GI Conditions: Part 2 Flashcards
Maldigestion and malabsorption
Maldigestion: Failure of the mechanical and chemical processes of digestion
Malabsorption: Failure of the intestinal mucosa to absorb (transport) digested nutrients
Pancreatic insufficiency
Insufficient pancreatic enzyme production (amylase, lipase, protease)
Caused by:
- Pancreatic issues: Chronic pancreatitis, cystic fibrosis, and duct obstructions
- Non-pancreatic issues: Celiac disease, Crohn’s disease (intestinal autoantibodies impair exocrine function), Zollinger-Ellison syndrome, GI/pancreatic surgery
S/S: Frequent gas/bloating, abdominal pain/cramps, weight loss, fatigue, D/, steatorrhea (fatty stool)
Diagnosed by: Stool elastase, fecal fat, and low chromotrypsin (signals bile secretion by duodenum)
Lactase deficiency (lactose intolerance)
Congenital defect in the lactase gene OR secondary to illness/surgery of SI (Crohn’s disease, celiac disease)
Inability to breakdown lactose into monosaccharides, preventing lactose digestion and absorption
S/S: Fermentation of lactose by bacteria (gas, cramping pain, flatulence); and osmotic D/
Tx: Avoiding milk products (lactose-free diet) and adequate calcium intake (to decrease risk of osteoporosis)
Bile salt deficiency
Conjugated bile salts are synthesized from cholesterol in the liver to emulsify and absorb fats (and vitamins)
Caused by: Liver disease and bile obstructions
Fat-soluble vitamin deficiencies
Deficiencies:
1. VITAMIN A (retinol): Healthy vision and immune support (Sources: Fish liver oil, animal liver, cereals, margarine, dark green/yellow/orange vegetables); Complications: Night blindness, hair loss, dry eyes, reduced immune function, and skin issues
- VITAMIN D: Intestinal absorption of Ca+ and phosphorus, and influences bone mineralization (Sources: Sunlight, liver, butter, fish, egg yolks); Complications: Decreased calcium absorption, bone pain, osteoporosis, and FXs
- VITAMIN K: Clotting (Sources: Leafy greens, intestinal bacteria); Complications: Prolonged PT (inability to clot), purpura, and petechiae
- VITAMIN E: Antioxidant, may protect against atherosclerosis; Complications (rare): Usually malabsorption-related vs. food deficiency; may cause testicular atrophy; and neurological defects in children
Dumping syndrome
Rapid emptying of hypertonic chyme from the stomach into the SI especially after eating foods high in sugar
Caused by: Partial gastrectomy, pyloroplasty, duodenectomy
S/S: N/V/D, cramping, hypoglycemia (d/t exaggerated insulin release), tachycardia, diaphoresis, dizziness, vertigo, and hypovolemia
Tx: Encourage small frequent meals, low-carb meals, limit fluid consumption at mealtime
Liver disease
Permanent liver damage:
- Liver fibrosis: encapsulation of injured tissue by scar tissue (advanced stage of liver damage)
- Distortion of hepatic vasculature
Clinical consequences: (1) Impaired liver function d/t cirrhosis (liver parenchyma is replaced with non-functioning connective tissue), (2) increased intrahepatic resistance (portal HTN), and (3) hepatocellular carcinoma
Types of liver disease:
1. VIRUS-RELATED: Hepatitis A (food and drink), Hepatitis B (bodily fluids), and Hepatitis C (blood-borne, sharing needles, and STDs; no vaccine)
- DRUG/TOXIN-RELATED: Fatty liver disease (alcoholic or non-alcoholic d/t DM, HTN, obesity), and toxic hepatitis
- CA
- INHERITED: Hemochromatosis (accumulation and storage of iron) or Wilson disease (copper)
Portal HTN and ascites
Pathogenesis:
1. Cirrhosis leads to increased blood flow resistance and portal HTN
- Increased hydrostatic pressure (and filtration)
- Decreased oncotic pressure (and absorption)
- Activation of RAAS and ADH d/t systemic arterial under-filling and renal hypoperfusion
- ASCITES (buildup of fluid in the abdominal cavity)
Common liver labs
Elevated ALT/AST (alanine/aspirate aminotransferase): Liver injury or damage
Elevated GGT (gamma-glytamyl transferase): Bile obstruction
Bilirubin: CONJUGATED (water-soluble; and excreted into the bile), and UN-CONJUGATED (a waste product of Hgb breakdown taken up by the liver)
Low albumin: Liver injury or damage
Elevated BUN (d/t decreased GFR): Often caused by hypovolemia and renal hypoperfusion (pre-renal injury)
Jaundice
Elevated serum bilirubin; bilirubin is normally conjugated (made water-soluble) by the liver, and excreted via bile
S/S: Yellowing of the skin or eyes, pale stools, dark urine, itching, fatigue, abdominal pain, weight loss, V/, fever; and common in neonates (unable to conjugate bilirubin; phototherapy beds add oxygen to bilirubin to become more water-soluble)
Types of jaundice:
1. INTRAHEPATIC: Originates from a diseased liver (CA, cirrhosis; inability to make bile)
- EXTRA-HEPATIC: Caused by a bile obstruction (GB stone, bile duct stenosis, pancreatic CA)
- HEMATOLOGIC: RBCs are broken down so quickly that the liver is unable to keep up with the amount of bilirubin to be conjugated
Stomach CA
Decreasing incidence in the U.S.; diagnosed by endoscopy with biopsy
Risk factors: Smoked fish/meats, pickled vegetables, nitrosamines, benzopyrene, decreased fruit/vegetable intake, H. pylori, chronic gastritis, and smoking
S/S: Asymptomatic until late in course (90% of patients); Weight loss, anorexia, epigastric pain that mimics peptic ulcers, early satiety, and occult bleeding with iron-deficient anemia
Colon CA
Common tumor involving multiple mutations that affect the APC gene, K-ras oncogene, and P53 gene
Risk factors: Diet (low fiber, low fruits/vegetables, high red meat/animal fat), colon polyps (often benign), colon disease (ulcerative colitis)
S/S: Asymptomatic in early stages; Rectal bleeding, blood in stool, change in bowel habits
Screening (after 50 y/o): Annual occult blood test or colonoscopy
Pancreatic CA (exocrine)
Exocrine pancreatic CA (adenocarcinoma) is more common; meanwhile, endocrine pancreatic CA (i.e. insulinomas) are much more rare, rarely metastasize, and tend to have higher survival rate
Risk factors: Smoking, older age, males, obesity, DM, environmental toxin exposure
S/S: Weight loss and malaise
Low-survival rate: Stage 1A (14%), stage 4 (1%)
