Specific malabsorption disorders

Question 1

celiac disease

Answer 1

-autoimmune response to gluten -> not an allergy
-Permanent dietary disorder caused by an immunologic response to gluten
-gluten- protein component to carbohydrates
-barely, rye, wheat- triticeae tribe (be careful with oats bc closely related)
-Diffuse damage to the proximal small intestinal mucosa with malabsorption of nutrients
-Can present in childhood or adulthood*
-Disease is present in 1:100 whites of Northern European ancestry (common)
-Frequent intrafamilial occurrence
-Close association with the HLA-DQ2 and/or DQ8 gene loci
-Current understanding of celiac disease:
-An autoimmune disorder TRIGGERED by an environmental agent (the gliadin component of gluten) in genetically predisposed individuals (HLA-DQ2 and/or DQ8 positive)
-Glutens are hydrolyzed to glutamines and further deamainated to glutamic residues which bind with HLA-DQ2 and/or DQ8 molecules leading to destruction of enterocytes and cells of small bowel and humoral immune response

Question 2

signs and symptoms of celiac disease

Answer 2

-Classic celiac disease
-can be latent or not as active in younger -> can present when older
-can be asymptomatic
-Diarrhea and/or signs and symptoms of malabsorption (eg, steatorrhea, weight loss, or other signs of nutrient or fat soluble vitamin deficiency)
-Villous atrophy seen on EGD
-Atypical ds: minor GI symptoms but extraintestinal manifestations (osteoporosis, iron deficiency anemia, rashes)
-Asymptomatic: villous atrophy but no symptoms/signs-40%
-dermatitis herpetiformis- cutaneous variant, pruritic - not common

Question 3

physical examination

Answer 3

-Normal in mild cases
-May reveal signs of malabsorption
-loss of muscle mass or subcutaneous fat
-pallor
-anemia
-easy bruising
-hyperkeratosis
-bone pain
-neurologic signs - b12 malabsorption
-abdominal distention with hyperactive bowel sounds
-skin lesions- dermatitis herpetiformis

Question 4

differential diagnosis

Answer 4

-IBS
-Bacterial overgrowth
-Lactose intolerance
-Gastroenteritis
-Mucosal damage caused by acid hypersecretion associated with gastrinoma
-Pancreatic or biliary disaese

Question 5

why establish the dx of subclinical celiac disease

Answer 5

-40% are asymptomatic- why do we need to treat if there are no symptoms?
-Risk of malignancy
-osteoporosis
-iron deficiency anemia
-Presence of unsuspected nutritional deficiencies
-infertility
-Association with low-birth weight infants in affected mothers
-Risk of other autoimmune disorders

Question 6

serologic tests for celiac disease*****

Answer 6

-should be done for anyone with chronic diarrhea
-IgA endomysial (EMA) antibody* and IgA tissue transglutaminase (tTG) antibody*
- ≥ 90% sensitivity and ≥ 95% specificity - Negative test reliably excludes celiac disease
-Levels of all antibodies become undetectable after 6–12 months of dietary gluten withdrawal
-Genetic testing- if they are on a gluten free diet they will test neg for IgA -> must do (or if they dont produce IgA)
-**must also test IgA levels -> some pts dont produce and therefore wont have IgA antibodies -> would be a false neg

Question 7

routine laboratory tests- celiac

Answer 7

-Anemia - Limited proximal involvement (duodenum)
-Microcytic anemia (Iron)
-More extensive involvement -> Megaloblastic anemia (B12) -> neurologic symptoms
-Low calcium or elevated alkaline phosphatase (bone mineral issues) - Impaired calcium or vitamin D absorption
-Elevations of prothrombin time (vitamin k is problematic), or decreased vitamin A
-Low albumin
-iron deficiency anemia and osteoporosis/penia***

Question 8

endoscopic mucosal biopsy

Answer 8

-Distal duodenum or proximal jejunum - Atrophy or scalloping of the duodenal folds
-Histology reveals:
-many biopsies to do
-Loss or blunting of intestinal villi - diff levels of severity
-Hypertrophy of the intestinal crypts
-Extensive infiltration of the lamina propria with lymphocytes and plasma cells

Question 9

treatment for celiac disease

Answer 9

-Gluten Free Diet:
-All wheat, rye, and barley must be eliminated
-eliminate oats until the celiac panel is neg and then slowly add back in
-Gluten is found in foods, additives, medications
-Knowledgeable dietitian
-Replete deficiencies- Dexa scan
-Secondary lactose intolerance
-Pneumococcal vaccination
-Monitor
-Family testing
-treat deficiency- iron, vitamin b12, calcium, vitamin d

Question 10

celiac: prognosis and complications

Answer 10

-Excellent prognosis
-Associated with other autoimmune disorders:
-Addison’s disease, Graves’ disease, type 1 diabetes mellitus, myasthenia gravis, scleroderma, Sjögren’s syndrome, atrophic gastritis
-keep eye out

Question 11

Celiac disease that is truly refractory to gluten withdrawal:

Answer 11

-Poor prognosis
-May be caused by the development of enteropathy-associated T cell lymphoma
-Patients with refractory sprue who do not have intestinal T cell lymphoma (Rare):
-treat with Corticosteroids or
-Immunosuppression- Azathioprine or cyclosporine

Question 12

exocrine pancreatic insufficiency

Answer 12

-Common Causes: chronic pancreatitis; gastric, pancreatic, or small bowel resection; cystic fibrosis; duct obstruction, fatty replacement
-Symptoms: bloating, diarrhea
-Signs: none or weight loss, anemia
-Lab findings: none or iron deficiency, vitamin A, D, E or K deficiency
-DDX: celiac, lactose intol, SIBO, Giardia
-Dx: Fecal elastase (make sure not falsely diluted with urine)
-if + ->
-Imaging-MRI or CT: fatty replacement/atrophy of pancreas; calcifications, ductal dilatation, enlargement of the pancreas, or peripancreatic fluid collections
-Treatment: Pancreatic enzymes

Question 13

bacterial overgrowth

Answer 13

-Small intestine: a small number of bacteria
-Bacterial overgrowth in small intestine-> malabsorption:
-Bacterial deconjugation of bile salts
-Bacteria directly damage epithelial cells and brush border
-Microbial uptake of specific nutrients
-colon bacteria goes to small bowel or stomach

Question 14

Causes of Bacterial Overgrowth

Answer 14

-Gastric achlorhydria
-Anatomic abnormalities of the small intestine with stagnation
-Afferent limb of Billroth II, resection of ileocecal valve, small intestine diverticula, obstruction, blind loop
-Small intestine motility disorders - Scleroderma, diabetic enteropathy
-Gastrocolic or coloenteric fistula- Crohn’s disease, malignancy, surgical resection
-Miscellaneous disorders - AIDS, chronic pancreatitis

Question 15

clinical findings in Bacterial Overgrowth

Answer 15

-Many patients asymptomatic
-Bloating, gas, abdominal pain
-Severe overgrowth: malabsorption symptoms and signs (RARE):
-Distention, weight loss, and steatorrhea
-Watery diarrhea is common
-Megaloblastic anemia or neurologic signs
-Testing: *Noninvasive breath tests vs empiric tx

Question 16

treatment for bacterial overgrowth***

Answer 16

-Correct the anatomic defect
-Rifaximin 500 mg three times daily x 14 days
-Nonabsorbable antibiotic
-Cyclic therapy may be used
-Probiotics

Question 17

short bowel syndrome

Answer 17

-Malabsorptive condition that arises secondary to removal of significant segments of the small intestine.
-Most common causes in adults:
-Crohn’s disease
-Mesenteric infarction
-Radiation enteritis
-Volvulus
-Tumor resection
-Trauma

Question 18

lactase deficiency

Answer 18

-Lactase is a brush border enzyme- hydrolyzes the disaccharide lactose into glucose and galactose
-The concentration of lactase enzyme levels is high at birth.
-Declines steadily in most people of non-European ancestry
-Degree is genetically determined

Question 19

secondary lactase deficiency

Answer 19

-Crohn’s disease
-Celiac ds
-Gastroenteritis
-Short bowel syndrome
-Malabsorbed lactose is fermented by intestinal bacteria, producing gas and organic acids- Increased stool osmotic load and fluid loss

Question 20

lactase deficiency S&S

Answer 20

-Great variability in clinical symptoms
-Severity of deficiency
-Amount ingested
-Symptoms:
-Bloating, abdominal cramps, and flatulence
-Osmotic diarrhea will result with higher lactose intake

Question 21

lactase deficiency diff dx

Answer 21

Inflammatory bowel disease, mucosal malabsorptive disorders, irritable bowel syndrome, and pancreatic insufficiency

Question 22

lactase deficiency dx and tx

Answer 22

-Diagnosis:
-Hydrogen breath test
-Blood test
-Bx
-Empiric trial- lactaid pills

-Treatment
-Lactaid
-Patient comfort is the goal
-Calcium and vitamin D

Question 23

tumors of small bowel

Answer 23

-Benign and malignant tumors-rare
-Often incidental finding and no symptoms/signs
-May cause acute or chronic gi bleed
-May cause obstruction
-Usually ID CT Scan or Small Bowel Series-Require bx
-Most are single
-Multiple polyps suggestive of hereditary polyposis syndrome
-With the exception of lipomas, surgical or endoscopic excision usually is recommended

Question 24

benign tumors of small bowel

Answer 24

-Adenomatous polyps-most common:
Majority asymptomatic +/- bleeding
Endoscopic or surgical resection warranted

-Lipomas occur commonly in ileum:
Most asymptomatic, incidental finding
Rarely obstruction with intussusception

Question 25

gastrointestinal stromal tumors

Answer 25

-Begin within the autonomic system of the GI tract so can be anywhere
-Stomach mc, Small bowel 2nd
-Most are asymptomatic but can ulcerate and cause acute or chronic bleeding or obstruction
-Benign stromal tumors:
Submucosal
Intraluminal, intramural, or extraluminal

-Malignant stromal tumors:
-1% of GI tumors
-Type of soft tissue sarcoma

Question 26

malignant small bowel tumors: lymphoma

Answer 26

-Most commonly in distal small intestine
-Majority are non-Hodgkin’s intermediate or high-grade B cell lymphoma
-T cell lymphoma

Question 27

malignant small bowel tumors: carcinoid

Answer 27

-30% in small intestine, most commonly in ileum
-Indolent with slow spread