Diabetes Insipidus in Canines

1. Diabetes Insipidus in Canines Lauren Liba Eric Malarney

3. What is Diabetes Insipidus??? • A disorder of water imbalance • This disorder is a completely different disease from diabetes mellitus, which is a disorder of glucose metabolism involving the hormone insulin

4. What is Diabetes Insipidus??? • The animal is unable to concentrate urine • The urine volume is high and very dilute • The urine is odorless (insipid), not sweet smelling as in diabetes mellitus • The disease is rare in canines and felines • The condition is usually permanent, but with proper treatment, the prognosis is good

5. Types of Diabetes Insipidus Central Diabetes Insipidus • Caused by the destruction of cells within the supraoptic and paraventricular nuclei of the hypothalamus which result in a deficiency in of antidiuretic hormone (ADH) • Can also be due to the loss of the ducts (axons) that transport (ADH) to the posterior pituitary

6. Hypothalamus x x Supraoptic Nucleus No production of antidiurectic hormone (ADH) Paraventricular Nucleus Ant. Pit. Posterior Pituitary

7. Hypothalamus Supraoptic Nucleus x Loss of ducts to the posterior pituitary - No antidiuretic hormone (ADH) Paraventricular Nucleus Ant. Pit. Posterior Pituitary

8. Other Causes of Central Diabetes Insipidus • Congenital Defect • Trauma • Tumor of the pituitary gland • Unknown cause

9. Types of Diabetes Insipidus Nephrogenic Diabetes Insipidus • Caused when the kidneys do not respond to antidiurtetic hormone (ADH) • Can be caused by congenital defects, drugs, or other metabolic disorders

10. Posterior Pituitary Nourine concentration (ADH) X

11. Differential Diagnoses • Hyperadrenocorticism (Cushing’s Disease) • Diabetes Mellitus • Hyperthyroidism (in felines) • Renal Failure • Liver Disease • Pyometra • Hypercalcemia of malignancy • Hyperparathyroidism

12. Signs of Diabetes Insipidus • Polyuria • Polydipsia • Dehydration - which can lead to stupor, coma, and even death if untreated • Housebroken canines urinating indoors

13. Treatment of Central Diabetes Insipidus • Treated with desmopressin (DDAVP) via intranasal drops, eyedrops, or subcutaneous injections

14. Treatment of Nephrogenic Diabetes Insipidus • Treat with a thiazide drug, chlorothiazide, or an oral drug, chloropropamide • NSAIDs can also be used • Regardless of treatment, water must ALWAYS be available

15. Diagnostic Tests • Images of pituitary gland should be taken if possible • Water deprivation test • An ADH trial with the drug desmopression (trade name DDAVP)

16. Additional Facts • Very rare disease, particularly central diabetes insipidus (a study in JAVMA found only 43 cases of CDI from 1986 to 1995 at UC-Davis and Purdue) • No breed predilections • Age does not appear to be a factor JAVMA, Vol 209, No. 11, December 1, 1996

19. Central Diabetes Insipidus Case Study: • Eddie • Pointer mix • NM • 4 years old

20. Chief Complaint • Inappropriate urination, polyuria/polydipsia one week duration • Physical exam otherwise normal • Consider behavioral issues

21. Polyuria and polydipsia

22. Polyuria and polydipsia

23. Polyuria and polydipsia questionable present

24. Polyuria and polydipsia Polyuria and polydipsia questionable present Monitor water intake and SG

25. Polyuria and polydipsia questionable present Monitor water intake and SG normal Consider incontinence

26. Polyuria and polydipsia questionable present Differential diagnosis abnormal Monitor water intake and SG normal Consider incontinence

27. Polyuria and polydipsia questionable present Differential diagnosis abnormal Monitor water intake and SG CBC Serum chem UA normal Consider incontinence

28. Polyuria and polydipsia questionable present Differential diagnosis abnormal Monitor water intake and SG CBC Serum chem UA normal Consider incontinence Consider hyperadrenocorticism

29. Polyuria and polydipsia questionable present Differential diagnosis abnormal Monitor water intake and SG CBC Serum chem UA normal Consider incontinence Consider hyperadrenocorticism normal Water Deprivation Test

30. Lab Test Results • Consistent with Diabetes Insipidus: • Normal serum chem and CBC or values consistent with mild dehydration • Increased PCV, TP and Na • Urinalysis: normal except specific gravity • Below 1.025 • Normal radiography

31. Abrupt Water Deprivation Test • Empty urinary bladder and measure urine specific gravity • Weigh animal • Withhold food and water • Every 2-4 hours, reweigh animal, empty urinary bladder and measure specific gravity

32. Gradual Water Deprivation Test • Quantify daily unrestricted water consumption • Measure urine specific gravity and weigh animal • Reduce water intake by 5% daily • Weigh animal and measure specific gravity daily

33. Deprivation Test Outcomes • Stop the test when: • The animal loses more than 5% of its body weight • The animal is clinically dehydrated or ill • The urine specific gravity exceeds 1.025

34. Lab tests Dehydration, azotemia, hypercalcemia?

35. Lab tests Dehydration, azotemia, hypercalcemia? yes

36. Lab tests Dehydration, azotemia, hypercalcemia? yes Water deprivation

37. Lab tests Dehydration, azotemia, hypercalcemia? yes no Water deprivation

38. Lab tests Dehydration, azotemia, hypercalcemia? yes no Water Deprivation Test Water deprivation

39. Lab tests Dehydration, azotemia, hypercalcemia? yes no Water Deprivation Test Water deprivation Concentrated urine?

40. Lab tests Dehydration, azotemia, hypercalcemia? yes no Water Deprivation Test Water deprivation Concentrated urine? yes Find underlying cause- nervous, behavioral

41. Lab tests Dehydration, azotemia, hypercalcemia? yes no Water Deprivation Test Water deprivation Concentrated urine? yes no Find underlying cause- nervous, behavioral Give ADH

42. ADH Response Test • Immediately following water deprivation test administer aqueous vasopressin • Withhold all food and water • Empty bladder and measure urine specific at 30, 60, 90 and 120 minutes

43. Therapeutic ADH Trial • Administer intranasal preparation of DDAVP in conjunctival sac (1 to 4 drops q12h) for 3-5 days • Should see a dramatic reduction in water intake if central diabetes insipidus is present

44. Urine is not concentrated after water deprivation Give ADH (DDAVP)

45. Urine is not concentrated after water deprivation Give ADH (DDAVP) Concentrated Not concentrated

46. Urine is not concentrated after water deprivation Give ADH (DDAVP) Concentrated Not concentrated Nephrogenic diabetes insipidus

47. Urine is not concentrated after water deprivation Give ADH (DDAVP) Concentrated Not concentrated Nephrogenic Diabetes Insipidus Pursue further renal testing

48. Urine is not concentrated after water deprivation Give ADH (DDAVP) Concentrated Not concentrated EDDIE Nephrogenic Diabetes Insipidus Central Diabetes Insipidus Pursue further renal testing

49. Urine is not concentrated after water deprivation Give ADH (DDAVP) Concentrated Not concentrated EDDIE Nephrogenic diabetes insipidus Central Diabetes Insipidus Pursue further renal testing Find underlying cause

50. Treatments • Desmopressin acetate (DDAVP) • Aqueous solution or oral tablets • Best solution, but expensive • Hydrochlorothiazide • Diruretic • Not as effective as DDAVP • Chlopropamide • Hypoglycemic agent • Only if ADH deficiency is partial