Gut Problems and Dysphagia Overview

Gut Problems

• The gut, or gastrointestinal tract, is a complex system responsible for food processing.

• Swallowing is a complex muscle action, moving food from the mouth to the stomach. Problems like anesthesia or neurological issues can compromise swallowing, which can lead to aspiration, potentially causing pneumonia. Liquids are harder to swallow and often need thickening. Difficult swallowing is dysphagia.

Causes of Dysphagia

• Esophageal issues include esophageal cancer, gastroesophageal reflux disease (GERD), and motility disorders like achalasia.

• Other potential causes include stroke, neuromuscular issues, and external compression.

Achalasia

• Achalasia is a condition where the lower esophageal sphincter (LES) does not relax properly.

• Swallowing triggers peristaltic waves and LES relaxation, but in achalasia, the relaxation fails.

• Patients often experience regurgitation and dysphagia.

• Epidemiology: Incidence is roughly 1/100,000, affects males and females equally, mostly presents in ages 25-60.

• Pathogenesis: Loss of ganglion cells in the myenteric plexus (Auerbach's) is a key component. Loss of inhibitory nerve function (NO) results in impaired relaxation; remaining cholinergic function is intact (excitatory). Autoimmune disease involving latent HSV-1 is possible. Allgrove Syndrome (AAA) is a rare autosomal recessive disorder linked with achalasia. Secondary achalasia includes instances such as Chagas' disease.

• Clinical Presentation: Chief symptoms include dysphagia (solids and liquids, 91% and 85% respectively). Regurgitation, difficult belching, chest pain, heartburn, and sometimes mild weight loss.

• Diagnosis: CXR (widened mediastinum and absence of gastric bubble), Manometry (confirmatory). Barium swallow is a primary screening test. Medical history is also crucial.

• Therapy: Treatments include medication (calcium channel blockers), Heller's myotomy (surgical incision of the LES), pneumatic dilatation, and Botulinum toxin injections.

Gastroesophageal Reflux Disease (GERD)

• Weak sphincter between esophagus and stomach lets acid reflux, causing heartburn and potential esophageal mucosa damage.

• Acid reflux can also cause ulcers in the duodenum.

• Pathophysiology involves low lower esophageal sphincter (LES) pressures and poor esophageal acid clearance. Issues like hiatus hernia (stomach portion protruding above diaphragm) and increased intra-abdominal pressure are causative factors.

• Possible consequences include esophageal ulceration, strictures (narrowing), glandular metaplasia (Barrett's esophagus), and esophageal cancer (adenocarcinoma or squamous cell carcinoma).

• Symptoms are various, from classic acid reflux, water brash, and retrosternal burning, to atypical symptoms like chest pain, asthma, dental erosion, and coughs. Prevalence ranges from 4-7% daily to 34-45% monthly.

• Diagnosis: In patients with classic symptoms, diagnosis is often clinical. Older patients experiencing new symptoms often require endoscopy.

• Treatment usually involves simple antacids, alginates like Gaviscon, acid suppressants (histamine 2 receptor antagonists, proton pump inhibitors like Omeprazole). Surgery is sometimes required.

Barrett's Esophagus

• Barrett's esophagus involves the replacement of normal esophagus lining to metaplastic columnar epithelium with goblet cells.

• This is commonly linked to long-standing GERD.

• Complication: High risk of progression to adenocarcinoma.

• Management: Requires screening and proton pump inhibitors (PPIs) for long-term management.

Esophageal Tumors

• Benign tumors (squamous papilloma and leiomyoma) are rare.

• Esophageal cancer is seen in squamous cell and adenocarcinoma forms.

• Symptoms include odynophagia, dysphagia; gradually increasing dysphagia; and ongoing weight loss.

• Risk factors include obesity, male sex, Barrett's esophagus, smoking and alcohol.

• Diagnosis involves barium swallow, gastroscopy, and biopsy analysis.

Squamous Cell Carcinoma

• Squamous cell carcinoma (SCC) is a common type of esophageal cancer worldwide, but occurs more frequently in certain populations (Southern Africa, China, Iran).

• Diet, including deficiency of Vitamins A & B, fungal contamination, nitrosamines, alcohol and tobacco also increase risk.

• Human papillomavirus (HPV) infection may also play a role.

• Chronic esophageal related conditions such as esophageal inflammation, achalasia, and Plummer-Vinson Syndrome are risk factors.

Morphology of Squamous Cell Carcinoma

• 20% in the upper esophagus, 50% in the middle and 30% in the lower third.

• Typically occurs as an exophytic, large occluding tumor (polypoid), but ulcerative or diffuse.

• The disease may begin as dysplasia before progressing into carcinoma in situ, and finally into invasive disease.

Adenocarcinoma

• Adenocarcinoma is the most common esophageal cancer type in North America and Europe.

• Often associated with Barrett's esophagus, which is largely caused by long-lasting GERD.

• Grossly, it may start as a flat lesion, followed by a larger nodular mass or ulcer.

• Microscopically, it presents as mucin-producing glandular tumors with intestinal features.

Stomach

• The stomach stores food, partially digests it physically & chemically.

• Acid and enzymes are key to the process of breaking down ingested materials.

• Stomach defenses, such as mucus and bicarbonate, can break down, allowing for conditions such as ulcers.

• Causes of peptic ulcer include H. pylori infection, drug-related issues, and excess acid secretion.

• Ulcers and acid can cause pain, bleeding, and perforation.

Bile Digestive Functions

• Bile acids are vital for digesting fats. The liver secretes bile acids, which are stored in the gallbladder.

• Bile is released into the small intestine to aid fat breakdown. The bile acids are reabsorbed in the ileum and returned to the liver for reuse (enterohepatic circulation).

• Bile breakdown product bilirubin is excreted by the liver.

• Issues with bilirubin excretion lead to jaundice. Causes of jaundice include excess bilirubin production (pre-hepatic), liver issues (hepatic), or bile duct issues (post-hepatic). Conditions such as gallstones can cause post-hepatic jaundice.

Gallstones

• Gallstones, often asymptomatic, may lead to complications like biliary colic (painful gallstone movement) or blockage of the bile duct. Blockages can lead to more serious problems.

Pancreas

• The pancreas secretes bicarbonate and enzymes like amylase breaking down carbohydrates.

• Pancreatitis causes inflammation and pain, characterized by the release of pancreatic enzymes into the bloodstream.

Small and Large Intestine

• Small intestine is the site of most food absorption. Digestion continues in the small intestine where neutral chyme is processed, and the large surface area aids the process.

• The large intestine absorbs water and electrolytes, forming feces that are ultimately evacuated from the body.

• Malabsorption and conditions like paralytic ileus may occur to interfere with proper passage.

Appendicitis, Peritonitis

• The appendix, a part of the lower intestine, is prone to inflammation, called appendicitis.

• Peritonitis occurs when the membrane lining the abdomen becomes inflamed. It often occurs following a perforation of the gut.

Inflammatory Bowel Disease (IBD)

Conditions such as Crohn's disease and ulcerative colitis.

Crohn's Disease

• Crohn's disease can affect any part of the gastrointestinal (GI) tract but commonly involves the distal small bowel and colon. It's characterized by transmural inflammation (affects all layers).

• Symptoms can include small ulcers over lymphoid tissue (aphthous ulcers), deep fissures, transmural scarring, and fistula formation.

• Granulomas (collections of immune cells) are found in the intestine, lymph nodes, liver, and joints in approximately 1/3 of all cases.

• Crohn's disease can be characterized by variable symptoms including diarrhea, fever, arthritis, uveitis, erythema nodosum, and ankylosing spondylitis.

Ulcerative Colitis

• Ulcerative colitis is limited to the colon and rectum, presenting as a diffuse, typically distal inflammatory condition. The inflammation, by necessity, progresses proximally in the bowel.

• It's primarily characterized by mucosal inflammation, frequently lacking granulomas in contrast to Crohn's.

• Peak incidence in early adulthood (20-25 years old).

• Patients with long-standing ulcerative colitis are at increased risk of developing colon cancer.

Colorectal Cancer

• Colorectal cancer is common and a major cause of mortality, often arising from large intestinal malignancies.