Ricardo A. Caicedo, MDPediatric Gastroenterology

University of Florida

Diarrhea Increase in frequency and water content of stools

MECHANISM Examples

MALABSORPTION Celiac disease, Rotavirus

OSMOTIC Lactase deficiency

SECRETORY Cholera, C. difficile toxin

HYPERMOTILITY IBS

INFLAMMATORY IBD, Shigella

Acute Diarrhea• Infection

– Viral gastroenteritis• Rotavirus• Enterovirus, adenovirus• Norwalk virus

– Bacterial enterocolitis• Shigella, Salmonella• Yersinia, Campylobacter• E.coli – enteroinvasive• C. difficile

– Foodborne• S.aureus, Bacillus cereus• E. coli – enterotoxigenic

– Other: UTI, OM

• Inflammatory– Hemolytic Uremic Syndrome (HUS)– Henoch-Schonlein Purpura (HSP)

• Anatomic– Intussusception– Appendicitis

• Toxic Ingestion– Iron, mercury, lead

• Other– Antibiotic-induced– Hyperconcentrated infant formula– Overfeeding infants

Duration > 2 weeksChronic Diarrhea• Infection – parasitic

– Giardia lamblia– Entamoeba histolytica– Cryptosporidium parvum

• Inflammatory– Milk protein intolerance– Food allergy– IBD

• Malabsorption– Celiac disease– Cystic fibrosis– Bacterial overgrowth

• Osmotic– Lactase deficiency

• Primary• Secondary post-infectious

– Excessive fructose intake– Laxative overuse

Parasitic Organism Sources Duration

Giardia Fecal-oral, water supplies 2 wks – years

Entamoeba Same Weeks

Cryptosporidium Same, plus petting zoos, swimming pools

2 wks

Cyclospora Water, unpasteurized apple cider

1wk-1month

Isospora Fecal-oral, water > 2 wks

Strongyloides Fecal-oralAppalachia

same

Blastocystis hominis Pathogenic? Tan KS et al (2002) Int J Parasitol 32: 789-804

Keating J (2005) Pediatr Rev 26: 5-13.

Giardiasis• Diagnosis

– Stool antigen test• Greater sensitivity than O+P • Simpler than duodenal bx

– Often overlooked• Fever, WBC, eosinophilia rare

• Natural history– Most become asx by 6 wks– Frequent re-infx (up to 35%)– Few develop prolonged diarrhea

with wt loss and growth failure• Treatment

– Flagyl 15 mg/kg/d X 10 d• Albendazole, furazolidone• Asx carriers usually not treated

• Presentation– Watery, foul stools– Abdominal distention

• Bloating, flatulence– Crampy abdominal pain– Malaise, weakness– Nausea/vomiting– Anorexia, wt loss

• Risk factors– Well water– Daycare– Public pools, summer camp– Immunodeficiency

Prolonged Viral/Bacterial DiarrheasAgent Sources DurationAdenovirus, Rotavirus,CMV

Avg. 11 dMonths in immunodeficient

C. difficile Abx, nosocomial Relapses in 10% of cases

Campylobacter Raw poultry, unpasteurizedmilk, contaminated water

5 d - weeks

Salmonella Poultry, fecal-oral Months in infants

Yersinia Raw pig intestines, fecal-oral

3 wks -3 months

Aeromonas Untreated water 1 wk – 1 yr

Keating J (2005) Pediatr Rev 26: 5-13.

Prolonged Diarrhea in Infants• Prolonged/recurrent

diarrhea• Failure to gain weight

– Intractable diarrhea of infancy, postenteritisenteropathy

– Metabolic acidosis– Treatment

• Initial lactose-free, sucrose-free formula

• Elemental formula• TPN

“Slick Gut” Syndrome

OTHER:ImmunodeficiencyCFVIPomaAbetalipoproteinemiaCeliac diseaseCongenital intestinal lymphangiectasia

due to malrotation

Sucrase-isomaltase deficiency

= diagnosable by SB bx

Small bowel biopsy

Microvillus inclusion diseaseNeonatal

Apical membrane autophagocytosisConsanguinity

TPN-dependence, SB Transplant

Tufting enteropathyNo effective tx

CongenitallymphangiectasiaProtein losing enteropathyVillous clubbingSubepithelial blebMCT and high protein diet

Toddler’s diarrhea• Chronic nonspecific diarrhea of childhood• Symptoms

– Explosive loose stools– Contain food particles– Frequent stools, decline as day goes on

• Management– Verify normal growth and absence of red flags

• Blood in stool, persistent fever, anemia– Exclude celiac disease (tTG) and Giardia– Trial of dietary modification

• Restrict fructose and/or lactose

Diarrhea in older children• OSMOTIC

– Lactase deficiency• Primary

– African, Asian, Hispanic • Secondary

– Postenteritis– Laxative overuse/Poisoning

• INFLAMMATORY– Infectious– IBD

• FUNCTIONAL/hypermotility– IBS– CNSD (Toddler’s)

• MALABSORPTIVE– Celiac disease– CF– Pancreatic insufficiency– Chronic cholestasis– Bacterial overgrowth– Zinc deficiency– Intestinal lymphangiectasia

• Cong. Heart Dz (Fontan physiol)• Tumor or radiation

• SECRETORY

steatorrhea

Secretory diarrheas• Voluminous watery• Persists despite bowel rest• Massive efflux of fluid/salt• Stool electrolyte content

similar to serum• WDHA syndrome

– Watery diarrhea– Hypokalemia– Alkalosis

• DIFFERENTIAL DX– Cholera– C. difficile– Severe mucosal injury– Short bowel syndrome– Secretory tumors

• Carcinoid• Gastrinoma• Ganglioneuroma• Neuroblastoma• Pheochromocytoma• VIPoma

Zinc deficiency• Acrodermatitis enteropathica

– Perineal and perioral rash– Chronic diarrhea & undernutrition– Low serum Zn and alk phos– Primary

• Rare, recessive, mutation in Zn transporter– Secondary

• CF• Crohn’s• Anorexia nervosa• Dialysis• Chronic TPN• Exclusively breastfed preterms

– Tx = longterm Zn supplementation

ImmunodeficiencyCONDITION DIARRHEAImmunosuppression CMV colitis, Cryptosporidium, Isospora,

Entamoeba, Microspora, Cyclospora

HIV Cryptosporidium, Giardia, +/- VIP-oma

SCID 50% have protracted diarrhea in infancy

CGD Crohn-like colitis early in life

Wiskott IBD-like early in life

CVID Campy, Giardia

Hyper IgM 50% have chronic diarrhea

Selective IgA deficiency Increased risk of chronic giardiasis

MHC II deficiency Death in infancy due to severe malabsorption

Approach• Impact of diarrhea

– How is the infant/child growing?– How is symptom affecting child’s life?

• Mechanism of diarrhea– Description of stool

• Blood? Oily? Food particles?• Frequency

– Diet and exposures• Complete physical exam

– Attention to skin, LN, spleen• Screening and diagnostic tests

Screening tests• BLOOD

– Electrolytes– Total protein/albumin– Liver tests– CBC– ESR– Celiac serology (tTG)– Vitamin levels

• B12, FA, Fe• A, D, E

• STOOL– Guaiac– pH and reducing substances– Spot fat stain– Gram stain/Culture– Giardia Ag– O+P– C. diff toxin– Osmolarity– Electrolytes

Secretory vs. OsmoticOsmotic Gap: 290 – {2 ([Na+] +[ K+])}

Stool Na > 70Osmotic Gap < 100

Stool Na < 70Osmotic Gap > 100

Persists while NPO Decreases when NPO

Malabsorption studies• FAT

– Spot fecal fat stain– Quantitative 72 hr

• Total excretion > 5g fat/24 h• Coefficient of absorption =

(fat ingested –excreted)/ingested X 100%

• PROTEIN– Fecal A1AT

• Suggests mucosal disorder such as celiac disease

• CARBOHYDRATE– Stool pH < 5.5– Reducing sugars

• Lactose, maltose, fructose, galactose

– Breath hydrogen test• H2 produced by bacterial

fermentation of undigested CHO

• Rise in H2 > 20 ppm above baseline: malabs.

• Elevated baseline or ∆20 ppm w/in 30 min: overgrowth

Barney Beagle

Thank You!