canis - Articles
Diabetes insipidus
Synonym(s): DI
Introduction
- Cause: absolute or relative deficiency of anti-diuretic hormone (ADH).
- Two forms:
- Hypothalamic-hypohyseal DI (HDDI).
- Nephrogenic DI (NDI).
- Signs:
- Polyuria/polydipsia.
- Urine: low SG/osmolarity.
- Diagnosis: urinalysis, hematology, biochemistry.
- Treatment: various chemotherapies.
- Prognosis: varies.
Presenting signs
- Polyuria (possibly incontinence).
- Extreme polydipsia (>100 ml/kg/day).
- Other neurological signs or hormonal defects if caused by functional lesions or neurohyperhysis.
Acute presentation
- If water intake restricted → dehydration, coma and death.
Pathogenesis
Etiology
Central form
- Partial or total failure to synthesize or release ADH.
- Rare.
May be
- 1° - idiopathic.
- 2° to:
- Head trauma.
- Neoplasia 1°/2°.
- Inflammatory/vascular damage.
Nephrogenic form
- Head trauma.
- Neoplasia 1°/2°.
- Inflammatory/vascular damage.
- Failure of distal renal tubules to respond to ADH (renal tubule insensitivity).
May be
- 1° - rare (inherited in man but no evidence for this in dogs).
- 2° (acquired):
- Non-specific condition - includes many conditions with impaired ADH action.
- Renal + metabolic disorder → loss of ability to respond to ADH.
- Most of these may be distinguished by typical history/signs/laboratory findings.
- May be caused by:
- Hyperadrenocorticism.
- Hypercalcemia.
- Hypoadrenocorticism.
- Renal insufficiency.
- Pyometra.
- Hypokalemia.
- Hepatic insufficiency.
- Hyperthyroidism.
- Iatrogenic.
- Post-obstructive ureteral diuresis.
Specific
Central form
- Neoplasia.
- Trauma.
- Inflammation.
- Idiopathic.
Nephrogenic form
- Renal medullary fibrosis, tubular necrosis.
- Hypercalcemia.
- Idiopathic.
Pathophysiology
- Absolute or relative deficiency of ADH → marked polyuria and resultant polydipsia.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Ramsey I D, Dennis R & Herrtage M E (1999) Concurrent central diabetes insipidus and panhypopituitarism in a German shepherd dog. JSAP 40 (6), 271-274 PubMed.
- Schwedes C S (1999) Transient diabetes insipidus in a dog with acromegaly. JSAP 40 (8), 392-396 PubMed.
- Haberer B & Reusch C E (1998) Glycated haemoglobin in various pathological conditions - investigations based on a new, fully automated method. JSAP 39 (11), 510-7 PubMed.
- Takemura N (1998) Successful long-term treatment of congenital nephrogenic diabetes insipdus in a dog. JSAP 39 (12), 592-594 PubMed.