Physical examination

PHYSICAL EXAMINATION OF URINE

Colour

  • The colour of the urine may be any one of the following: colourless, pale yellow, dark yellow, yellowish-brown, greenish-yellow, red, reddish-brown, brown, green, blue and milky. The yellow colour of the urine is due to urochrome pigment.
    • Cloudy - Pus in urine
    • Dark yellow - Dehydration in vomition, diarrhoea, serous exudations, fever and deficient intake of water
    • Pale - Diabetes mellitus, diabetes insipidus, increased water intake, pyometra and chronic interstitial nephritis in dogs
    • Yellowish brown/Greenish yellow - Jaundice
    • Red - Haemorrhage
    • Faint pink - Congenital porphyria
    • Green - Medication with methylene blue or diazan
    • Brown/coffee coloured - Haemoglobinuria /Myoglobinuria

Transparency

  • The transparency of the urine is tested by viewing it against light in a test tube. Normally, it should be transparent and clear. But in the horse, normally, the urine is cloudy and thick due to the presence of mucus and calcium carbonate crystals. So, the sample of horse urine must be allowed for sometime to settle. The supernatant urine is then used for other tests.

Interpretation

  • The urine is cloudy if it contains epithelial cells in large numbers

    • Leucocytes in large numbers as in pyuria
    • Large numbers of bacteria
    • Mucus in the urine of the horse
    • Crystals-calcium carbonate or amorphous urates or amorphous phosphates
    • When blood is present, it gives a red or brown smoky appearance
  • In dogs, if the freshly voided urine is cloudy, then it is pathological due to the presence of pus, blood or mucus.

Odour

  • The odour of the urine is due to volatile acids; it becomes ammonical due to decomposition.
    • Sweetish odour in diabetes mellitus
    • In ketonuria, there is odour of acetone.
    • In turpentine medication, the urine may have odour of violet

Foam

  • Normal urine may foam if it is shaken. In albuminuria foam occurs in plenty.

Specific gravity

  • This is a measure of the relative amounts of solids in solution in the urine. It indicates the capacity of the kidney to concentrate the urine by reabsorption. Generally, specific gravity varies inversely with the quantity of urine. Exceptionally, in diabetes mellitus due to the presence of sugar the specific gravity is high though the quantity is also high. Specific gravity is determined by means of urinometer. This consists of a cylinder and float at the stem of which is scale from top to the neck of the stem.

Procedure

  • Fill the cylinder with urine up to one inch from the top. Ensure that there are no air bubbles since the presence of air bubbles at the top interferes with the reading
  • Place the float in the urine and spin it, so that it finds its level
  • Read the mark on the stem that is in level with the highest level of the meniscus of the urine. This gives the specific gravity of the urine
  • To test the accuracy of the urinometer, use distilled water instead of urine in the above test. The reading must be 1000 at 20ยบ C

Increased specific gravity is seen in:

  • Acute interstitial nephritis, the specific gravity is elevated due to the inability of the kidney to excrete water
  • Cystitis due to the presence of products of inflammation
  • Diabetes mellitus due to glycosuria
  • Dehydration, vomition, diarrhoea and reduced feed intake

Decreased specific gravity is seen in :

  • Increased fluid intake
  • Inability of the kidney to concentrate urine
  • Advanced stages of uraemia
  • Diabetes insipidus
Last modified: Wednesday, 16 May 2012, 6:47 AM