acute gastroenteritis

Acute Gastroenteritis: An ApproachPaolo Aquino, M.D., M.P.H.

Outline

Approach Etiology Diagnosis Treatment Prevention

Approach

Considerations Rule out acute/surgical abdomen Hydration status

Acute AbdomenIntraluminal Obstruction Extraluminal ObstructionGastrointestin al DiseaseAppendicitis Crohn disease Ulcerative colitis Vasculitis Peptic ulcer disease Meckels AGE

Paralytic Ileus

Blunt Trauma

Miscellaneous

Foreign Body Bezoar Fecalith Gallstone Parasites Cystic fibrosis Tumor Fecaloma

Hernia Intussusceptio n Volvulus Duplication Stenosis Tumor Mesenteric cyst SMA syndrome Pyloric stenosis

Sepsis Pneumonia Pyelonephritis Peritonitis Pancreatitis Cholecystitis Renal stones Gallstones PID Lymphadenitis

Accident Battered child syndrome

Lead poisoning Sickle cell disease Familial Mediterranean fever Porphyria DKA Addisonian crisis Testicular torsion Ovarian Torsion

Approach

History Symptoms

Nausea, emesis, retching Abdominal pain Bowel movements Timing Age Onset Relation to feeds

Focus of infection, other affected individuals

Approach

Physical examination Temperature, heart rate, blood pressure, pain Abdominal examination

Auscultation before palpation Palpation Masses Tenderness

Auscultation for bowel sounds

Approach

Objectives Assess the degree of dehydration Prevent spread of the enteropathogen Selectively determine etiology and provide specific therapy

Dehydration

Mild (3-5%) Normal or increased pulse Decreased urine output Thirsty Normal physical exam

Dehydration

Moderate (7-10%) Tachycardia Little/no urine output Irritable/lethargic Sunken eyes/fontanelle Decreased tears Dry mucous membranes Skin- tenting, delayed cap refill, cool, pale

Dehydration

Severe (10-15%) Rapid, weak pulse Decreased blood pressure No urine output Very sunken eyes/fontanelle No tears Parched mucous membranes Skin- tenting, delayed cap refill, cold, mottled

Dehydration

Treatment Calculate deficits

Water: % dehydration x weight Sodium: water deficit x 80 mEq/L Potassium: water deficit x 30 mEq/L

Treat mild-moderate dehydration with oral rehydration solutions May treat severe dehydration with intravenous fluids Hyponatremic v. isotonic v. hypernatremic

Etiology

Enteropathogens Non-inflammatory vs. inflammatory diarrhea

Non-inflammatory Enterotoxin production Destruction of villi Adherence to GI tract

Inflammatory Intestinal invasion Cytotoxins

Etiology

Chronic diarrhea Giardia lamblia Cryptosporidium parvum Escherichia coli: enteroaggregative, enteropathogenic Immunocompromised host Non-infectious causes: anatomic, malabsorption, endocrinopathies, neoplasia

Etiology

Bacterial Inflammatory diarrhea

Aeromonas Campylobacter jejuni Clostridium dificile E. coli: enteroinvasive, O157:H7 Plesiomonas shigelloides Salmonella Shigella Vibrio parahaemolyticus Yersinia enterocolitica

Etiology

Bacterial

Non-inflammatory

Viral

E. coli: enteropathogenic, enterotoxigenic Vibrio cholerae

Rotavirus Enteric adenovirus Astroviruus Calcivirus Norwalk CMV HSV

Etiology

Parasites Giardia lamblida Entamoeba histolytica Strongyloides stercoralis Balantidium coli Cryptosporidium parvum Cyclospora cayetanensis Isospora belli

Diagnosis

History Stool examination Mucus Blood Leukocytes Stool culture

Diagnosis

Examination for ova and parasites Recent travel to an endemic area Stool cultures negative for other enteropathogens Diarrhea persists for more than 1 week Part of an outbreak Immunocompromised May require examination of more than one specimen

Antimicrobial therapy

Aeromonas TMP/SMZ Dysentery-like illness, prolonged diarrhea

Campylobacter Erythromycin, azithromycin

Clostridium dificile Metronidazole, vancomycin

E. coli TMP/SMZ

Antimicrobial therapy

Salmonella Cefotaxime, ceftriaxone, ampicillin, TMP/SMZ Infants < 3 months Typhoid fever Bacteremia Dissemination with localized suppuration

Shigella Ampicillin, ciprofloxacin, ofloxacin, ceftriaxone

Vibrio cholerae Doxycycline, tetracycline

Therapy

Antidiarrheal medication Alter Alter Alter Alter intestinal motility adsorption intestinal flora fluid/electrolyte secretion

Antidiarrheal medication generally not recommended Minimal benefit Potential for side effects

Prevention

Contact precautions Education Mode of acquisition Methods to decrease transmission

Exclusion from day care until diarrhea subsides Surveillance Salmonella typhi vaccine

Any questions?