GI Flashcards
Cholestatic LFT+IBD
PSC
PSC Ddx:
- secondary causes of sclerosing cholangitis and
- IgG4-associated cholangitis/autoimmune pancreatitis.
- PSC-autoimmune hepatitis overlap syndrome
PSC should be considered in patients with a cholestatic pattern of liver test abnormalities (particularly an elevated alkaline phosphatase), especially those with underlying inflammatory bowel disease.
DxMethod: cholangiography characteristic bile duct changes (multifocal strictures, segmental dilations) and excluding secondary causes of sclerosing cholangitis.
A percutaneous liver biopsy may support the diagnosis of PSC, but it is rarely diagnostic. In patients with characteristic findings on cholangiography, a liver biopsy is typically not required. However, liver biopsy is required for patients with suspected small duct PSC or if other conditions such as an overlap syndrome with autoimmune hepatitis are suspected.
% of long term NSAID users who develop significant GI bleed or ulcer perforation
2 to 4%
% of patients who have varices at time of diagnosis of cirrrhosis
50%
Gastroesophageal varices are present in almost half of patients with cirrhosis at the time of diagnosis, with the highest rate among patients with Child–Turcotte–Pugh (hereinafter called Child) class B or C disease
% of patients with GERD undergoing endoscopy who have Barrett
14
Abdominal pain out of proportion + new onset atrial fibrillation
CT Angiogram
The CT scan should be performed without oral contrast, which can obscure the mesenteric vessels, obscure bowel wall enhancement, and can lead to a delay of the diagnosis. The origins of the celiac axis and superior mesenteric artery should also be evaluated for the presence of calcification that indicates an underlying atherosclerotic process as a possible etiology for mesenteric ischemia.
This patient presents with new-onset atrial fibrillation, as well as acute abdominal pain with an unremarkable abdominal examination. This is concerning for mesenteric ischemia, which in this case could have been caused by an embolic event. The most appropriate initial study for the diagnosis of mesenteric ischemia would be CT angiography (Answer C), which would facilitate identification of vessel occlusions that could be causing this patient’s symptoms. The classic description of mesenteric ischemia is the presence of marked abdominal pain with relatively benign findings on abdominal exam—“pain out of proportion to exam.”
Achalasia: pathogenesis
progressive degeneration of ganglion cells in the myenteric plexus
- Progressive degeneration of ganglion cells in the myenteric plexus leading to failure of relaxation of LES + loss of peristalsis in the distal esophagus.
- The etiology of primary or idiopathic achalasia is unknown.
- Secondary achalasia is due to diseases that cause esophageal motor abnormalities similar or identical to those of primary achalasia.
Bacterial-overgrowth-syndrome.Causes
- Small bowel stasis:
- Diverticula, surgery
- Motility problems: eg scleroderma
- Entero-colic fistula:
- Crohn
- Resection of ileocecal valve
Bacterial-overgrowth-syndrome.Rx
- Broad-spectrum antibiotics (ciprofloxacin, rifaxamin) x 2 to 3 weeks
- Nutrition deficiency support
- Fix underlying problems
Barrett: Mx parameters
- Non-dysplastic: Endocopic surveillance, biopsy, PPI
- Low grade dysplasia: Endoscopic eradication
- High grade dysplasia: Endoscopic eradication
- EAC: surgery
Endoscopic eradication: resection + ablation
Our approach to endoscopic eradication therapy is to perform endoscopic resection of any visible mucosal irregularities, followed by RFA to ablate the remaining metaplastic epithelium. (See ‘Endoscopic resection’ above and ‘Endoscopic ablative therapies’ above.)
Barrett: DxCriteria
- columnar epithelium in distal esophagus.
- Histology: intestinal metaplasia
The endoscopist must document that columnar epithelium lines the distal esophagus.
•Histologic examination of biopsy specimens from that columnar epithelium must reveal specialized intestinal metaplasia
Barrett: Risk factors
- White ethnicity
- Age
- Central obesity
- Long GERD
Factors known to increase the risk for Barrett’s esophagus include white ethnicity, older age, obesity (especially central obesity), and long duration of GERD symptoms.
Barrett, nondysplastic: risk of adenocarcinoma
0.1 to 0.4% annually
- Risk of esophageal adenocarcinoma in patients with nondysplastic Barrett is ~ 0.1 to 0.4 percent annually
- RR: 30
Bile-acid-diarrhea.Causes
Bile acids are absorbed in the ileum. Diseases that affect the ileum (i.e., Crohn disease) or where the ileum has been resected will cause bile acid diarrhea.
Bile-acid-diarrhea.types
- Bile acid diarrhea: liver can compensate, cholestyramine sensitive.
- Fatty acid diarrhea: steatorrhea, cholestyramine resistant; try low fat diet
Bleeding.Mx
Stable patient; GI bleed over; negative upper and lower endoscopy. Next step?
Video capsule endoscopy
- suspected small bowel bleeding
- suspected Crohn disease
- assess mucosal healing
- detect small bowel tumors.
- detect small bowel injury associated with NSAIDs
Bleeding
Commonest cause of small bowel bleeding?
Angioectasia
Associated with AS
Homozygosity for the C282Y genotype
Classical HH
Cancer associated with Plummer-Vinson
Squamous Cell
Candida esophagitis: Rx
Fluconazole
Ceftriaxone: why should it be given in varceal bleeding?
20% have positive blood cultures and SBP
Celiac-disease.Serology.BestTest
- IgA endomysial antibody (IgA EMA)
- IgA tissue transglutaminase antibody (IgA tTG)
- ●IgG tissue transglutaminase antibody (IgG tTG)
- ●IgA deamidated gliadin peptide (IgA DGP)
- ●IgG deamidated gliadin peptide (IgG DGP)
Serum IgA endomysial and tissue transglutaminase antibody testing have the highest diagnostic accuracy. The IgA and IgG antigliadin antibody (AGA) tests have lower diagnostic accuracy with frequent false positive results as compared with IgA tTG and IgA DGP assays and are therefore no longer recommended for initial diagnostic evaluation or screening [2]. However, the newer anti-deamidated gliadin peptide (DGP) assays described above show high diagnostic accuracy. IgA EMA, IgA tTG, IgA DGP and IgG DGP levels fall with treatment; as a result, these assays can be used as a noninvasive means of monitoring the response to a gluten-free diet. (See ‘Monitoring adherence and response to gluten-free diet’ below.)
Celiac-Sprue.also-known-as
Gluen sensitive enteropathy
Celiac-sprue.associations
- Dermatitis herpetiformis
- Autoimmune disorders
Dermatitis herpetiformis is characterized by intensely itchy, chronic papulovesicular eruptions, usually distributed symmetrically on extensor surfaces (buttocks, back of neck, scalp, elbows, knees, back, hairline, groin, or face).[1]:616[9][12] The blisters vary in size from very small up to 1 cm across.
Celiac-Sprue.DDx
IBS
Diagnosis is often delayed for many years after the onset of symptoms
Celiac-sprue.micronutrient-loss
Iron, calcium, Vitamin D
Celiac-Sprue.pathology
Flattened villi of the proximal small bowel
Prevalence: 1: 200
(HLA) DQ2 or DQ8
Celiac-sprue.refractory-to-rx
The possibility of early-onset small bowel lymphoma should be considered in refractory cases
Celiac-sprue.Rx
Life-long gluten free diet
Celiac-sprue.screening
Osteoporosis
Celiac-sprue.testing
- Antiendomysial antibody is an IgA antibody that is 85% to 98% sensitive and 97% to 100% specific
- Tissue transglutaminase (tTG) antibody is an IgA antibody that is 90% to 98% sensitive and 95% to 97% specific
- Antigliadin antibody (immunoglobulin G [IgG] and IgA) has lower sensitivity and specificity
- If there is a high suspicion of disease but negative antibodies, check total IgA concentration to rule out IgA deficiency. In these cases, an IgG-based assay (serum IgG tTG antibody) can be used or upper endoscopy with biopsies.
- Diagnostic: small bowel biopsy, which demonstrates flattened or blunted villi and increased lymphocytes
- Gold standard: repeat endoscopy with biopsies after gluten-free diet. These should show resolution. Rarely performed nowadays, with the diagnosis made by serology,
Child-Pugh
- Encephalopathy
- Ascites
- Bilirubin
- albumin
- INR
None (1 point)
Grade 1: Altered mood/confusion (2 points)
Grade 2: Inappropriate behavior, impending stupor, somnolence (2 points)
Grade 3: Markedly confused, stuporous but arousable (3 points)
Grade 4: Comatose/unresponsive (3 points)
Ascites
Absent (1 point)
Slight (2 points)
Moderate (3 points)
Bilirubin
< 34.2 mcmol/L (1 point)
34.2-51.3 mcmol/L (2 points)
> 51.3 mcmol/L (3 points)
Albumin
> 35 g/L (1 point)
28-35 g/L (2 points)
< 28 g/L (3 points)
Prothrombin time prolongation
Less than 4 seconds above control/INR < 1.7 (1 point)
4-6 seconds above control/INR 1.7-2.3 (2 points)
More than 6 seconds above control/INR > 2.3 (3 points)
Chronic NSAID use: Indxn for ulcer prophylaxis
- 2 or more risk factors
- History of complicated ulcer
Misoprostol or PPI
Cirrhosis: DxCriteria
- Exam: (small liver, splenomegaly, telengectasia)
- Labs: poor synthetic function, pancytopenia
- USG findings
Colonoscopic screening interval after finding polyps
- Family history, pathology, size and number
- If more than 10: repeat in 1 to 3 years
- if 3 to 10 small, low risk: 3 years.
- if big (> 10 mm), 3 years
- If If 1 to 2, tubular adenoma, no villous component: 5 years
- Small, hyperplastic: sigmoid, rectum: 10 years
Copper chelating agent used in Wilson’s
Penicillamine
Crohn.disease-sites
- 80% : distal ileum
- 50%: ileum + colon
- Small number: upper GI
- 30%: perianal disease
A 25-year-old man comes to your office because he has diarrhea. Four months ago, he had an exploratory laparotomy for a small bowel obstruction. He was found to have 30 cm of distal ileal Crohn disease, which was resected with ileocolonic continuity re-created. He received therapy with antibiotics during an uneventful perioperative period. Shortly after beginning a normal diet and despite feeling well otherwise, he began to have six to eight watery bowel movements daily, which have not resolved. Most bowel movements occur after breakfast. He has had no fever, bloating, hematochezia, nocturnal diarrhea, or weight loss. He has not traveled abroad. Physical examination of the abdomen is normal except for a well-healed, midline scar. Results of complete blood count, biochemical profile, and examination of the stool for leukocytes are negative. What would be the best initial therapeutic intervention?
Corticosteroids
Metronidazole
Cholestyramine
Sulfasalazine
Codeine sulfate
Common and challenging problem of recurrent diarrhea after the initial operation. Possible causes include recurrent Crohn disease, partial obstruction caused by adhesions with or without bacterial overgrowth, antibiotic-associated diarrhea, and either bile-salt diarrhea or malabsorption secondary to the ileal resection.
It would be unusual, but not impossible, for Crohn disease to recur within 1 month of a resection. Signs of inflammation (e.g., leukocytosis, blood or leukocytes in the stool, fever) or obstruction (e.g., bloating, distention, postprandial pain, weight loss) are absent. Thus empirical therapy with either corticosteroids or sulfasalazine is incorrect.
The persistence of diarrhea for 4 months without systemic symptoms or fever and the absence of leukocytes in the stool make antibiotic-associated colitis extremely unlikely.
Operations for cancer, inflammatory bowel disease, and intestinal infarction can lead to resection of varying lengths of ileum. The pathophysiologic consequences of the resection depend on the length of the ileum resected. Normally, more than 95% of bile acids secreted into the intestine are reabsorbed and recirculated to the liver.
Resection of a short segment of the ileum leads to malabsorption of conjugated bile acids, resulting in secretory diarrhea. Typically, bile-salt diarrhea is watery, may not start until a normal diet is resumed after surgery, is precipitated by a meal (most commonly breakfast, when a large quantity of bile is stored in the gallbladder), and does not lead to weight loss.
In bile-salt diarrhea: cholestyramine, can dramatically reduce troublesome watery diarrhea.
With ileal resections of about 100 cm or more, the liver synthesis of bile acids cannot keep up with the colonic losses; the concentration of bile acids in the duodenum falls, and steatorrhea develops.
It should be expected, however, that such a patient with steatorrhea would lose weight and not maintain weight as in this case.
Dysphagia: FirstStudy
Barium swallow
Esophageal webs and rings: Sx
Solid food dysphage
- thin, delicate structures that partially occlude the lumen.
- Rings: distal esophagus. Typically: mucosal
- Schatzki rings: commonest; mucosal structures at the squamocolumnar junction that are smooth and thin, and are evident radiographically either at the junction between the esophagus and stomach or within a sliding hiatal hernia.
- Web refers to a thin mucosal fold that protrudes into the lumen and is covered with squamous epithelium.
- Usually: anteriorly in the cervical esophagus, causing focal narrowing in the postcricoid area.
- Esophageal rings and webs characteristically cause solid food dysphagia, particularly evident with meat or bread.
Evidence for screening for Barrett
Weak
- It has been proposed that patients with GERD symptoms should be screened endoscopically for Barrett.
- Expert suggestion: if multiple risk factors for esophageal adenocarcinoma then screening.
- Evidence supporting this recommendation is weak
GE Varices: pathogenesis
Portal hypertension is the cause
Portal hypertension in cirrhosis is caused by:
- increased resistance to portal flow:
- structural (distortion of liver vascular architecture by fibrosis and regenerative nodules)
- dynamic (increased hepatic vascular tone due to endothelial dysfunction and decreased nitric oxide bioavailability)
- Increased portal venous blood inflow.
GERD: DDx
- gastroparesis,
- gastrinoma (rare),
- gallbladder dysfunction,
- eosinophilic esophagitis
- Angina