Chronic Diarrhea: Approach to the Patient diagnostic evaluation must be rationally directed by a careful history and physical examination history, physical.

Chronic Diarrhea:Approach to the Patient

• diagnostic evaluation must be rationally directed by a careful history and physical examination

• history, physical examination, and routine blood studies– characterize the mechanism of diarrhea– identify diagnostically helpful associations– assess the patient's fluid/electrolyte and nutritional status

• onset, duration, pattern, aggravating (especially diet) and relieving factors, and stool characteristics of the diarrhea

• note presence or absence of fecal incontinence, fever, weight loss, pain, certain exposures (travel, medications, contacts with diarrhea), and common extraintestinal manifestations (skin changes, arthralgias, oral aphthous ulcers)

Chronic Diarrhea:Approach to the Patient

• family history of IBD or sprue

• physical findings may offer clues such as a thyroid mass, wheezing, heart murmurs, edema, hepatomegaly, abdominal masses, lymphadenopathy, mucocutaneous abnormalities, perianal fistulae, or anal sphincter laxity

• peripheral blood – leukocytosis, elevated sedimentation rate, or C-reactive protein

suggests inflammation– anemia reflects blood loss or nutritional deficiencies– eosinophilia may occur with parasitoses, neoplasia, collagen-vascular

disease, allergy, or eosinophilic gastroenteritis

• blood chemistries may demonstrate electrolyte, hepatic, or other metabolic disturbances

• measuring tissue transglutaminase antibodies may help detect celiac disease

INITIAL MANAGEMENT BASED ON ACCOMPANYING SYMPTOMS OR FEATURES

EVALUATION BASED ON FINDINGS FROM A LIMITED AGE APPROPRIATE SCREEN FOR

ORGANIC DISEASE

Chronic Diarrhea

Chronic Diarrhea

• Diarrhea lasting > 4 weeks

Major Causes of Diarrhea According to Predominant Physiologic Mechanism

Chronic Diarrhea

Secretory

Osmotic

Steatorrheal

Inflammatory

Dysmotility

Factitial

Secretory Causes of Diarrhea

• Due to derangements in fluid and electrolyte transport across the enterocolonic mucosa.

• Characterized by a watery, large volume fecal outputs that are typically painless and persist with fasting.

• No fecal osmotic gap.

Secretory Causes of Diarrhea

Medications Hormones

Stimulant laxatives

Chronic ethanol consumption

Environmental toxins

Metastatic GI carcinoid tumors

Primary bronchial carcinoids

Gastrinoma

Pancreatic cholera

VIPoma

Medullary carcinoma of the thyroid

Systemic mastocytosis

Colorectal villous adenoma

Secretory Causes of Diarrhea

Bowel Resection, Mucosal Disease, Enterocolic Fistula

Congenital Defects in Ion Absorption

Congenital chloridorrhea

Addison’s Disease

Osmotic Causes of Diarrhea

• When ingested, poorly absorbable, osmotically active solutes draw enough fluid into the lumen to exceed the resorptive capacity of the colon

• fecal water output increases in proportion to such solute load

• Ceases with fasting or with discontinuation of the causative agent

Osmotic Causes of Diarrhea

Osmotic laxatives

Magnesium containing antacidsHealth supplements

laxatives

Carbohydrate Malabsorption

Acquired or congenital defects in brush border disaccharidases and other enzymes

Lactase deficiency

Steatorrheal Causes of Diarrhea• Increased in fecal output is caused by the

osmotic effects of fatty acids, especially after bacterial hydroxylation and to a lesser extent by a neutral fat

• Quantitatively: stool fat>7g/d• Rapid transit diarrhea may result in fecal fat up

to 14g/d• Daily fecal fat averages

– 15-25g with SI diseases – >32 g with pancreatic exocrine insufficiency

Steatorrheal Causes of Diarrhea

Intraluminal Maldigestion

Chronic pancreatitisCystic fibrosis

Pancreatic duct obstructionsomatostatinoma

Mucosal Maldigestion

Celiac diseaseTropical sprue

Whipple’s diseaseMycobacterium avium

intracellulare infection in AIDS patient

AbetalipoprotenemiaGiardia infection

Colchicine, cholestyramine, neomycin

Chronic schemia

Steatorrheal Causes of Diarrhea

Postmucosal Lymphatic Obstruction

Congenital intestinal lymphangiectasia

Acquired lymphatic obstruction secondary to trauma, tumor, or

infection

Inflammatory Causes of Diarrhea

• Accompanied by pain, fever, bleeding and other manifestation of inflammation

• Mechanism of diarrhea may be due to exudation, fat malabsorption, disrupted fluid/electrolyte absorption, hypersecretion or hypermotility from release of inflammatory mediators

• Stool analysis: leukocytes or leukocyte derived protein (calprotectin)

Inflammatory Causes of Diarrhea

• with severe inflammation, exudative protein loss can lead to anasarca

• middle aged or older person with chronic inflammatory type diarrhea, especially with blood, should be carefully evaluated to exclude colorectal tumor

Inflammatory Causes of Diarrhea

Idiopathic Inflammatory Bowel Disease

Crohn’s diseaseChronic ulcerative colitis

Microscopic colitis

Primary or Secondary Forms of Immunodefeciency

hypogammaglobulinemia

Inflammatory Causes of Diarrhea

Eosinophilic Gastroenteritis

Hypersensitivity to certain food

Other causes

Radiation enterocolitisChronic graft vs host disease

Behcet’s syndromeCronkite-Canada Syndrome

Dysmotility Causes of Diarrhea

• Rapid transit time may accompany many diarrheas as a secondary or contributing phenomenon, but primary dysmotility is an unusual etiology

• Stool features often suggest a secretory diarrhea, but mild steatorrhea of up to 14 g/d can be produced by maldigestion from rapid transit alone

Factitial Causes• Accounts for up to 15% unexplained

diarrheas• Munchausen syndrome( deception or self

injury) or eating disorders (self administer laxatives alone or in combination with other medication(diuretics)

• Women with histories of psychiatric illness and disproportionately from careers in health care

• Hypotension and hypokalemia

Dysmotility Causes of Diarrhea

• Hyperthyroidism, carcinoid syndrome, certain drugs( PG and prokinetic drugs) may produce hypermotility with diarrhea

• Primary visceral neuropathies or idiopathic acquired intestinal obstruction

• Diabetic diarrhea

• Irritable bowel syndrome