Gi and Liver UWorld
CIRRHOSIS
Complications
- Hepatic hydrothorax
o Cirrhosis —> low albumin —> low oncotic pressure —> fluid shifts out of intravascular
space —> fluid goes through diaphragm defect (microperforations)
o This causes one sided (typically right side) pleural effusions and peripheral edema
o Similar mechanism happens with pancreatitis
LOWER GI BLEED
Diverticulosis – most common cause of lower GI bleed
- Outpouchings of the colonic wall that form at points of weakness
- Deformation in the colonic wall can cause weakness in the associated arterial supply and lead to
bleeding into the diverticular lumen
- Diverticulosis is most common in the sigmoid colon
- Diverticular bleeding is more common in the right colon
o Painless, large volume bleeding, lightheadedness, hemodynamic instability
o Irritation due to bleeding can cause urge to defecate
- Diagnosis
o Colonoscopy – indicated in the management of presumed diverticular bleed but
contraindicated in diverticulitis due to inflamed diverticula
- Treatment
o Most resolve spontaneously
o Minority require endoscopic or surgical intervention
- Seen on abdominal CT
- Plan radiographs are normal
Colonic Angiodysplasia
- Painless bleeding in the right colon
- Usually venous
- Low-volume bleeding
Colon cancer
- Chronic occult blood loss w/ abdominal pain
- Altered passage of stool and weight loss
- Gross bleeding is less likely
Hemorrhoids
- Painless rectal bleeding
- Bright red blood in the toilet bowl or on the paper
Ischemic colitis
- Sudden onset of abdominal pain and tenderness followed by rectal bleeding
- Due to inadequate perfusion of watershed areas of the colon (splenic flexure) in the setting of
nonocclusive ischemia or surgical or endovascular interventions
SPLENIC ABSCESS
- Life threatening complication from distant infection (infective endocarditis, cholecystitis)
o Consider in patients who recently underwent laparoscopic cholecystectomy for
cholecystitis
- Risk factors: immunocompromised from HIV, hematologic malignancy, or DM.
- Clinical manifestations
o LUQ pain
o High fever
o Tender splenomegaly
o Anorexia
o Weight loss
- Laboratory studies
o Leukocytosis w/ left shift
- CXR shows elevated left hemidiaphragm and/or left pleural effusion
- Diagnosis
o CT scan of the abdomen
- Treatment
o Antibiotic therapy
o Splenectomy
SPLENIC INFARCTION
- Clinical manifestations
o LUQ
o Fever and splenomegaly occasionally occur
o Underlying hypercoagulable disorder, a source of embolic disease (a-fib), a
myeloproliferative neoplasm, or hemoglobinopathy (sickle cell disease
SPLENIC VENOUS THROMBOSIS
- Occurs in the setting of portal hypertension from liver disease or pancreatitis
LACTOSE INTOLERANCE
- Caused by deficiency of intestinal lactase, an enzyme in the brush border that metabolized
dietary lactose
- Undigested lactose is metabolized by colonic bacteria, releasing hydrogen gas and other
byproducts
- Etiology/risk factors
o Asian, African, Hispanic ethnicity
o Congenital or developmental lactase deficiency
o Small intestinal infection or inflammation
Can be precipitated by inflammatory disorders affecting the brush border –
infectious gastroenteritis, celiac disease, and Crohn disease
- Clinical features
o Gastrointestinal distress after dairy intake
Abdominal pain
Flatulence/bloating
+/- watery diarrhea
- Diagnosis
o Resolution of symptoms on dairy-restricted diet
o Lactose breath hydrogen test
Detects hydrogen released from standardized dose of oral lactose – can be
diagnostic
- Management
o Dietary restriction of lactose
o Lactase replacement if dairy ingested
Stool fat measurement – helps w/ diagnosis of malabsorptive diarrhea – occurs in the setting of small-
intestine infection (giardiasis), bacterial overgrowth, chronic pancreatitis
Tumor necrosis factor inhibitors – often used for refractory UC
Endoscopic retrograde cholangiopancreatography – used to evaluate choledocolithiasis
Evaluation of upper GI – esophagogastroduodenoscopy
- When there are features suggesting bleeding (iron deficiency anemia) or malignancy (progressive
dysphagia or odynophagia)
Evaluation of lower GI – colonoscopy
- Features associated with bleeding (hematochezia) or risk factors for malignancy (age>50,
unexpected weight loss)
CHOLESTASIS
Primary sclerosing cholangitis (PSC)
- Type of acute cholangitis caused by biliary obstruction (stricture) – predisposes patients to
bacterial invasion of the normally sterile biliary tree
- Chronic disease characterized by fibrosis and structuring of the medium and large- intra-and
extrahepatic bile ducts
o Promoted cholestasis and obstruction
- Clinical features
o Usually men
o Asymptomatic
o Fatigue and pruritus
o Associated with IBD, particular ulcerative colitis (>90% of patients)
Hematochezia
o Features of acute cholangitis – RUQ pain, fever, jaundice, hypotension, AMS)
- Laboratory/imaging
o Cholestatic liver injury (very high ALP, high bilirubin)
o Multifocal structuring/dilation of intrahepatic and/or extrahepatic bile ducts on
cholangiography (i.e. magnetic resonance cholangiopancreatography)
o Patients usually have normal ultrasonography because intrahepatic bile ducts are not
easily visible
- Liver biopsy
o Fibrous obliteration of small bile ducts with concentric replacement by connective tissue
in onion-skin pattern
- Complications
o Biliary stricture
o Cholangitis or cholelithiasis
o Cholangiocarcinoma, colon cancer, biliary cancer
o Cholestasis (low fat-soluble vitamin, osteoporosis)
- Treatment
o Endoscopic interventions for strictures
o Therapy for coexisting UC
o Antibiotics for cholangitis
o Occasionally ursodeoxycholic acid
Primary biliary cholangitis (PBC)
- Results from an immune response against the intrahepatic bile ducts
- Can present with cholestasis
- More common in women
PANCREATITIS
Acute pancreatitis
- Severe epigastric pain radiating to the back
- Elevated lipase (>3 times normal)
- Common causes: alcohol use, gallstones
o After alcohol and gallstones have been excluded (RUQ ultrasound) consider other less
common causes
Hypercalcemia
Hypertriglyceridemia
- Diagnosis – 2/3 classic features
o Class symptoms (severe epigastric pain radiating to the back)
o Elevated amylase/lipase
o Characteristic imaging findings
Patient does NOT require a CT scan if they have symptoms and lab findings
Triglyceride-induced pancreatitis
- Risk
o Triglyceride levels
<500: minimal risk
500-999: mild risk
1,000-1,999: moderate risk
>2,000: high risk
o Other risk factors: pregnancy, alcoholism, obesity, uncontrolled diabetes
- Clinical features
o Acute epigastric pain radiating to back
o +/- fever, nausea, vomiting
o Elevated serum lipase (>3 times upper limit of normal)
- Diagnosis
o Lipid panel – triglyceride level >1000mg/dL is required for diagnosis
- Management
o IV fluid hydration, pain control
o Glucose >500 mg/dL: consider insulin infusion
o Glucose <500 mg/dL or severe pancreatitis (i.e. lactic acidosis, hypocalcemia): consider
apheresis (therapeutic plasma exchange – removes triglyceride-rich plasma)
DIARRHEA
Factitious disorder
- Intentional falsification of illness in the absence of external reward (financial compensation,
disability benefits)
- Purposely cause large, voluminous stools via improper use of laxatives and can create the
appearance of diarrhea by adding fluid to the stool
- Stool osmolality
o Stool osmolality is in equilibrium with plasma osmolality
o Typically remains constant (i.e. 290 mOsm/kg) in organic GI disease
o Hypoosmolality suggests addition of water or other dilute fluid
o Hyperosmolality suggests addition of a concentrated fluid (urine)
- Stool electrolytes
o Elevated stool magnesium or phosphate levels suggest overuse of saline osmotic
(magnesium or phosphate containing) laxatives
- Stool osmotic gap
o Osmotic laxatives (lactulose, polyethylene glycol) cause a high osmotic gap diarrhea,
whereas senna and bisacodyl produce a low osmotic gap secretory diarrhea.
o 290 mOsm/kg – 2 x (stool Na + stool K)
<50 – secretory diarrhea
50-125 – indeterminate
>125 - osmotic diarrhea
Celiac disease
- Tissue transglutaminase IgA antibodies
- Weight loss
- Signs of malabsorption
o Iron deficiency anemia
o Vitamin D deficiency w/ hypocalcemia
Norovirus
- Causes chronic diarrhea in immunocompromised patients (HIV, solid-organ transplant)
- 1-2 days of symptoms
- Self-limited in immunocompetent individuals
Clostridioides difficile infection (CDI)
- Development of large-volume watery stool and leukocytosis after antibiotic use
- Risk factors
o Antibiotic use
o Recent hospitalization
o IBD and other comorbid illnesses
HELICOBACTER PYLORI
- Plays a critical role in the pathogenesis of extranodal marginal zone B cell lymphomas (low-grade
B cell lymphoma of MALT) of the stomach.
- Present in 90% of patients with tumors
- Chronic inflammation from H. Pylori infection results ins timulation of large numbers of antigen-
dependent B and T cells in the gastric lamina
- Chronic activation and proliferation eventually results in a monoclonal population of B cells that
no longer depends on normal stimulatory pathways for growth
- All patients with MALT lymphomas should be tested for H. Pylori
- Treatment
o Positive H. Pylori + MALT lymphoma – quadruple therapy
o Majority of patients achieve complete remission w/ antibiotic treatment
