Gastroenterology Flashcards
Treatment options for Opioid-induced constipation
1) SQ methylnaltrexone
2) oral naloxegol
3) oral naldemedine
What are the four phases of HBV infection?
1) Immune tolerant
2) Immune active - evidence of hepatic inflammation
3) Immune control (inactive)
4) Reactivation
Treatment is indicated in the immune active phase
Routine screening for HCC indicated (AFP, U/S)
- SE asian patients >40 y/o (male), >50 y/o (female)
- sub-saharan Africa > 20 y/o
What are the criteria for cholecystecomy with regard to asymptomatic gallbladder polyps?
1) Polyp >1 cm
2) Polyp of any size in the presence of gallstones
3) Polyp >8 mm in size with coexsting PSC
Indications for SBP prophylaxis in new ascites
1) Ascitic fluid protein <1.5 g/dL AND
2) Hyponatremia (<130) OR
3) Kidney dysfunction (serum Cr >1.2) OR
4) CTP Class B or C Cirrhosis
Choose fluoroquinolones for prophylaxis (norfloxacin or ciprofloxacin)
Indications for resection of pancreatic cyst
1) Symptoms related to the cyst (pancreatitis, jaundice)
2) Cyst size >3 cm
3) Dilated main pancreatic duct
4) Solid component of the cyst
Surveillance: annual MRI abdomen
Etiologies of secretory diarrhea (occurs despite fasting)
1) Medications - colchicine, NSAIDs
2) VIPoma, Carcinoid, Gastrinoma
3) SIBO
4) Short bowel syndrome (bile acid malabsorption)
5) Villous adenoma
Biopsy findings in Crohn’s Disease
1) Distorted and branching colonic crypts
2) Neutrophilic and lymphocytic infiltration
3) Skip lesions
What test helps diagnose SIBO?
Glucose hydrogen breath testing
Positive anitmitochondrial antibodies are associated with what disease?
Primary Biliary Cholangitis (PBC)
~10% may test negative for antimitochondrial Abs
Think about PBC in a middle-aged woman (40-60) with a cholestatic picture +/- symptoms of jaundice, pruritis, and fatigue
Criteria for Lynch Syndrome
1) Three family members affected with Lynch-syndrome associated cancers
2) Two successive generations affected
3) One affected family member is a first-degree relative of the other two affected members
4) One cancer was diagnosed <50 years
5) FAP has been ruled out
Lynch-Syndrome associated cancers:
- Colorectal
- endometrial
- Others: stomach, ovary, hepatobiliary, urinary tract, small bowel brain, pancreas, and sebaceous skin adenoma/cancer
Where is colorectal cancer as part of Lynch Syndrome likely to occur? What are the histologic characteristics?
1) Proximal colon
2) Tumor-infiltrating lymphocytes, medullary growth
Genes implicated in Lynch Syndrome
1) MLH1, MSH2, MSH6, PMS2 - mismatch repair genes
2) EPCAM - epithelia cell adhesion molecule
Treatment for pyogenic vs amebic liver abscess
Pyogenic - usually polymicrobial, via gut translocation (most common in US). Tx is often antimicrobials plus surgery. Surgical indications:
- > 5 cm in size
- complex abscess
- presence of gas-formation
- hemodynamic instability
- biliary fistulization
- presence of foreign body
Amebic abscess - usually Entamoeba histolytica, from an endemic area (South/Central America, India, Africa). Symptom onset 3-5 months after infection, which is indicative of hepatic necrosis. Treatment:
- metronidazole
- luminal agent (paromomycin)
Treatment of Wilson’s Disease
Trientine is preferred to penicillamine due to a lower rate of adverse effects.
Consider zinc supplements to decrease intestinal absorption of copper.
GI bleed with hypotension in patient with prior aortic grafting
Aortoenteric fistula
- evaluate with CT + contrast
- mortality rate 50% (even with surgical intervention)
What is alosetron used for?
IBD-D in women whose symptoms have not responded to conventional therapy
Risk for ischemic colitis and severe constipation
Drug monitoring program enrollment is required
What is the Meltzer Triad? What does it indicate?
1) Aesthenia (weakness)
2) Arthralgias
3) Palpable purpura
Classic presentation of Type II cryoglobulinemia
Hep C a common cause, treat the virus
How do you calculate the stool osmolar gap?
290 - 2[stool Na + stool K]
> 100 is consistent with osmotic
< 50 is consistent with secretory (think high stool Na and high stool K)
Fever, diarrhea, weight loss in an AIDS patient: etiologies
1) Cryptosporidium
2) E. histolytica
3) Giardia
4) isospora
5) Strongyloides
6) AIDS enteropathy
Rarer causes of chronic diarrhea
1) Diabetes
2) Amyloidosis - visceral autonomic neuropathy, gastroparesis, postural hypotension
3) Carcinoid syndrome
4) Lactase deficiency
5) IBS-D
How to diagnose Carcinoid Syndrome
1) 24hr urine 5-HIAA (positive if >25 mg/day)
2) CT may show metastases in liver
3) MRI and octreoscan (many carcinoid tumors express somatostatin receptors, which are bound by the radiolabeled somatostatin analogue octerotide)
A 24 hour fast will improve osmolar diarrhea, but not secretory diarrhea
Malabsorption (chronic diarrhea) can cause which 6 major deficiencies?
Think “PIC ACC”
P: PT/INR - Vitamin K deficiency I: Iron deficiency C: Calcium deficiency A: Albumin C: Cholesterol C: Carotene (Vitamin A) deficiency
Which ARB has been associated with enteropathy/malabsorption?
Olmesartan: causes sprue-like enteropathy
Whipple’s Triad:
1) Arthraligas
2) Abdominal pain
3) Diarrhea/malabsorption leading to weight loss
Caused by gram + bacillus T. whipplei
Can see Neuro sx (depression, paranoia, dementia)
Biopsy: Foamy macrophages, +PAS staining
Tx: Ceftriaxone or PCN IV x14 days, then TMP/SMX x1 year
Medications for IBS-C
1) Linaclotide
2) Lubiprostone
Both stimulate intestinal secretion
What are the inherited polyposis syndromes
1) FAP: AD, APC gene, 100s to 1000s of adenomas, 100% CA risk, proctocolectomy needed, screen for duodenal CA
2) Attenuated FAP: AD, APC gene, 10s-100s of polyps, delayed-onset CRC
3) MUTYH polyposis - AR, phenotype is similar to attenuated FAP, screen for duodenal CA as well
4) Gardner Syndrome: Variant of FAP with tumors outside of the colon (osteomas, thyroid cancer, desmoids)
5) Peutz-Jeghers syndrome: harmartomatous polyps, small bowel, stomach and colon. Freckles on lips/buccal mucosa, intussusception is common, increased CA risk (CRC, stomach, breast, pancreatic)
6) Juvenile Polyposis: consider if 3-5 juvenile polyps of the colon
7) Serrated Polyposis Syndrome
- Five or more serrated polyps proximal to the sigmoid colon, with two or more greater than 10 mm in size
- Any number of serrated polyps in patients with first-degree relatives with serrated polyposis syndrome
- More than 20 serrated polyps throughout the colon
Non-polyposis Colorectal Syndromes
1) Lynch
2) PTEN Hamartoma (Cowden Syndrome)
Colonoscopy follow up interval for one or two tubular adenomas (<1 cm)?
5 years
Colonoscopy follow up interval for 3-10 adenomas?
3 years
Colonoscopy follow up interval for an adenoma >1 cm?
3 years
Colonoscopy follow up interval for small rectal hyperplastic polyps?
10 years
Colonoscopy follow up interval for adenoma with high-grade dysplasia or villous features?
3 years
Colonoscopy follow up interval for >10 adenomas?
<3 years, consider familial polyposis syndrome
Colonoscopy follow up interval for large (>2 cm) sessile polyp removed in piecemeal fashion?
2-6 months
Colonoscopy follow up interval for polyp with adenocarcinoma (minimal invasion, >2 mm margin)?
2-3 months
Treatment for HBV
Tenofovir
Entecavir
Pegylated interferon
