Small Intestine And Colon

Small intestine and colon Meckel’s diverticulum: a persistent vitello-intestinal duct, which is usually obliterated 2% of population 2cm in length 2 ft proximal to ielocaecal valve. Usually asymptomiatic but may present as a picture very similar to appendicitis. Hence if the abdomen is discovered laparoscopically for an appendicitis, but this is not found, search for a meckles. Bleeding-most common cause of profuse GI bleed in youngsters- due to ectopic gastric mucosa. Volvulus: if the merkel’s diverticulum is attached to the anterior abdominal wall Intususseption: the diverticulum is the apex Investigation:discovered by laparoscopy, or technicium scan when GI blled, this will label the meckels diverticulum because it detacts the gastric mucosa.

Tumours of small intestine- relatively rare Benign Tumours: from all elements of bowel wall Lipomas Leiomyomas Neurofibromas Adenomas Adenomatous polyps of the small intestine like of the colon can be pre malignant, and also like in the small bowel can be associated with polyposis sydroms and Peutz-Jegher’s syndrome( pigmentation around mouth and small bowel polyps.

Incidental finding or present with bleeding and intususseption. Malignant Adenocarcinomas- from pre-existing adenomas Lymphoma

Carcinoid- low grade malignancy- mostly in appendix but all through GIT, also in lung. Release serotonin and kinins- if in GIT no effect as 1st pass metabolism by liver. If however mets or bronchial carcinoid then no 1st pass metabolism and flushing, bronschospasm and diarrhea. Intussusceptions:-part of bowel gets invaginated into its own lumen. Cross section: 2 layers of bowel: intussusceptum enclosed by intussusciptiens. Very common in children, especially before 1 year of age, especially with parystalsis against a hypertrophied peyer’s patches or merchel’s diverticulum. The apex may be felt from a rectal examintation, or may protrude down the anus. Rare in adulthood- suspect tumour as apex. Patients complains of colicky abdominal pain and redcurrent jelly stools with mucous and blodd is produced. May be reduced with barium enema, if not reduce surgically, if not possible remove bowel section. Recurrence rare. Acute appendicitis Most common surgical emergency. Caused by obstruction and subsequent infection. Obstruction may be due to faecoliths, hypertrophy of lymphoid follicle after viral infection, carcinoma of caecum or carcinoid of appendix. Pain is first colicky midline, due to wall of appendix being inflamed. As infection progresses to include the surrounding tissues and peritoneum, the pain moves to the RIF, and is typical of localised peritonitis with guarding, rigidity and rebound tenderness. Diagnosis is purely clinically. Appendectomy: Mc Burney’s point: point 2/3rds the way a line drawm drom the anterior superior iliac spine to the umbilicus: base of appendix. For cosmetic reasons surgeons prefer a slightly lower point. Incision of skin, subcutaneous fat, muscles split alongdirection of muscle fibres, not actually splintting, open peritoneum. The caecum and appendix are brought out of incision. The artery and mesentry of appendix is cut, and the appendix ligated. The stump is usually tied to the caecum by a purse-string sutre. The operation is covered by metronidazole prohphylactically. Any fluid, puss has to be drained and swabbed, drain insertion if necessary. Muscles- absorbable sutures. Sometimes, the appendix is surrounded by omentum and small bowel, and right iliac mass may be felt, and later presentation. An abcess may form and will need radiological guiding for drainage. Interval appendectomy after 3,mnths as recur in 20% of patients. Rectal examination may reveal tenderness due to peritoneal fluid flowing to most dependnt area: ppuch of douglas. DD of RIF mass: Appendix

Gynaecological mass, eg ovarian cyst Caecal cancer Soft tissue mass, eg sarcoma Lymph node mass TB Actinomycosis- infectious bacterial disease Transplant kidney Iliac aneurysm Mesenteric adenitis Main dd for acute appendicitis. Enlargement of mesenteric lymph nodes, causing pain ad tenderness, increased temp, but even higher than appendicitis. Pain may not be very localised. Lymphocytes are high in mesenteric adenoma rather than neurrophils. More in children and adolescence, especially following viral or upper resp tract infection. Treatment paracetamol. If laparotomy performed for exploration, appendix should be removed. Small bowel obstruction Most common causes adhesions and strangulated hernias. INtraluminal causes: faesis/ food bolus obstruction, foreign body bolus, polypoid tumours and intisusseption. Intramural: Tumours, Ischaemia, Crohons Benign Stricture Extramural: adhesions, strangulated hernia, volvulus, extrinsic compression. Features : pain: colicky due to bowel wall obstruction, felt around umbilicus in midline since visceral Abdominal distention: if obstruction is more distal, more distention Vomiting: obstruction more proximal: vomiting earlier Absolute constipation: not passing faesis or flatus. On examination: distended abdomen; increased bowel sounds. If tender over particular area suspect strangulation, if it becomes sign of peritonitis, strangulated bowel has become gangrenous and perforation. Ab x ray: distended small bowel loops

Treatment of small intestine obstruction

Examination: look for scars of previous operations: possible adhesions. Look for hernias, do not forget groin. If der is a hernia, this needs to be repaired. The bowel must be intact before it is reduced or else a small part of bowel sould be removed. Resolving obstruction, means reduced pain, vomiting and distention, and improved x rays. If adhesions are the cause: 1st conservative treatment: nil by mouth, NG tube draining with 2 hourly aspirate to decompress bowel, IVI. Check if obstruction resolving: decreased pain, dec NG aspirates, flatus passed, Xray better. If not managed on conservative treatment: divide adhestions laparotomy. Subacute obstruction: when not all four signs of obstruction are present Psaudo obstruction: a cause cannot be found. Cold be due to electrolyte abnormalties, trauma and medication. Large Bowel Obstruction: Commonest causes: ca, diverticulitis and volvulus of sigmoid or caecum. Sypmtoms: Colicky pain, Distention, vomiting (later stage) and constipation. In 20% of people the ileo-caecal valve is competent and decompression of large bowel into small bowel cannot occur. Hence distention, may lead to perforation, esp in caecum, having thinnest wall. If signs of peritonitis, immediate surgery, also if caecum is larger than 10cm or v tender- signs of v imminent perforation.

Investigations: Blood tests, x ray. Sigmoidoscopy: identifies site of obstruction and barium enema helps distinguish from a pseudoobstruction. Treatment: resuccitation and insertion of NG tube. insertion of metal expansible stents, to relieve obstruction for palliation. Or in patients unfit for surgery.stents may be used in Ca pts, to relieve obstruction by decompressing ca and prevent emergency op. Inflammatory bowel disease Crohn’s Definition: chronic relapsing transmural granulomatous disorder of unknown aetiology. It may effect all parts of GIT, but especially terminal ileus(terminal ileitis- former term). It is characterized by skip lesions: seperate area of bowel affected separated by normal bowel in between. Healing is by fibsosis and may secult in strictures or adhesions to bowel, bladder, vagina or skin surface. Presentation: change in bowel habit, painful diarrhea, colicky pain centrally or RIF, anorexia, weight loss, general malaise. Investigations: examination: tenderness or mass(RIF) but may be normal. Blood tests show high acute phase proteins especially c reactive protein. Main stay is contrast studies and colonoscopy.

Management is usually medical with mesalazine and corticosteroids, but 65% will require surgery. If small bowel is effected the operation is stricturoplasty or resection of very diseased bowel( only the least possible should be removed, as many of these will require further surgeries and hence may result in short gut syndrome: where diarrhea is the main problem plus vitamin and nutritional defects. If large bowel surgery is necessary, then panproctocolectomy + ileostomy or subtotal colectomy withe ileorectal anastamosis if the rectum is intact. Studies have shown that small bowel removal results in recurrences. DD: UC Other related conditions: perianal diseases such as absesses and fistulation, erythema nodosum, polyderma gangrenosum, arthritis and ocular problems.

Ulcerative Colitis Definition: chronic relapsing condition, it affects only the colon and does not invade the whole wall, but up to the mucosa. It usually effects the rectum and spreads proximally as the disease progresses hence there are no skip lesions. Patients present with a bloody diarrhea, with abdominal pain relieved on defeciating. No physical signs are seen. Access with sigmoidoscopy and colonoscopy and take biopsies. If jistologist cannot differentiate between Crohn s and UC then indeterminate. Treatment: medically in more than 85%- mesalazine, antidiarrheals, steroids. Complications include toxic megacolon, diagnosed by a TC larger than 6cm. Patients present with fever, nausea, vomiting, and an increased WCC. Manage conservatevly:IVI, Iv steroids, correct electrolyte abnormality. If TC getting wider...chance of perforation: surgery: total colectomy + ileostomy, and rectal stump is oversewn or brought out of skin to inspect. Then electively reservoir: where piece of small bowel made as a pouch in pelvis or opt for completion proctectomy: with removal of rectal stump and anus leaving permanetnt ileostomy. Imp rectal pouch cannot be done in Crohns as no of surgeries of small bowel may be required. UC is a premalignant condition- increases risk by 10% every 10 yr of disease for Ca. Screening 2-3 yrs with bippsy. Look for dysplasia, if severe proctatectomy with ileostomy or pouch. Colon Cancer The symptoms depend on where the cancer is. On the right, it will present later with bleeding and obstruction, since the contents of the intestine are more liquidy and hence the tumour does not offer much obstruction until late. On the left hand side, symptoms present before since the contents are solid and patients present with an altered bowel habit. If the mass is in the rectum: tenesmus

Rectal exam, colonoscopy, FBC, U&E, LFTs, CEA: carnioembryinic antigen- tests performed. Also US and CT to stage and screen for mets. Dukes Classification: A: confined to mucosa and submucosa (90% 5yr survival) B: invasion into/through bowel wall into surrounding tissue but lymph nodes clear (60% 5 yr survival) C: lymph nodes involved (overall 30% 5 yr survival) C2: highest LN in surgical specimen involved, implying further spread. D: distant spread (5-10% 5yr survival ) TNM- T: depth of tumour invasion N: lymph node involvement M- mets. Treatment of choice: resection : if tumour in ascending colon: right sided hemicolectomy. If in TC extended right sided hemicolectomy. DC left sided hemicolectomy. Imp: pre-op bowel prep. Blood supply is empirical: imp of good blood supply to the 2 cuts. The entire part of the bowel supplied by the same blood vessel as the tumour needs to be removed. For mass in upper rectum an anterior resection is done with a primary anastamosis via sutures or staple gun. If the integrity of the anastamosis is in doubt, a transient stoma is performed to divert faesis away from the healing anastamosis. If the rectal tumour is lower down and the integrity of the anal spincters is damaged, an AP(abdomino perineal) resection is done. The operation involves the removal of rectum and anus : leaving two wounds( laparoscopic and perineal) and a permanent stoma. Ror rectal cancer a radial spread into the mesentry is a poor prognostic indicator. For ths reason, many surgeons do a total mesorectal incision together with an anterior resection, to reduce the risk of recurrence. For Dukes C: chemotherapy with 5-fluorouracil + levamisole. Radiotheray is useless as the tumour is too mobile and radioinsensitive, but improves outcome when given pre-op. Stomas and types of colonic resections A stoma in the right lower quadrant: ileostomy. It can be an end ileostomy after a total colectomy or a loop ileostomy for temporary defunctioning bowel. This gives tie to an anastamosis to heal. This type has 2 openings. Ileostomies, have spuouts as the small bowel content is irritant to skin. A patients may have huge fluid losses from ileostomies, and hence the amount of fluid escaping from ileostomies should be measures and water balance arranged by iv fluids. A stoma in the right upper qauadrant is a transverse colon defunctioning stoma, with 2 openings which are flush with the skin surface.

Stomas in the left upper quadrant are not usually done, unless der are technical problems forcing the surgeon to displace the stomas from the left lower quadrant The left lower quadrant are colonic colectomies. There are three types: all flush with the skin: end, which can be temporary (Harmann- rectum sutured and left in pelvis, sig colon brought out as temp stoma. This is usually done for a perforated diverticulitis where contamination makes it unsafe to anastamose immediately. An end colostomy is done, after an AP resection. A loop colostomy is done with the apex of the sigmoid colon, when der is a rectal tumour which is causing obstruction, and this cannot be removed, but here symptomas are relieved. This colostomy does not involve a resection. In a double barrelled colostomy, the distal part, if long enough is brought out as a stoma together with the proximal part. This is done after resection when it is thought unsafe join together. This when possible ie the distal part is long enough, is preferred to harmann as can be easily reversed. Screening for colorectal cancer Colonoscopy is ideal. Haemoccult test, where one looks for faecal occult blood, is not very sensitive, and has a number of false positives, however studies have shown a decreased mortality in screened patients. CEA is not very specific, it is raised in inflammation of the GIT, smoking, renal imparement, also it is usually not elevated in early disease. It is not good for screening, but good for follow ups. Example, after resection, cea should fall down, if recurrence cea will start to rise again. So who should be screened 1: familial adenomatous polypososis 2. strong family history: more than 2 close relatives effected 3. history of polyps and colon cancer 4. pt with 10 yrs of UC, peutz-jeghers, juvenile polyosis. Colonic polyps: lesions projecting into the lumen of the bowel. They are relevant because some types may become maliganant. Polyp is a purely morphological term. Adenomatous polyps: their importance lies in the fact that most progress to colonic cancer. This gransition depends on the size, and it is rare in less than 1cm polypsa. To prove this transformation: early stages of malignancy, include dysplasia and carcinoma in situ, features also seen in polyps. Familial adenomatous polyposis, die of a young age due to colon cancer, if a colectomy is done prophylactically. Another proof is that the carcinogens that prodeuce polyps in experimental setups also produce carcinomas. There are 3 types of adenomatous polyps: better-differentiated tubular adenomas- most commn which are often on a stalk, kess-differentiated villous adenomas that are sessile(FLAT) or the mixed tubulovillous type.

Adenomatous polyps may be sporadic or familial. Familial multiple polyposis coli is an autosomal dominant disease presenting with multiple neoplastic polyps in the 20-30s. Prophilactic colectomy necessary in early 20s. Gardner, also autosomal dominant- presenting with multiple colonic adenomas, bony osteomas, and epidermoid cysts. Presentation: 1. Bleeding, frank or microscopic, hence anemia 2. tenesmus if in rectum 3. passing slime/jelly secreted by polyp 4. protruding through anus or apex of intususseption Diagnosis: Ba enema, colonoscopy the best: it can biossy, or total removal of polyp. Histo done for confirmation plus see level of dysplasia: mild, mod, severe. Hamartomous polyps. A hamartoma, is an overgrowth of a cell type/s which are normal constituents of the organ from which it arises. It is an abnormality of development. In the GIT: 1. Juvenile polyps: low malignat potential. Present with bleeding, or intusucception. May slough off spontaneously and witnessed in faesis. Management: colonoscopically. 2. Peutz- Jegher Syndrome: rare autosomal dominant, multiple hamartomas along GIT and pigmented lips and dums. Low malignat potential, but these pts at higher risk then rest for bot GIT and non-GIT cancers. Polyps due to protrusions of mesenchymal tissue: lipomas, leiomyomas, neurofibromas, haemangiomas. May form a lump. Rare, but may mimic carcinoma. Metaplastic Polyps/ Hyperplastic Small, multiple, slightly elevated from rest of mucosa. Easy to distinguish hisologically, no potential of becoming malignant. Imp to differentiate between adenomatous polyps. Gives no symptoms, found incidentally in IBD and lymphoid hyperplasia. Inflammatory polyps: those found in IBD such as UC. Diverticular Disease: outpouchings from tubular structure, happens wer mucosa bulges out due to entry of blood vessles entering muscle layer, making dis area weak. Very common in Western wolrd in middle age and elderly patients with a lack of fibre and history of constipation, causing the muscle to spasm and the mucosa to bulge out. Commoner on left side of colon. Presentation: 1. Chronic gripey ab pain, diarrhea and pellet stools. Given antispasmodics and high fibre die.

2. Acute diverticulitis: due to inspissated faesis in diverticumlum and inflammation: think of it as left appendix: LIF pain, fever, signs of localised perinotis and raised wcc count. Conservative measurement: rest bowel, IVF, antibiotics, if not work surgery. 3. Perforated diverticulitis: more sudden onset of pain, or previous symptoms of acute diverticulitis. More generalised peritonitis, seen on erect CXR as free gas. Laparotomy: clean contaminated ab, and hartmann 4. Diverticular absecc- perforation is walled off by a piece of bowel. LIF mass. CT scan. Conservative measumments at 1st: rest bowel, IVF, antibiotics, check for growth, if so drainage and hartmann 5. Haemmorhage- sudden and painless. Usually stops spontaneously, but if persists, angiography and surgey to remove affected part. 6. Stricture, as acute diverticulitis heals with fibrosis, ehich may form stricture. Strictures caused by: acute diverticulitis, cancer, IBD, ischaemic colitis, poat radiotherapy, and surgery where anastimosis.

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Haemmarhoids Carcinoma Diverticular disease Angioplasia Infective colitis Polyps Anal fissure UC

Age is imp: haemmorhoids, carcinoma and diverticular disease are common in the elderly. Infective colitis and UC common in young History of frequency and amount of bleeding, colour (bright red suggestive of lower GI bleed, dark: could be both upper and lower), if related with deafeciation,if it is mixed with it?mocous? ab pain(IBD). If immense bleeding, but stops suddenly, urgent investigation, if bleeding wasn’t dat much den outpatients investigation. If bleeding does not stop, angiography to see bleeding. If angidysplasia, cut out bowel effected. In some cases impossible to tell if bleeding from lower or upper GIT hence gastroscopy also 2 exclude.