Diarrhea

Definition

• Increased liquidity, frequency or decreased consistency of stools

Mechanisms

• Osmotic Diarrhea

• Secretory Diarrhea

• Deranged Motility

• Exudation

Osmotic Diarrhea

• results from poorly absorbable osmotically active solutes in the gut lumen

• stops when the patient is fasting

• stool analysis - Inc osmotic gap 290 mosm/kgH2O-2(Na+K)mmol/l

Some Causes of Osmotic Diarrhea

• Carbohydrate malab– gluc-galact malab

– fructose malab

– disaccaridase def

– ingestion (poorly absorbable carbs)

• lactulose

• sorbitol

• fructose

• fiber

• Magnesium-Induced– Nutritional supplemts

– antacids

– laxatives

• GI Lavage solutions• Laxative

– sodium citrate

– sodium phophate

– sodium sulfate

Secretory Diarrhea

• Results from abnormal ion transport in intestinal epithelial cells

• Main categories of secretory diarrhea– congenital defects of ion absorptive process– intestinal resection– diffuse mucosal disease– abnormal mediators

Secretory Diarrhea

• Diarrhea persist during a fast

• stool Na, K and the accompany anions account for the stool osmolality (small osmotic gap)

Some Causes of Secretory Diarrhea

• Laxatives– Phenolophthalein, aloe

• Medications– diuretics

• Toxins– coffee, tea, cola, ETOH

• Bacterial Toxins– S.aureus, C.perf +bot,

B.cereus

• Congenital• Bacterial entertoxins

– V. cholera, C.diff, Y.enterocol, toxigenic E. coli

• Endogenous laxatives– bile acids, LCFA

• Hormone producing tumors

Deranged Motility

• Enhanced Motility (Intestinal Hurry) - decrease contact time of the stool to the absorptive surface

• Abnormally slow motility may results in bacterial overgrowth and resultant diarrhea

Exudation

• Results from disruption of the intestinal mucosa from inflammation or ulceration

• blood, mucus and serum proteins in gut lumen– bacillary dysnentery– Inflammatory bowel disease

Approach to Patients with Diarrhea

• History– Characteristics of the onset of diarrhea should be

precisely noted (congenital, abrupt, gradual)– Pattern of diarrhea should be recorded

(continuous or intermittent)– Duration of the symptoms– Epidemiological factors (travel, exposure to

contaminated food or water, illness in other contacts)

History

– Stool characteristics should be investigated (watery, bloody, fatty)

– Presence of fecal incontinence– Presence of abdominal pain– Presence of weight loss– Aggravating factors (diet or stress)– Mitigating factors (alteration of diet, OTC meds)– Previous evaluations

History

– Iatrogenic causes (medication history, surgical history, radiation history)

– Factitious diarrhea (history of eating disorders, secondary gain and malingering)

– Careful ROS (hyperthyroidism, diabetes mellitus, CVD, AIDS, etc)

Approach to Patients with Diarrhea

• Physical Exam– Presence of rashes or flushing– mouth ulcers– thyroid masses– wheezing– arthritis– anal rectal examination

Erythema Nodosum

Acute Diarrhea• Less than 2-3 weeks duration

• Majority of cases are mild and self limiting

• 4 million deaths world-wide per year in children under 5 years

• Categories– infectious– noninfectious

• drugs, fecal impaction, elixir diarrhea, enteral feedings, chemotherapy or radiation therapy, runner’s diarrhea

Who Needs Evaluation?

• High fever (>102F)

• orthostatic symptoms or presyncope

• bloody diarrhea

• severe abdominal pain

• immunocompromised persons

Diagnostic Tests for Acute Diarrhea

• Spot Stool Sample– Culture, Ova and Parasite, C.diff toxin, fecal

leukocytes

• Blood Tests– CBC, electrolytes, SMA 7, blood culture

• Plain X-rays

• Endoscopy– flex sig

Treatment for Acute Diarrhea• Symptomatic

– fluid replacement• Oral replacemet solutions or IV fluids

– antidiarrheals

– Bismuth subsalicylate

• Antimicrobial therapy– quinolones

– metronidazole

– Bactrim

– Rifaximin

Antidiarrheals and Infectious Acute Diarrheas

• Bismuth Subsalicylates (Pepto-Bismol)– safe and efficacious– antidiarrheal effects, antibacterial,

antiinflammatory

• Loperamide– safe in traveler’s diarrhea

• Kaolin-pectin, opiates, anticholingerics– not effective

Antibiotics in Acute Diarrheas

• Recommended– Shigellosis

– Cholera

– Traveler’s diarrhea

– Pseudomembranous enterocolitis

– parasites

– STDs

• Not Recommended– E.coli 0157:H7

Antibiotics

• First Line– Ciprofloxacin - effective against most enteric

infections– Metronidazole - if symptoms suggest Giardia

• Second Line– Bactrim - effective second line therapy for most

infectious diarrheas

Rifaximin (Xifaxan)

• Nonabsorbed

• Broad-spectrum antibacterial activity invitro

• No known drug interactions

• 200 mg PO TID or 400 mg PO BID comparable to cipro

Nosocomial Acute Diarrheas

• Fecal impaction

• Drugs

• Elixir Diarrhea

• Enteral Feedings

• Infectious Nosocomial Diarrhea

• Chemotherapy/Radiation Therapy

Infectious Nosocomial Diarrheas

• Usually from C.difficile

• Salmonella, Shigella, 0+P extremely rare if diarrhea develops after 3-4 days in hospital

• In the immunosuppressed, viral infections are an important cause

Algorithm for Acute Diarrhea

Infectious

Assess severity, durationimmocompetence of host

Noninfectious

Eval and Rx of underlying cause

Symptomatic therapy

Continues

Rehydrationand wu

Possible abxantidiarrheal agents

resolves

Chronic Diarrhea

• At least 3 to 4 weeks duration

• accounts for 30% of patients in GI practices

• Categories– Organic

• malabsorpitive, secretory, exudative (inflammatory)

– Functional

Diagnostic Test for Chronic Diarrhea

• Blood tests– CBC, SMA, ESR, Thyroid function

• Stool studies– Spot

• WBCs, occult blood, O+P, culture, giardia Ag

– Quantitative• volume/weight, electrolytes, osmolality, fat, pH

• fecal osm gap: 290-2([Na] + [K])

Diagnostic Tests

• Endoscopy– Flex sig or colonoscopy with biopsies– Upper endoscopy

• biopsies

• aspiration for bacterial counts and parasites

• Radiology– Plain Radiographs– UGI/Small Bowel Series

Malabsorptive Diarrhea

• Fat Malabsorption– intraluminal maldigestion– mucosal malabsorption– postmucosal malabsorption

• intestinal lymphangiectasia, vasuclitis

• Carbohydrate Malabsorption

• Protein Malabsorption (Azotorrhea)

Malabsorptive Diarrheas (Fat)

• Intraluminal Phase– Cirhosis

– Bile duct obstruction

– Bacterial overgrowth

– Pacreatic exocrine insufficiencyl

• Mucosal Phase– Drugs

– Infectious disease

– Immune system dz

– Tropical sprue

– Celiac sprue

– Whipple’s dz

– Abetalipoproteinemia

Celiac Sprue

Normal small bowel

Schilling Test

• Vitamin B 12 deficiency– 1. Intrinsic factor deficiency– 2. Pancreatic insufficiency– 3. Bacterial overgrowth– 4. Extensive Ileal disease or resection

Schilling Test1. Ingestion of labeledVit B12 and Non- labeledIM Vit B12

2. Urine labeledVit B12 <8%/24 hr=malabsorption

Intrinsic factor

Pancreatic enzymes

Antibiotic therapy

Ileal disease or resection

IF def (PA)

Panc exoc def

Bact overgrowth

(Corrects)

Malabsoprtive Diarrhea (Carbs)

• Sorbitol diarrhea

• Fructose diarrhea

• Glucose-galactose deficiency

• Diasaccharidase deficiency

Lactose/Hydrogen Breath Test

• Step 1 - measure baseline end-expiratory breath hydrogen levels

• Step 2 - ingestion of lactose 50 gm

• Step 3 - measure breath Hydrogen levels at 30, 60, 90, 120 min

• rise >20 ppm suggest lactose malabsorption

D-Xylose Test

• Step 1 - 25 gm dose of D-xylose ingestion

• Step 2 - urine collected for next 5 hours

• Step 3 - at 1 hour, a blood sample taken (optional)

• <4gm (16% excretion) in urine or serum conc <20mg/dl of d-xylose = abnormal intestinal absorption

Secretory Diarrheas

• Carcinoid Syndrome

• Gastrinoma (ZE syndrome)

• Vipoma or Watery Diarrhea-Hypokalemia Achlorhydria Syndrome

• Medullary Carcinoma of the Thyroid

• Glucagnoma

• Villous Adenomas

• Systemic Mastocytosis

Inflammatory Diarrheas

• Inflammatory Bowel Disease

• Eosinophilic Gastroenteritis

• Protein-Losing Enteropathy

Inflammatory bowel disease

Crohn’s disease Granuloma

Treatment for Chronic Diarrhea

• Antidiarrheal therapy– Mild to Moderate Diarrhea

• Bismuth subsalicylates, opiates, bulk-forming agents, silicates, anticholingerics, cholestyramine

– Secretory Diarrhea• octreotide, clonidine, Ca++ channel blockers,

H2blockers, PPIs, H1 blockers, serotonin antagonist, indomethacin, glucocorticoids