Gastrointestinal Disorders Lectures 6-11 2022 PDF

**[Lecture 6 ]** **Congenital disorders of intestine** **Intestinal atresia** Failure of the gut to canalize, most commonly found in the duodenum or small intestine. **Meckel\'s diverticulum** - **[Meckel's diverticulum]**: is a remnant of the vitello-intestinal duct. It is a tubular blin...

**[Lecture 6 ]** **Congenital disorders of intestine** **Intestinal atresia** Failure of the gut to canalize, most commonly found in the duodenum or small intestine. **Meckel\'s diverticulum** - **[Meckel's diverticulum]**: is a remnant of the vitello-intestinal duct. It is a tubular blind pouch present on the antimesenteric border of small intestine - **[Rule of 2:]** - Occur in 2% of the population. - Are 2 inches (5cm) long. - Are 2 feet (60cm) from the ileocaecal valve. - 2/3rds have ectopic mucosa. - 2 types of ectopic tissue (gastric and pancreatic). - And 2% become symptomatic. - **[Complications:]** - Meckel's diverticulum can become **inflamed** - Ectopic gastric mucosa can cause **peptic ulcer**. - Meckel's diverticulum may results in **volvulus** ** ** **Hirshsprung Disease (Congenital megacolon)** - **[Definition:]** - Children less than one year old - Manifested by severe constipation and abdominal distention. - **[Etiology:]** Congenital **absence of the ganglionic cells** in the myenteric plexus at the recto-sigmoid junction. Peristalsis stops at the affected site resulting in **functional chronic intestinal obstruction.** - **[Gross:]** - The distal aganglionic segment is narrow - The proximal ganglionic segment is dilated (Megacolon). **Acute Intestinal Obstruction** - **[Definition:]** Sudden complete bowel obstruction. - **[Types:]** **1) [Functional Cause:]** - **Paralytic Ileus.** **2) [Organic/Other Causes:]** a. **Outside Adhesions.** b. **Endophytic tumor.** c. **Volvulus.** d. **Intussception.** e. **Strangulated hernia**. f. **MVO (Mesenteric Vascular Occlusion**). **[Functional (paralytic ileus)]** - A segment of the intestine loses its peristaltic movement - **[Causes:]**\ 1) Operative trauma to the intestine. 2\) Septic peritonitis disturb the normal autonomic control of peristalsis. **[Organic/Mechanical/ Vascular]** 1. **[Outer Fibrous Adhesions]** 2. **[Inner Lumen obstruction]**: by foreign body, (solid stools) or tumor. 3. **[Strangulated hernia ]** N.B. A hernia is a loop of intestine, which passes through a congenital or acquired defect in the abdominal wall 4\) **[Volvulus: ]** Volvulus is complete twisting of a bowel loop about its- mesentery. 4. **[Intussusception:]** - Intussusception occurs when upper loop of intestine is invaginated into the lower segment. 5. **[Thrombosis or embolism of mesenteric artery:]** - Producing infarction of a segment, which loses its peristalsis & does not function. - **[Gross:]** - **The proximal** segment is markedly dilated. - **The distal segment** is collapsed. - **[Clinical Picture:]** - Abdominal distension, persistent vomiting leading to dehydration & shock (hypovolemic). - No passage of stools or flatus (gas). - **[Complications:]** 1. **Septic peritonitis.** 2. **Gangrene:** The marked dilatation causes compression on the vessels of the wall leading to ischemic necrosis, followed by putrefaction &, wet gangrene **[Lecture 7]** **Chronic Intestinal Obstruction** - **[Definition:]** Gradual incomplete obstruction of intestinal lumen. - **[Types]** **1) [Functional Cause:]** - **Hirschsprung disease.** **2) [Organic/Other Causes:]** **a) Outside Adhesions.** **b) Endophytic tumor.** **c) Fibrous stricture after dysentery, Crohn's disease.** - **[Gross:]** - **The proximal** segment is markedly dilated and **hypertrophy**. - **The distal segment** is collapsed. **Diverticular Disease of The Colon** - [**Definition**:] Acquired herniations of mucosa and submucosa into intestinal wall. It is a disease of old age. - **[Complications:]** 1. Diverticulitis or abscess. 2. Bleeding 3. Perforation & septic peritonitis. 4. Fibrosis &stricture. **Acute Diffuse Suppurative Appendicitis** - **[Etiology: ]** - **Organisms:** Staphylococci, E. coli - **Predisposing factor: Obstruction with** - Fecolith & seeds, - Children: lymphoid hyperplasia (viral infections) - Adults: carcinoid tumor. - **[Gross & Microscopic : see practical]** - ** [Complications:]** 1. **Perforation & septic peritonitis.** 2. **Peri-Appendicular Inflammatory Mass/ Abscess.** 3. **Gangrene.** 4. **Portal Pyemia** 5. **Mucocele (Bag full of mucus)** 6. **Empyema (Bag full of pus)** 7. Chronic appendicitis **[Lecture 8]** **MALABSORPTION** - **[Definition:]** Defective absorption of fats, proteins, carbohydrates, water, electrolytes, minerals, fat and vitamins. - **[Etiology:]** 1\. **[Celiac Disease]** (***gluten-induced enteropathy***) - Hypersensitivity reaction to a protein in wheat. - Characterized by partial to total villous atrophy of small intestine. 2\. **[Tropical sprue]:** - Disease of tropics due to chronic intestinal bacterial infections. - Characterized by partial villous atrophy of the small intestine. 3\. **[Giardiasis.]** 4\. **[Secondary malabsorption]**: Complicating other diseases with diffuse destruction of small intestinal mucosa, e.g. - **Inflammation**: Tuberculosis, Crohn's disease (Regional ileitis) - **Tumors**: Intestinal lymphoma - **Post-surgical** resections (short gut) - **[Clinical Picture:]** Chronic diarrhoea with **steatorrhea** & weight loss **Typhoid Fever** - **[Definition: ]** - *Systemic* infective disease of the small intestine & other organs, caused by *Salmonella typhi*. - Children and adolescents are most often affected. - **[Route of infection:]** Ingestion of contaminated water or food. - **[Pathogenesis:]** - **[Pathological features:]** 1. **Payer\'s patches** are enlarged and swollen. 2. **Oval Longitudinal ulcers** in the intestinal mucosa. 3. Enlarged **spleen**. - **[Complications:]** +-----------------------------------+-----------------------------------+ | **Primary Intestinal | **Secondary Intestinal | | Tuberculosis** | Tuberculosis** | +===================================+===================================+ | - **[Mode of infection: | - **[Mode of infection: | | ]** | ]** | | | | | Swallowing of **human tubercle** | **[Ingestion of infected | | or **bovine tubercle** bacilli. | sputum]** in patients | | | with pulmonary TB | +-----------------------------------+-----------------------------------+ | - **[Pathology:]** | - **[Pathology:]** | | Primary complex: | | | | **1.The lesions** | | 1. **The initial lesion:** | | | | - In terminal ileum &caecum. | | - In terminal ileum. | | | | - Bacilli reaches Peyer\'s | | - Group of tubercles in | patches (& solitary follicles | | **Payer\'s patches.** | of caecum) → caseous necrosis | | | and erosion of the covering | | - forming a **[small | mucosa → multiple | | nodule.]** | **[Tuberculous Girdle | | | Ulcers]** | | - **[Minimal | | | ulceration]** | | | of the covering mucosa. | | | | - Multiple terminal ileal | | 2. **Tuberculous lymphangitis.** | ulcers | | | | | 3. **Tuberculous lymphadenitis | - Transverse (girdle) | | (Tabes Mesenterica)** | | | | - Undermined edges, | | | | | | - Caseous floor. | | | | | | | | | | | | - Mesenteric lymph nodes show | | | minimal lesions. | +-----------------------------------+-----------------------------------+ | - **[Fate & Complications | - **[Fate & Complications | | ]** | ]** | | | | | **With good body | 5-Spead | | resistance**→Localization. | | | | - **Direct** → TB peritonitis. | | **With low body | | | resistance**→Spread | - **Lymphatic**→ TB | | | lymphadenitis. | | - **Direct** → TB peritonitis. | | | | - **Blood** →isolated | | - **Lymphatic**→ TB | organ/military TB | | lymphadenitis. | | | | | | - **Blood** →isolated | | | organ/military TB | | +-----------------------------------+-----------------------------------+ **[Intestinal Tuberculosis]** **[Lecture 9: Dysentery]** **Dysentery:** Inflammation of large intestine characterized by diarrhea, tenesmus, mucous & blood in the stools. +-----------------------+-----------------------+-----------------------+ | **Bacillary | **Amoebic Dysentery** | **Bilharzial | | Dysentery** | | Dysentery** | +=======================+=======================+=======================+ | **Caused by:** | **Caused by:** | **Caused by:** | | | | | | **Bacteria "Shigella | **Parasite: | **Parasite: | | Bacilli"** | "Entamoeba | "Shistosoma | | | Histolytica"** | Mansoni"** | +-----------------------+-----------------------+-----------------------+ | **Exotoxins** | **Invasive amoeba** | **Delayed type | | | | hypersensitivity** | | | **To mucosa** | | | | | | | | **&++ submucosa** | | +-----------------------+-----------------------+-----------------------+ | **Acute | **Acute | **Chronic | | Inflammation** | inflammation** | Inflammation** | | | | | | **(Pseudomembranous)* | | **(Granulomatous)** | | * | | | +-----------------------+-----------------------+-----------------------+ | **Large intestine | **++Proximal Colon** | **++ Distal Colon** | | (diffuse)** | | | | | **(cecum & | **( rectum)** | | | ascending)** | | +-----------------------+-----------------------+-----------------------+ | **Gross:** | 1. **Flask shape | **1- Sandy patches** | | | ulcers** | | | 1. **Yellow | | **2- Bilharzial | | pseudo-membrane** | 2. **Healthy mucosa | polyps ([the | | | in between** | commonest | | 2. **Superficial | | )]** | | bleeding ulcers | | | | in between** | | **3- Bilharzial | | | | ulcers** | | | | | | | | **4- Fibrosis** | +-----------------------+-----------------------+-----------------------+ | **Microscope** | **Microscope** | **Microscope** | | | | | | **[Pseudo-membrane]{. | **[Ulcer floor & | [**Bilharzial Ova** | | underline};** | edges]** | +**Granuloma**]{.unde | | | | rline} | | **necrotic epithelial | **show amoebae, as | | | cells** | rounded bodies | Macrophages (M) | | | surrounded by clear | | | **+** | zones (due to lysis | Modified M | | | by proteolytic | (Epithelioid cells) | | **++Neutrophils** | enzymes** | | | | | Fused M (giant cells) | | | **- Few inflamm | Lymphocytes | | | cells** | | | | | \+ | | | | | | | | **Eosinophils** | +-----------------------+-----------------------+-----------------------+ | **Complications** | **Complications** | **Complications** | | | | | | **Intestinal** | **Intestinal** | **Intestinal** | | | | | | 1. 2. 3. 4. 5. | 1. **Bleeding.** | 1. **Bleeding.** | | | | | | **Extra-intestinal** | 2. **Perforation.** | 2. **Obstruction (by | | | | large polyps)** | | **Toxic: Myocarditis, | **Extra-intestinal** | | | arthritis** | | 3. **Intussusception | | | **Spread** | ** | | | | | | | ***Direct spread*: | 4. **Healing by | | | perianal fistula** | fibrosis with | | | | stricture** | | | ***Blood spread*:** | | | | | **Extra-intestinal** | | | **Liver amoebic | | | | abscess.** | **Spread** | | | | | | | **Lung amoebic | ***Blood spread*:** | | | abscess.** | | | | | **To portal vein | | | | (then liver)** | | | | | | | | **,... Portal | | | | Hypertention** | | | | | | | | **N.B:** Intestinal | | | | bilharziasis **[is | | | | NOT] a | | | | cause of intestinal | | | | carcinoma** | +-----------------------+-----------------------+-----------------------+ **[Antibiotic Associated Colitis:]** Severe colitis with severe diarrhea and dehydration due to overgrowth of ***Clostridium difficile*** which causes a wide toxic mucosal injury. The colon shows **pseudomembranous** colitis. **[Lecture 10: Inflammatory Bowel Disorders]** +-----------------------------------+-----------------------------------+ | **Crohn's disease (Regional | **Ulcerative Colitis** | | Ileitis)** | | +===================================+===================================+ | **Etiology: Idiopathic/ | **Etiology: Idiopathic/ | | Autoimmune** | Autoimmune** | +-----------------------------------+-----------------------------------+ | **CP: Severe diarrhea/abdominal | **CP: Severe diarrhea/abdominal | | pain** | pain** | | | | | **May present with fistulas** | **Bleeding per rectum** | | | | | | **Periods of Activity and Periods | | | of Remission** | +-----------------------------------+-----------------------------------+ | **Chronic Active Inflammation** | **Chronic Active Inflammation** | | | | | **N.B: Active means with | **N.B: Active means with | | neutrophils** | neutrophils** | +-----------------------------------+-----------------------------------+ | **[Site:]** | **[Site:]** | | | | | **Mainly Terminal Ileum** | **Starts in rectum then sigmoid | | | and spread to involve all colon | | **But May Affect any part Of | (pancolitis)** | | GIT** | | +-----------------------------------+-----------------------------------+ | **[Gross | **[Gross (Up)]** | | (2C+2S+3F)]** | | | | - **Ulcers ( small & | | 1. **Skip lesions** | irregular)** | | | | | 2. Elongated **Serpentine | - **Pseudo-polyps** | | ulcers**). | | | | | | 3. **Cobblestone** appearance of | | | the mucosa | | | | | | 4. Adherent **Creeping | | | mesenteric fat**; | | | | | | 5. Deep **Fissures, Fistula** | | | tracts and **Fibrosis**. [ | | | ] | | +-----------------------------------+-----------------------------------+ | **Microscopic** | **Microscopic** | | | | | **Chronic Active Inflammation | **Chronic Active Inflammation | | With Deep ulcers, Fissures | With Superficial ulcer & | | &Neutrophils** | Neutrophils** | | | | | - **Affect all wall | - **Affect Mucosa ± submucosa** | | (transmural)** | | | | - **Ulcers + Pseudo-polyps** | | - **Fibrosis** | | | | - **Crypt abscesses** | | - **Granulomas; non caseating | | | (35%)** | **Chronic Phase:** | | | | | **Chronic Phase:** | **Epithelial dysplasia in long | | | standing conditions | | **No Dysplasia** | (premalignant)** | | | | | | Note: Pseudo-polyps are formed of | | | regenerating epithelium & | | | granulation tissue | +-----------------------------------+-----------------------------------+ | **Complications** | **Complications** | | | | | 1. **Hemorrhage.** | 1. **Hemorrhage.** | | | | | 2. **Fissures, Fistulae, | 2. **Perforation.** | | Fibrosis with strictures.** | | | | 3. **2ry Amyloidosis.** | | 3. **2ry amyloidosis.** | | | | 4. **Dysplasia & | | 4. **Malabsorption.** | adenocarcinoma.** | | | | | | 5. **Liver damage (Associated | | | primary sclerosing | | | cholangitis).** | +-----------------------------------+-----------------------------------+ **[Lecture 11: Intestinal polyps and tumors]** 1. **[Non Neoplastic Polyps:]** 1-**B**ilharzial polyps. 2-**P**seudopolyps: in ulcerative colitis. 3-**H**yperplastic Polyps 4-**H**amartomatous Polyps: these include - [**Juvenile polyps:** in children , cause bleeding per rectum] - [**Peutz-Jeghers Polyps:** In Peutz-Jeghers Syndrome]: Hamartomatous polyposis syndromes with intestinal & extraintestinal (mucocutaneous hyperpigmentation, risk of several malignancies) 2. **[Neoplastic Polyps (Adenomas): ]** - **Tubular adenoma**: pedunculated , small, precancerous - **Villous adenoma**: sessile, large , more precancerous - **Tubulo-villous adenoma**: combined tubular & villous, precancerous - Adenomas are very common, their incidence increases with age - Adenomas are probably the ***precursor of most colorectal cancers.*** - Risk of malignancy is correlated to - Size of adenoma (polyps \> 4 cm have a 40% risk of cancer involvement) - Degree of dysplasia (low or high grade dysplasia). **FAP** is an **autosomal dominant** hereditary disease marked by the appearance of numerous colorectal adenomas by the teenage years. - It is caused by mutations of the **APC gene.** - A count of at least **100 polyps** is necessary for diagnosis of classic AFP. - Colorectal carcinoma develops in 100% of patients before 30 years old. - Prophylactic colectomy is standard therapy for patients carrying APC mutations. **\ ** **[Tumors of the colon]** [**1-Carcinoma of the colon**:] **Incidence:** Most common gastrointestinal malignancy **Age:** It commonly occurs above 50 years, with a peak at 60-70 years. **Site:** 75 % occurs in the **recto-sigmoid.** Small intestinal is rare. **Predisposing factors** : A+P+C+D - **[A]denomas**: All adenomas especially villous adenomas are more likely to show invasion - **[D]iet:** high fat & low fiber - **Ulcerative [C]olitis with dysplasia** - **Familial adenomatous [P]olyposis (FAP)**. **Gross:** **-**Polypoid fungating (More in proximal colon), -Ulcerative -Annular stricture (More in distal colon) **Microscopic:** - **Adenocarcinoma** (Well, moderately and poorly differentiated) - **Mucoid carcinoma** - **Signet ring carcinoma** (rare & poor prognosis) **Complications:** 1. **Bleeding**. 2. **Perforation** → septic peritonitis & **transcoelomic spread**. 3. Intestinal **Obstruction**: Mechanical obstruction of lumen by tumor. 4. **Intussuception** (tumor induces abnormal peristalsis). 5. **Spread**: - direct: malignant fistula formation. - Lymphatic - Blood spread mainly to the liver. **[2-Carcinoid Tumor (Argentafinnoma)]** **Definition:** arises from **neuroendocrine** (argentaffine) cells in the mucosa **Site: commonest** is the ***Appendix*** but may occur anywhere in GIT **Gross:** Yellow firm nodule. **Microscopic:** groups of monotonous cuboidal cell. The cytoplasm is rich in argyrophilc granules, observed by silver stains. **Behavior**: The tumor is classified into \- Typical ( low grade) \- Atypical ( intermediate grade), high incidence of distant metastasis. ***Liver metastasis*** release serotonin and other substances that will go direct to systemic circulation ( unmetabolized) leading to ***Carcinoid Syndrome***. ***Manifestation of Carcinoid syndrome*** : 1. Fibrous stenosis of tricuspid and pulmonary valve. 2. Bronchoconstriction producing bronchospasm. 3. Skin flushin and diarrhea. **[3-Intestinal lymphoma:]** Lymphoma is the *[**commonest malignant tumor in the** **small intestine**]* but uncommon in the colon. - They are commonly ***B-cell lymphomas*** - They appear as plaques or polypoid masses , may be multiple. - May cause intestinal obstruction directly or by intussusception. **Definition: Passage of fresh red blood in stools.** **[General causes of bleeding] : hemophilia, purpura, leukemia, and vit C and vit K deficiency.** **[Local causes]: Intestinal (anywhere below the stomach & duodenum).** - - **Ameobic dysentery**, - **Ankylostomiasis** - **Bacillary dysentery** - **Bilharizial**, - **Typhoid ulcers** - **Tuberculous ulcers** - **Neoplastic** - **Benign Polyps** - **Malignant tumors** - **Vascular** - **Piles (hemorrhoids)** - **Autoimmune/ Idiopathic: Ulcerative colitis**