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 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’s diverticulum - 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. Sonnei most frequently isolated in developed world – 77% of cases

SHIGELLA

BACTERIA SALMONELLA Gram-negative rod Nonspore forming, motile Many serotypes

SALMONELLA

BACTERIA CHOLERA Only infects humans Transmission by faecal contamination of water and food Organism secretes an enterotoxin Results in watery diarrhoea

CHOLERA

BACTERIA CAMPYLOBACTER Gram-negative rod- comma or S-shaped Transmission is faecal-oral Cattle, chickens and dogs are sources

CAMPYLOBACTER LIFECYCLE

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

ROTAVIRUS

VIRUS ADENOVIRUS DNA virus 31 antigenic types High swinging fevers Pneumonia Conjunctivitis Diarrhoea Diagnosis – antigen testing on the stool

ADENOVIRUS

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

ENTEROBIUS VERMICULARIS

ENTEROBIUS VERMICULARIS(PINWORM)

PARASITES ASCARIS LUMBRICOIDES Transmission-eating eggs in contaminated soil Diagnosis- oval eggs in the stool or adult worms seen

ASCARIS LUMBRICOIDES EGG

ASCARIS LUMBRICOIDES LIFECYCLE

PARASITES TRICHURIS TRICHURIUM Whipworm infection Transmission-eating eggs in contaminated soil Diagnosis- barrel-shaped eggs in the stool

TRICHURIS TRICHIURA EGGS

TRICHURIS TRICHURIUM LIFECYCLE

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 EGG

TAENIA SAGINATA FOUR SUCKERS NO HOOKS

TAENIA SOLIUM FOUR SUCKERS DOUBLE ROW OF HOOKS

TAENIA LIFECYCLE

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

GIARDIA LAMBLIA TROPHOZOITE

PARASITES-PROTOZOA CRYPTOSPORIDIUM Coccidian protozoa Waterborne transmission Direct person to person contact Immunocompromised patients Diagnosis- oocysts in faecal smears

CRYPTOSPORIDIUM OOCYSTS

CRYPTOSPORIDIUM OOCYSTS-EM

PARASITES-PROTOZOA ENTAMOEBA HISTOLYTICA Transmission-faecal-oral route, contaminated food and water Diagnosis - trophozoites in diarrhoeal stools - cysts in formed stools – 4 nuclei

ENTAMOEBA HISTOLYTICA CYST

PARASITES-PROTOZOA ISOSPORA BELLI Faecal-oral transmission Immunocompromised patients Diagnosis-oocysts in faecal specimen

ISOSPORA BELLI OOCYSTS

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

CANDIDA ALBICANS

PANCREATIC FUNCTION Faecal elastase >200ug/g faeces - normal Low in chronic diarrhoea <15ug/g indicates pancreatic insufficiency-cystic fibrosis

INTESTINAL MALABSORPTION CARBOHYDRATE MALABSORPTION Faecal reducing substances – positive – osmotic diarrhoea Faecal osmolar gap (FOG) – serum osmolarity-2x(faecal sodium + potassium concentration) FOG >100 mosm/l – osmotic diarrhoea FOG <100 mosm/l – secretory diarrhoea Need a liquid stool

INTESTINAL MALABSORPTION PROTEIN MALABSORPTION Stool alpha 1 anti-trypsin Need a pre-weighed container Clearance rate 0.8-5.4ml/24hrs

INTESTINAL MALABSORPTION FAT MALABSORPTION 3 day faecal fat measurement Histology- free fat Steatocrit-not specific for free fat

INFLAMMATORY MARKERS COLPROTECTIN Calcium and zinc binding protein Accounts for 30-40% of neutrophil cytosol Resistant to enzymatic degradation Strongly correlated with 111-indium labelled leucocytes References range- upper limit 2-9yrs – 166ug/g faeces 10-59yrs- 51 ug/g faeces