Clinical approach to evaluate infectious diarrhea. Diarrhea. Defect Stool exam Examples mechanism. stool

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1 Clinical approach to evaluate infectious diarrhea Diarrhea Mechanism Clinical manifestation Having three of more loose or liquid stools per day, or having more stools than normal for that person 1ry Defect Stool exam Examples mechanism Secretory Osmotic Increased motility Decreased motility Decreased surface area active secretion, absorption Maldigestion or absorption of nonabsorbable solutes influx of water & electrolyte into lumen transit time Watery Voluminous Osmolarity=2(Na+K) Watery Lesser volume Acidic High osmolarity >2(Na+K) Stop with fasting Loose to normal stool stimulated by gastrocolic reflex Viruses Cholera Toxingenic E.Coli carcinoids Lactase deficiency Laxatives Malabsorption syndrome DM Thyrotoxicosis Irritable bowel syndrome Post vagatomy Pseudo obstruction Stasis, bacterial overgrowth Loose to normal stool Blind loop functional capacity Watery Short bowel syndrome Celiac disease Rotavirus Inflammatory (exudative) Inflammation, mucosal invasion & damage of brush border Blood, mucus and WBCs in stool Salmonella Campylobacter amoebiasis Shigella Yersinia IBD absorption, motility TB enteritis Non inflammatory diarrhea Inflammatory diarrhea Mechanism Osmotic or secretory Mucosal invasion and inflammation Nausea, vomiting, abdominal pain Fever, abdominal pain, tenesmus Fever are not major feature Stool Voluminous, watery Frequent small volume, blood stained, pus and mucus present Site Proximal small intestinal Distal ileum, colon Common pathogens Viruses, toxigenic E. Coli, Cholera, Cryptosporidium, G. Lamblia Dysentery Enteroinvasive E. Coli, Shigella, Salmonella, Yersinia, Campylobacter, E. Histolytica Etiology If there is blood visible in the stools. Infectious Viruses Norovirus Rotavirus Adenovirus 40/41 Bacteria E. Coli Campylobacter Clostridium (difficile, perferingens) Salmonella Protozoa E. Histolytica Cryptosporidium Astrovirus Calcivirus Yersinia enterocolitica Shigella Cholera Staph Aureus G. Lamblia Isospora Belli Non infectious Malabsorption (congenital or acquired) IBD IBS Laxative abuse

2 Rotavirus transmission characteristic Incubation period Prevention Most common causes of severe diarrhea among infants and young children Feco oral route It infects and damages the cells that line the small intestine and causes gastroenteritis Vomiting, watery diarrhea, low grade fever 2 days Specific: viral isolation in the stool by enzyme immunoassay General: electron microscopy, PCR Maintenance of hydration Vaccine Cholera Incubation period Diarrhea Patient Dehydration Prevention Profuse, painless diarrhea, vomiting of clear fluid usually starts suddenly 1 5 days Described as rice water in nature and may have a fishy odor An untreated person with cholera may produce liters of diarrhea daily with fatal results Cholera has been nicknamed the blue death due to a patient s skin turning a bluish gray from extreme loss of fluids Typical symptoms: low BP, poor skin turgor ( wrinkled hands), sunken eyes, rapid pulse 1. Clinical presentation 2. Rapid dip stick test 3. Futher testing should be done to determine antibiotic resistance 4. Stool and swab samples collected and cultivated using 4.1 Enrichment media : alkaline peptone water at PH 8.6 / Monsur s taurocholate tellurite peptone water at PH 9.2 Fluids : ORT Antibiotic for 1 3 days; doxycycline is first line antibiotic - Cotrimoxazole - Tetracycline - Furazolidone - Erythromycin - Chloramphenicol - Fluoroquinolones; norfloxacin 1. Surveillance 2. Vaccine: safe and effective oral vaccines injectable vaccine was found to be effective for 2 to 3 years immunization of high risk groups, such as children and people with HIV and countries where this disease is endemic

3 Causative agent Clinical presentation Amoebiasis It is a disease occur due to infection by Entamoeba Histolytica Entamoeba Histolytica - the active (trophozoite) stage exists only in the host and in fresh loose feces; - cysts survive outside the host in water, soils, food especially under moist conditions for months 1. Infection may be asymptomatic or symptoms may be so severe up to fulminating colitis 2. Amoebic dysentery with bloody diarrhea, weight loss, fatigue, abdominal pain 3. Amoebic liver abscess: the amoeba can actually bore into the intestinal wall, causing ulcers intestinal symptoms, and it may reach the blood stream vital organs; the liver (most common), lungs, brain, spleen 4. A common outcome of this invasion of tissues is amoebic liver abscess which can be fatal if untreated Stool samples ELISA or RIA Metronidazole Luminal amoebicide Paromomycin or Diloxanide furoate (Furamide) Giardiasis infection Causative agent transmission Clinical presentation Ingestion of dormant microbial cysts of flagellated protozoan parasite called Giardia Lamblia in contaminated water, food or by faecal oral route Giardia Lamblia Feco oral route It colonizes and reproduces in the small intestine. The parasite attaches to the epithelium by a ventaral adhesive disc. Colonization inflammation and villous atrophy reduce the gut s absorptive capability diarrhea : diarrhea, malaise, excessive gas, steatorrhoea (pale foul smelling, greasy stools), epigastric pain, bloating, nausea, loss of appetite, weight loss. Pus, mucus and blood are occasionally present in stool The condition usually self limiting, although the infection can be prolonged in patients who are immunocompromised or who have decreased gastric acid secretion Multiple stool examination Upper endoscopy Duodenal aspirate analysis Biopsy Treated on the basis of empirical evidence Metronidazole (7 days) Tindazole (single dose) Nitazoxanide (3 days)

4 Cryptosporidiosis Causative agent Characteristic Cryptosporidium (protozoa) GIT illness with diarrhea In humans, it remains in the lower intestine and may remain for up to 5 weeks and result in an infection of intestinal epithelial tissue Typically an acute, short term infection but can become severe and non - resolving in children and immunocompromised individuals. Most commonly isolated in HIV positive patients presenting with diarrhea Fluid rehydration electrolyte correction Management of any pain Nitozoxanid may be needed in immunocompromised person and children for 2 weeks Traveller s diarrhea Causative agent Nb Three or more unformed stools in 24 hours passed by a traveler, commonly accompanied by abdominal cramps, nausea and bloating Enterotoxigenic Esherichia coli Antibiotics for 3 to 5 days but single doses of azithromycin or levofloxacin have been used If diarrhea persists despite therapy, travelers should be evaluated for possible viral or parasitic infections, bacterial or amoebic dysentery, Giardia, Helminths Shigellosis (bacillary dysentery; Marlow Syndrome) Type Causative agent transmission (C/P) Onset time Recovery Food borne disease Shigella (bacteria) Direct: person to person, feco oral, poor hygiene *less than 100 bacterial cells can be enough to cause an infection mild abdominal discomfort to severe dysentery characterized by Cramps Diarrhea Fever Vomiting blood, pus or mucus in stools or tenesmus as infections are associated with mucosal ulceration rectal bleeding 12 to 96 hours 5 to 7 days 1. Oral replacement 2. Antibiotics: trimethoprim sulfamethoxazole, norfloxacin, ciprofloxacin, furazolidone 3. Ampicillin 4. Antidiarrheal drug (loperamide) may prolong the infection and should not be used

5 Enteritis salmonellosis / Food poisoning Salmonella Source of infection Incubation period Is an infection with Salmonella bacteria 1. Poultry, pork and beef if the meat is prepared incorrectly or is infected with the bacteria after preparation 2. Infected eggs, egg products and milk Nausea Blood diarrhea with mucus Fatigue Vomiting Headache Rose spots Abdominal cramps 12 to 72 hours Stool smear revealed RBC, WBC Culture (from stool or vomitus Antibiotics 1. Norfloxacin 2. Ciprofloxacin 3. 3 rd generation cephalosporin Clostridium difficile General nb It is a species of G+ve bacteria of the genus Clostridium C. Difficile is a commensal bacterium of the human intestine in 2 5% of the population It causes severe diarrhea and other intestinal disease when competing bacteria in the gut flora have been wiped out by antibiotics (clindamycin) and chemotherapeutic antineoplastic drugs Bacteria release toxins that can cause bloating and diarrhea, with abdominal pain, which may become severe Oral administration of oral metronidazole; if that fails give vancomycin and if unsuccessful again, IV metronidazole can be used It is the most common cause of pseudomembranous colitis and in rare cases this can progress to toxic megacolon which can be life threatening Escherichia coli transmission Food poisoning 1. Faecal oral transmission 2. Unhygienic food preparation 3. Farm contamination due to manure fertilization 4. Irrigation of crops with contaminated greywater or raw sewage 5. Direct consumption of sewage contaminated water Production of enterotoxin or diffuse mucosal adherence Culturing on sorbitol MacConkey medium and then using typing antiserum

6 Method of infection Staphylococcs Aureus Food poisoning Ingestion of performed Stephylococcus toxins 1 6 hours after ingestion of contaminated food with heat stable toxins Nausea, vomiting, abdominal pain followed by diarrhea Fever is rare Culturing the organism from contaminated food, stool or vomitus is supportive No role for antibiotics as the whole pathology is due to bacterial toxins Additional notes Need further investigations Rehydration Indication of antibiotics Role of antibiotics 1. Infants 2. Moderate or severe diarrhea in young children 3. Associated with blood 4. Continues for more than 2 days 5. Associated non cramping abdominal pain, fever, weight loss 6. In travelers 7. In food handlers because of the potential to infect others 8. In institutions such as hospitals, child care centers or geriatric and convalescent homes It is the primary treatment of infective diarrhea in both children and adults - ORT - IV ORT if decreased level of consciousness or if dehydration is severe Antibiotics are not usually used for gastroenteritis although they are sometimes recommended if - are particularly sever - If a susceptible bacterial cause is isolated or suspected - Certain bacteria and protozoans that are amenable to treatment include Shigella, Salmonella typhi, and Giardia species 1. Infection with Giardia species of E. Histolytica Tinidazole Metronidazole 2. Pseudomembranous colitis : caused by prolonged antibiotic use Discontinuing the causative agent Give Metronidazole or vancomycin 3. Antibiotics may increase the risk of hemolytic uremic syndrome in people infected with E. Coli O157:H7 4. Antimotility drugs should be avoided (children) 5. Physical adsorbants: Compounds as kaolin, charcoal are postulated to act by adsorbing toxins. They have little effects 6. Role of micronutrients: trials of Zinc supplementation demonstrated clinically important decrease in serverity and duration of diarrhea 7. Role of probiotics: administration of Lactobacillus casei GG may resulted in decrease of duration and frequency of watery diarrhea