1. STOOL EXAMINATION
DR RONALDA DE LACY

2. WHY IS IT DONE? Colour Consistency Frequency Blood Bacteria Viruses
Parasites
Fungal
Pancreatic function
Intestinal malabsorption
Inflammatory markers

3. STOOL COLOUR

5. STOOL CONSISTENCY

6. 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

7. BLOOD FRESH BLOOD Lower GIT bleed - anal fissure - rectal haemorrhoids
- polyps
- inflammatory bowel disease
- infections i.e. Shigella, salmonella
- meckel’s diverticulum
- intussception
- NEC

8. BLOOD ALTERED BLOOD (MALAENA) Upper GIT bleed - oesophagitis
- mallory-weiss tear
- gastritis
- ulcers–gastric, duodenal, small bowel
- vascular malformations
- anastomotic sites

9. 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

10. SHIGELLA

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

12. SALMONELLA

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

14. CHOLERA

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

16. CAMPYLOBACTER LIFECYCLE

17. BACTERIA YERSINIA ENTEROLITICA Gram-negative oval rod
Contaminated food
Enterocolitis

18. BACTERIA
CLOSTRIDIUM DIFFICILE
Antibiotic use
Fresh stool sample

19. 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

20. VIRUS ROTAVIRUS RNA virus Most common cause for diarrhoea
Vaccine available
Diagnosis antigen testing on the stool

21. ROTAVIRUS

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

23. ADENOVIRUS

24. 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

25. ENTEROBIUS VERMICULARIS

26. ENTEROBIUS VERMICULARIS(PINWORM)

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

28. ASCARIS LUMBRICOIDES EGG

29. ASCARIS LUMBRICOIDES LIFECYCLE

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

31. TRICHURIS TRICHIURA EGGS

32. TRICHURIS TRICHURIUM LIFECYCLE

33. 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 primary
uterine branches

34. TAENIA EGG

35. TAENIA SAGINATA
FOUR SUCKERS
NO HOOKS

36. TAENIA SOLIUM
FOUR SUCKERS
DOUBLE ROW OF HOOKS

37. TAENIA LIFECYCLE

38. 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

39. GIARDIA LAMBLIA TROPHOZOITE

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

41. CRYPTOSPORIDIUM OOCYSTS

42. CRYPTOSPORIDIUM OOCYSTS-EM

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

45. ENTAMOEBA HISTOLYTICA CYST

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

47. ISOSPORA BELLI OOCYSTS

49. 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

50. CANDIDA ALBICANS

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

52. 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

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

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

55. 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