Disorders of the Small Bowel

Question 1

Diarrhea

Answer 1

Increased frequency or volume of stool
-3 or > liquid or semi-solid stools qd for at least 2-3 consecutive days

Acute diarrhea: ≤ 14 days duration
Persistent diarrhea: > 14 days duration
Chronic diarrhea: > 30 days duration

Question 2

Causes of Diarrhea

Answer 2

1. Infectious
A. Most cases of acute diarrhea due infections w/virus or bacteria → self-limited
2. Bacterial Toxins
3. Dietary
-Laxative use
4. Other GI disease
-HIV
5. Noninfectious etiology more common as diarrhea persists & becomes chronic

Question 3

Acute infectious diarrhea: Viruses and bacteria and protozoa

Answer 3

Viruses 
Norovirus
Rotavirus
Adenoviruses 
Astrovirus 
 
Bacteria 
Salmonella
Campylobacter 
Shigella 
Enterotoxic E. coli 
C. difficile  
 
Protozoa
Cryptosporidium
Giardia
Cyclospora
Entamoeba

Question 4

Secretory Diarrhea

Answer 4

Large volumes w/out inflammation
Indicative of:
-Pancreatic insufficiency
-Ingestion of bacterial toxins
-Laxative use

Question 5

Inflammatory Diarrhea

Answer 5

A. Bloody diarrhea w/out fever
B. Indicative of:
-Invasive organisms
(Salmonella, Shigella, Campylobacter (3 most common US))
-Inflammatory bowel disease (IBD)
Crohn’s Dz
Ulcerative Colitis

Question 6

Antibiotic Associated Diarrhea

Answer 6

1. Pseudomembranous colitis

A. Primary organism Clostridium difficile

Question 7

Diagnostic Studies : Diarrhea

Answer 7

1. Stool WBC’s
A. Inflammatory process
2. Stool C&S
A. Identifies bacterial pathogens
3. Stool O&P 
A. Microscopy
B. Identifies parasites
-Diarrhea > 10 days
-Recent travel to endemic region
-Community water borne outbreak
4. Toxin identification
A. Used to identify enterotoxic E. coli or C. difficile

Question 8

Indications for Diagnostic Studies :Diarrhea

Answer 8

• Diarrhea > 7 days
• Fever > 38.5°C (101.3°F)
• Bloody diarrhea
• Abd pain
• IBD
• Profuse watery diarrhea w/dehydration
• Frail or elderly
• Immunocompromised
• Hospital acquired diarrhea
• Systemic illness w/diarrhea, especially pregnant women (R/O listeriosis)
• Food handlers

Question 9

Listeriosis in Pregnancy : What is it?

Answer 9

1. Listeria monocytogenes
   A. Bacteria inwater & soil
   B. Found in uncooked meats & vegetables, unpasteurized milk, & processed foods* (hot dogs & deli meats)
   -*Contamination may occur aftercooking & before packaging

Incubation 2-30 days

Question 10

Listeriosis in Pregnancy : Sx’s

Answer 10

• Mild flu-like symptoms, headaches, myalgias,fever, N/V
• Can cause meningitis, endocarditis, bacteremia, brain abscess, osteomyelitis
• Most common 3rd trimester

Question 11

Listeriosis in Pregnancy: Complications

Answer 11

• Miscarriage
• Prematuredelivery
• Infection to newborn
• Death to newborn

Question 12

Diarrhea Treatment

Answer 12

1. Supportive therapy
   A. Hydration- (water, salt, sugar)
2. BRAT diet
   A. Rest bowel
3. Antidiarrheal
   A. Loperamide (Imodium)
   -Acute diarrhea w/o fever or hematochezia
4. Antibiotics
   A. Empiric Tx for moderate to severe travelers’ diarrhea
   B. Elderly
   C. (+) signs & sx’s of invasive bacterial diarrhea such as fever and bloody diarrhea
   D. NO antibiotic Tx w/enterohemorrhagic E. coli (unless severe)

Question 13

Antibiotic Therapy

Answer 13

1. Shigella
   - Fluoroquinolone (Cipro 500 mg po bid x 7 days)
2. Campylobacter
   - Fluoroquinolone (Cipro 500 mg po bid x 7 days)
3. C. difficile
   - Metronidazole 500 mg po tid x 10-14 days
4. Giardia
   - Metronidazole 250 mg po tid x 10 days
5. Listeria
   - 1st line: ampicillin ≥ 6 g/d IV 7–14 d; if fetus survives, longer Tx
   - 2nd line: erythromycin 4 g/d IV, 7–14 d; if fetus survives, longer Tx

Question 14

Malabsorption

Answer 14

1. May involve a single nutrient, enzyme deficiency, or global
   A. Pernicious anemia – Vit B12 def
   B. Lactase deficiency – inability to digest lactose products
   C. Celiac disease

Question 15

Causes for Malabsorption

Answer 15

• Digestion problem
• Absorption problem
• Impaired blood flow & lymph flow

Question 16

Malabsorption: Signs & Sx’s

Answer 16

1. Most common
A. Diarrhea
-Usually 1° complaint
B. Bloating
C. Abd pain

2. Less common
A. Weight loss
B. Steatorrhea
-Large, greasy, foul smelling stools
3. Specific deficiencies can cause:
-Bone demineralization
-Bleeding
-Anemia

Question 17

Diagnostic Studies : Malabsorption

Answer 17

1. Fecal fat test
2. D-Xylose Absorption test (Monosaccharide) 25 g po
   

Question 18

Fecal Fat Test

Answer 18

1. Measures fat content in stool
   a. If (+) fat in stool → not digested or absorbed

b. If 72 hr fecal fat test is normal
- R/O pancreatic insufficiency
- R/O abnormal bile salt metabolism

Question 19

D-Xylose Absorption test

Answer 19

1. Now redundant due to Ab tests
2. Does not require enzyme (amylase) for digestion prior to absorption
3. Result determined by absorptive function of small intestine
   a. Normal=Urine D-Xylose 4.5 g in 5 hr
   b. Abnormal < 4.5 g in 5 hr

Question 20

What is Polymerase chain reaction (PCR) based assay?

Answer 20

a. DNA sequencing test
b. PCR of saliva, gastric, intestinal fluid, stool are highly sensitive, but not specific (use like D-Dimer to R/O bacteria)
c. (-) PCR=healthy

EGD w/duodenal Bx to detect bacteria

Question 21

Treatment: Malabsorption

Answer 21

1. Lactase deficiency
   a. Lactose free diet
2. Celiac disease
   a. Gluten free diet
3. Pancreatic insufficiency
   a. Pancreatic enzyme replacement
4. Pseudomembranous colitis
   a. Metronidazole 500 mg po bid x 10-14 days

Question 22

General Characteristics : Celiac Disease

Answer 22

1. Permanent dietary disorder caused by immunologic response to gliadin (gluten protein)
   a. Storage protein found in certain grains
   - Wheat, barley, rye, sometimes oats
2. Characterized by mucosal inflammation, villous atrophy & crypt hyperplasia
3. Results in diffuse damage to proximal small intestinal mucosa –> malabsorption of nutrients

Question 23

Epidemiology & Etiology : Celiac Disease

Answer 23

1. Most cases undiagnosed
2. More prevalent in Northern Europeans
3. May be genetic
   a. HLA-DQ2 or HLA-DQ8
4. Immunologic
   a. T-cell mediated response in intestinal mucosa
   b. B-cell response
   - Ab to gluten

Question 24

Celiac Disease: Signs & Sx’s

Answer 24

1. Classic sx’s
   - Diarrhea
   - Steatorrhea
   - Weight loss
   - Abd pain
   - Distention
   - Weakness
   - Muscle wasting
2. Atypical sx’s
   a. Fatigue
   b. Depression
   c. Iron def anemia
   d. Osteoporosis
   e. Amenorrhea
   f. Dermatitis herpetiformis
   - Pruritic papules & vesicles occurring in groups
   (Elbows, dorsal forearms, knees, scalp, back, & buttocks)

Question 25

Diagnostic Studies: Celiac Disease

Answer 25

1. Serologic tests a. > 90% sensitivity & > 95% specificity - IgA endomysial Ab - IgA tTG Ab b. (-) test excludes celiac disease c. False (-) & (+) Ab undetectable after 6-12 mo gluten free diet 2. Mucosal tissue Bx of distal duodenum or proximal jejunum a. Gold standard for Dx b. Done if - (+) serology to confirm Dx - (-) serology w/high suspicion

Question 26

Differential Dx: Celiac Disease

Answer 26

1. IBS 2. Bacterial overgrowth - Pseudomembranous colitis - Whipple’s Dz 3. Lactose intolerance

Question 27

Treatment: Celiac Disease

Answer 27

1. Gluten free diet 2. Dietary guides 3. Support groups 4. Lactose free diet a. Many pts with celiac disease have co-existing lactose intolerance 5. Dietary supplements early in disease - Iron, folate, Ca, Vit A, B12, D, E

Question 28

Prognosis: Celiac Disease

Answer 28

- Excellent prognosis with Dx & Tx - Most common cause recurrent sx’s is dietary noncompliance - Celiac disease refractory to dietary management may be result of intestinal T cell lymphoma