INFECTIOUS DIARRHEA 林口長庚急診醫學部 吳孟書 醫師

Definition of Diarrhea  A softening in the consistency of the stool with or without an increase in the number of stool

Causes of Diarrhea  Infections : 一. Enteral  Nongastrointestinal (parenteral diarrhea)

Causes of Diarrhea  Dietary disturbances: 1)Overfeeding 2)Food allergy 3)Starvation stools

Causes of Diarrhea  Anatomic abnormalities: 1)Intussusception 2)Hirsprung ’ s disease 3)Partial obstruction 4)Appendicitis 5)Blind bowel syndrome 6)Intestinal lymphangiectasis 7)Short bowel syndrome

Causes of Diarrhea  Inflammatory bowel diseases: 1)Ulcerative colitis 2)Crohn ’ s diseases

Causes of Diarrhea  Malabsorption or Increased secretion: 1)Cystic fibrosis 2)Celiac disease 3)Disaccharide deficiency 4)Acrodermatitis 5)Enteropathica 6)Secretory neoplasms

Causes of Diarrhea  Systemic diseases: 1)Immunodeficiency 2)Endocrinopathy --

Causes of Diarrhea  Psychogenic disturbances (irritable bowel syndrome)  Miscellaneous: 1)Antibiotic-induced diarrhea 2)Secondary lactase deficiency 3)Neonatal drug withdrawal 4)Hemolytic-uremic syndrome (HUS)

Common Causes of Diarrhea  Infections: 1)Enteral — Viruses Bacteria 2)Nongastrointestinal ( “ parenteral ” diarrhea)  Dietary disturbances  Psychogenic disturbances  Miscellaneous: 1)Antibiotic induced 2)Secondary lactase deficiency

Life-Threatening Causes of Diarrhea  Intussusception  Hemolytic uremic syndrome  Pseudomembranous colitis  Appendicitis  Salmonella gastroenterolitis (with bacteria in neonate or compromised host)  Hirschsprung ’ s disease (with toxic megacolon)  Inflammatory bowel disease (with toxic megacolon)

Intussusception  Peak frequency between 5 and 10 months  Tapers off rapidly after 2 years old, unless there is a predisposing pathologic condiction  Lethargy or flaccid out of proportion to the degree of dehydration: “ neurologic ” sign  Plain film of abdomen  Abdominal echo  Contrast enema with air or barium

Hemolytic Uremic Syndrome (HUS)  In the first 3 years of life  Initially mild AGE  Complicated by hematochezia first  Pallor (anemia)  Purpura (thrombocytopenia)  Hematuria (nephritis)  Finally, renal failure  CBC, U/A, Coagulation studies  Helmet cell and RBC fragment  Intravascular hemolysis

Pseudomembranous Colitis  Overgrowth of toxin-productive clostridial organisms  A course of antibiotic therapy  Prostration  Abdominal distention  Significant amount of blood in stool  Stool toxin analysis

Appendicitis  Usually, there is constipation rather than diarrhea

Evaluation And Decision  Preexisting conditions; in particular, history of surgery or chronic illnesses  Immune status, recent travel history, and institutionalized before?  Characteristics of abdominal pain  Bloody stool ?  Vomiting ?  Assess the degree of dehydration  Fever ?  Abdominal physical examination including rectal examination

Clinical Findings in Dehydration Degree of Dehydration (%) SkinMucosaPulseBlood pressure 0Good turgorMoistNormal 5DryDry, no tearsMild increased Orthostatic decrease 10Tenting present Very dryModerate increased, weak Mildly decreased 15Poorly perfused ParchedMarkedly increased, thready Markedly decreased

Diagnostic Approach to the Immunocompetent Child with Diarrhea Ill appearing ? Peritonitis ? Abdominal mass ? Yes Hemolytic uremic syndrome Intussusception Acute appendicitis Toxic megacolon Sepsis (Salmonella) No Acute ? No Appendiceal abscess Irritable bowel syndrome Inflammatory bowel diseases Malabsorption Secretory disorders Anatomic abnormalities Infections Systemic illness Fever ? Yes Next page ……

Diagnostic Approach to the Immunocompetent Child with Diarrhea Fever ? NoYes Bloody ? No Viral enteritis Parenteral diarrhea Bacterial enteritis Yes Prior antibiotics ? YesNo Pseudomembranous colitis Antibiotic-induced Viral/bacterial enteritis Baterial enteritis Viral enteritis Amebiasis Inflammatiry bowel disease Bloody ? YesNo Viral enteritis Antibiotic-induced Overfeeding Bacterial enteritis Severe abdominal pain ? Abdominal mass ? “ Currant jelly ” stool ? Yes Intussusception (usually, 2yr) No Severe pallor ? Purpura ? Hematuria ? Yes Hemolytic uremic syndrome (usually, 3yr) No Prior antibiotics ? No Viral enteritis Bacterial enteritis Yes Pseudomenbranous colitis Antibiotic-induced

Acute Diarrhea  Fever ?  Blood stool ?  Travel to endemic area ?  Non-enteric infection ? – AOM, UTI  Immunocompromised patient ?

Viral Gatroenterolitis  Rotavirus  Norwalk virus  Enterovirus  Corronavirus  Adenovirus

Clinical Features in Viral AGE  Diarrhea and/or vomiting  Semisolid to watery stool  Hematochezia – most common in bacterial AGE  Cramping abdominal pain  Dehydration  Fever  Usually remit in 2 to 5 days

Management of Viral AGE  Introduce of oral electrolyte and glucose solution  Early reintroduction of feeding  Oral antiemetics and antidiarrheal agents  Intravenous rehydration for moderate to severe dehydration

Bacterial Gastroenterolitis  % of diarrheal illness  Salmonella (81%)  Shigella  Yersinia  Campylobacter (13%)  E. coli – O157 (HUS)  Clostridium difficile

Pathophysiology of Salmonella  Oral ingestion  Defense of gastric acid  Penetrate mucosal cells and proliferate within them  Destroy cells and cause ulceration  Bleeding with dysentery  Production of several toxin causes secretion and fluid and electrolytes

S/S of Salmonella Infection  A careful epidemiologic history  Summer  Incubation period : 8-48 hr  Cramping abdominal pain and nausea  Watery stool may contain blood  Fever  Abdominal distention  Rectal swab  Tenesmus – more often in shigellosis

Complication of Salmonella AGE  Usually occur in very young children or children with hemoglobulinopathy  Dehydration  Spread out septicemia  Meningitis  Osteomyelitis  Endocarditis  Hypo- or hyper-natremia  Typhoid fever – Salmonella typhi

Typhoid Fever  Fever – step-like pattern  A relative bradycardia in relation to the height of fever  Splenomegaly  Macular rash or rose spot  Leukopenia  A fourfold rise in the agglutinin titers -- diagnostic

Treatment of Salmonella AGE  Usually self-limiting  Adequate rehydration  Limitation of the diet to electrolyte solution (clear liquids)  Admission – Dehydration not responsive to treatment ‚Focal infection or bacteremia/sepsis ƒAge < 3 mo „Sickle cell anemia  Cefotaxime 50mg/kg iv q6h  Ceftriaxone 50mg/kg iv q12h  TMP-SMZ (4mg/kg of trimethoprim, q12h) is the first choice of oral medication as out-patient treatment

Chronic Diarrhea  More than 5 days  A period of observation and laboratory evaluation  Infants – Hirschsprung ’ s disease, Cystic fibrosis  HIV infection  Stool culture and examination for parasite or testing for clostridial toxin  Persistency of acute diarrhea: Bacterial infection ‚Secondary lactase deficiency from mucosal sloughing ƒStarvation stool in the children who inadvertently has been continued on a clear liquid diet for several days „No extensive evaluation is needed in children of presumed viral enteritis without evidence of malnutrition or dehydration.

Treatment  Differentiate surgical abdomen  Rehydration – oral or intravenous  Antidiarrheal agent – no role in infectious diarrhea  Agent decreasing intestinal mobility X  Appropriate antimicrobial agents for bacterial or parasite infection

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