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STOOL EXAMINATION. DR RONALDA DE LACY. WHY IS IT DONE?. Colour Consistency Frequency Blood Bacteria Viruses Parasites Fungal Pancreatic function Intestinal malabsorption Inflammatory markers. STOOL COLOUR. STOOL CONSISTENCY. STOOL FREQUENCY.
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STOOL EXAMINATION DR RONALDA DE LACY
WHY IS IT DONE? • Colour • Consistency • Frequency • Blood • Bacteria • Viruses • Parasites • Fungal • Pancreatic function • Intestinal malabsorption • Inflammatory markers
STOOL FREQUENCY • Breastfed infants – stool after every breastfeed - once to twice a week • Children on average 1 to 2 stools per day • Some children might have a stool every 2nd day
BLOOD FRESH BLOOD • Lower GIT bleed - anal fissure - rectal haemorrhoids - polyps - inflammatory bowel disease - infections i.e. Shigella, salmonella - meckel’sdiverticulum - intussception - NEC
BLOOD ALTERED BLOOD (MALAENA) • Upper GIT bleed - oesophagitis - mallory-weiss tear - gastritis - ulcers–gastric, duodenal, small bowel - vascular malformations - anastomotic sites
BACTERIA SHIGELLA • Gram-negative rod • Nonspore forming, non-motile • Four serogroups - S. Dysenteriae (12 serotypes) - S. Flexeneri (6 serotypes) - S. Boydii (18 serotypes) - S. Sonnei (1 serotype) • S. Flexeneri most frequently isolated in developing world – 60% of cases • S. Sonneimost frequently isolated in developed world – 77% of cases
BACTERIA SALMONELLA • Gram-negative rod • Nonspore forming, motile • Many serotypes
BACTERIA CHOLERA • Only infects humans • Transmission by faecal contamination of water and food • Organism secretes an enterotoxin • Results in watery diarrhoea
BACTERIA CAMPYLOBACTER • Gram-negative rod- comma or S-shaped • Transmission is faecal-oral • Cattle, chickens and dogs are sources
BACTERIA YERSINIA ENTEROLITICA • Gram-negative oval rod • Contaminated food • Enterocolitis
BACTERIA CLOSTRIDIUM DIFFICILE • Antibiotic use • Fresh stool sample
BACTERIA MYCOBACTERIA Tuberculosis • Transmission by respiratory droplets • Mainly respiratory disease • Dissemination can result in intestinal involvement Bovis • Transmission by unpasteurised cow’s milk • Intestinal involvement • Difficult to culture from stool-need tissue
VIRUS ROTAVIRUS • RNA virus • Most common cause for diarrhoea • Vaccine available • Diagnosis antigen testing on the stool
VIRUS ADENOVIRUS • DNA virus • 31 antigenic types • High swinging fevers • Pneumonia • Conjunctivitis • Diarrhoea • Diagnosis – antigen testing on the stool
PARASITES ENTEROBIUS VERMICULARIS • Pinworm infection • Lifecycle confined to humans • Eggs recovered from peri-anal area with tape • Adult worms may be found in the stool
PARASITES ASCARIS LUMBRICOIDES • Transmission-eating eggs in contaminated soil • Diagnosis- oval eggs in the stool or adult worms seen
PARASITES TRICHURIS TRICHURIUM • Whipworm infection • Transmission-eating eggs in contaminated soil • Diagnosis- barrel-shaped eggs in the stool
PARASITES TAENIA SOLIUM • Ingestion of larvae in undercooked pork • Diagnosis- proglottids in stool gravid proglottids have 5-10 primary uterine branches TAENIA SAGINATA • Ingestion of larvae in undercooked beef • Diagnosis- gravid proglottids have 15-20 primary uterine branches
TAENIA SAGINATA FOUR SUCKERS NO HOOKS
TAENIA SOLIUM FOUR SUCKERS DOUBLE ROW OF HOOKS
PARASITES-PROTOZOA GIARDIA LAMBLIA • Flagellated protozoan • Waterborne transmission • Faecal-oral route • Infects the small intestine • Difficult to isolate, need minimum of 3 stool specimens • Diagnosis - trophozoites or cysts in diarrhoeal stools - trophozoites- pear-shaped, 2 nuclei, 4 pairs of flagella, suction disk
PARASITES-PROTOZOA CRYPTOSPORIDIUM • Coccidian protozoa • Waterborne transmission • Direct person to person contact • Immunocompromised patients • Diagnosis- oocysts in faecal smears
PARASITES-PROTOZOA ENTAMOEBA HISTOLYTICA • Transmission-faecal-oral route, contaminated food and water • Diagnosis - trophozoites in diarrhoeal stools - cysts in formed stools – 4 nuclei
PARASITES-PROTOZOA ISOSPORA BELLI • Faecal-oral transmission • Immunocompromised patients • Diagnosis-oocysts in faecal specimen
FUNGAL CANDIDA ALBICANS • Part of normal gut flora • Overgrowth in diabetes, immunocompromised patients and prolonged antibiotic use. • Diagnosis- oval yeast with a single bud in the stool