G19 - Disorders of the small bowel, malabsorption, and maldigestion Flashcards
What is maldigestion?
impaired digestion of nutrients
What is malabsorption?
- impaired intestinal absorption of nutrients
- imperfect digestion of nutrients leads to imperfect absorption
- maldigestion can lead to malabsorption
What is malabsorption syndrome?
it can be maldigestion and/or malabsorption
What is the role of salivary enzymes in digestion?
amylase to breakdwon complex carbohydrates
What is the role of stomach enzymes in digestion?
- pepsin to breakdown proteins
- intrinsic factor for B12 binding
What is the role of pancreatic enzymes in digestion?
- protein degradation: trypsin, chymotropsin, procaboxipeptidase, proelastase
- lipid degradation: lipase, phospholipase A, cholesterol esterase
- carbohydrate degradation: amylase, hydrolase
- nucleolytic degradation: ribonuclease, desoxyribonuclease
What is the role of bile enzymes in digestion?
there are no enzymes but micelle formation of fat
What is the role of intestinal brush border enzymes in digestion?
- disaccharide splitting: dextrinase, maltase, sucrase, lactase
- peptide degradation: aminopeptidase, dipeptidase
- nucleolytic degradation: nucleosidase, phosphatase
What are the classifications for malabsorption?
I. generalized or selective
II. innate or acquired
III. premucosal/luminal, mucosal or postmucosal
What are the causes of fat and fat soluble vitamin malabsorption?
- fat-soluble vitamins: A, D, E, K
- pancreatic enzyme insufficiency: maldigestion of fat
- bile acid insufficiency:
- impaired production
- increased loss that cannot be compensated (steatorrhea)
- increased loss that can be compensated by production (no malabsorption but diarrhea due to bile acids irritating the colon mucosa)
What are the causes of protein malabsorption?
pancreatic enzyme insufficiency and decreased surface area of absorption
What are the gastrointestinal symptoms of malabsorption?
- watery/fatty diarrhea (CH, fat)
- stinky stool (CH, fat)
- gasification (CH)
- stomach ache
- ascites (albumin↓)
What are the musculoskeletal symptoms of malabsorption?
- tetania (ionized Ca ↓)
- muscle weakness (↓ of Mg, Ca, Na, K, phosphate)
- paresthesia (↓ of Ca, Mg)
- bone pain (↓ of Ca, Vitamin D)
- osteomalacia (vitamin D ↓)
- bone fracture (↓ of Ca, vitamin D)
What are the skin and mucosal symptoms of malabsorption?
- vulnerability
- bleeding (↓ vitamin K/C)
- petechia ( ↓ vitamin K/C)
- glossitis (↓ B6, B12)
- cheilosis (↓ B2)
- oedema (↓ of protein and Vitamin B1)
- acrodermatitis (↓ Zn)
- follicular hyperkeratosis (↓ vitamin)
- hyperpigmented dermatitis (↓ B12)
- nail deformities (↓ vitamin A)
- perifollicular bleeding
- hair loss (↓ iron)
- hyperkeratosis (↓ niacin/vitamin B3)
What are some general symptoms of malabsorption?
- weight loss
- hyperphagia
- growth disturbance
- infantilism
- anemia
- kidney stone
- amenorrhea
- impotence
- infertility
- visual impairment
- xerophthalmia
- peripheral neuropathy
- fatigue
- neurological symptoms (ataxia)
What are the blood count abnormalities in malabsorption syndrome?
- MCV (↓ iron deficiency, ↑ B12 deficiency)
- MCHC (↓ iron deficiency)
- WBC ↓ (B12, folic acid deficiency)
- lymphopenia (lymphangiectasy, malnutrition)
