STOOL EXAMINATION DR RONALDA DE LACY WHY IS

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 2 nd 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 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 �>200 ug/g faeces - normal �Low in chronic diarrhoea �<15 ug/g indicates pancreatic insufficiency-cystic fibrosis

INTESTINAL MALABSORPTION CARBOHYDRATE MALABSORPTION �Faecal reducing substances – positive – osmotic diarrhoea �Faecal osmolar gap (FOG) – serum osmolarity 2 x(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. 4 ml/24 hrs

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 -9 yrs – 166 ug/g faeces 10 -59 yrs- 51 ug/g faeces