PU/PD

Question 1

Polydipsia definition (PD)

Answer 1

water intake is greater than 100ml/kg/day
- >50 in cats

Question 2

polyuria definition

Answer 2

urine output is >50ml/kg/day compared to a normal output of 1-2ml/kg/hour

Question 3

USG < __ confirms PU while USG >__ is unlikely PU

Answer 3

1.020, 1.030

Question 4

Antidiuretic Hormone

Answer 4

produced in the hypothalamus then stored/released from the posterior pituitary targeting V2 receptors and creating increased aquaporins

Question 5

central diabetes insipidus is __ ADH deficiency while nephrogenic is a lack of__ to ADH

Answer 5

partial/complete, responsiveness

Question 6

what is the most common cause of PU/PD in small animals?

Answer 6

secondary nephrogenic DI

primary is rare

Question 7

primary polydipsia is __ while primary polyuria is __

Answer 7

behavioral, impaired renal concentrating capacity

Question 8

psychogenic polydipsia

Answer 8

behavioral disorder of unknown cause, anxiety is speculated

Question 9

non-pathologic polydipsia

Answer 9

pain, stress, hyperthermia, heat, exercise

Question 10

Hyperadrenocorticism

Answer 10

glucocorticoids inhibit ADH release and renal response to ADH

Question 11

Hepatic Disease

Answer 11

unknown; behavorial secondary to encephalopathy vs decreased urea concentration in medullary insterstitium

Question 12

hyperthyroidism

Answer 12

unclear, decreased medullary solute washout from increased renal blood flow vs thyrotoxicosis- induced psychogenic polydipsia

Question 13

primary polydipsia differentials

Answer 13

psychogenic polydipsia
non-pathologic polydipsia
hyperadrenocorticism
hepatic dz
hyperthyroidism

Question 14

primary polyuria - extra renal causes

Answer 14

• central DI
• hypercalcemia
• hypokalemia
• pyometra
• hypoadrenocorticism (hyponatremia)
• DM
• Hypersomatotropism (acromegaly)
• pheochromocytoma
• hyperviscosity syndrome/polcythemia
• neoplasia
• low protein diet
  -splenic hemangiosarcoma
• drug induced secondary nephrogenic DI

Question 15

Central DI

Answer 15

absent or decreased ADH production

Question 16

hypercalcemia

Answer 16

downregulation of aquaporin, impaired ADH action, impaired NaCl transport in loop of henle, decreased GFR from vasoconstriction, and eventually tubular dysfunction from nephrocalcinosis

Question 17

hypokalemia

Answer 17

downregulation of aquaporin/decreased ADH response

Question 18

pyometra

Answer 18

bacterial endotoxin competitively inhibits and damages ADH receptors and decreases NaCl transport into medullary interstitium

Question 19

hypoadrenocorticism

Answer 19

decreased medullary osmolarity from sodium loss which also impairs normal stimuli for ADH release in dehydration

Question 20

Diabetes mellitus

Answer 20

osmotic diuresis from glucosuria

Question 21

pheochromocytoma

Answer 21

catecholamine- induced inhibition of ADH release and response

Question 22

hyperviscosity syndrome/polycythemia

Answer 22

decreased ADH secretion from inhibition from ANP

Question 23

neoplasia (intestinal leiomyosarcoma)

Answer 23

paraneoplastic secondary nephrogenic DI

Question 24

low protein diet

Answer 24

loss medullary gradient from decreased urea nitrogen

Question 25

splenic hemangiosarcoma

Answer 25

paradoxical: compensatory polyuria following ADH release from hypovolemia in addition to stimulated thirst mechanism

Question 26

drug induced secondary nephrogenic DI

Answer 26

impaired renal ADH response. Vasopressin, ofloxacin, amp b, aminoglycosides, cisplatin, etc.

Question 27

primary polyuria - renal causes differentials

Answer 27

- Primary/congenital nephrogenic DI - CKD - AKI - pyelonephritis - fanconi syndrome

Question 28

primary/congenital nephrogenic DI

Answer 28

mutation of V2 receptors or aquaporin

Question 29

CKD

Answer 29

decreased number of functional nephrons -> osmosis diruesis of remaining nephrons + distortion of medullary architecture -> disruption of counter-current mechanism

Question 30

AKI or post- obstructive diuresis

Answer 30

osmotic diuresis

Question 31

Pyelonephritis

Answer 31

loss of medullary gradient from interstitial inflammation + impaired ADH action from endotoxemia

Question 32

fanconi syndrome

Answer 32

osmotic diuresis from renal glucosuria

Question 33

> 100ml/kg/day __ PD and 80-100 is __

Answer 33

confirms, suggestive

Question 34

if you see hyperglycemia on a chem what do you think of first?

Answer 34

DM

Question 35

elevated ALP and hypercholesterolemia is suggestive of what?

Answer 35

hyperadrenocorticism

Question 36

hypoalbuminemia , hypocholesterolemia, low BUN, hypoglycemia +/- elevated liver enzymes indicates what?

Answer 36

liver disease

Question 37

differentials for azotemia

Answer 37

CKD, AKI, pyelonephritis

Question 38

differentials for hypothenuria (USG <1.008)

Answer 38

central DI primary nephrogenic DI primary psychogenic PD hypercalcemia hyperadrenocorticism liver disease pyelonephritis or pyometra hemangiosarcoma/hemorrhage

Question 39

lack of app concentration (USG 1.008 -1.030) differentials

Answer 39

CKD Hypercalcemia cushings liver disease DM pyelonephritis or pyometra hyponatremia hypokalemia

Question 40

concentrated urine (USG > 1.030) differential

Answer 40

NOT PU intermittent PU DM Fanconi syndrome

Question 42

what additional dx tests can be performed for pu/pd?

Answer 42

- abdominal ultrasound - urine culture (pyelonephritis) - MAT+ PCR (lepto) - Bile acid stimulation Test (liver dz) - endocrine testing

Question 43

when is the water deprivation test indicated?

Answer 43

when the remaining dx's are primary/psychogenic polydipsia (most commoon) and central and nephrogenic DI

Question 44

desmopressin is a synthetic form of __ that if after administered the patient decreases water intake and increases USG indicates __ while an absent/decreased response would indicate __

Answer 44

ADH, central DI, primary nephrogenic DI or primary polydipsia