Transcript Slide 1

DIARRHEA
WHAT TO ORDER
Criteria for Conducting Stool Studies:
 Perform a complete history which includes the
following:
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Travel history
Sexual practices
Antibiotics in the past 2 months or usage any other
medications
Attendance of large group gatherings where others
have become ill with same symptoms
Recent surgeries or procedures
Recent meals
Water source
Pets (high risk are snakes, turtles)
Onset and duration of illness
Criteria for Conducting Stool Studies:
 Does the patient have the following:
 Fever >101.3 F
 Bloody stools
 Symptoms of dehydration
 Worsening diarrhea after 48 hours
 Six or more stool samples in 24 hours
 Advanced age (>70 years of age)
 Compromised immune system
 Age greater than 50 with severe abdominal
pain
DIARRHEA
 Definition:
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To most patients, diarrhea means an
increased frequency and/or decreased
consistency of bowel movements.
Diarrhea
 Diarrhea occurs because more fluid passes
through the large intestine than can be
absorbed.
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Caused by:
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Infections or illnesses
 Excess production of fluids
 Inability to absorb fluids
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Certain substances in the colon, such as fats and
bile acids
 Interfere with water absorption
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Rapid passage of material through the colon
Diarrhea Cont…
 Diarrhea can be classified as:
 Acute, which lasts one or two weeks
 Chronic, which continues for longer than 2 or 3 weeks.
 The most common causes of acute diarrhea are:
 Infections (viral or bacterial)
 Food poisoning
 Frequently overlooked:
 Medications especially antibiotics, antacids, laxatives
 various sugar free foods
 sometimes contain poorly absorbable materials
Causes of Acute Diarrhea
 Bacterial Infection
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Indications for stool culture:
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Bloody diarrhea
Fever
Tenesmus
Persistent or severe symptoms
Recent travel to a third world country
Known exposure to bacterial agent
Presence of fecal leukocytes
Stool Culture
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Campylobacter, Salmonella, Shigella, E. coli
0157:H7
Coming soon: Shiga toxins
Causes of Acute Diarrhea
 Shiga toxin
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Produced by enterohemorrhagic E. coli strains
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Shiga toxin 1 (ST1) and Shiga toxin 2 (ST2)
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Most famous serotype is O157:H7
Others include O26, O103, O111, O145
Only one may be present, or both
CDC recommendation
Causes of Acute Diarrhea
 Yersinia Culture
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Not included in routine stool culture
Primarily affects young adults and immunocompromised individuals
Indicators for Yersinia culture
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Exposure to contaminated pork, milk, water, tofu
Exposure to contaminated blood via blood transfusions
Sheds for 90 days after symptoms are resolved
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Early detection key in prevention of transmission and outbreaks
Causes of Acute Diarrhea Cont…
Bacterial cont….
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CDA Toxin (caused by Clostridium difficle)
 10x more likely to affect >65 year olds than
any other age group
 Indicators
 Extended hospital or nursing home stay post
treatment with antibiotics accompanied with the
following:
 Watery diarrhea (>3 times a day for >3
days)
 Fever
 Severe abdominal cramps/pain
 Presence of fecal blood
 C. difficile toxin (CDA)
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Most often diarrhea is caused by antibiotics or
nosocomial infection
Rapid kits test for toxin A and toxin B
Do not order C. difficile culture
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Test of cure is NOT a negative toxin assay
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Not all strains of C. difficile produce toxin
Toxin is shed for period of time after diarrhea is
resolved
Hard, non liquid stool will be rejected
Causes of Acute Diarrhea Cont…
 Viral Infection
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Rotavirus
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Most common cause of viral diarrhea in infants
and young children (up to 3 years of age)
May affect all ages, especially the elderly and the
immunocompromised
Extremely contagious
Indications for performing test:
 Fever >101 F
 Vomiting
 Watery stools lasting 5 to 7 days
Causes of Acute Diarrhea Cont…
 Parasitic Infection
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Giardia/Cryptosporidium Screen
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Giardia and Cryptosporidium are the most
common causes of diarrhea
Indicators
 Exposure to contaminated water, food, or soil
 Acute, watery diarrhea accompanied with
 Excess gas
 Stomach/abdominal pain
 Nausea
Chronic Diarrhea
 Chronic diarrhea is frequently due to many of the same things
(infections, medications, etc.); symptoms just last longer.
 Parasitic Infections
 AIDS
 colon cancer and other bowel tumors
 endocrine or hormonal abnormalities (thyroid, diabetes
mellitus, etc.)
 food allergy
 inflammatory bowel disease (Crohn's disease and ulcerative
colitis)
 lactose intolerance
 malabsorption syndromes (celiac and Whipple's disease)
 other (alcohol, microscopic colitis, radiation, surgery)
Chronic Diarrhea Cont…
 Parasitic Infection
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Ova and Parasite
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3 samples over 10 day period recommended
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Indicators for ordering
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Suspected parasitic infection
Prolonged diarrhea with unknown origin
Diarrhea with few leukocytes present
Immunocompromised individuals
History of foreign travel or travel to mountainous areas
of North America
 Children in daycare
 Not typically indicated for acute diarrhea
Causes of Chronic Diarrhea Cont…
 Ova and Parasite Cont…
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Test includes:
 Fecal Concentration Exam,
 Fecal Trichrome Stain:
 Giardia/Cryptospiridium Antigen Assay
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Does not include exam for:
 Cyclospora, Isospora
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Most common in our area is Giardia
 History is extremely important
Complete Stool Exam
 At Salina Regional, Complete Stool Exam
includes:
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Stool Color & Consistency
Presence of gross blood
Occult blood
Stool pH
Giardia/Cryptosporidium antigen assays
Presence of charcot-leydon crystals, meat
fibers, neutral fat, split fat, RBCs, & WBCs
Wet mount exam for parasites
Complete Stool Exam Cont…
Tests not included:
 C. Diff Toxin (CDA) or Culture
 Stool Culture
 Yesinia Culture
 O&P
 Reducing substances
Occult Blood and/or Fecal RBC
 Occult Blood vs. Fecal RBC
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Occult Blood: Detects hemoglobin in stool
Fecal RBC: Tests for intact RBCs in stool
 Associated with:
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Gastrointestinal bleeding
Hemorrhoids
Colon cancer
Ulcers
Parasitic infections
Celiac Disease, Crohns Disease
Fecal pH
 Results vary with specific age groups
 7-7.5 for adults and children
 5-7 for neonates
 Acidic stools are typically associated with the following:
 Carbohydrate intolerance, such as lactose intolerances
 Fat malabsorbtion
 E. coli infections
 Rotavirus infections
 Strongly alkaline stools may indicate cholerheic
enteropathy
Fecal WBC
 Evaluates acute, inflammatory cause of diarrhea
 Indicates need for a stool culture
Fecal Meat Fibers
 Indicator of malabsorption and pancreatic
insufficiency
Charcot-Leyden Crystals
 What are they?
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Crystals found in stool that result from
an enzyme released by damaged
eosinophil cells which are present due
to an allergy or parasitic infection.
 Diagnostic uses
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Indicator of possible parasitic infection
Other inflammatory or allergic
condition such as eosinophilic
gastroenteritis
Complete Stool Exam w/Ova and
Parasite
 Includes all tests found in a complete stool
exam plus the following:
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Fecal Concentration
Fecal Trichrome Stain
Qualitative Fecal Fat
 Steatorrhea
 Possible biological causes
 Olestra: not since 2003
 Orlistat
 Patient preparation:
 Patient should not use suppositories, mineral oils, or
any other oil based products before collection of
sample.
 Patient should also avoid taking castor oil, bismuth,
Metamucil and oily salad dressings for 1 week prior to
testing.
Qualitative Fecal Fat Cont….
 Test Includes:
 Neutral Fecal Fat
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Positive results indicate:
 Deficiency of pancreatic enzymes
 Small bowel disease
 Aids in diagnosis of malabsorption and/or
maldigestion
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Split Fecal Fat
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Positive results indicate:
 Impaired bile secretion
 Inadequate adsorption of nutrients
Fecal Reducing Substance
 Test is not performed at SRHC
 sent out to Labcorp of America
 Reference Range:
 Normal: <0.25 g/dL
 Trace: 0.25-0.50 g/dL
 Increased: >0.50 g/dL
 Use: Detect malabsorption of primarily
sucrase and lactase
Total cost of testing
 Complete stool exam
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$600.40
 Complete stool exam with Ova and Parasite
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$828.70
 How much will insurance pay?
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Depends on insurance and diagnosis
 What if patient has no insurance?
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Payment is usually patient’s responsibility
Laboratory recommendations
 A complete stool exam is not indicated in
every instance of diarrhea
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Pick and choose what tests are necessary
when dealing with acute diarrhea based on
patient history
Often see orders for CDA, WBC, culture
 Do not order C. difficile culture
 Tell the outpatient to disregard orders for
stool testing if he/she no longer has diarrhea