Download chronic diarrhea

CHRONIC DIARRHEA
Chronic Diarrhea
 Chronic diarrhea, defined as the production of loose
stools with or without increased stool frequency for more
than four weeks, is a common symptom that has a
prevalence in the United States of approximately 3 to 5
percent.
 Chronic diarrhea may be caused by any one of many
conditions.
 Correlation of data from history, physical examination,
laboratory tests, radiographic studies, and endoscopic
examinations usually results in an accurate diagnosis.
ETIOLOGY
Osmotic diarrhea
 Mg, PO4, SO4 ingestion
 Carbohydrate malabsorption
ETIOLOGY
Fatty diarrhea
 Malabsorption syndromes
Mucosal diseases
Short bowel syndrome
Postresection diarrhea
Small bowel bacterial overgrowth
Mesenteric ischemia
 Maldigestion
Pancreatic exocrine insufficiency
Inadequate luminal bile acid
Inflammatory diarrhea
 Inflammatory bowel disease
Ulcerative colitis
Crohn's disease
Diverticulitis
Ulcerative jejunoileitis
Inflammatory diarrhea
Infectious diseases
Pseudomembranous colitis
Invasive bacterial infections
Tuberculosis, yersinosis, others
Ulcerating viral infections
Cytomegalovirus
Herpes simplex
Amebiasis/other invasive parasites
Inflammatory diarrhea
 Ischemic colitis
 Radiation colitis
 Neoplasia
Colon cancer
Lymphoma
Secretory diarrhea






Laxative abuse (nonosmotic laxatives)
Post-cholecystectomy (from bile salts)
Congenital syndromes (chloridorrhea)
Bacterial toxins
Ileal bile acid malabsorption
Inflammatory bowel disease
Ulcerative colitis
Crohn's disease
Microscopic (lymphocytic) colitis
Collagenous colitis
Diverticulitis
 Vasculitis
 Drugs and poisons
Secretory diarrhea
 Disordered motility
Postvagotomy diarrhea
Postsympathectomy diarrhea
Diabetic autonomic neuropathy
Hyperthyroidism
Irritable bowel syndrome
Secretory diarrhea
 Neuroendocrine tumors
Gastrinoma
VIPoma
Somatostatinoma
Mastocytosis
Carcinoid syndrome
Medullary carcinoma of thyroid
Secretory diarrhea
 Neoplasia
Colon carcinoma
Lymphoma
Villous adenoma
 Addison's disease
 Epidemic secretory (Brainerd) diarrhea
 Idiopathic secretory diarrhea
HISTORY
 The characteristics of the onset of
diarrhea: Whether it was congenital,
abrupt, or gradual in onset.
 The pattern of diarrhea : continuous or
intermittent?
 The duration of symptoms should be
identified clearly.
HISTORY
 Travel before the onset of illness,
 Exposure to potentially contaminated
food or water,
 Illness in other family members should
be elicited.
 Stool characteristics: watery, bloody, or
fatty.
HISTORY
 Risk factors for HIV infection
 Weight loss
 Occurrence of diarrhea during fasting or
at night (suggesting a secretory
diarrhea)
 Family history of IBD
HISTORY
 The volume of the diarrhea
 The presence of systemic symptoms,
which may indicate inflammatory bowel
disease (such as fevers, joint pains,
mouth ulcers, eye redness)
 All medications (including over-the-
counter drugs and supplements)
HISTORY
 A relevant dietary (use of sorbitol-
containing products and use of alcohol)
 Association of symptoms with specific
food ingestion (such as dairy products or
potential food allergens)
 A sexual history
HISTORY
 The presence or absence of fecal
incontinence. Some individuals complain
of diarrhea when their major difficulty is
disordered continence.
PHYSICAL EXAMINATION
 Extent of fluid and nutritional
depletion
 Flushing or rashes on the skin
 Mouth ulcers
 Thyroid masses
 Wheezing
PHYSICAL EXAMINATION
 Arthritis
 Heart murmurs
 Hepatomegaly or abdominal masses
 Ascites, and edema
 Anorectal examination: sphincter tone
and contractility and the presence of
perianal fistula or abscess.
Differentiation of chronic diarrhea from irritable
bowel syndrome and fecal incontinence

IBS :combination of abdominal pain and
abnormal bowel habits (constipation, diarrhea,
or variable bowel movements) in the absence of
other defined illnesses .
 Patients with painless diarrhea may have a
functional process (i.e., without a known
organic cause) but should not be characterized
as having IBS.
CAUSES OF CHRONIC DIARRHEA IN
DEVELOPED CONTRIES
 IBS
 Idiopathic inflammatory bowel
disease
 Malabsorption syndrome
 Chronic infections
 Idiopathic secretory diarrhea (which
also may be a chronic, but
eventually self-limited, infection).
CAUSES OF CHRONIC DIARRHEA IN LESS
DEVELOPED CONTRIES
 Chronic bacterial
 Mycobacterial
 Parasitic infections
 are the most common causes of chronic
diarrhea;
 functional disorders, inflammatory bowel
disease, and malabsorption are also
common in this setting .
ROUTINE LABORATORY
TESTS
 Anemia.
 Leukocytosis suggests the presence of
inflammation
 Eosinophilia is seen with neoplasm, allergy,
collagen-vascular diseases, parasitic
infestation, and eosinophilic gastroenteritis or
colitis.
 Serum chemistry screening: fluid and
electrolyte status, nutritional status, liver
problems, and dysproteinemia.
SPOT STOOL ANALYSIS
 Occult blood
 White blood cells
 Sudan stain for fat
 Fecal cultures
 pH, electrolytes and minerals, and
laxatives
QUANTITATIVE STOOL
COLLECTION AND ANALYSIS
 General principles:Quantitative stool collection fixed diet








80 to 100 g of fat
Fecal weight
Electrolytes and calculation of an osmotic gap
Measured osmolality
Fecal pH
Fecal fat concentration and output
Tests for fecal carbohydrate
Analysis for laxative
Tests for protein-losing enteropathy
BLOOD AND URINE TESTS
 Analysis of urine. for laxative identification and for measurement
of excretion of 5-hydroxyindole acetic acid (for carcinoid
syndrome), vanillylmandelic acid (VMA); for
pheochromocytoma, metanephrine (for pheochromocytoma),
and histamine (for mast cell disease and foregut carcinoids).
 If volume depletion or hypokalemia are present, analysis of
urine electrolytes can determine whether renal conservation of
sodium and potassium is appropriate. If the urinary
concentration or output of sodium or potassium is
inappropriately high, surreptitious diuretic use may be present
and may suggest coexisting laxative abuse.
 Measurement of urine electrolytes and aldosterone may
distinguish hypervolemia from volume depletion in the setting of
hypernatremia caused by ingestion of sodium-containing
laxatives
Vasoactive intestinal polypeptide
and other peptide hormones
 Pancreatic cholera :secretory diarrhea
attributable to secretion of (VIP) by a
neuroendocrine tumor. It should be suspected if
diarrhea of unknown origin has lasted longer
than four weeks, has the clinical features of
secretory diarrhea, has a volume greater than 1
L/day, is associated with hypokalemia, and
causes clinically significant volume depletion.
 Measurement of calcitonin for the diagnosis of
medullary carcinoma of the thyroid, gastrin for
suspected Zollinger-Ellison syndrome, and
glucagon for the rare patient with a
glucagonoma .
Serological tests
 Antinuclear antibodies
 Antigliadin immunoglobulin Ig A and Ig G




antibodies and antiendomysial IgA antibodies
Perinuclear antineutrophil cytoplasmic
antibodies
HLA typing
Quantitation of serum immunoglobulin
concentrations
Antibodies to HIV and Entamoeba histolytica
ENDOSCOPIC EXAMINATION
AND MUCOSAL BIOPSY
 Sigmoidoscopy and colonoscopy
 Upper tract endoscopy
RADIOGRAPHY
 Barium radiography
 Mesenteric angiography
 Computed tomography
PHYSIOLOGICAL TESTS
 Mucosal absorption
 Tests of ileal absorptive function
 Breath tests for physiological testing
 Tests for bacterial overgrowth
TESTS FOR GASTROINTESTINAL
FOOD ALLERGY
 Allergy to food antigens may be the cause of
chronic diarrhea in some patients, but
documentation of this has been difficult.
 Reports have described detection of antibodies
to food in feces or small intestinal secretions.
 Serum antibody testing and skin testing are not
of proven value in detection of gastrointestinal
food allergies.
Role of empiric therapy
 A daycare worker who develops diarrhea after a known




outbreak of Giardiasis within the daycare,
a patient who develops diarrhea following limited (<100
cm) ileal resection in whom bile acid malabsorption is
likely,
A patient with known recurrent bacterial overgrowth
An otherwise healthy patient with suspected lactose
intolerance in whom relief of symptoms is observed
following a temporary trial of a lactose-free diet.
When comorbidities limit diagnostic evaluation.
SUMMARY AND
RECOMMENDATIONS
Optimal strategies for the evaluation of
patients with chronic diarrhea have not
been established.
The selection of specific tests, timing of
referral, and the extent to which testing
should be performed depend upon an
appraisal of the likelihood of a specific
diagnosis, the availability of treatment,
the severity of symptoms, patient
preference, and comorbidities
SUMMARY AND
RECOMMENDATIONS
 A thorough medical history include
findings suggestive of IBD (eg, mouth
ulcers, a skin rash, episcleritis, an anal
fissure or fistula
 The presence of visible or occult blood
on digital examination
 Abdominal masses or abdominal pain
 Evidence of malabsorption (such as
wasting, physical signs of anemia
SUMMARY AND
RECOMMENDATIONS
 Scars indicating prior abdominal surgery
 Lymphadenopathy (possibly suggesting HIV
infection)
 Abnormal anal sphincter pressure or reflexes
(possibly suggesting fecal incontinence).
 Palpation of the thyroid and examination for
exopthalmus and lid retraction may provide
support for a diagnosis of hyperthyroidism.
SUMMARY AND
RECOMMENDATIONS
 The history and physical examination
may point toward a specific diagnosis for
which testing may be indicated.
 As an example, serologic testing for
celiac disease would be appropriate in
patients with risk factors (such as type 1
diabetes mellitus or a family history of
celiac disease).
SUMMARY AND
RECOMMENDATIONS
 The minimum laboratory evaluation in most
patients should include a complete blood count
and differential, thyroid function tests, serum
electrolytes, total protein and albumin, and stool
occult blood.
 In addition, most patients require some form of
endoscopic evaluation (either sigmoidoscopy,
colonoscopy, or sometimes upper endoscopy)
depending upon the clinical setting.