Nutritional assessments and diagnosis of digestive disorders AASER ABDELAZIM Assistant professor of Medical Biochemistry Zagazig University, Egypt University of Bisha, KSA aaserabdelazim@yahoo.com 7
Mal nutrition: Definition: Its is a common problems among peoples in developed countries It may means starvation but it had a much wider meaning (both inadequacy in any nutrient in the diet as well as excess food intake). Mal nutrition can be resulted from exposing the body to injuries or in major surgical operations Consequence of mal nutrition: Decrease intake Loss of nutrients Decrease the nutrient store Specific metabolic and biochemical effects Clinical signs and symptoms 8
Assessment of mal nutrition: HISTORY EXAMNATION BIOCHEMICAL INVESTIGATIONS Change in weight Poor wound healing Exposed to heavy infections History of food and water intake over past 7 days. Asking about appetite Types of food intake Examine: Height Weight Arm circumference Skin-fold thickness Body mass index(bmi) BMI = BMI Weight (Kg) (Height)2 meters < 18.5 Underweight 18.5-24.9 Normal weight 25-29.9 Overweight > 29.9 Obese Nutritional state Proteins : but affected by other factors e.g. liver Blood glucose: low and ketosis in starvation Lipids: fasting plasma TGs Vitamins: Minerals: trace and major elements 9
Lab assessment of vitamins deficiency: Vitamin Deficiency state Lab assessments Water soluble Ascorbate Scurvy Plasma level Thiamine (B1) Beri-Beri Plasma level /Transketolase activity Riboflavin (B2) Rare single deficiency Plasma level /GRD activity Pyridoxine (B6) Dermatitis/anemia Plasma level/ast activity Cobalamine (B12) Pernicious anemia Serum B12/full blood count Folate Megaloblastic anemia Serum/blood folate/ CBC Niacin Pellagra Urinary niacin metabolites Fat soluble Vitamin A Blindness Serum vitamin A Vitamin D Osteomalcia /rickets Serum 25-hydroxychalciferol Vitamin E Anemia/ neuropathy Serum vitamin E Vitamin K Defective clotting Prothrombin time PT 10
It may ranges from simple dietary supplements to total parenteral nutrition (TPN) Spectrum of nutritional support: 11
Patients requirements of nutrients: (1) ENERGY: Principle Sources Of Energy: CARBOHYDRATES: (4 Kcal/g) LIPIDS: (9 Kcal/g) AMINO ACIDS: (4 Kcal/g) (2) NITROGEN: Amino acids provide nitrogen and also yield energy. Proteins should be 10-15 % of total calories requirements (3) VITAMINS AND TRACE ELEMENTS: They called micronutrients because they needed by minute amount. Recommended Dietary allowances (RDAs) postulate these requirements Harris-Benedict equation for energy need calculation 12
Average daily requirements of vitamins and essential trace elements/day: Average daily requirements of vitamins Average daily requirements of essential trace elements 13
Digestive system: Is a tube runs through the body. Its function is to prepare nutrients to be absorbed in to blood then transported to all tissues. Nutrients will be digested in oral cavity, stomach and intestine. Salivary, pancreatic and intestinal secretions aid in the digestive sate. 14
Digestive Disorders 15
MALABSORPTION Definition: Impairment of absorptive mechanism; it can be occurred at any stage of life form many causes. Resulting in weight loss in adults and growth failure in children. Causes and consequences of malabsorption: 16
Biochemical investigations of malabsorption Tests identify malabsorption Tests identify pancreatic functions 1. Fecal fats test 2. Fecal microscopy 3. butterfat test 1. Lundh test 2. Secretin test 3. pancreolauryl test 4. C14 triglycerides test 5. Xylose absorption test 17
Tests identify malabsorption: 1) Fecal fats: presence of fatty stool; measurement of total fats in five days collected stool. 2) Fecal microscopy: presence of fat globules 3) Butterfat test: presence of CM in patient blood after fat load indicates normal absorption 4) C14 triglycerides test: oral load of radio-labelled C14 triolein is absorbed and metabolized and C14 CO2 is measured in breath If present indicates normal digestion and absorption 5) Xylose absorption test: serum measure of xylose after oral load indicates normal absorption of monosaccharides. 18
Tests identify pancreatic functions: 1) Lundh test: collection of duodenal contents after meal and the activities of pancreatic trypsin and amylase were measured. 2) Secretin test: I/V injection of secretin lead to stimulation of pancreatic secretions which is assessed by measurement of pancreatic amylase and trypsin in duodenal contents. 3) Pancreolauryl test: flourescein dilaurate is hydrolyzed by cholesterol esterase in pancreatic secretions then the water soluble flourescein is absorbed and excreted in urine while its fluorescent color indicates Normal absorption. Normal pancreatic functions 19
Other biochemical tests investigate malabsorption and GIT diseases Test Purpose 1. Urea breath test Used to identify patients with helicobacter pylori which is strongly associated with peptic ulcer 2. Hydrogen breath test Assesses bacterial overgrowth in intestine 3. Lactose /sucrose Measure functions defects in disaccharidases like tolerance test lactase and sucrase. 4. Fecal chymotrypsin/ elastase 5. Intestinal permeability Used to measure of pancreatic functions mainly in cystic fibrosis. Biologically inert polymers are used to assess mucosal permeability by measuring their excretion in urine after oral load. 6. Schilling test Assess vitamin B12 absorption 20
GASTROINTESTINAL DISEASE Generalized malabsorption occurs due to a lot of gastrointestinal diseases include: Gastrointestinal disease Description (1) Inadequate digestion Seen in chronic pancreatitis due lack of pancreatic enzymes. (2) Inadequate intestinal mucosal surface Seen in coeliac disease (an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward. Symptoms include pain and discomfort in the digestive tract, chronic constipation and diarrhoea, failure to thrive (in children), anaemia and fatigue, but these may be absent. (3) Infections of bowel Affecting the mucosa and sub mucosa or entire bowel (4) Abnormal bowel anatomy (5) Insufficient bowel Occurs after removal of bowel in bowel infarction or repeat surgery for chronic bowel disorders (6) Malignant diseases Usually not associated except in cases associated of abnormal bowel motility or tumors secretes VIP 21
Other conditions associated with specific malabsorption Condition Inadequate bile salt secretion Vitamin B12 malabsorption Inherited deficiencies of intestinal saccharidases Effect Occurs in many types of liver diseases and give rise to fat malabsorption. Associated with Osteomalcia or rickets due to failure of vitamin D absorption. Condition associated with pernicious anemia due failure to secrete the intrinsic factor in gastric mucosal atrophy. Due to deficiency of some enzymes that digest disaccharides like lactase& sucrase (lactose/sucrose intolerance). 22
Gastrointestinal equations: Item Stool osmolal gap Fractional excretion of amylase Equation / description Stool osmolar (2xNa+K) > 100 osmotic diarrhea < 100 Secretory diarrhea 100 x (urine amylase) x (plasma creatinine) / (plasma amylase) x (urine creatinine) >5% acute pancreatitis < 1% macro amalyasemia 23