Transcript STOOL EXAMINATION

DR RONALDA DE LACY
WHY IS IT DONE?
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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 osmolarity2x(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