GI Diseases

Appendix

I.                    Appendicitis

a.      Pathology:

                                                               i.      Lymphoid hyperplasia (60%) – can be 2ndary to virus infection

                                                             ii.      Fecalith (35%)

b.      Diagnosis:

                                                               i.      Fever with WBC of 11 to 13K with left shift

                                                             ii.      Rebound tenderness

                                                            iii.      Rovsing’s – pressure on LLQ causes pain in RLQ

                                                           iv.      CT scan optional to find abscess

c.      Differential Diagnosis:

                                                               i.      Kidney stone – r/o with UA: appy has no blood or white cells

                                                             ii.      Ruptured ovarian cyst

                                                            iii.      Colitis

                                                           iv.      Intussusception in kids

d.      Sequellae:

                                                               i.      Perforation: RLQ abscess if contained, otherwise spreads to liver

                                                             ii.      Death – 10,000 per year

e.      Treatment:

                                                               i.      Medical: 2nd or 3rd generation cephalosporin pre-op (others include piperacillin + metronidazole and aminoglycoside + ampicillin + clindamycin) given 24 hours for non-ruptured, 10-14 days if perforated

                                                             ii.      Surgical: open or lap

1.      lap has same LOS but less post-op pain

II.                 Carcinoid of Appendix

a.      Pathology: 3% are malignant, more likely if >2cm and through mucosa

b.      Treatment: appendectomy if <2cm, hemicolectomy if >2cm (malignant)

 

Small Intestines

I.                    Meckel’s

a.      Pathology: remnant of vitelline duct, on antimesenteric border

b.      Diagnosis: most commonly present at age 2

                                                               i.      Painless red rectal bleeding, small bowel obstruction, intussusception, fistula

                                                             ii.      Less commonly: Fe deficiency, perforation, Littre’s hernia (incarcineration of diverticulum in hernia)

c.      Treatment: lap removal

II.                 Crohn’s

a.      Pathology:

                                                               i.      skip lesions of noncaseating granulomas anywhere between mouth and anus

                                                             ii.      Scope shows beefy red covered with gray exudate and creeping mesenteric fat

                                                            iii.      Inflammation not contained to bowel

b.      Diagnosis: two peaks: 20s and 60s

                                                               i.      Abdominal pain, diarrhea (bloodless), weight loss

                                                             ii.      Extraintestinal:

1.      Skin: pyoderma gangrenosum, erythema nodosum multiforme, vasculitis

2.      Eyes: conjunctivitis, iritis, uveitis

3.      Joint: arthritis, ankylosing spondylitis

4.      Liver: rarely

5.      Metabolic: Hypoproteinemia due to protein secretion into gut, vitamin deficiency due to malabsorption of fat

                                                            iii.      Plain films show thickened walls, CT shows abscess, avoid barium enema (but it will show aphthous lesion: doughnut)

c.      Treatment: no cure

                                                               i.      Medical: diarrhea relieved with codeine or loperamide, TPN for weight, immunosuppressants (steroids) for inflammation

                                                             ii.      Surgical: remove appendix, resect skip lesions

d.      Sequellae: fistulae, short bowel after multiple resections, death is rare

III.               Benign Tumors

a.      Leiomyomas: most common benign tumor of small intestine, often in small bowel

b.      Adenomas: tubular and Brunner’s can be ignored, villous should be removed due to 30% chance of malignancy

c.      Olser-Weber-Rendu: hemangioma of the entire small bowel

d.      Hamartoma: can cause intussusception; found in Peutz-Jeghers

IV.              Malignant Tumors

a.      Adenocarcincoma: 50% of all tumors, resect with lymph nodes, poor prognosis due to late presentation, chemo not useful

b.      Carcinoid:

                                                               i.      derived from Kulchitsky cells of APUD system, most commonly in appendix

                                                             ii.      carcinoid syndrome: flushing, watery diarrhea, bronchospasm with wheezing, right heart valve disorders

c.      lymphoma: most often in ileum

V.                 Small Bowel Obstruction

a.      Pathology: adhesions cause most obstructions in industrialized world, volvulus is less common, gallstone ileus is uncommon (requires fistula between gallbladder or duct to duodenum)

b.      Diagnosis:

                                                               i.      Intermittant crampy abdominal pain

                                                             ii.      strangulation correlated with tachycardia, fever, focal ab tenderness and leukocytosis;

c.      Differential Dx:

                                                               i.      paralytic ileus (no movement but no focal obstruction either)

                                                             ii.      colonic obstruction

d.      Sequellae: bowel death = patient death

e.      Treatment: IV fluids (LR or normal saline) for dehydration, surgery is typically required for complete obstructions

 

Colon and Nether Regions

I.                    Diverticular disease

a.      “true” diverticulum: involve entire colonic wall, found most often in cecum and ascending colon, rare

b.      “false” diverticulum: mucosal herniations through muscles of the colonic wall near penetrating vasculature; 95% found in sigmoid; common in US

II.                 Diverticulosis: lots of diverticuli; pain without elevated WBC or fever; bowel frequency issues resolved with bran and fiber

a.      Secondary bleeding: 70% is sources is distal to ligament of Treitz; rectal exam and sigmoid scope to r/o cancer;

III.              Diverticulitis

a.      Pathology: infection of diverticulum caused by fecalith obstruction of neck

b.      Diagnosis: left lower abdominal pain with elevated WBC and fever; barium is counterindicated in acute phase

c.      Differential

d.      Sequellae: rupture into peritoneal cavity; fistula formation

e.      Treatment: IV antibiotics (cover B. fragilis), elective colectomy for repeat offenders; fistulas must be surgically closed

IV.            Polyps: 50% in rectosigmoid, 50% have friends nearby

a.      Colon carcinoma:

                                                               i.      Pathology: most near rectum;

                                                             ii.      Diagnosis: right sided ones cause anemia; left cause obstruction and bleeding; track CEA

                                                            iii.      Differential

                                                           iv.      Sequellae: Dukes classification used; prognosis negatively correlated to lymph node involvement

                                                             v.      Treatment: radiation + 5FU before or after resection of tumor and its lymph drainage

V.         Ulcerative Colitis: most cases appear in ages 15-30, then a peak at 55

a.      Pathology: rectum involvement without skip lesions; muscle layers are spared

b.      Diagnosis: fever only if microabscesses; can be seen with ankylosing spondylitis, peripheral arthritis, uveitis, pyoderma gangrenosum, sclerosing cholangitis, pericarditis

c.      Differential: Crohn’s, bacterial colitis, c. diff

d.      Sequellae: toxic megacolon, perforation, hemorrhage, carcinoma

e.      Treatment:

                                                               i.      55% are indolent: only need anti-diarrhea meds

                                                             ii.      30% need prednisone

                                                            iii.      15% are life-threatening; use sulfasalazine and steroids

VI.              Colonic Obstruction

a.      Pathology: most commonly in sigmoid due to adenocarcinoma (65%), diverticulitis (20%) or volvulous (5%)

b.      Diagnosis: abdominal distention with crampy hypogastric pain; barium is countraindicated;

c.      Differential dx: small bowel obstruction (hard to tell if ileocecal valve is incompetent), Ogilvie’s (ileus without mechanical obstruction – resolve with rectal tube)

d.      Sequellae: perforation

e.      Treatment: complete obstruction go to the OR; incomplete can get NG tube and IV fluids to hope for self-resolution

VII.                 Volvulus: kidney-bean shaped cecum or sigmoid without haustra

a.      cecal volvulus requires surgery to tack it down or remove it

b.      sigmoidal volvulus treated with rectal decompression tube

VIII.              Hemorrhoids: internal are above dentate and painless; external are painful

a.      Pathology: bleeding or protrusion of vascular beds in the rectum; cause by thrombosis or increased pelvic pressure (constipation, pregnancy, ascites)

b.      Classes:

                                                               i.      First degree: not prolapsed, seen only by anoscope

                                                             ii.      Second: prolapse with defecation but return on their own

                                                            iii.      Third: prolapse and need manipulation to return

                                                           iv.      Fourth: not reducible

c.      Diagnosis: found most often in three places: left laternal, right anterior and right posterior; blood and pain with bowel movements; itching is 2ndary to poor hygiene

d.      Differential Dx: rectal prolapse

e.      Sequellae:

f.        Treatment: ignore if asymptomatic; banding is best for 2nd and 3rd degree; 4th degree get hemorrhoidectomy; thrombosed hemorrhoid self-correct in a week

IX.            Perianal abscess

a.      Pathology: from the perianal glands located between internal and external sphincters

b.      Diagnosis: pain, fever, redness, swelling

c.      Differential Dx:

d.      Sequellae: fistula

e.      Treatment: drain it; antibiotics only as adjuvant to surgery

X.         Anal Cancers: epidermoid carcinoma (sqaumous cell, basaloid, others) and malignant melanoma (3rd most common site, after skin and eyes)

a.      Treatment:

                                                               i.      Epidermoid: chemo and radiation is curative 85% of the time

                                                             ii.      Melanoma: nothing works

XI.         Sexually transmitted anorectal diseases:

a.      Condylomas: caused by HPV, often recurrent after treatment

b.      Chlamydia: blistering leading to ulcers; treat with tetracycline

c.      Gonorrhea: yellow muscus discharge; treat with penicillin

d.      Herpes: pain and burning worsened by defecation; vesicular lesions; cytology shows intranuclear inclusion bodies and giant cells; can go on to lumbosacral radiculopathy and impotence; treat with acyclovir acutely and chronically only for the worst repeat offenders