GI Flashcards
Define cirrhosis.
chronic liver disease characterized by fibrosis replacing hepatocytes, disruption of the liver architecture, and widespread nodules in the liver
What are the downstream effects due to disruption of the normal liver architecture by cirrhosis?
- decreased blood flow through the liver with subsequent hypertension in portal circulation
- hepatocellular failure that leads to impairment of biochemical functions
Describe the pathogenesis of portal hypertension in those with cirrhosis.
fibrosis contributes to a disruption of the normal liver architecture, which reduces blood flow through the liver, leading to hypertension in portal circulation
What are the possible causes of cirrhosis?
- alcoholic liver disease is the most common cause
- chronic hepatitis B and C are the second
- drugs such as acetaminophen toxicity
- autoimmune hepatitis
- primary or secondary biliary cirrhosis
- hemochromatosis or Wilson’s disease
- hepatic congestion secondary to right-sided heart failure or pericarditis
- a1-antitrypsin deficiency
- hepatic venoocclusive disease after bone marrow transplantation
- nonalcoholic steatohepatitis
What is the gold standard for diagnosing cirrhosis?
liver biopsy
What are the classic signs of chronic liver disease?
- ascites
- varices
- gynecomastia or testicular atrophy
- palmar erythema and spider angiomas
- hemorrhoids
- caput medusa
What procedure is used to reduce portal hypertension?
trans jugular intrahepatic portal-systemic shunt (TIPS)
What is the most life-threatening complication of portal hypertension?
bleeding secondary to esophagogastric varices
Describe the presentation and treatment of esophagogastric varices.
- clinical features include hematemesis, melon, hematochezia, and exacerbation of hepatic encephalopathy
- prophylaxis with nonselective B-blockers
- bleeding is best treated with hemodynamic stabilization (fluids) followed by IV antibiotics, 3-5 days of octreotide, and an emergent upper GI endoscopy
- endoscopic ligation is preferred over endoscopic sclerotherapy
- IV vasopressin can be a substitute for octreotide because it causes vasoconstriction of mesenteric vessels, reducing portal pressure
Why is endoscopic vatical ligation preferred over endoscopic sclerotherapy of esophageal varices?
because the rebleed rate is considerably lower in patients who receive ligation
What causes ascites in those with liver disease?
portal hypertension and hypoalbuminemia
Describe the clinical presentation and treatment of ascites.
- presents with abdominal distention, shifting dullness, and a fluid wave
- treated with bed rest, low-sodium diet, and diuretics
- therapeutic paracentesis can be used for those with tense ascites, shortness of breath, or early satiety
- followed by TIPS to relieve portal hypertension
What is the differential diagnosis for ascites and how can we differentiate between these causes?
- the differential includes cirrhosis and portal hypertension, CHG, chronic renal disease, fluid overload, tuberculous peritonitis, malignancy, hypoalbuminemia, impaired liver inactivation of aldosterone
- a diagnostic paracentesis is performed and the serum-ascites albumin gradient is measured
- a difference of more than 1.1 g/dL is suggestive of portal hypertension while a difference less than that suggests another cause
Describe hepatic encephalopathy, including precipitating factors, clinical features, and treatment.
- it is a cognitive dysfunction caused by a build up of ammonia in those with chronic liver disease
- precipitated by alkalosis, hypokalemia, sedating drugs, GI bleeding, systemic infection, or hypovolemia
- presents with decreased mental function, confusion, poor concentration, asterisks, rigidity and hyperreflexia, and fetter hepaticus (musty odor of breath)
- treat with lactulose to prevent absorption of ammonia form the GI tract, rifaximin to kill bowel flora and halt ammonia production, or protein-restricted diet
List the complications of liver failure.
AC, 9H
- ascites
- coagulopathy
- hypoalbuminemia
- portal hypertension
- hyperammonemia
- hepatic encephalopathy
- hepatorenal syndrome
- hypoglycemia
- hyperbilirubinemia/jaundice
- hyperestrinism
- HCC
Describe hepatorenal syndrome including definition, clinical features, and treatment.
- it is a progressive renal failure in advanced liver disease secondary to renal hypo perfusion resulting from vasoconstriction of renal vessels
- precipitated in many cases by infection or diuretics
- presents with azotemia, oliguria, hyponatremia, hypotension, and low urine sodium
- does not respond to volume expansion and liver transplantation is the only cure
Describe SBP including the typical agents, clinical features, method for diagnosis, and treatment.
- it is an infection of the ascitic fluid, usually by E. coli, Klebsiella, or S. pneumoniae
- usually presents as fever, change in mental status, abdominal pain, vomiting, and rebound tenderness in those with known ascites
- diagnosed based on a paracentesis with a finding of more than 250 PMNs or 500 WBCs; very often culture negative
- treat with broad-spectrum antibiotic therapy and improvement should be seen in 1-2 days
Why do those with liver failure experience hyperestrinism?
because they have reduced hepatic catabolism of estrogens
Hyperestrinism has what manifestations in those with liver failure?
- spider angiomas
- palmar erythema
- gynecomastia
- testicular atrophy
What is unique about the coagulopathy caused by liver disease? What is the preferred treatment?
the PT is prolonged and vitamin K is an ineffective treatment because the liver cannot utilize it; instead, patients must be given fresh frozen plasma
Cirrhosis
- chronic liver disease characterized by fibrosis replacing hepatocytes, disrupted architecture, and widespread nodules
- most often caused by alcoholic liver disease or chronic hepatitis B or C; other causes include autoimmune, drugs, a1-antitrypsin deficiency, right-sided heart failure
- classic signs include ascites, varices, gynecomastia, testicular atrophy, palmar erythema, spider angiomas, hemorrhoids, caput medusa
- complications include ascites, coagulopathy, hepatorenal syndrome, hyperestrinism, hyperammonemia, hypoalbuminemia, portal hypertension, hepatic encephalopathy, hypoglycemia, hyperbilirubinemia, and HCC
- treat varices prophylactically with beta-blockers and symptomatically with fluids, octreotide, and endoscopy
- use the serum-ascites albumin gradient (>1.1) to determine if it is secondary to portal hypertension and treat with sodium restriction and diuretics
- treat hepatic encephalopathy with lactulose, rifaximin, and protein-restricted diet
- diagnose SBP with a paracentesis showing more than 250 PMNs and treat with broad spectrum antibiotics covering E. coli, Klebsiella, and S. pneumoniae
- treat coagulopathy with FFP
What is the most common type of colorectal cancer?
an endoluminal adenocarcinoma arising from the mucosa
Describe the various methods available to screen for colorectal cancer?
- fecal occult blood testing has poor sensitivity and specificity, but a positive result should be followed by a colonoscopy
- colonoscopy is the most sensitive and specific test
- flexible sigmoidoscopy is an imaging technique that can reach the area where 50-70% of polyps and cancers arise
- barium enema evaluates the entire colon and is often complementary to a flexible sigmoidoscopy
What is the most significant tumor marker for colorectal carcinoma and what is its utility?
CEA is not a good screening test but can be used for monitoring response to treatment and to monitor for recurrence
What is the most common site of metastasis for colorectal carcinoma?
the liver via the portal circulation
When does colorectal cancer screening begin?
typically at age 50, but if a family member has colon cancer, it should begin at age 40 or 10 years before the age of onset in that family member
Hyperplastic Colonic Polyps
- the most common type of colonic polyp
- they form due to hyperplasia of glands
- have a “serrated” appearance on microscopy
- they have no malignant potential but cannot be differentiated from adenomatous polyps on colonoscopy so are typically removed
Juvenile Polyps
- a sporadic, hamartomatous, benign polyp
- usually arises in children younger than 10
- tends to prolapse and bleed because they are highly vascular, so they are typically removed
- increase the risk for carcinoma
What are pseudopolyps?
an inflammatory colorectal polyp associated with ulcerative colitis
Adenomatous Colonic Polyps
- a neoplastic proliferation of glands
- benign but premalignant and may progress to adenocarcinoma via the adenoma-carcinoma sequence
- most have tubular histology, which has a small risk of malignancy, but may be villous which carry a greater risk
- other characteristics that increase the risk for progression are size greater than 2 cm and sessile growth
What is the goal of a colonoscopy?
to remove all adenomatous colonic polyps
What characteristics of an adenomatous colonic polyp increase the risk for malignant progression?
- size greater than 2 cm
- villous histology rather than tubular
- presence of atypical cells
- sessile architecture rather than pedunculated
What are the most significant risk factors for colorectal carcinoma?
- age over 50
- personal history of adenomatous polyps or prior CRC
- inflammatory bowel disease; UC more than Crohns
- family history of a first degree relative with CRC
- polyposis syndromes including FAP, HNPCC, Gardner syndrome, Turcot syndrome, Peutz-Jeghers, familial juvenile polyposis coli
Describe the following polyposis syndromes:
- familial adenomatous polyposis
- hereditary nonpolyposis CRC
- Gardner syndrome
- Turcot syndrome
- Peutz-Jeghers
- FAP: an autosomal dominant mutation in the APC tumor suppressor which leads to the formation of hundreds of adenomatous polyps and eventually CRC
- HNPCC: aka Lynch syndrome, it is a microsatellite instability brought on by a DNA mismatch repair enzyme defect and increases the risk of colorectal without adenomatous polyps, ovarian, and endometrial carcinoma
- Garder syndrome: a variant of FAP characterized by polyps, osteomas, dental abnormalities, benign soft tissue tumors, demoed tumors, and sebaceous cysts
- Turcot syndrome: a variant of FAP characterized by polyps plus cerebellar medulloblastoma or glioblastoma multiform
- Peutz-Jeghers: an autosomal dominant condition characterized by multiple hamartomatous, benign polyps throughout the GI tract with hyperpigmentation of the lips, oral mucosa, and genital skin in addition to increased risk of gynecological and breast cancers
Hereditary Nonpolyposis Colorectal Carcinoma
- aka Lynch syndrome, the typical example of microsatellite instability
- an inherited mutation in a DNA mismatch repair enzyme increases the risk for colorectal, ovarian, and endometrial carcinoma
- in such cases, colorectal carcinoma tends to arise de novo rather than from an adenomatous polyp and at a relatively early age on the right-side
Familial Adenomatous Polyposis
- an autosomal dominant disorder characterized by 100s or 1000s of adenomatous colonic polyps
- due to an inherited APC mutation on chromosome 5 (a tumor suppressor gene involve in the adenoma-carcinoma sequence)
- colon and rectum are removed prophylactically; otherwise, almost all patients develop carcinoma by age 40
- associated with CRC on the left-side of the colon
- Gardner syndrome is a subpopulation of FAP with fibromatosis and osteomas
- Turcot syndrome is a subpopulation of FAP with CNS tumors
What is Gardner syndrome?
a syndrome including familial adenomatous polyposis (APC mutation), fibromatosis, osteoma, dental abnormalities, demoed tumors, and sebaceous cysts
What is Turcot syndrome?
a syndrome of familial adenomatous polyposis (APC mutation) and CNS tumors like cerebellar medulloblastoma and glioblastoma multiforme
Peutz-Jeghers Syndrome
- an autosomal dominant syndrome of multiple hamartomatous, benign polyps throughout the GI tract with hyperpigmentation of the lips, oral mucosa, and genital skin
- increases the risk for colorectal, breast, and gynecologic cancer
Colorectal Carcinoma
- adenoma-carcinoma sequence tends to be at work in cancer on the left and microsatellite instability on the right
- right-sided usually grow as a raised lesion with occult blood or melena, iron-deficiency anemia, no change in bowel habits, and vague or RLQ pain
- left-sided carcinoma tends to grow as a napkin-ring lesion with decreased stool caliber, alternating constipation/diarrhea, hematochezia, and LLQ pain
- rectal tend to present with hematochezia, tenesmus, and a feeling of incomplete evacuation of stool
- most commonly spreads to the liver
- CEA is an important tumor marker, useful for assessing treatment response and detecting recurrence but not for screening
- after surgery, surveillance typically includes annual CXR or CT for 5 years, colonoscopy at 1 year and then every 3 years, and CEA monitoring every 3-6 months
Compare and contrast the presentation of right-sided and left-sided colonic carcinomas.
- both tend to be characterized by abdominal pain due to partial obstruction or peritoneal dissemination, weight loss, and some form of blood in the stool
- left-sided tend to grow as napkin-ring lesions with decreased stool caliber, signs of obstruction, alternating constipation/diarrhea, and hematochezia
- right-sided tend to present with occult blood in the stool or melena, iron deficiency anemia, weakness, and RLQ mass
- in short, left to to obstruct while right tend to bleed
What is the typical presentation of rectal cancer?
- hematochezia is the most common symptom
- tenesmus
- feeling of incomplete evacuation of stool due to the rectal mass
What is the typical protocol for surveillance of recurrence in those with colorectal cancer?
- CXR or CT abdomen/pelvis annually for 5 years
- colonoscopy at 1 year post-op and then every 3 years
- CEA level every 3-6 months
Diverticulosis
- an out pouching of mucosa and submucosa through the muscularis propria (false diverticulum)
- risk factors are those that are related to wall stress: constipation, straining, low-fiber diet, and age
- they arise where the vase recta transverse the muscularis propria because this is a weak point in the wall; and most often in the sigmoid colon
- usually asymptomatic but may cause present with LLQ discomfort, bloating, constipation or diarrhea
- diagnosed based on barium enema
- treat with high-fiber foods or psyllium to reduce wall stress
- may be complicated by painless renal bleeding, which usually stops spontaneously, or diverticulitis
Diverticulitis
- due to feces becoming impacted in a diverticulum, which then causes erosion and microperforation
- presents with LLQ pain, fever, and leukocytosis
- may be complicated by abscess formation, colovesical fistula, obstruction due to chronic inflammation and thickening of the bowel wall, or free colonic perforation and peritonitis
- diagnosed with CT abdomen and pelvis with oral and IV contrast, which may reveal swollen, edematous bowel wall or an abscess; note that barium enema and colonoscopy are contraindicated due to the risk of perforation
- manage with 7-10 days of IV antibiotics, bowel rest, and IVF; resection recommended for recurrent episodes
How is diverticulitis diagnosed?
with a CT scan of the abdomen and pelvis with oral and IV contrast; barium enema and colonoscopy are contraindicated because of the risk of perforation
What is the typical presentation and treatment for angiodysplasia of the colon?
these AV malformations are a common cause of lower GI bleeding but the bleeding usually stops spontaneously and only rarely requires colonoscopies coagulation
What are the four primary causes of acute mesenteric ischemia and how do they differ in presentation?
- embolic: symptoms are more sudden and painful
- arterial thrombosis: symptoms are more gradual and less severe
- nonexclusive ischemia: typically occurs in critically ill patients
- venous thrombosis: symptoms may be present for several days or weeks with gradual worsening
Acute Mesenteric Ischemia
- a compromised blood supply, usually involving the SMA
- can be due to an arterial embolism (rapid onset and severe), arterial thrombosis (history of atherosclerotic disease with more gradual and less severe presentation), non-occlusive (splanchnic vasoconstriction secondary to low cardiac output seen in critically ill elderly patients), or venous thrombosis
- presents with severe abdominal pain disproportionate to physical findings, anorexia, vomiting, mild GI bleeding
- if bowel becomes infarcted, signs include tachypnea, lactic acidosis, fever, and altered mental status
- may be complicated by peritonitis, sepsis, or shock
- the diagnosis is made by mesenteric angiography; may see thumbprinting on barium enema due to thickened edematous mucosal folds
- treat with IV fluids and broad spectrum antibiotics plus direct intra-arterial infuse of the vasodilator papaverine during arteriography for arterial causes or heparin for venous thrombosis
Chronic Mesenteric Ischemia
- caused by atherosclerosis occlusive disease of main mesenteric vessels like the SMA
- presents with abdominal angina characterized as a dull, typically postprandial, pain and weight loss
- diagnosed with mesenteric arteriography
- treated with surgical revascularization
Ogilvie Syndrome
- a syndrome of signs, symptoms, and radiographic evidence of large bowel obstruction without mechanical obstruction
- causes include recent surgery or trauma, serious medical illness like sepsis or malignancy, and medications like narcotics, anticholinergics, etc.
- treat with IV fluids, electrolyte repletion, decompression with gentle enemas or NG suction
Pseudomembrane Colitis
- aka, antibiotic-associated colitis, it is an overgrowth of C. difficile with toxin production
- can occur with almost any antibiotic but clindamycin, ampicillin, and cephalosporins are most common
- symptoms of profuse watery diarrhea and crampy abdominal pain usually may begin within 6 weeks of antibiotic usage
- may be complicated by toxic megacolon with a risk for perforation
- diagnosed based on C. difficile toxin assay and abdominal radiograph to evaluate for toxic megacolon; leukocytosis is supportive; flexible sigmoidoscopy is the most rapid test but is invasive and rarely used
Which antibiotics are most commonly associated with C. diff?
ampicillin, clindamycin, and cephalosporins
Colonic Volvulus
- a twisting of the bowel along it’s mesentery, resulting in obstruction and vascular compromise
- most commonly in the sigmoid colon for adult populations and in the cecum in pediatric patients
- presents with acute onset of colicky abdominal pain, obstipation, abdominal distention, anorexia, n/v
- sigmoidoscopy is the preferred test for sigmoid volvulus as it is both diagnostic and therapeutic
- other tests: an omega loop sign on plain film indicates sigmoid volvulus, a coffee bean sign indicates a cecal volvulus, and a barium enema shows a bird’s beak sign at the point of twisting
What are the omega loop and coffee bean signs?
- omega loop is a bent inner-tube shape seen on plain abdominal films indicative of sigmoid volvulus
- coffee bean sign is a large air-fluid levels in the RLQ on plain abdominal films indicative of cecal volvulus
Which is more sensitive and specific of liver damage, ALT or AST?
ALT is more sensitive and specific
What is the hallmark lab finding indicative of alcoholic hepatitis?
an AST to ALT ratio greater than 2
What should low/normal, mildly, moderately, and severely elevated aminotransferases suggest to you about liver pathology?
- low/normal: cirrhosis or metastatic liver disease
- mild: think of chronic viral or acute alcoholic hepatitis
- moderate: think acute viral hepatitis
- severely: think extensive hepatic necrosis secondary to ischemia and shock liver, acetaminophen toxicity, or severe viral hepatitis
How elevated would you expect aminotransferases to be in someone with cirrhosis?
both cirrhosis and metastatic liver disease typically have normal or low liver transaminases because the number of healthy functioning hepatocytes i markedly reduced
What are possible causes of a rise in ALT or AST levels in asymptomatic patients?
A-I
- Autoimmune hepatitis
- hepatitis B
- hepatitis C
- Drugs or toxins
- Ethanol
- Fatty liver
- Growths (tumors)
- Hemodynamic disorders (e.g. CHF)
- Iron (hemochromatosis), copper (Wilson disease), or AAT deficiency
What would cause a decrease in albumin levels?
chronic liver disease, nephrotic syndrome, malnutrition, and inflammatory states
Is the PT or PTT affected by chronic liver disease?
PT
What hepatic pathology causes an elevated alkaline phosphatase? What test should you perform to improve the specificity for hepatic pathology?
- measure the gamma-glutamyl-transferase level, which should be elevated if ALK-P
- if both are elevated, it suggests an obstruction to bile flow in some part of the biliary tree
What does the presence of HBsAg in an individual indicate?
it is the first serologic marker to rise in those with an HBV infection and it is indicative of present infection, either acute or chronic
What does the presence of HBeAg or HBV DNA in an individual indicate?
- it is a marker of infectiousness, so it is positive during the acute phase and can be positive or negative during the chronic phase
- it is absent in all other phases
What do IgM and IgG against HBc indicate in an individual being assessed for hepatitis?
- IgM is seen only in the acute and window stages early in infection
- IgG is seen in the later phases (chronic infection or resolution)
- importantly no such antibodies are seen in individuals who have only been immunized and not exposed to HBV
What does the presence of antibodies to HBs indicate in an individual being assessed for hepatitis?
it is protective and as such, is seen in those with resolved past infection and who have been immunized
What is the typical presentation of Wilson disease?
- liver disease including acute hepatitis, cirrhosis, and fulminant hepatic failure
- Kayser-Fleischer rings, which don’t impact ivision
- extrapyrmidal signs and psychiatric disturbances
- renal involvement leading to aminoaciduria and nephrocalcinosis