Step Up - Diseases Of The GIT Flashcards
Virtually, all colorectal tumors arise from?
Adenomas - Majority are endoluminal adenocarcinomas arising from the mucosa.
Bleeding and colorectal cancer - What should be noted?
Some colorectal CA may bleed intermittently or not at all.
Screening for colorectal cancer - FOBT?
Poor sensitivity + Poor specificity.
–> Positive predictive value 20%.
If FOBT comes back positive, what should be done?
Colonoscopy, regardless.
What percentage of colorectal tumors are palpable by DRE?
10%.
Most sensitive and specific test for colorectal cancer screening?
Colonoscopy.
Diagnostic test of choice for patients with a positive FOBT?
Colonoscopy
Role of flexible sigmoidoscopy?
Can be used to reach the area where approx. 50-70% of polyps and cancers occur (with a 60cm scope).
–> Diagnostic in about 2/3 of all CRCs.
Barium enema as a screening method for CRCs?
Evaluates entire colon; complementary to flexible sigmoidoscopy.
Disadvantage of barium enema as a screening method for CRCs?
Any abnormal finding needs to be evaluated by colonoscopy.
CEA - What is its significance?
- NOT for screening.
- For recurrences.
- Prognostic significance - Patients with PRE-operative CEA >5ng/mL have a worse prognosis.
Clinical staging of CRCs - How is it done?
CT scan of chest, abdomen, pelvis, and by physical examination (ascites, hepatomegaly, lymphadenopathy).
Is it possible for a CRC to give metastases to the lung?
Yes - Via the lumbar/vertebral veins.
What percentage of CRC patients have distant metastases at presentation?
20%.
Incidence of CRC in patients with ulcerative colitis - At 20yrs and at 30yrs?
5-10% at 20yrs.
12-20% at 30yrs.
Which sites of the GIT are involved in FAP?
Colon always + the DUODENUM in 90% of cases.
Polyps may also form in the stomach, jejunum, and ileum.
Gardner syndrome - Features?
- Polyps + osteomas
- Dental abnormalities
- Benign soft tumors
- Desmoid tumors
- Sebaceous cysts
Gardner syndrome - Risk of CRC?
100% by approx. age 40.
Turcot syndrome - Inheritance pattern?
AR
Turcot syndrome - Features?
Polyps + cerebellar medulloblastoma or GBM.
Peutz-Jeghers - Where do we find the hamartomas?
78% - Small bowel.
60% - Colon.
30% - Stomach.
Peutz-Jeghers - Where are the pigmented spots?
- Lips
- Oral mucosa
- Face
- Genitalia
- Palmar surfaces
Peutz-Jeghers - Associations with cancer?
- Hamartomas have very low malignant potential.
2. Slightly increased incidence in various carcinomas - stomach, ovary, breast, cervix, testicle, lung.
Complications of Peutz-Jeghers?
Intussusception or GI bleeding may occur.
Familial juvenile polyposis coli - Features?
- RARE - Presents in childhood, only small risk of CRC.
2. >10 up to HUNDREDS of juvenile colon polyps.
Hereditary nonpolyposis CRC - without adenomatous polyposis - Lynch syndromes?
Lynch syndrome I and II.
Lynch syndrome I - What happens?
- Early onset CRC.
2. ABSENCE of antecedent multiple polyposis.
Lynch syndrome II - What happens?
Cancer family syndrome - All features of Lynch I + incr. number and early occurrence of other cancers - female genital tract, skin, stomach, pancreas, brain, breast, biliary tract.
Presence of symptoms in CRC usually indicates what?
Advanced disease.
MC presenting symptom in CRC?
Abdominal pain.
MCC of large bowel obstruction in adults?
CRC
Right-sided CRC - Common findings?
- Occult blood in stool.
- Iron def. anemia.
- Melena.
- -> Changes in bowel habits is UNCOMMON!
Rectal cancer - What percentage of all CRCs?
20-30%.
MC symptoms of rectal cancer?
Hematochezia
Prognosis of rectal cancer in relationship to colon cancer?
Higher recurrence rate and a lower 5-yr survival than colon cancer.
Only curative treatment for CRC?
Surgery
Radiation therapy - Indicated in colon or in rectal cancer?
In rectal cancer.
Follow-up after surgery of CRCs:
Varies among physicians:
- Stool guaiac test
- Annual CT scan of abdomen/pelvis + CXR for up to 5yrs.
- Colonoscopy at 1yrs and then every 3yrs.
- CEA levels checked periodically - every 3-6months.
Very high elevations of CEA suggest?
Liver involvement.
After surgery of CRCs, what percentage recurs within 3yrs?
90%.
Colonic polyps - Non neoplastic polyps?
Benign lesions with no malignant potential.
MC non neoplastic polyp?
Hyperplastic (metaplastic) polyp - 90%.
Generally, remain small and asymptomatic.
Non neoplastic polyps in children?
Juvenile polyps (typically in children younger than 10yrs).
Main feature of juvenile polyps?
Highly vascular and common - should be removed.
Diverticulosis - What usually causes it?
Increased intraluminal pressure - Inner layer of colon bulges through focal area of weakness in colon wall –> usually an area of blood vessel penetration!
Risk factors for diverticulosis?
- Low-fiber diets –> Constipation incr. intraluminal pressure.
- Family history.
Clinical features of diverticulosis?
- Usually asymptomatic and discovered incidentally on barium enema or colonoscopy done for another reason.
- Vague LLQ discomfort, bloating, constipation/diarrhea may be present.
What percentage of patients with diverticulosis is symptomatic?
Only 10-20%.
Test of choice in diverticulosis?
Barium enema.
Abdominal x-rays in diverticulosis?
Usually normal, and are NOT diagnostic.
Diverticulosis - Treatment?
- High-fiber foods (such as bran) to increase stool bulk.
2. Psyllium (if the patient cannot tolerate pain).
Complications of diverticulosis?
- Painless rectal bleeding
2. Diverticulitis
Complications of diverticulitis?
- Bowel obstruction
- Abscess
- Fistulas
Painless rectal bleeding in diverticulosis - Percentage?
Up to 40%.
Painless rectal bleeding in diverticulosis - Problem?
Usually insignificant and stops spontaneously.
Severe in 5%.
Diverticulitis in diverticulosis - Percentage?
15-25%
Free colonic perforation in diverticulitis?
UNCOMMON but catastrophic (leads to peritonitis).
Percentage of recurrence in patients with medically-treated diverticulitis within the first 5yrs?
About 30%.
Lower GI bleeding - More common in diverticulosis or diverticulitis?
Diverticulosis.
Diverticulosis - Test of choice?
Barium enema
Diverticulitis - Test of choice?
CT scan - Barium enema and colonoscopy contraindicated.
Why are barium enema and colonoscopy contraindicated in acute diverticulitis?
Due to risk of perforation.
Treatment for acute diverticulitis?
- Mild –> IV antibiotics, bowel rest (NPO), IV fluids.
- If symptoms persist after 3-4 days –> surgery.
- Antibiotics for 7-10days.
After successful treatment of diverticulitis, what is the recurrence percentage?
About 30%.
Interesting relationship between aortic stenosis and bleeding AV malformations?
25% of patients with AV malformations have aortic stenosis.
Angiodysplasia - Percentage with massive bleeding?
15%.
Angiography or colonoscopy for diagnosing angiodysplasia?
Colonoscopy
Angiodysplasia - How often does bleeding stops spontaneously?
90%.
Acute or chronic Mesenteric ischemia is more common?
Acute is much more common.
Patients with acute mesenteric ischemia, often have what?
Preexisting heart disease - CHF, CAD.
Types of acute mesenteric ischemia:
- Arterial embolism (50%)
- Arterial thrombosis (25%)
- Non occlusive mesenteric ischemia (20%)
- Venous thrombosis (<10%)
Acute mesenteric ischemia due to arterial embolism?
Almost all emboli are of cardiac origin - A-fib, MI, Valvular disease.
Acute mesenteric ischemia due to arterial thrombosis:
- Most of these patients have atherosclerotic disease at other sites.
- Acute occlusion over preexisting atherosclerotic disease.
- Collateral circulation has usually developed.
Acute mesenteric ischemia due to non occlusive mesenteric ischemia:
- Splanchnic vasoconstriction secondary to low CO.
2. Typically seen in critically ill elderly patients.
Acute mesenteric ischemia due to venous thrombosis - Predisposing factors?
- Infection
- Hypercoagulable states
- OCPs
- Portal HTN
- Malignancy
- Pancreatitis
Presentation of acute mesenteric ischemia - Embolic?
Sudden and more painful than other causes.
Presentation of acute mesenteric ischemia - Arterial thrombosis?
More gradual and less severe than embolic causes.
Presentation of acute mesenteric ischemia - Non occlusive ischemia?
Typically in critically ill patients.
Presentation of acute mesenteric ischemia - Venous thrombosis?
Symptoms for several days or even weeks, with gradual worsening.
Overall mortality for acute mesenteric ischemia?
60-70% - If bowel infarction has occurred, mortality can exceed 90%.
Classic presentation of acute mesenteric ischemia?
Acute onset of severe abdominal pain DISPROPORTIONATE to physical findings.
Examination may appear benign even when there is severe ischemia - This can lead to delay in diagnosis.
Signs of intestinal infarction in acute mesenteric ischemia?
- Hypotension
- Tachypnea
- Lactic acidosis
- Fever
- Altered mental status
Eventually leading to shock.
Which biochemical component needs to be checked if acute mesenteric ischemia is suspected?
Lactate level
Acute mesenteric ischemia - Definitive diagnostic test?
Mesenteric angiography
Is a plain abdomen film necessary in acute mesenteric ischemia?
To exclude other causes of abdominal pain.
Acute mesenteric ischemia - What do we see on barium enema?
“Thumbprinting” due to thickened Edematous mucosal folds.
Supportive measures for acute mesenteric ischemia?
IV fluids and broad-spectrum antibiotics.
Therapy of choice for all arterial causes of acute mesenteric ischemia?
Direct intra-arterial infusion of papaverine (vasodilator) into the superior mesenteric system during arteriography.
Do we give Thrombolytics in patients with acute mesenteric ischemia?
May be indicated in some patients with embolic acute mesenteric ischemia.
Treatment of choice for acute mesenteric ischemia due to venous thrombosis?
Heparin
Surgery for acute mesenteric ischemia - When?
May be needed in ALL types of acute mesenteric ischemia if signs of peritonitis develop.
Chronic mesenteric ischemia - Presentation?
- Causes by atherosclerotic occlusive disease of main mesenteric vessels.
- Abdominal angina.
- Significant weight loss.
Chronic mesenteric ischemia - What confirms the diagnosis?
Mesenteric angiography
Chronic mesenteric ischemia - Definitive treatment?
Surgical Revascularization and leads to pain relief in 90% of cases.
Ogilvie’s syndrome - What happens?
Unusual problem in which signs, symptoms, and radiographic findings of large bowel obstruction are present, but there is NO MECHANICAL OBSTRUCTION.
Ogilvie’s syndrome - Commom causes:
- Recent surgery or trauma.
- Serious medical illnesses (sepsis, malignancy)
- Medications (narcotics, psychotropic drugs, malignancy)
Ogilvie’s syndrome - Treatment?
- Stopping any offending agent (narcotics) and supportive measures (IV fluids, electrolyte repletion).
- Decompression with gentle enemas or nasogastric suction may be helpful if above fail.
- Surgical decompression with cecostomy or colostomy is a last resort.
3 antibiotics frequently associated with Pseudomembranous colitis?
- Clindamycin
- Ampicillin
- Cephalosporins
What is the max colonic Distention in which the risk of impending rupture is very high?
> 10cm diameter.
Complications of severe pseudomembranous colitis:
- Toxic megacolon
- Colonic perfusion
- Anasarca, electrolyte disturbances
Diagnosis of pseudomembranous colitis:
Demonstration of C.difficile toxins is diagnostic - results take at least 24h. 95% sensitivity.
What is the importance of abdominal radiograph in pseudomembranous colitis?
To rule out toxic Megacolon and perforation.
Drug of choice in pseudomembranous colitis?
Metronidazole
Where is metronidazole contraindicated?
Infants or pregnant patients.
When do we use oral vanco instead of metronidazole?
If the patient is resistant to metro or cannot tolerate it.
Recurrence of pseudomembranous colitis?
15-35% within 2-8wks after successful treatment.
Role of abdominal radiograph in pseudomembranous colitis?
To rule out toxic megacolon and perforation.
Role of cholestyramine in pseudomembranous colitis treatment?
May be used as an adjuvant treatment to improve diarrhea.
Colonic volvulus - Definition?
Defined as twisting of a loop of intestine about its mesenteric attachment site.
Colonic volvulus - Complication?
May result in obstruction or vascular compromise - potential for necrosis and/or perforation if untreated.
MC site of colonic volvulus?
The sigmoid colon - 75% of all cases.
Is cecal volvulus common?
25% of cases.
Risk factors for colonic volvulus:
- Chronic illness
- Age
- Institutionalization
- CNS disease
- Chronic constipation - laxative abuse - antimotility drugs
- Prior abdominal surgery
Risk for cecal volvulus?
Due to congenital lack of fixation of the right colon and tends to occur in younger patients.
Colonic volvulus - Presentation:
- Acute onset of colicky abdominal pain.
- Obstipation, abdominal distention.
- Anorexia
- Nausea
- Vomiting
Diagnosis - Sigmoid volvulus - Plain abdominal film:
Omega loop sign (or bent inner-tube shape) indicates a dilated sigmoid colon.
Cecal volvulus - Diagnosis - Plain abdominal film:
Coffee bean sign indicates a large air-fluid level in RLQ.
Role of sigmoidoscopy in diagnosing colonic volvulus?
Preferred diagnostic and therapeutic test for sigmoid volvulus –> Leads to successful treatment (untwisting and decompression) in many cases.
Barium enema - colonic volvulus?
Reveals the narrowing of the colon at the point where it is twisted (“bird’s beak”).
Treatment of sigmoid volvulus:
> 70% decompression via sigmoidoscopy.
–> Recurrence is HIGH –> Elective sigmoid colon resection is recommended.
Treatment of cecal volvulus?
Emergent surgery is indicated.
Gold standard for diagnosing cirrhosis:
Liver biopsy.
Cirrhosis - Distortion of liver anatomy causes 2 major events:
A. Decreased blood flow through the liver.
B. Impairment of biochemical functions.