Chapter-19 Clinical Investigation

Complete stool Examination

Macroscopic Examination

1- Volume :

Normally less than 200 gm/day unless excessive dietary fibers are ingested

Large volumes indicate diarrhea 2- Consistency :

Normal stools are found but soft

Watery diarrhea is characteristic of bowel infection ( viral or bacterial )

Soft stools are seen in mal-absorption 3- Colour : • The normal colour varies from light to dark brown depending on diet • Black stools may be due to :

- Bleeding from upper gastrointestinal tract melena - Iron intake

• Red blood is usually due to bleeding from the lower alimentary tract and anal e.g. hemorrhoids , ulcerative colitis • Dark green stools are seen in diarrhea due to intestinal hurry . In cholera , the stools are almost watery and conatin epithelial cells and shreds of mucus ( rice water ) . • Greyish white stools in obstructive jaundice ( lack of bile pigments ) • Clay stools are produced by excessive amounts of fat ( Steatorrhea ) 4- colour : + The normal odour is mainly due to products of protein putrefaction ( Indole , skatol ) + Offensive stool are seen in :

- Excessive protein intake - Melena stools - Infective diarrheas , but cholera stools are odourless - Mal-absorption ( stools smell rancid ) - Obstructive jaundice ( absence of bile leads to putrefaction )

5- Other changes : - Mucus : o Normally , stools contain very little mucus o Excessive mucus is seen in :

Chapter-19 Clinical Investigation

Irritable colon ( mucus may be in casts ) Inflammatory conditions Intake of purgatives and antibiotics Neoplasms ( often with pus and blood )

- Pus is seen commonly in : • Dysentry • Ulcerative colitis • Malignancy

Microscopic Examination

1- Examination for red blood cells : excess RBCs is seen in the presence of hemorrhage , inflammation or ulceration . 2- Examination for pus cells : a large number is seen in dysentery and ulcerative colitis . 3- Examination for muscle fibers : undigested muscle fibers indicate deficient digestion usually due to diarrhea 4- Examination for fats :

Normally , present in minimal amounts as neutral fats , ( as oily globules ) fatty acid crystals ( as slender needles ) or soaps ( irregular plaques with rolled edges)

Excess fats indicates deficient digestion , or absorption 5- Examination for parasites : examination should be made from specimens

Bacterial Examination

1- A gram stained film : Is useful to show moniliasis or severe staphylococcal infection 2- Cultures : are made to identify pathogenic bacteria

Normal Amoebic dysentery

Bacillary dysentery

Steatorrhoea

Volume Normal Normal ↑ Large

Odour Normal Offensive Offensive Offensive

Consistency Soft Loose slimy

Watery Loose

Mucus - Excessive Slight +

Reaction Alkaline Acidic Alkaline Alkaline

Undigested food

- ++ + +++

Red cells - ++++ + -

Chapter-19 Clinical Investigation

Pus cells - ++ ++ - Fat content -- - Excessive

Chapter-19 Clinical Investigation

Chemical Examination

1- Occult blood : to detect small amounts , not seen by naked eyes .The test is simple using strips impregnated with benzidine or guaiac which gives blue colour if positive . 2- Fat balance test : the patient is put on a diet containing 50 g fat daily for 1 week . several estimation of faecal fat content is made after the first 3 days :

Normally more than 90 % of the fat is absorbed

Reduced % indicates deficient absorption or digestion of fats