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Understanding Intestinal Infections: A Comprehensive Guide

Learn about the causes, symptoms, and treatment of intestinal infections including diarrhea caused by viruses, bacteria, and parasites. Explore the pathogenesis, diagnosis, and therapy for acute and chronic cases.

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Understanding Intestinal Infections: A Comprehensive Guide

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  1. INTESTINAL INFECTIONS MUDr. RNDr. František Stejskal, Ph.D. November 19, 2007 Department ofTropicalMedicine 1stFaculty of Medicine Charles University and Hospital Bulovka Studničkova 7, 128 00 Praha 2

  2. DIARRHEA - DEFINITION • DIARRHEA • Increase in fluidity, volume or frequency of bowel movement • Normal bowel habit varies greatly from person to person • Above 12 mo age, more than 3 loose stools per day are abnormal • ACUTE DIARRHEA • Subside spontaneously within a few days • PERSISTENT AND CHRONIC DIARRHEA • Persist for more than 2 – 3 weeks

  3. TERMINOLOGY OF DIARRHEAL DISEASES

  4. INFECTIVE DIARRHEA VIRUSES • Rotaviruses • Norwalk virus (Noroviruses) • Caliciviruses • Astroviruses • Enteric adenoviruses

  5. INFECTIVE DIARRHEA - BACTERIA • Enterotoxicoses (preformed toxin) • Bacillus cereus • Staphylococcus aureus • Clostridium perfringens C • Cholera and other Vibria • Enterotoxigenic E. coli (ETEC) • Salmonellosis • Campylobacter jejuni • Yersinia enterocolitica • Shigellosis • Enteroinvasive (EIEC) and enteroadherent E. coli • Aeromonas hydrophila • Plesiomonas shigelloides

  6. INFECTIVE DIARRHEA - PARASITES • Protozoa • Giardiasis • Amebiasis • Cryptosporidium • Cyclospora • Isospora • Helminths • Ascariasis • Trichuriasis • Ancylostomosis • Strongyloidosis • Taeniasis

  7. PATHOGENESIS OF INFECTIVE DIARRHEA • Toxin production • Staphylococcus pyogenes, St. aureus (preformed toxin) • Vibrio cholerae, ETEC toxin (↑cAMP – inhibition of Na+ absorption) • Enterocytes adhesion and colonisation • E.coli • Giardia intestinalis • Destruction of intestinal mucous membrane at the bacterial or parasite attachment place • Enteropathogenic E. coli, viruses • Cryptosporidium • Mucous membrane and submucose invasion • Salmonella, Campylobacter jejuni, Yersinia enterocolitica • Isospora, Cyclospora • Colonic wall invasion and ulcers formation • Shigella, enteroinvasive E.coli (EIEC) • Entamoeba histolytica

  8. PATHOGENESIS OF DIARRHEA II • Host defense mechanism: • Increased risc: • - Treatment with anacides, proton pump inhibitors, H2 inhibitors • - Immunity defects – IgA deficiency • Infective dose: • Low (less than 103 bacteria cells) • - shigellosis, Campylobacter (contagious infections) • High (more than 103 bacteria cells) • - salmonellosis

  9. SOURCE OF INFECTION EPIDEMIOLOGY • Contaminated water • Undercoched or roh meat, fish or seafood • Fruits and vegetabele • Milk products

  10. ACUTE DIARRHEA – DIFFERENTIAL DIAGNOSIS • With fever and with blood • Shigellosis, Campylobacter, EIEC, Cl. perfringens C – enteritis necroticans, (salmonellosis - 50%, typhoid) • With fever and without blood • Rotaviruses, Norwalk, salmonellosis (50 %); any localized infection at small children (otitis, tonsillitis, pneumonia), malaria • Without fever and with blood • Amoebiasis, intestinal schistosomiasis, balantidiosis, trichuriasis • Without fever and without blood • cholera, ETEC, enterotoxicosis (stafylococcal, B. cereus), cryptosporidiosis, isosporiasis, cyclosporiasis

  11. CHRONIC DIARRHEA • With fever • Intestinal tuberculosis, visceral leishmaniasis, yersiniosis, HIV infection, CMV • Without fever and with blood • Amoebiasis, intestinal schistosomiasis, balantidiosis, trichuriasis, Crohn disease, idiopatic proctocolitis • Without fever and without blood • Giardiasis, tropical sprue, coeliacal sprue, lactase deficiency, strongyloidosis, cryptosporidiosis, Whipple disease, intestinal malignant lymphoma, mucoviscidosis

  12. INVESTIGATION IN DIARRHEA • Fecal smear: fecal leucocytes • Stool culture • Parasitic stool investigation (persistantdiarrhea, for more than 2-3 weeks)

  13. DIRECT FAECAL SMEAR • Place a drop of sterile saline on the left hand site of the slide; place a drop of iodine on the right hand site of the slide and add a small portion of stool to each drop and mix to form suspension • Cover with a coverslip and examine with the x10 objective first Mr. Brown X 10/12/04

  14. FECAL LEUCOCYTES • Mucus (pus) from stool is stained with 2 drops of Lőffler’s methylen blue

  15. DIRECT FAECAL SMEAR - RESULTS • Cysts (Giardia, amoebas, etc.) • Trophozoites (amoebas, Giardia, trichomonads, other flagellates, etc) • Oocysts (Isospora, Cyclospora) of parasitic protists • Blastocystis hominis • Yeasts (Candida, Saccharomyces) • Ova of parasitic helmints • Vibrio cholerae Negative in cryptosporidiosis, special staining

  16. STOOL CULTURE • Routine: Salmonella sp., Shigella, Citrobacter, Proteus sp., Morganella sp. and other enterobacteria • Special: Campylobacter, Vibrio cholerae, Yersinia enterocolitica • Yeasts • Virus isolation (enteroviruses) • Parasites – special culture media: • Amoebas, trichomonads, other flagellates

  17. THERAPY OF DIARRHEA

  18. ORAL REHYDRATATION SOLUTION • NaCl 3,5 g • KCl 1,5 g • Na-bicarbonate 2,5 gor Na-citrate 2,9 g • glucose 20 g or saccharose 40 g • in 1 L of boiled water • Add 1 tsp of salt and 2-3 tsp of sugar or honey and 1 lemon to 1 liter of water.

  19. ORS WITH REDUCED OSMOLARITY • ORS solution does not reduce stool output or duration of diarrhoea • This solution, which is slightly hyperosmolar when compared with plasma, may cause hypernatraemia or an osmotically driven increase in stool output, especially in infants and young children • For this reason paediatricians in some developed countries recommended the ORS with reduced osmalarity containing about 60 mEq/l sodium and having a total osmolarity of 250 mOsm/l

  20. COMPARISON OF ORS and Valík solution

  21. ORS WITH REDUCED OSMOLARITY • Na+: 60-75 mEq/l (original ORS 90 mEq/l) • Glucose: 75-90 mmol/l • Total osmolarity: 215 - 260 mOsm/l (original ORS 311 mOsm/l)

  22. USE OF ANTIMICROBIAL DRUGS • Bloody diarrhea with fever (dysentery) which does not improve after 2-3 days or rehydratation • Cholera with severe dehydratation • Bacterial diarrhea at immunocompromised patients • Diarrhea with high fever in small children • Parasitic diarrhea

  23. CHOLERA

  24. CHOLERA PANDEMIC Seventh pandemic of cholera, 1961-1971 (CDC)

  25. CHOLERA • Humans are the only known natural host • Large infective dose – contaminated food or water • Incubation period: a few hours to 5 days • Severe watery diarrhea (up to 30 L per day), painless, without fever • Electrolyte imbalances, metabolic acidosis, prostration, dehydration • Management: ORS, doxycyclin 300 mg in single dose in the severe cases

  26. DIAGNOSIS OF CHOLERA • In epidemics based on clinical grounds alone • In non-epidemic periods, acute watery diarrhea resulting in severe dehydration: • Dark-field microscopy of faecal material • Transportation of samples in alkaline peptone water and kept cool • Culture in selective media such as TCBS agar • Bio- and serotyping in the reference laboratory • Notify the infection!

  27. CHOLERA PANDEMIC IN SOUTH AMERICA

  28. CHOLERA OUTBREAK IN 2005

  29. Shigella – species and serogroups

  30. EPIDEMIOLOGY OF SHIGELLOSIS • Shigella is causing 80 mil. of symptomatic infections and 700 000 deaths each year • 99% of infections are in developing countries • 70% of cases and 60% of deaths at children under 5 years • The recent epidemics: • 1969 – 73: Central America – 0,5 mil. of cases, 20 000 of deaths • 1993 – 95: countries of central and south Africa • 1994: Rwandian refugies to DR of Congo (20 000 of deaths during the first month) • 1999 – 03: Sierra Leone, Liberien, Guinea, Senagal, … • 2000: India a Banglades – resistance to FQ

  31. EPIDEMIOLOGY OF SHIGELLOSIS • S. sonnei and S. boydiiare causind ussually mild disease with watery or bloody diarrhea, they are more common in developed countries of temperate climate • S. flexneriis the main cause of endemic shigellosis in developing countries • S. dysenteriae typ 1 (Sd1, Shiga bacillus) is causing the most serious disease, it is causing epidemies in developing countries

  32. Shigella dysenteriae serotype 1 • It deffer from other species: • It produces a potent cytotoxin (Shiga toxin) • It is causing more severe, long-lasting, potentially deadly diarrhea • The resistance to antibiotics is more common • It may cause large, often regional epidemics: • „high attack rates“ • „high case fatality rates“

  33. DYSENTERY SYNDROME • Diarrhea with blood and pus • Abdominal pain and cramps • Tenesms

  34. DIFFERENTIAL DIAGNOSTICS • Entamoeba histolytica • Campylobacter jejuni • Entheroinvasive E. coli • Enthero-hemorrhagic E. coli • Salmonella sp. • Intentestinal schistosomosis (Schistosoma mansoni, S. japonicum)

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