L2 (What Can Go Wrong With The Gut) PDF

What can go wrong with the gut Dr. Ghasaq M. Kareem M.B. Ch. B. / FIBMS (Path) University of Zakho Dept. of Pathology  Food enters the gut by mastication and swallowing. Swallowing is a complex set of muscle contractions which form a ‘bolus’ of food in the mouth...

What can go wrong with the gut Dr. Ghasaq M. Kareem M.B. Ch. B. / FIBMS (Path) University of Zakho Dept. of Pathology  Food enters the gut by mastication and swallowing. Swallowing is a complex set of muscle contractions which form a ‘bolus’ of food in the mouth, then propel it towards the Pharynx, then into the esophagus for rapid propulsion into the stomach. The swallow may be compromised by anaesthesia or neurological deficits. This may lead to aspiration of food into the lungs, which is very dangerous and may cause pneumonia. Liquids are more difficult to swallow, so where swallowing is compromised liquids are often thickened to assist the process. Difficult swallowing is known as Dysphagia  Causes of dysphagia – Esophageal causes: a. esophageal cancer, b. gastro-esophageal reflux disease (GERD), c. motility disorders- achalasia – Others: stroke/neuromuscular causes, extrinsic compression E Involuntary contraction Relaxation one > - - sphincter Lower Esophageal  & - ↓ - - Lack of tears Addison's disease Secondary achalasia e.g. Chagas’ disease (South American trypanosomiasis) causing destruction of myenteric plexus.  ③ - S= to clinical history measure Ov lower pressure Esophagus  Achalasia Therapy of achalasia: 1. Medication [calcium channel blockers], 2. Heller’s myotomy, E ↳ M Esophagus 3. Pneumatic dilatation,- > os Endoscopy 8 + x - - 4. Botulinum Toxin , - Heller myotomy is a surgical procedure in which the muscles of the cardia (lower esophageal sphincter or LES) are cut, allowing food and liquids to pass to the stomach. It is used to treat achalasia, a disorder in which the lower esophageal sphincter fails to relax properly, making it difficult for food and liquids to reach the stomach.  Gastro- Esophageal Reflux Disease (GERD) If the sphincter between the esophagus and stomach is weak, acid may reflux into Es esophagus causing irritation which leads to pain known as heartburn, but may also cause much more serious damage to the esophageal mucosa. Acid leaving the stomach may also cause ulceration in the duodenum. 95. 3 > pyloric sphincter > , *& ↳ &. (16 )  Gastro- Esophageal Reflux Disease (GERD) Pathophysiology – Low lower esophageal sphincter [LES] pressures –-155125 Impaired esophageal acid clearance Se – Hiatus hernia (Presence of segment of stomach above the diaphragm in thoracic cavity – due to increased intra-abdominal pressure. It’s of 2 types: 1. Axial (sliding hernia) 95% 2. Non axial (paraesophagial) Consequences Ulceration = 5 Stricture - > ~. Glandular metaplasia (Barrett’s esophagus) Carcinoma Cadenocarcinoma or squamous more common in · cell Carcinoma >  GERD symptoms/ incidence Classical: acid reflux, water brash, retrosternal burning T e If thewith carity oral is filled Atypical symptoms: chest pain (mimic heart attacks), asthma, dental erosion, cough - Due to Acid teeth Damaging 4-7 % daily symptoms 34-45% monthly symptoms  GERD - Investigations In patients with classical symptoms the diagnosis can be made clinically Older patients [with recent onset of symptoms] require an endoscopy Patients with uncontrolled symptoms should be investigated A normal endoscopy does not exclude GERD  GERD treatment Simple antacids Alginates as Gaviscon Acid suppressants Histamine 2 receptor antagonists Proton pump inhibitors (ex: Omeprazole) Surgery  Barrett’s esophagus Replacement of the normal distal stratified squamous mucosa by metaplastic columnar epithelium containing goblet cells in lower esophagus as a complication of long standing reflex. Common Complications: Ø Associated with risk of progression to adenocarcinoma Ø Ulcer & stricture Management > Screening - Proton pump inhibitors (PPI) for life  Esophageal tumors Benign tumors (rare) squamous papilloma, leiomyoma Esophageal cancer painful swallowing Symptoms: Odynophagia, dysphagia (gradually progress dysphagia), weight loss - - Main types: Squamous and adenocarcinoma Risk factors: obesity, male sex (3:1), Barrett’s (Barrett’s →adenocarcinoma), Smoking, alcohol. Investigations: Barium swallow, Gastroscopy + biopsy - -  Squamous Cell Carcinoma Commonest worldwide (more in blacks) - High incidence in Southern Africa, China, Iran Predisposing factors Diet related (Vitamin A & B deficiency, fungal contamination, nitrosamines), tobacco & alcohol - -- Human papillomavirus Chronic non-specific esophagitis Achalasia Plummer-Vinson syndrome (esophageal webs, microcytic hypochromic anemia and atrophic glossitis) 17 17 Dr. Mayada  Morphology of Squamous carcinoma 20% in the upper, 50% in the 20% middle & 30% in the lower third of esophagus. Gross: often large polypoid exophytic occluding tumors, but could be necrotizing 50% ulcerative or diffuse. Invasive disease preceded by dysplasia & carcinoma in situ 30% 18  Adenocarcinoma Adenocarcinoma is now the commonest type in Europe/N. America, associated with Barrett’s esophagus (more in whites) - Ø Occurs in lower third of the esophagus Ø Gross: initially flat then large nodular mass or ulcer Ø Microscopy: mucin-producing glandular tumors with intestinal features. 19 19 Dr. Mayada  Stomach The stomach stores ingested food and subjects it to preliminary physical & chemical disruption. This requires the secretion of acid and enzymes which attack biological material.  Stomach The stomach is defended against its own acid by mucus and hydrogen H20z carbonate secretion, - These defenses may break down- for example: 1. H Pylori, Byi 2. Drugs which affect prostaglandin secretion) 3. Excess acid secretion, leading to peptic ulceration. This typically cause pain relieved by eating, and ulcers may bleed or occasionally perforate. A variety of drugs may be used to reduce acid secretion.  The acid, hypertonic and only partly digested food called chyme that leaves the stomach is conditioned by : diff btwn bulos and chyme - exam 1. secretion of alkali from the liver and pancreas, 2. osmotic movement of water across the duodenal wall, 3. secretion of a cocktail of enzymes from the pancreas and intestines. Bile enters the gut via the bile duct.  The digestive functions of bile mainly relate to the digestion of fats, by secretion of the bile acids. Bile acids assist with digestion of fats in the intestines and are then re-absorbed in the terminal ileum and recycled to the liver, where they are immediately re-secreted in bile. enterohepatic circulation.  This bile is then stored until the next meal in the gall-bladder before being released to begin the cycle again. The liver also excretes bilirubin, a breakdown product of haemoglobin. If the liver cannot excrete bilirubin then this will accumulate in the blood – a condition known as jaundice.  The capacity of the liver to excrete bilirubin is limited, so if there is excess production because of excess breakdown of haemoglobin, then pre- hepatic jaundice may occur. The liver may also be damaged by: 1. disease (infection) 2. alcohol 3. drugs, causing amongst other things hepatic jaundice.  Alcohol may cause serious liver damage, leading to fibrotic changes known as cirrhosis. This leads to loss of liver functions but may also impair the flow of blood from the hepatic portal vein through the liver to the systemic venous circulation, causing portal hypertension. 11] ; /,s This may lead to the formation of ascites, and Through - also increased flow though collateral venous pathways around the esophagus and the anus.  The bile duct may obstructed, causing back-up of bile, and resulting liver damage, - post- - - hepatic or obstructive jaundice. Obstruction may come about because of the formation of gallstones from the precipitation of bile acids and cholesterol in the gall bladder.  Gallstones are often asymptomatic, but may move within the gall bladder, causing - biliary colic, which is very painful, or into the bile duct, where they may obstruct and lead to serious problems. Tumours of the pancreas may also obstruct biliary outflow.  The pancreas secretes alkali and a cocktail of enzymes including amylases which break down carbohydrates. The pancreas may become inflamed, leading to pancreatitis. This causes considerable pain, and is characterized by the release of amylases into the blood stream.  The remainder of the small intestine is the principal site of absorption. Neutral chyme is propelled gently along its - C length by segmentation and the large surface area allows a complex of absorptive processes to occur. Pancreas & Ss & Cali livers Have Already secreted All which neutralized Chyme's s  Some conditions affect these processes of absorption, leading to malabsorption. The motility of the ileum may be compromised under some circumstances, leading to paralytic ileus and it may also become obstructed either from an internal obstruction or external compression. Paralytic ileus is the condition where the motor activity of the bowel is impaired, usually without the presence of a physical obstruction  One part of the intestines, the appendix is particularly at risk of inflammation, leading to appendicitis. The major parts of the gut are enclosed in a virtual space created by the peritoneum, which may become inflamed, leading to peritonitis, which will normally follow any perforation of the gut as the contents are released into the space.  The large intestine is the site of absorption of remaining water and electrolytes after chyme exits the small intestine. During passage through this large tube feces are formed and then periodically propelled into the rectum prior to defecation.  The large and small intestines may be affected by "idiopathic" >) inflammatory bowel disease -> Crohn's disease & ulcerative colitis "Active" IBD is characterized by acute inflammation. Crypt abscesses (neutrophils in crypt lumens) Inflammatory bowel disease leads to diarrhoea, pain and blood loss, as well as problems with absorption particularly if the small intestine is affected. Crypts, in histology, refer to invaginations or pits in the lining of certain tissues, particularly in the epithelium of organs like the intestines. In the context of the gastrointestinal tract, intestinal crypts are small tubular structures in the mucosal lining, containing stem cells that 34 give rise to various cell types, contributing to the continuous renewal of the epithelium.  & Ulcerative colitis (UC) Involves the colon as a J Widespread diffuse mucosal disease with distal predominance. The rectum is virtually always involved, then extend proximally in a continuous pattern. The etiology for UC is unknown. UC is more common in persons of Caucasian race, (peak incidence at ages 20 - 25 years). Patients with prolonged UC are at increased risk for developing colon cancer. 35  Crohn's Disease Crohn's disease can involve any part of the GI tract, but most frequently the distal small bowel and colon. Inflammation is typically transmural and can produce: - (GIT) affects layers Con all of It &- - ser ~ Su musi Small ulcer over a lymphoid follicle (aphthoid ulcer) Deep fissuring ↳ Analmucosa Transmural scarring Fistulas between loops of bowel and other structures. ↳ between two structure Abnormal opening 36  Crohn's Disease Inflammation is typically segmental with uninvolved bowel separating areas of involved bowel. 1/3 of cases have granulomas in the - intestin and sites such as lymph nodes, liver, and joints. The clinical manifestations are variable: diarrhea, fever, as well as arthritis, uveitis, erythema nodosum, and ankylosing spondylitis. 37  Comparison of Ulcerative Colitis and Crohn's Disease Feature Ulcerative Colitis Crohn's Disease Segmental or diffuse, Diffuse, distal often proximal Distribution predominance usually predominance Involves Confined to colon any part of GI tract Rectum Always involved Often spared Often focal Abnormal Diffuse Inflammation areas are interspersed Leion Distribution continuous from rectum with normal “skip lesions” Lesion g Depth of Inflammation Mucosal Transmural Sinus Tracts and Absent Often present Fistulae Strictures Absent Often present 38 Granulomas Absent Often present  The colon also has a large bacterial flora, much of it beneficial, but on occasion the balance may be disturbed by pathogens, which can lead to diarrhoea, and resulting water and electrolyte disturbances. The large intestine is also a common site of malignancies, and colo-rectal cancer is a major cause of mortality. -