Urinalysis Flashcards
Physical examination of urine
Colour- haemoglobin, blood, myoglobin, dietary or medication metabolites
Turbidity- pyuria, lipiduria, blood, crystals (esp. horses)
Odour- urease bacteria, ketonuria
Significance fo urine pH
Generally reflects body acid-base status
- except paradoxic aciduria in metabolic alkalosis of vomiting or gastric/Abomasal torsion/obstruction
May be influenced by diet
Helps interpret other results
How does pH help interpret other results
very alkaline urine may yield false positive protein
Identifiable solubility characteristics of crystals may influence whether you will see them
What does USG measire
urine osmolality
Effect of non-typical soluted on USG
Give us a false impression of USG
e.g. in proteinuria or myoglobinuria etc.
At what % of nephron loss is concentrating ability affected
60-70%
What to interpret USG with
Needs correlation with hydration state and/or azotaemia
how does proteinuria occur
failure of kidneys to resorb all protein
Important consideration in interpreting urine protein
Think about daily urine output
If animal is polyuric (dilute urine), low protein could still be large loss over the day
Pre-glomerular proteinuria
A condition that results in unusually high concentrations of small proteins in the blood means kidneys can not resorb all of it
Glomerular proteinuria
Basement membrane barrier has failed due to inflammation, immune attack, accumulation of content (e.g. amyloid, immune complexes) which disrupts its architecture
can also be caused by diabetes, hypertension and kidney disease
Tubular cause of proteinuria
Damaged tubular cells are not able to resorb filtrate protein as well as they should
Which type of proteinuria cuases blood albumin concentrations to fall and ‘nephrotic syndrome’
Glomerular proteinuria
Why does high urine glucose occur
Hyperglycaemia above renal threshold- stress, diabetes, PPID
Tubular failure (renal tubular acidosis) - if without hyperglycaemia
What causes ketones in urine
Negative energy balance
Diabetic ketoacidosis
What causes bilirubin in blood (bilirubinuria)
haemolysis, hepatic dysfunction
biliirubinuria may precede bilirubinaemia
less significant in dogs than cats
Significance of leukocytes in urine
Not generally reliable in dogs and cats
May correlate with bactiuria in dogs (specific but not sensitive)
Significance of casts in urine (cyclinduria)
Should not be any
Suggests tubule disease/damage
What are casts seen in urine
protein/cell collections moulded in lumen of tubules are deposited into urine
What does cellular csts indicate
Disease proces in tubules
What do granular casts indicate
Will be fine/coarse
Degenerate cellular casts- implies longer stasis
Precipiated protein
Degenerate epithelial cells
Why might myoglobin be present in urine
The presence of myoglobin in a dog’s urine can be a sign of muscle damage or injury. Myoglobin is a protein that is found in muscle tissue and is responsible for storing oxygen. When muscle cells are damaged or injured, myoglobin is released into the bloodstream and can be filtered by the kidneys and excreted in the urine.
The most common cause of myoglobinuria in dogs is exertional rhabdomyolysis, which is a condition that occurs when there is severe muscle damage due to strenuous exercise or activity. Other possible causes of myoglobinuria in dogs include trauma, inflammation, toxins, infections, and certain genetic disorders.
possible conditions leading to hyperproetinaemia
Dehydration: When an animal is dehydrated, the concentration of proteins in the blood can become elevated. This is because the volume of fluid in the blood is reduced, leading to a higher concentration of proteins.
Inflammation: Inflammation caused by infections, injuries, or chronic diseases can cause an increase in blood protein levels. This is because the liver produces more proteins, such as C-reactive protein, to help fight the inflammation.
Kidney disease: In animals with kidney disease, the kidneys may not be able to filter out waste products and excess proteins from the blood. This can lead to an accumulation of proteins in the blood.
Liver disease: The liver plays a key role in producing many of the proteins found in the blood. If the liver is damaged or diseased, it may not be able to produce enough proteins or may produce abnormal proteins, leading to an increase in blood protein levels.
Cancer: Certain types of cancer, such as multiple myeloma, can cause an increase in blood protein levels. This is because cancer cells can produce abnormal proteins, known as monoclonal gammopathies.
