Disorders of the Small Bowel Flashcards Preview

Gen Med: GI > Disorders of the Small Bowel > Flashcards

Flashcards in Disorders of the Small Bowel Deck (28):
1

Diarrhea

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

2

Causes of Diarrhea

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

3

Acute infectious diarrhea: Viruses and bacteria and protozoa

Viruses
Norovirus
Rotavirus
Adenoviruses
Astrovirus

Bacteria
Salmonella
Campylobacter
Shigella
Enterotoxic E. coli
C. difficile

Protozoa
Cryptosporidium
Giardia
Cyclospora
Entamoeba

4

Secretory Diarrhea

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

5

Inflammatory Diarrhea

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

6

Antibiotic Associated Diarrhea

1. Pseudomembranous colitis
A. Primary organism Clostridium difficile

7

Diagnostic Studies: Diarrhea

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

8

Indications for Diagnostic Studies:Diarrhea

-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

9

Listeriosis in Pregnancy: What is it?

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

Incubation 2-30 days

10

Listeriosis in Pregnancy: Sx's

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

11

Listeriosis in Pregnancy: Complications

-Miscarriage
-Premature delivery
-Infection to newborn
-Death to newborn

12

Diarrhea Treatment

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)

13

Antibiotic Therapy

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

14

Malabsorption

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

15

Causes for Malabsorption

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

16

Malabsorption: Signs & Sx’s

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

17

Diagnostic Studies: Malabsorption

1. Fecal fat test
2. D-Xylose Absorption test (Monosaccharide) 25 g po
3. Differentiates maldigestion vs malabsorption
a. Maldigestion=pancreatic insufficiency or bile salt deficiency or bacterial* overgrowth
-*Whipple’s Dz-responds to antibx
b. Malabsorption=Celiac Dz
4. Polymerase chain reaction (PCR) based assay
5. CBC & vitamin assays
a. Vit B12 def
6. Hydrogen breath test
a. Used to diagnose lactase deficiency
-After ingesting 50 g lactose, ↑ breath hydrogen > 20 ppm w/in 90 min = (+) test

18

Fecal Fat Test

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

19


D-Xylose Absorption test

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

20

What is Polymerase chain reaction (PCR) based assay?

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

21

Treatment: Malabsorption

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

22

General Characteristics: Celiac Disease

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

23

Epidemiology & Etiology: Celiac Disease

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

24

Celiac Disease: Signs & Sx's

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)

25

Diagnostic Studies: Celiac Disease

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

26

Differential Dx: Celiac Disease

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

27

Treatment: Celiac Disease

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

28

Prognosis: Celiac Disease

-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