2. Objectives List and describe the 3 phases of normal digestion and absorption. Discuss the normal process of digestion and absorption including anatomical locations of absorption for: Vitamins Carbohydrates Fats Protein
3. Objectives Define malabsorption Describe the following in terms of etiology, epidemiology, risk factors, signs and symptoms, diagnostic work-up, treatment, and complications: Celiac disease Whipple’s Bacterial overgrowth Compare and contrast the causes of short bowel syndrome, and discuss the resulting malabsorptions from each cause. Describe lactase deficiency in terms of etiology, epidemiology, risk factors, signs and symptoms, diagnostic work-up, and treatment.
4. Normal Digestion Functions of intestinal epithelium Nutrient digestion and absorption Barrier and immune defense Fluid and electrolyte balance Production of proteins, amines, and peptides
5. Normal Digestion Three phases of digestion Intraluminal phase (digestive) Dietary fats, proteins and carbohydrates are hydrolyzed and solubilized by pancreatic and biliary secretion Mucosal phase (absorptive) Occurs in small intestine by brush border enzymes Delivery phase (post-absorptive) Dysfunction in this stage can lead to significant protein losses
6. Malabsorption Disruption of digestion and nutrient absorption Signs and symptoms Steatorrhea Diarrhea Weight loss, malnutrition Iron deficiency anemia/megaloblastic anemia
7. Malabsorption Signs and symptoms Bone pain and fractures Paresthesia and tetany Bleeding problems Edema Milk intolerance Nocturia; abdominal distention
8. Malabsorption Diagnostic testing Labs – CBC, PT, alkphos, CMP, folate, B12, iron, amylase, lipase Fecal fat Upper endoscopy with biopsy Barium study of the small bowel
9. Celiac Disease AKA celiac sprue Permanent dietary disorder caused by an immunologic response to gluten The disease is present in 1:100 caucasians of Northern European descent Only 60% of those will have symptoms
10. Celiac Disease Symptoms Children < 2 years Chronic diarrhea, steatorrhea, weight loss, abdominal distention, weakness, muscle wasting or growth retardation Children >2 years and adults Chronic diarrhea, dyspepsia, or flatulence +/- weight loss Many have no GI symptoms but present with fatigue, depression, Fe def anemia, osteoporosis, short stature, delayed puberty or reduced fertility
12. Celiac Disease Signs PE may be normal Malabsorption signs – loss of muscle mass or subcutaneous fat, pallor, easy bruising (vit K def), bone pain or neurologic signs (vit B12 or E def) Abdominal exam – may reveal distention with hyperactive bowel sounds
13. Celiac Disease Dermatitis herpetiformis a cutaneous form of celiac disease Pruriticpapulovesicles over the extensor surfaces of the extremities and over the trunk, scalp and neck Occurs in <10% of patients with celiac disease
15. Celiac Disease Laboratory findings Microcytic anemia or megaloblastic anemia on CBC Low calcium or elevated alkphos Increased prothrombin time Specific tests Stool for fecal fat Serologic tests for celiac disease IgAendomysial antibody and IgAtTG antibody
16. Celiac Disease Special tests (cont’d) Endoscopic mucosal biopsy of the distal duodenum or proximal jejunum Confirms the diagnosis in pt with positive serologic tests Differential diagnosis IBS Bacterial overgrowth Lactose intolerance
17. Celiac Disease Treatment Gluten-free diet (wheat, rye, barley) Clinical improvement on gluten-free diet after a few weeks Dietary supplements (folate, iron, Ca, Vit A, B12, D and E) should be provided in the initial stages of therapy Prognosis – excellent once diagnosed
18. Whipple’s Disease Rare multisystemic illness caused by infection with the bacillus Tropherymawhippelii Commonly affects white men 30 – 50 years old Source of infection is unknown Will not spread human-to-human
19. Whipple’s Disease Symptoms Weight loss (most common presenting symptom) Arthalgias or migratory non-deforming arthritis GI symptoms – abdominal pain, diarrhea, malabsorption, flatulence, steatorrhea Intermittent low-grade fever Signs Enteric protein loss with edema and hypoalbuminemia Generalized LAD Enlarged and warm peripheral joints
20. Whipple’s Disease Signs (cont’d) Ocular symptoms (uveitis, retinitis, etc.) Congestive heart failure or valvular regurgitation Diagnostic studies Labs may show malabsorption Diagnosis is made by endoscopic biopsy of the duodenum showing the Whipple bacillus
21. Whipple’s Disease Differential diagnosis Other malabsorptive conditions FUO Celiac sprue Mycobacterium avium complex (MAC) infection Sarcoidosis and other autoimmune diseases
22. Whipple’s Disease Treatment Antibiotic therapy for at least one year IV Rocephin (ceftriaxone) 2 g daily for 2 weeks Bactrim DS (TMP-SMX) 1 po bid for 1 year Doxycycline if allergic to sulfa Prognosis Fatal if untreated Patients must be followed closely for recurrence
23. Bacterial Overgrowth Overgrowth damages mucosa of small intestine and interferes with absorption Causes of overgrowth Gastric achlorhydria Anatomic abnormalities with stagnation Motility disorders Gastrocolic or coloenteric fistula
24. Bacterial Overgrowth Signs and symptoms Most patients are asymptomatic S/S of malabsorption – distention, weight loss and steatorrhea or watery diarrhea Diagnostic testing Fecal fat Aspiration and culture of proximal jejunum secretions (invasive) Lactose breath test (noninvasive)
25. Bacterial Overgrowth Treatment Correction of anatomic defect if needed Broad-spectrum antibiotics for 1-2 weeks Cipro 500 mg PO bid Amoxicillin clavulanate 875 mg PO bid May need cyclic antibiotic therapy (1 week out of every 4 weeks)
26. Short Bowel Syndrome Malabsorptive condition that arises secondary to removal of significant segments of small intestine Crohn’s disease Mesenteric infarction Trauma Radiation enteritis Tumor resection Trauma Can usually tolerate resection of 40-50% of the small intestine
27. Short Bowel Syndrome Terminal ileum resection Malabsorption of bile salts and B12 Treatment is low-fat diet, cholestyramine, and vitamins Extensive small bowel resection Weight loss and diarrhea Treatment Parenteral vitamin and mineral supplementation Lperamide – slows transit and reduces diarrheal volume TPN in most severe cases
28. Lactase Deficiency Lactase is a brush border enzyme that hydolyzes lactose into glucose and galactose Lactase enzyme levels decline with age in most people of non-European ancestry 50 million Americans 95% of Native Americans 90% of Asian Americans 70% of African Americans 60% of Jewish Americans 50% of Mexican Americans <25% Caucasian Americans
29. Lactase Deficiency Foods high in lactose Milk (12g/cup) Ice cream (9g/cup) Cottage cheese (8g/cup) Aged cheeses (0.5g/cup)
30. Lactase Deficiency Signs and symptoms Vary with severity of deficiency and amount of lactose ingested Most can drink one or two 8 oz glasses of mild daily without symptoms, if taken with food and at wide intervals Bloating, abdominal cramps, flatulence and diarrhea after lactose ingestion No weight loss Laboratory findings Hydrogen breath test
