled or obstruction

Colon (primary disorder)

Primary Disorders: Bleeding, inflammation, infection, obstructions.

Appendix, Rectum, and Anus (Rectum/Anus Function, Primary Disorders, Secondary Disorders)

• Rectum/Anus Function: Repository and exit point for stool.

• Primary Disorders: Bleeding, inflammation.

• Secondary Disorders: Obstruction/constipation (stool collection)

General Signs and Symptoms of GI Disorders

• Nausea: Irritation of nerve endings in the stomach; often precedes vomiting.

• Vomiting: Caused by anything that precipitates nausea.

• Diarrhea: Abnormal frequency/consistency of stools; leads to poor absorption, fluid deficit, and acidosis.

• Constipation: Hard stool or infrequent bowel movements causing discomfort; affects up to 25% of the American population.

• Dysphagia: Difficulty swallowing.

Gastrointestinal Bleeding (Detailed)

General: Characterized by specific symptoms depending on the lesion's location.

Types of Bleeding

• Coffee-ground emesis: Vomiting of blood that has been in contact with gastric acid (texture and appearance like coffee grounds).

• 2. Hematemesis: Vomiting of bright red blood (not in contact with gastric acid).

• 3. Melena: Black, tarry stools (indicative of upper GI bleeding).

• 4. Hematochezia: Maroon-colored stools or bleeding from the rectum (indicative of lower GI bleeding).

Gastroesophageal Reflux Disease (GERD)

• Definition

• Common Signs & Symptoms

• Pain Characteristics

• Relieving Factors

• Aggravating Factors

• Definition: stomach acid flows backward (regurgitates) into the esophagus, irritating its mucosal lining.

• Common Signs & Symptoms:

  • Coughing, changes in voice, difficulty swallowing (dysphagia), and a burning sensation.

  • In younger adults, primary symptoms include heartburn, reflux into the mouth, belching, dysphagia, and painful swallowing.

• Pain Characteristics: burning sensation that moves up and down and may radiate to the back, neck, or jaw. Heartburn typically occurs 30 to 60 minutes after a meal.

• Relieving Factors: Upright position (standing/walking), drinking fluids, dietary modifications, and medications.

• Aggravating Factors: Lying down (recumbent position), bending over, or eating meals.

Gastritis

• Definition

• Classification

• Symptoms

• Definition: Gastritis is not a single disease but a group of disorders characterized by inflammation of the stomach lining. If left untreated, this inflammation can lead to erosion of the stomach lining.

• Classification: Can be classified as acute or chronic. Acute gastritis may be further divided into erosive or hemorrhagic types.

• Symptoms: Heaviness, pain, heartburn, nausea, and vomiting.

Peptic Ulcer Disease (PUD)

• Progression

• Types of Ulcers

• Progression: When the erosion of the GI lining becomes deep enough, it forms an ulcer. The ulcer is named based on its specific location.

• Types of Ulcers:

  • Gastric Ulcer: Located in the stomach.

  • Duodenal Ulcer / Peptic Ulcer: Located in the duodenum (the first part of the small intestine). The term "peptic ulcer" is often used collectively for ulcers in the stomach or duodenum.

Malabsorption Disorders

• Malabsorption is a general term for the inadequate absorption, digestion, or mobility of nutrients by the digestive tract.

• In most cases, food is fully digested, but the nutrients are not properly absorbed through the intestinal wall.

• This leads to complications such as nutritional deficits (due to lack of essential vitamins/minerals) and/or excessive excretion of feces (due to unabsorbed materials passing through the gut).

Malabsorption Scope of the Disorder

• Malabsorption can be specific to one type of nutrient (e.g., fat, carbohydrate, or protein) or can involve multiple nutrients at once.

Celiac Disease (Mechanism, Results)

• Example of a malabsorption disorder.

• Cause: It is triggered by gluten, a protein found in wheat and related grains.

• Mechanism: In individuals with celiac disease, gluten provokes an immune response in the small intestine. This immune reaction damages the villi—tiny, finger-like projections on the intestinal lining that are essential for absorbing nutrients.

• Result: The damaged villi cannot effectively absorb nutrients, leading to the characteristic nutritional deficits of the disorder.

Early Symptoms

• Weight loss (from poor nutrient uptake)

• Fatigue (from energy and nutrient deficiencies)

• Abdominal bloating (from gas and unabsorbed material)

• Depression (potentially linked to nutritional imbalances)

Causes of GI Infections

viruses, parasites, bacteria, or by entry of an infectious agent through trauma.

Bacterial infections are most commonly introduced by ingesting contaminated food or water (commonly known as food poisoning).

• Infections can also spread from other areas of the abdomen due to:

  • Perforated ulcers

  • Penetrating trauma (e.g., stab or gunshot wounds)

  • Spread from diverticulitis, fallopian tubes, or a ruptured appendix

  • Ruptured diverticula or pre-existing infections

Common Intestinal Infections

• Small Intestine: E. coli and rotavirus.

• Large Intestine: E. coli, shigella bacteria, viruses, and entamoeba.

Acute Appendicitis (Definition, Epidemiology, Symptoms)

• Definition: An acute infection of the appendix.

• Epidemiology: Most commonly occurs between the ages of 15 and 19, with a higher incidence in men than women. The cause is often idiopathic (unknown), though obstruction or tumor may be involved.

• Symptoms:

  • Nausea and vomiting

  • Low-grade fever

  • Pain in the right lower quadrant, specifically over McBurney's point (a classic landmark for appendicitis pain).

Peritonitis (Definition, Causes, Progression of Symptoms, Effect on Motility)

• Definition: Inflammation of the serous membrane (peritoneum) that lines the abdominal cavity and covers the abdominal organs.

• Causes: Occurs when microorganisms are introduced into the peritoneal cavity. This can happen:

  • Spontaneously (no identifiable treatable source)

  • Secondarily, due to trauma, surgery, or contamination by bowel contents (e.g., from a perforated duodenal ulcer or a ruptured appendix).

• Progression of Symptoms:

  • Early: Vague, generalized abdominal pain.

  • Progressive: The abdomen becomes rigid with involuntary guarding, extremely tender to touch, and exhibits rebound tenderness (pain upon release of pressure).

  • Pain is severe, worsens with movement and breathing, and may be referred to the shoulder or thoracic area.

  • Late: Nausea, vomiting, and high fever follow.

• Effect on Motility: Peritonitis commonly decreases intestinal motility, leading to intestinal distention with gas.

Treatment of Appendicitis or Peritonitis

Antibiotics

Intestinal Obstructions

• Small Intestine: Obstructions are more common in the small intestine than the large intestine, primarily due to the narrow diameter of its lumen (the inner space).

• Common Causes of Obstruction:

  • Hernias (intestinal tissue protruding through a weak spot in the abdominal wall)

  • Intestinal adhesions (bands of scar tissue that can bind loops of intestine together)

  • Intussusception (telescoping of one portion of the bowel into another)

  • Volvulus (torsion or twisting of a loop of intestine)

Hernias (Definition, Causes, Common Locations)

• Definition: A hernia occurs when there is a weakness in the abdominal wall, allowing a portion of the intestine (or other tissue) to push through.

• Causes: Can result from a congenital weakness, surgical incisions, or trauma.

• Common Locations: Hernias are frequently seen in:

  • Inguinal region (groin)

  • Femoral ring (upper thigh)

  • Umbilical region (navel)

Hiatal Hernia (A Specific Type) [Definition, Symptoms]

• Definition: A hiatal hernia is a protrusion of the stomach upward through the diaphragm into the chest cavity.

• Symptoms:

  • Heartburn after meals, especially when lying down (supine or recumbent position)

  • Substernal pain (pain behind the breastbone)

  • Dysphagia (difficult and painful swallowing)

Inflammatory bowel disease (loos at deepseek)

Deepseek

Diverticular GI Disorders (Definition and Terminology)

• Diverticular disease is the general term for this condition, which has two forms:

  • Diverticulosis: The presence of outpouchings (diverticula) without inflammation (uncomplicated disease).

  • Diverticulitis: When the diverticula become inflamed or infected (disease complicated by inflammation).

Diverticulosis (The Underlying Condition) [Mechanism, Location of Formation, Contents]

• Mechanism: Diverticula are outpouchings that form when the mucosa and submucosa layers of the intestinal wall herniate (push) through the muscular layers of the colon or small intestine.

• Location of Formation: These pouches typically form at weak points in the colon wall, most commonly where arteries penetrate the muscularis to supply blood to the mucosal layer.

• Contents: The pouches can become filled with feces.

Diverticulitis (The Complication) [Causes and treatment]

• Cause: Diverticulitis occurs when food particles or feces become trapped inside the diverticula, leading to infection and inflammation of the pouches.

• Treatment: When diverticulitis develops, antibiotics may be necessary to treat the infection.

Symptoms of Diverticular GI Disorders

• Asymptomatic: Approximately 80% of people with diverticular disease experience no symptoms.

• Symptomatic Cases: Some individuals may report:

  • Passing fresh blood and clots in their stool.

  • A sense of urgency to defecate.

Drugs for Acid-Related Disorders

1. Antacids

2. H₂ Receptor Blockers (H2RAs)

3. Proton Pump Inhibitors (PPIs)

Antacids (Mechanism, Use, Side Effects, Drug Interactions, Other Concerns)

• Mechanism: Neutralize stomach acid by combining with excess hydrogen ions (H⁺) to increase intragastric pH. They contain bases like hydroxide or carbonate combined with aluminum, magnesium, calcium, or sodium.

• Use: Approved for mild, occasional heartburn or indigestion (e.g., after heavy or spicy meals).

• Side Effects:

  • Constipation: Associated with aluminum-containing antacids.

  • Diarrhea: Associated with magnesium-containing preparations.

  • Hypercalcemia: Possible with prolonged use of calcium carbonate antacids.

• Drug Interactions: Can alter the metabolism, solubility, and renal elimination of other drugs by changing gastric and urine pH. Do not take within 2 hours of other oral drugs like warfarin, digoxin, iron supplements, and certain antibiotics.

• Other Concerns: Can cause electrolyte imbalances with prolonged high-dose use, and may be abused as a solution for poor eating habits.

H₂ Receptor Blockers (H2RAs) [Examples, Mechanism, Efficacy, Adverse Effects & Considerations]

• Examples: Cimetidine, famotidine, nizatidine, and ranitidine.

• Mechanism: Block H₂ receptors on stomach parietal cells, preventing histamine-induced gastric acid release (both under normal conditions and in response to food).

• Efficacy: Less effective than Proton Pump Inhibitors (PPIs).

• Adverse Effects & Considerations:

  • Generally well-tolerated for short-term or periodic use.

  • Acid rebound can occur with sudden withdrawal after long-term use.

  • Tolerance may develop with continuous daily use.

  • Joint and muscle pain have been reported with cimetidine.

  • Ranitidine has been discontinued in the pediatric population.

Proton Pump Inhibitors (PPIs) [Examples, Mechanism, Efficacy, Additional Actions, Adverse Effects & Considerations)

• Examples: Omeprazole (Prilosec), esomeprazole (Nexium), pantoprazole (Protonix), and others (all end in "-prazole").

• Mechanism: Block the proton pump (H⁺-K⁺-ATPase enzyme) on parietal cells, which is the final step in gastric acid secretion.

• Efficacy: Drugs of choice for long-term treatment of ulcers and GERD. Highly effective, reducing gastric acid secretion by 80–95% —more effective than H2 blockers and antacids.

• Additional Actions: May have antibacterial effects against H. pylori and anti-inflammatory properties that reduce gastric irritation.

• Adverse Effects & Considerations (Long-Term Use):

  • Generally well-tolerated, but acid rebound can occur upon discontinuation after prolonged use.

  • Potential risks with long-term use include:

    • Increased risk of gastric polyps.

    • Increased risk of infections (e.g., C. diff, pneumonia).

    • Increased risk of fractures (hip, wrist, vertebrae).

    • Decreased absorption of certain nutrients (e.g., Vitamin B₁₂).

    • Interstitial nephritis (kidney problem).

  • Despite these risks, the benefits for long-term ulcer and GERD treatment generally outweigh the risks, but patients should be monitored periodically.

Drugs for Diarrhea

Opioid Derivatives

Bismuth Salicylate

Opioid Derivatives (examples, mechanism, side effects

• Examples: Diphenoxylate (often combined with atropine in Lomotil) and loperamide (Imodium). Older agents like laudanum and paregoric are now rarely used.

• Mechanism: Stimulate opioid receptors in the enteric nervous system, causing anti-peristalsis (slowing intestinal motility).

• Side Effects: GI disturbances such as nausea, abdominal discomfort, and constipation. Newer agents (loperamide, diphenoxylate) have fewer side effects than older opium tinctures.

Bismuth Salicylate (Examples, Use, Mechanism, Side Effects)

• Examples: Active ingredient in Pepto-Bismol and Kaopectate.

• Use: Often used to prevent and treat traveler's diarrhea.

• Mechanism: Has multiple effects:

  • Increases absorption of water and electrolytes from the colon.

  • Decreases secretion of gastric acid.

  • The salicylate component reduces irritation of the intestinal lining.

• Side Effects: Relatively free from serious side effects, but salicylate intoxication can occur with overdose or in individuals sensitive to aspirin/other salicylates.

General Principles of GI Imaging

• Challenge

• Role of Imaging

• Screening Tool

• Challenge: Abdominal radiography is challenging because standard X-rays are not optimal for viewing soft tissues. CT scans are often preferred for better visualization.

• Role of Imaging: In bowel obstructions, imaging helps:

  • Differentiate true mechanical obstruction from constipation.

  • Localize the obstruction (small bowel vs. large bowel).

  • Identify the underlying cause.

• Screening Tool: Radiographs are used as a screening tool, but a normal radiograph does not exclude pathology.

Bowel Obstruction (Findings on Radiograph, Findings on CT Scan, Normal Bowel Appearance, Paralytic Ileus)

• Findings on Radiograph: Dilated bowel loops and fluid levels (on erect radiographs).

• Findings on CT Scan:

  • A clear point where the bowel diameter changes from normal to abnormal.

  • Dilated bowel loops proximal to the obstruction.

  • Size criteria for dilation: Small bowel > 3 cm; Large bowel > 5 cm.

• Normal Bowel Appearance:

  • Large bowel tends to be peripheral and has a larger caliber.

  • Small bowel tends to be central.

• Paralytic Ileus: A functional (non-mechanical) obstruction, often seen after abdominopelvic surgery. Imaging shows diffuse gaseous dilation of both small and large intestines with air-fluid levels. Recovery can take up to 72 hours.

Hernias (Imaging Appearance, Types Visualized)

• Imaging Appearance: Hernias appear as protrusions through weak points in the abdominal wall, with bowel structures (including radiolucent gas) visible within the hernial sac.

• Types Visualized:

  • Femoral Hernia: Characterized by a funnel-shaped neck protruding through the femoral ring, medial to the femoral vein.

  • Inguinal Hernia: Seen as a protrusion in the groin region.

Ulcers (Gastric/Duodenal) [CT Findings, Limitation, Perforated Ulcer]

• CT Findings: May show gastric or duodenal wall thickening and outpouching of the mucosa from ulcerations.

• Limitation: CT has traditionally not been sensitive enough for ulcer diagnosis, though resolution improvements are ongoing.

• Perforated Ulcer: If an ulcer perforates and leaks air into the peritoneal cavity, an erect chest radiograph can show free abdominal gas immediately below the hemidiaphragms (which become visible due to the gas). This is sufficient for diagnosis.

Appendicitis (Imaging Modality, CT Findings, Clinical Context)

• Imaging Modality: CT is the modality of choice in acute settings for appendicitis, with 94–98% sensitivity and up to 97% specificity. It also helps rule out other causes of abdominal pain.

• CT Findings: A dilated appendix with distension of the lumen and thickening of its wall.

• Clinical Context: Imaging may be guided by patient presentation (e.g., postoperative status, fever, white blood cell count).

Inflammatory Bowel Disease (IBD) (Relevance to Physical Therapists, Radiographic Signs)

Inflammatory Bowel Disease (IBD)

• Relevance to Physical Therapists: Patients with IBD (e.g., Crohn's disease) are more likely to have spondyloarthritis, including sacroiliac joint pain, as well as hip and wrist pain.

• Radiographic Signs:

  • "Lead Pipe" Sign: Loss of normal haustral sacculations in the colon (e.g., transverse and sigmoid colon), commonly seen in chronic ulcerative colitis.

  • Sacroiliitis: Signs of inflammatory arthritis in the sacroiliac joints, with ankylosis (fusion) on one or both sides.

7. Imaging Recommendations for Acute Nonlocalized Abdominal Pain

Deepseek 7