Required Knowledge base to manage patients
with Chronic Diarrhea
Dr A.J. Chandrasekhar
Normal stool
Normal bowel frequency ranges from three times a week three times a day
Weight 200 g/d
Definition for diarrhea
The definition of diarrhea is somewhat controversial. It depends on the patient’s as well as the physician’s perspective.
Patients usually consider diarrhea as being an increase in the daily frequency, liquidity, or volume of the stool.
Also an urgency to defecate.
Scientifically, diarrhea exists if more that 300 gms stool is passed daily on the Western diet.
Clinically, it may be defined as an increased number of stools/day.
Relative to what the patient’s “usual” habit has been.
It is important to take a good history
and ask appropriate questions regarding stooling. Don’t just accept the patient’s statement of diarrhea.
Pseudodiarrhea or hyper defecation
Increase in frequency without an increase in weight of the stool.
Irritable bowel syndrome
Proctitis
Hyperthyroidism
Fecal incontinence
Involuntary release of rectal contents
Classification of Diarrhea
Diarrhea lasting two weeks or less is considered to be Acute Diarrhea
Diarrhea lasting longer than two weeks or is intermittent over months or years is considered Chronic Diarrhea.
Acute Diarrhea
lasts two weeks or less
self-limited
requiring no diagnostic work-up
symptomatic treatment only (fluids)
Acute diarrhea should be investigated only if there is
evidence of tissue invasion such as blood or pus in the stool
fever
leukocytosis
severity that produces significant fluid and electrolyte loss
Chronic diarrhea
lasts longer than two weeks
or is intermittent over months or years
This form requires a diagnostic work-up and a treatment strategy
Questions to ask a patient with diarrhea
Compare the patient’s usual or normal frequency and pattern with that of the current pattern or frequency.
Ask about the characteristics
Watery, bulky, color, presence of blood or pus
Bulky greasy foul smelling stools : Intestinal malabsorption
Change in odor
Change in timing
Frequency, duration
Continuous, intermittent
Time of day or night
Diarrhea alternating with constipation : Irritable bowel syndrome, Cancer colon
Precipitating events such as food or drug
Causes of relief
Improves with fasting : Osmotic diarrhea
Ask about associated symptoms
Fever, nausea, vomiting, abdominal pain, anorexia: Inflammatory diarrhea
Symptoms of autonomic dysfunction: Diabetic diarrhea
Flatulence and bloating : Intestinal mucosal disease
Arthritis, skin lesions, ocular symptoms: Idiopathic inflammatory bowel disease
Edema, Ascites: Protein loosing enteropathy
Ask about predisposing factors such as travel, diet, drug history, family history, other medical surgical problems.
Physical findings you should look for in the evaluation of a patient with Chronic diarrhea
Consequences to diarrhea
Edema, Ascites / Protein loosing enteropathy
Signs of Vitamin deficiency of fat-soluble vitamins (A, D, E, K)./ Steatorrhea
Signs of hypovolemia and dehydration
Etiology of diarrhea
CNS disturbances / Altered motility
Signs of autonomic dysfunction / Diabetes
Arthritis, skin lesions, ocular signs: Idiopathic inflammatory bowel disease
Classification of the chronic diarrhea into subgroups:
Chronic diarrhea can be classified as follows:
Steatorrhea : Passage of stools containing an excessive amount of fat (>7 gm fecal fat/24 hrs or more than 10% of ingested fat)
Intraluminal stage
Deficiency of pancreatic enzymes/Chronic pancreatitis
Bacterial overgrowth in the small bowel/decreased motility in a diabetic
Deficient bile salts/biliary tract disease
Intestinal stage
Damage to the absorptive surface (mucosa)/Celiac disease
Removal stage
Damaged lymphatic channels/Whipple disease
Watery diarrhea
Osmotic diarrhea. A consequence of increased amounts of poorly absorbable, osmotically active solutes in the lumen of the intestine
Disaccharide deficiency/lactase deficiency
Ingestion of drugs such as laxatives and antacids containing magnesium or phosphate
Chewing gum (sorbitol)
Secretary diarrhea: Secretion of electrolytes and water exceed absorption or absorption of electrolytes and water are impaired
Certain laxatives/castor oil
Bacterial toxin/infection
Exudative Inflammation of the bowel mucosa may result in loss of pus, mucus, blood, protein
E. histolytica
Giardia
Intestinal dysmotility
Increased motility/hyperthyroidism
Delayed transit time with bacterial growth/ blind loop syndrome or diabetic neuropathy
Investigational options in the workup of patients with Chronic diarrhea, based on the knowledge of subgroups of chronic diarrhea ?
Stool
Blood and leukocytes in stool : Inflammatory diarrhea. Inflammatory colonic disease.
Fecal fat. Steatorrhea (>7 gm fecal fat/24 hrs)
Stool for ova and parasites
Stool for C/S
C. dificile toxin.
Malabsorption
Iron, folate, B12 : Malabsorption
Vitamin deficiency of fat-soluble vitamins (A, D, E, K).
Fecal fat. Steatorrhea (>7 gm fecal fat/24 hrs)
D-xylose absorption test
Bowel changes
EGD: Small intestine biopsy
Colonoscopy indicated if stool is negative for pathogens. Colonic mucosa may have to be looked at endoscopically and biopsied if inflammatory bowel disease is suspected.
D-xylose test
D-xylose test should be done when there is steatorrhea .
Helps distinguish steatorrhea due to Pancreatic disease from small bowel disease
Normal D-xylose indicates pancreatic disease.
Abnormal D-xylose indicates small bowel disease and small bowel biopsy is indicated.
>25% of ingested dose (25gm) in the 5 hr urine collection.
Understanding of the mechanism of the D-xylose test.
Diagnostic workup strategy for chronic diarrhea