Approach to Polyuria/Polydipsia Flashcards
What is the specific gravity of urine relative to plasma if Hyposthenuria
1.000 to 1.008
What is the specific gravity of urine relative to plasma if Isosthenuria
1.008 to 1.012
What is the specific gravity of urine relative to plasma if Hypersthenuria
1.030 to 1.055
Causes of Polyuria / polydipsia in the dog
Diabetes mellitus
Renal failure
Hyperadrenocorticism
Hypercalcaemia
Neoplasia
Liver failure
Pyogenic foci
Diabetes insipidus
Causes of Polyuria / polydipsia in the cat
Renal failure
Hyperthyroidism
Diabetes mellitus
Pyogenic foci (CBA)
Liver failure
Neoplasia
Causes of hyposthenuria
Loss of conc gradient-diuresis/hypoadrenocorticism
Loss of ADH or receptors- primary diabetes insipidus
Antagonism of ADH- Hyperadrenocorticism
Excessive water consumption
Causes of isothenuria
Loss of nephrons/Normal
Causes of Hypersthenuria
Decreased renal perfusion
Most dogs with PUPD have a normal SG of urine (T/F)
True!
SG of 1.008 – 1.035 excludes diabetes insipidus (T/F)
True!
No glucose in urine excludes diabetes insipidus (T/F)
True!
High levels of liver enzymes in a biochemistry test suggest a cause of PUPD (T/F)
False! Every disease cause liver disease. Test also does not test liver function.
Diabetes insipidus-
Lose ADH hormones (DDAVP)
What does the water deprivation test differentiate
Diabetes Insipidus and Psychogenic polydipsia
Indications for water deprivation test
Severe PU/PD
Normal renal function
Not hypercalcaemic
Not hyperglycaemia
Not hypercortisolaemic
Summarise water deprivation test
Phase 1 - water restriction
Phase 2 – water deprivation- dehydrate 5.8% of body weight
Empty bladder and weigh every 2 hours
Check urea and creatinine every 2 hours
Preserve urine and plasma samples
What is DDAVP
Desmopressin
Why is rectal exam relevant for PUPD cases
Anal adenocarcinoma release hormones cause hypercalcaemia causing PUPD
Why is thyroid exam relevant for PUPD cases
Hyperthyroidism esp cats cause PUPD
Top 3 Important tests in PUPD (Bloods)
Glucose
Calcium
Urea and Creatinine
Does high liver value mean anything in a PUPD case
Not really, high liver values happens in most systemic diseases and does not measure liver function. It will be high anyway
What could neutrophilia with left shift be diagnostic with patient with PUPD when doing cytology
Pyogenic focus
What could neutrophilia with lymphopenia be diagnostic with patient with PUPD when doing cytology
Hyperadrenocorticism
Why could survey radiographs be important in PUPD patients
Picture non palpable lymph nodes
Neoplasia- Metastatic
Changes in organ size e.g Pyometra
Is ultrasound a good diagnostic tool in PUPD patients
Limited value in survey scans but good when disease is identified
Hard to do
How to differentiate between central and nephrogenic diabetic inspidious
Central DI will respond to water deprivation test ( USG will increase after administering DDAVP)
