Small Intestine Flashcards
The first main artery that branches off the abdominal aorta is :
The celiac artery and then give off 3 of its own brnaches : 1)splenic artery 2) left gastric artery 3) common hepatic
The peritoneum :
Double layer of serous membrane or mesothelium with 2 parts : parietal and visceral
It forms folds such as mesentries , omenta and ligaments
The 2 types of contractions of small bowel:
1) to and fro- motion mixes chyme digestive juices
2) peristaltic- contraction moves food distallyb
Enteroclysis :
Is washing out of the intestine
Minimally invasive radiographic procedure ( catheter introduction) for the small intestine followed by injection of barium and methylcellulose
Advantages of enteroclysis:
1) increase in the distention of the lumen , which will help to determine : Fold thickness Polyps Ulceration Constrictions Adhesive bands
USS of the abdomen can differentiate :
Can differentiate Fluid filled dilated small bowel loop from abdominal cystic structures
- can assess free fluid within the peritoneal cavity
- can assess solid mass belonging to small bowel if large enough
Estimation of fecal fat -normal fecal fat output is :
Less than 6g/day ( if standard diet of 100gr)
Most sensitive test of disorders of digestion and absorbtion
Causes of intestinal obstruction:
1) mechanical (dynamic) ->
intraluminal ( foreign bodies, faecal impaction, gallstones..)
Intramural(stricture, malignancy, volvulus..)
Extramural(bands/adhesions, hernia)
2)ileus (adynamic)->
Paralytic ileus
Pseudo-obstruction
Clinical features of intestinal obstruction:
1) colicky central abdominal pain
2) vomiting
3) abdominal distention
4) constipation
Treatment of acute intestinal obstruction:
1) GI drainage via nasogastric tube
2) fluid and electrolyte replacement
3) relief of obstruction
* surgical treatment is done after complete resuscitation
Indication for early surgical intervention:
- obstruction of external hernia
- clinical features suspicious of intestinal strangulation
- obstruction in a ‘virgin’ abdomen
Paralytic ileus:
Failure of transmission of peristaltic waves 2nrdy to neuromuscular failure
-will lead to accumulation of fluid an gas within the bowel
With associated distention, vomiting , absence of bowel sounds and constipation .
Symptoms of acute mesenteric ischemia:
Sudden abdominal pain
Passage of altered blood
Shock
Sympt. Of chronic mesenteric ischemia:
Abdominal angina
Weight loss Or diarrhea
Treatment of mesenteric ischemia :
Resuscitation
Gut resection
Embolectomy
Vascular bypass or endarterectomy
Pathological features of Crohn’s disease:
* disease of uncertain etiology characterized by full thickness inflammatory process
1) Full thickness inflammation
2) Edema
3) Fissures/ ulcerations
4) Non caseating foci of epithelioid and giant cells
Clinical features of acute Crohn’s disease :
- Pain R. Iliac fossa with tenderness
- features of low small intestine obstruction
- rare, perforation causing peritonitis
Clinical features of chronic Crohn’s diseases :
- colicky abdominal pain + diarrhea
- weight loss
- perianal fistulas
- fistulation into adjacent organs
Treatment of Crohn’s disease :
✅corticosteroid ✅aminosalicylates ✅immunomodulators (ex. Azathioprine) ✅monoclonal Ab ✅ Antibiotics for perianal disease ✅ surgery: resections , strictureplasty or colectomies
Intestinal tuberculosis:
Starts when ingested from infected source or from swallowed sputum from open pulmonary tuberculosis
-Pathology: ulcerations , stricture formation and LN enlargement
-General clinical features: wight loss , low grade fever , fatigue
Abdominal clinical features : distention, borborygmi, diarrhea , constipation and ulceration , palpable mass in R. Iliac fossa
Borborygmi:
Rumbling or gurgling noise made by the movement of fluid and gas in the intestine
Treatment of intestinal TB:
✅ Anti-tuberculosis drugs (RIFAMPIN, isoniazid, pyrazinamide, ethambutol)
✅ surgery for complications ( stricture , perforation, hemorrhage)
Small bowel diverticulosis:
-duodenal diverticula: 90% asymptomatic
-Meckel’s diverticulum 40cm of the ileocecal valve, congenital anomaly, may cause bleeding, obstruction and acute inflammation
*asymptomatic Meckel’s diverticulum are left as they found , while narrow necked , inflamed or symptomatic are excised
✅treatment : resection with enterorrhaphy (stitching an intestine)
Etiological factors for tumors of the small intestine include :
1) inherited conditions - polyposis coli , peutz-jegherz synd., gardner’s syndrome
2) immunocompromised states ( AIDS, coeliac disease ..)
3) geographical areas ( lymphomas more common in middle east )
Hyper-plastic polyps:
*benign tumors have a slow growth and delayed clinical presentations.
- are benign mucosal growth
* generally asymptomatic- has malignant potential
Stromal tumors :
Leiomyomas
- most common symptomatic small bowel lesions
* differentiating : between benign gut stromal tumors and malignant is difficult
Peutz-Jeghers synd.:
- autosomal dominant disorder
* mucocutaneous pigmentation( face, lips , and buccal mucosa)
Frequent complication of hemangiomas :
GI bleeding
Causes of malignant tumors in the small intestine :
- genetic risk factors:
- familial adenomatous polyposis
- hereditary nonpolyposis colorectal cancer
- diet
- tabacco and alcohol
- crohn disease
- celiac disease
Most common symptoms of small bowel malignant cancer:
Typically asymptomatic in the early stages
Abdominal pain+ weight loss
- bleeding, nausea, vomiting and obstruction are LESS COMMON
lab studies in Malignant tumor of small intestine :
- mild anemia
- liver function tests
- carcinoembryonic Ag levels are ↗️↗️
- imaging studies: plain abd. X ray films , abd. CT scan
- procedures : upper GI endoscopy, small bowel enteroscopy, colonoscopy
Adjuvant therapy of malignant cancer :
✅irinotecan therapy
✅FOLFOX 4 regimen ( combination of 5-FU, oxaliplatin and leocuvorin)
✅IMATINIB mesylate
Surgical care in tumors :
✅generally- wide local excision
✅proximal duodenum- pancreaticduodenectomy
✅palliation in pts with symptomatic advanced disease
Carcinoid tumors arise from a special type of cells and produce :
- > enterochromaffin cells
- > produce : gastrin , calcitonin , insulin vasoactive intestinal peptide , neurotensin , catecholamines and corticotropin .
- pts with these tumors have elevated urinary excretion of 5HIAA
Carcinoid synd.:
Pts with this syndrome have commonly been diagnosed with irritable bowel synd. Or idiopathic flushing
*characterized :
hepatomegaly , diarrhea , flushing in 80% of pt
R. Heart valvular diseases in 50%
Asthma in 25%
*cutaneous flushing is earliest sign of the syndrome
Some characteristics in the physical examination of carcinoid synd. :
face , neck and upper chest flushing , hT *Skin: Facial telangiectasis \+ Extremity rash *Abdomen: Disetended , hepatomegaly, bowel sounds * increased lacrimation *fever *lungs- wheezing *heart: tricuspid valve regurgitation Pulmonic stenosis
Indications for small bowel transplant :
▪️short bowel syndrome( condition where the body cannot absorb enough nutrients from the foods intake bc of no enough SI ).
▪️irreversible intestinal failure
▪️end stage liver disease for combined liver and small intestine transplantation
▪️cong. Mucosal disorders
▪️locally invasive tumors
Gastroschisis =
Birth defect where there is a hole in the abdominal wall beside the belly button
Hirschsprung disease =
Birth defect in which some nerve cells are missing in the large intestine so the childs intestine cant move stool and becomes blocked
Postoperative of small bowel transplantation:
*Induction therapy with :
Tacrolimus and steroids
Is typically begun most often in conjunction with an interleukin 2 receptor Ab
* high levels of immunosuppression early in the post operative period ( when the rejection risk is greatest)
Mesentery=
+ its function
The fan shaped layer of the peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen Function: -keeping the guts in place -limiting gut movement -protection from injury -conduit
Intussusception:
Is a serious condition in which part of the intestine slides into an adjacent part of the intestine
Medical and surgical treatment of carcinoid syndrome :
Medical=
✅chemotherapy - for palliative purposes
✅radiation- palliative role
✅OCTREOTIDE- reduction of symptomes
✅Antidiarrheal- diarrhea
Surgical=
✅larger than 1.5cm segmental resection with lymphadenectomy
✅metastatic stage : resection even if only for palliation
✅obstruction lesions- resection or bypass
✅intraarterial chemotherapeutic infusion
Rarity of Small intestinal tumors causes=
1) rapid intestinal transit
2) greater fluidity of small bowel chyme
3) alkaline ph
4) low bacterial colony counts
5) higher levels of benzyl peroxidase
6) increased levels of immunoglobulin A
7) widespread gut lymphoid tissue
Mesenteric lymphadenitis:
- inflammation of the LNs in mesentery
- usually results from an intestinal infection
- occurs mainly in children and teens
- often mimics the signs and sympts of appendicitis
- unlike appendicitis, it is seldom serous and clears on its own
