CS: PU/PD

Question 1

What are the most important (i.e. common and/or life-threatening) causes of PU/PD in DOGS (most to least common)?

Answer 1

• Hyperadrenocorticism
• Diabetes mellitus
• Chronic renal failure
• Pyelonephritis
• Pyometra
• Hypercalcaemia
• Atypical leptospirosis
• Psychogenic polydipsia
• Diabetes insipidus
• Liver disease
• Hypoadrenocorticism
• Acromegaly

Question 2

What are the most important (i.e. common and/or life-threatening) causes of PU/PD in CATS (most to least common)?

Answer 2

• Chronic renal failure
• Diabetes mellitus
• Hyperthyroidism
• Hypercalcaemia
• Pyelonephritis
• Hypokalaemia
• Acromegaly
• Postobstructive diuresis
• Hyperadrenocorticism
• Hypoadrenocorticism
• Diabetes insipidus

Question 3

Is PUPD usually a primary PU or a primary PD?

Answer 3

usually a primary PU

Question 4

What are the mechanisms of primary PU?

Answer 4

• osmotic diuresis
• inability of ADH to work in the nephron
• lack of ADH from the pituitary gland

Question 5

Differentials - primary PD?

Answer 5

• Behavioural (psychogenic PD)

- Metabolic problems (hepatic problems)

Question 6

Renal causes - PU/PD (* is common)

Answer 6

o	CKD*
o	Pyelonephritis*
o	Renal glucosuria
o	NDI
o	Post-obstruction

Question 7

Endocrine causes - PU/PD (* is common)

Answer 7

o	DM*
o	Hyperadrenocorticism*
o	Hypoadrenocorticism*
o	Hyperthyroidism (cat)*
o	Acromegaly
o	Hyperaldosteronism

Question 8

Electrolyte disorders as causes of PUPD (* is common)

Answer 8

o Hypercalcaemia*

o Hypokalaemia

Question 9

Other organ disorders causing PUPD (* is common)

Answer 9

o Pyometra

o Liver failure*

Question 10

Miscellaneous causes of PUPD (* is common)

Answer 10

o Drugs/toxins*
o Psychogenic PD
o Polycythemia vera

Question 11

How would you investigate PUPD?

Answer 11

• COMMONLY USED: Hx and PE, haematology, biochemistry (include electrolytes Na, K, Ca and dynamic bile acids), UA
• SOME tests: endocrine tests, imaging
• RARELY NECESSARY: water deprivation tests (dangerous if done unnecessary)
  Glucose in urine = DM or renal glycosuria (so consult bloods)

Question 12

What differentials of PU/PD are difficult to rule out? 3

Answer 12

• Early CKD (do LDDST, urine cortisol: creatinine)
• Occult pyelonephritis (ultrasound, repeat culture, pyelocentesis, renal biopsy trial tx)
• HAC (measure GFR)
• THEN (once these three have been ruled out, do water deprivation test (for NDI, CDI and psychogenic PD). Otherwise this can be a very dangerous test.

Question 13

How do you diagnose primary polydipsia?

Answer 13

by ruling out ALL other causes of PD

Question 14

T/F: only 1/3 dogs with pyelonephritis have changes on blood test results

Answer 14

True!