Diabetes Insipidus - Revision history

Bara at 23:07, 7 August 2012

2012-08-07T23:07:40Z

Alexia91 at 17:58, 4 April 2012

2012-04-04T17:58:00Z

Sazwillo729: /* Introduction */

2011-12-08T19:14:03Z

Introduction

HelenD at 07:32, 9 August 2011

2011-08-09T07:32:11Z

Bara: /* Introduction */

2011-04-28T11:21:01Z

Introduction

Bara: /* Introduction */

2011-04-28T11:20:29Z

Introduction

Bara at 11:19, 28 April 2011

2011-04-28T11:19:56Z

Kthompson at 18:53, 12 March 2011

2011-03-12T18:53:17Z

Kthompson at 18:51, 12 March 2011

2011-03-12T18:51:43Z

Bara at 15:22, 24 February 2011

2011-02-24T15:22:10Z

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 == Introduction  ==
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 {{review}}
 [[Category:Expert_Review - Small Animal]] [[Category:Endocrine_Diseases_-_Dog]] [[Category:Endocrine_Diseases_-_Cat]] [[Category:Endocrine_System_-_Pathology]]

@@ Line 4: / Line 4: @@
 Causes of deficiency may be:
-:'''Central''': failure to synthesise or release of ADH
+:'''Central''': Central DI is characterized by decreased secretion of antidiuretic hormone (ADH)—also known as arginine vasopressin (AVP)—which gives rise to polyuria and polydipsia by diminishing the patient’s ability to concentrate urine.
-:'''Nephrogenic''': failure of the [[:Category:Nephron|nephrons]] to respond to ADH present in the kidney
+Diminished or absent ADH can be the result of a defect in 1 or more sites involving the hypothalamic osmoreceptors, the supraoptic or paraventricular nuclei, or the supraopticohypophyseal tract.
 == Clinical Signs  ==

@@ Line 4: / Line 4: @@
 Causes of deficiency may be:
-:'''Central''': failure to synthesise or release or ADH
+:'''Central''': failure to synthesise or release of ADH
 :'''Nephrogenic''': failure of the [[:Category:Nephron|nephrons]] to respond to ADH present in the kidney

← Older revision		Revision as of 07:32, 9 August 2011
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	Central diabetes insipidus secondary to head trauma varies in prognosis and spontaneous recovery may occur.		Central diabetes insipidus secondary to head trauma varies in prognosis and spontaneous recovery may occur.
		+
		+	{{Learning
		+	\|flashcards = [[Feline Medicine Q&A 04]]
		+	}}

	== References ==		== References ==

@@ Line 1: / Line 1: @@
 == Introduction  ==
-[[Pituitary Gland - Anatomy & Physiology#Antidiuretic Hormone|Anti-Diuretic Hormone (ADH) from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water. Release is regulated by osmoreceptors in the hypothalamus and volume receptors in the hypothalamus. A deficiency of ADH is known as '''Diabetes insipidus'''.
+[[Pituitary Gland - Anatomy & Physiology#Antidiuretic Hormone|Anti-Diuretic Hormone (ADH)]] from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water. Release is regulated by osmoreceptors in the hypothalamus and volume receptors in the hypothalamus. A deficiency of ADH is known as Diabetes insipidus.
 Causes of deficiency may be:

@@ Line 1: / Line 1: @@
-== Introduction<br>  ==
+== Introduction  ==
-Anti- Diuretic Hormone ADH, from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water. Release is regulated by osmoreceptors in the hypothalamus and volume receptors in the hypothalamus.A deficiency of ADH is known as '''Diabetes insipidus'''.
+[[Pituitary Gland - Anatomy & Physiology#Antidiuretic Hormone|Anti-Diuretic Hormone (ADH) from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water. Release is regulated by osmoreceptors in the hypothalamus and volume receptors in the hypothalamus. A deficiency of ADH is known as '''Diabetes insipidus'''.
-Causes of deficiany may by '''central'''''': '''failure to synthesise or release ADH,'''or''''''ne''''''phrogenic''': failure of the nephrons to respond to ADH present in the kidney.
+Causes of deficiency may be:
-<br>
+== Clinical Signs  ==
-== Clinical Signs<br>  ==
+There will be a marked '''polyuria, 5-20X normal output''', often resulting in nocturia and incontinence. There will also be a desperate '''polydipsia''', animal will search for water.
 Other clinical signs include dehydration, weight loss, anorexia and neurological signs if neoplastic in origin.
-<br>
+== Diagnosis  ==
-== Diagnosis<br>  ==
+The differential diagnosis of '''psychogenic polydipsia '''must be excluded. In this disease, patients drink excessively leading to overhydration and a functional lack of ADH (none is released as water does not need to be conserved). The kidney in this case will have decreased ability to concentrate urine due to '''medullary washout'''. The hypertonicity within the medulla is abolished by the excess water.
-The differential diagnosis of '''psychogenic polydipsia '''must be excluded. In this disease, patients drink excessively leading to overhydration and a functional lack of ADH (none is released as water does not need to be conserved). The kidney in this case will have decreased ability to concentrate urine due to '''medullary washout'''. The hypertonicity within the medulla is abolished by the excess water.''<br>''
+A urine sample should be taken. In Diabetes insipidus, urine specific gravity is low ('''1.001-1.005''').
 Blood tests will show dehydration so will see mildly elevated PCV and TP.
-<br>
+When other differentials have been excluded, it may be necessary to perform a '''water deprivation test''': This aims to measure urine osmolality after 12-24 hours water deprivation to determine whether ADH is indeed deficient.
-When other differentials have been excluded, it may be neccessary to perform a '''water d''''''eprivation test''': This aims to measure urine osmolality after 12-24 hours water deprivation to determine whether ADH is indeed deficient.
+Steps: Collect initial urine and plasma samples for osmolality and weigh patient. Withhold food and fluid. Collect urine and plasma after 6 hours and thence 2 hourly. This test can be damaging to the animals health and must not be performed unless diagnosis is strongly presumed as it can become an animal welfare issue if not. '''STOP''' when: patient displays concentrating ability or patient loses >5% bodyweight or 24 hours have passed.
-Steps: Collect initial urine and plasma samples for osmolality and weigh patient. Withhold food and fluid.&nbsp;Collect urine and plasma after 6 hours and thence 2 hourly.This test can be damagine to the animals health and must not be performed unless diagnosis is stongly presumed as it can become an animal welfare issue if not. '''STOP''' when: patient displays concentraing ability or patient loses &gt;5% bodyweight or&nbsp;24 hours have passed.
+A positive test for diabetes insipidus is a failure to concentrate urine >1.010 after 12-24 hours.
-A positive test for diabetes insipidus is a failure to concentrate urine &gt;1.010 after 12-24 hours.
+An '''ADH response test''' can also be performed. Administer '''Desmopressin''' i/m and monitor specific gravity of urine 2 hourly. '''Central''' diabetes insipidus will concentrate urine (>1.020) whereas '''nephrogenic''' diabetes insipidus will not be able to concentrate the urine at all in response to the synthetic ADH (SG <1.010.)
-''<br>'' An'''ADH response test''' can also be performed. Administer '''Desmopressin''' i/m and monitor specific gravity of urine 2 hourly. '''Central''' diabetes insipidus will concentrate urine &gt;1.020 whereas '''n''''''ephrogenic''' diabetes insipidus will not be able to concentrate the urine at all in response to the synthetic ADH. SG &lt;1.010.<br> Nb. A positive ADH response test means nothing unless preceded by a water deprivation test to prove the presence of diabetes insipidus.
+Nb. A positive ADH response test means nothing unless preceded by a water deprivation test to prove the presence of diabetes insipidus.
-<br>
+== Treatment  ==
-== Treatment<br>  ==
+A few different treatment options have been described for this disease such as '''Desmopressin''': used for central disease only as is expensive.
-A few different treatment options have been described for this disease such as '''Desmopressin''': used for central disease only as is expensive.&nbsp;'''Thiazide diuretics''' work by p''aradoxical effect'' by inhibiting the reabsorption of sodium in the proximal convoluted tubule the volume of fluid within the ECF will fall and hence the GFR will also decrease, reducing water loss. '''Chlorpropamide '''works by potentiates effect of ADH on the tubules. '''Carbemazepine''': Acts similarly to chlorpropamide.
+'''Thiazide diuretics''' work by ''paradoxical effect'' by inhibiting the reabsorption of sodium in the proximal convoluted tubule. The volume of fluid within the extracellular fluid (ECF) will fall and hence the [[GFR]] will also decrease, reducing water loss. '''Chlorpropamide '''works by potentiating the effect of ADH on the tubules. '''Carbemazepine''' acts similarly to chlorpropamide.
 Many owners choose not to medicate and will manage the disease by keeping animal outdoors with free access to water at all times.
-<br>
+== Prognosis  ==
 Congenital central diabetes insipidus has a favourable prognosis and can be treated with desmopressin. Nephrogenic diabetes insipidus has a more guarded prognosis.
@@ Line 49: / Line 45: @@
 Any expanding tumour, particularly if neurological signs are present, carries a poor prognosis.
-Central diabtetes insipidus secondary to head trauma varies in prognosis and spontaneous recovery may occur.
+Central diabetes insipidus secondary to head trauma varies in prognosis and spontaneous recovery may occur.
-<br>
+== References  ==
-== References<br>  ==
+Ettinger, S.J. and Feldman, E. C. (2000) '''Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 '''(Fifth Edition)'' W.B. Saunders Company''
-Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company<br>Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)W.B. Saunders Company <br>Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier. <br><br>
+Ettinger, S.J, Feldman, E.C. (2005) '''Textbook of Veterinary Internal Medicine '''(6th edition, volume 2) ''W.B. Saunders Company ''
-<br>
+Nelson, R.W. and Couto, C.G. (2009) '''Small Animal Internal Medicine '''(Fourth Edition)'' Mosby Elsevier. ''
-[[Category:To_Do_-_Review]] [[Category:Endocrine_Diseases_-_Dog]] [[Category:Endocrine_Diseases_-_Cat]] [[Category:Endocrine_System_-_Pathology]]

@@ Line 1: / Line 1: @@
-{{unfinished}}
+== Introduction<br>  ==
-ADH from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water.  Release is regulated by:
+Anti- Diuretic Hormone ADH, from the posterior pituitary stimulates water uptake from the distal convoluted tubule and collecting ducts of the kidney and so conserves water. Release is regulated by osmoreceptors in the hypothalamus and volume receptors in the hypothalamus.A deficiency of ADH is known as '''Diabetes insipidus'''.
-A deficiency of ADH is known as '''Diabetes insipidus'''.
+Causes of deficiany may by '''c''''''entral''': failure to synthesise or release ADH, or '''n''''''ephrogenic''': failure of the nephrons to respond to ADH present in the kidney.
-''Clinical Signs''
+<br>
-''Differential diagnosis'':
+== Clinical Signs<br> ==
-Presents similarly to '''Psychogenic polydipsia'''.  Patients drink excessively leading to overhydration and a functional lack of ADH (none is released as water does not need to be conserved).  The kidney in this case will have decreased ability to concentrate urine due to '''medullary washout'''.  The hypertonicity within the medulla is abolished by the excess water.
+There will be a marked polyuria; '''5-20X normal outpu''''''t''', often resulting in nocturia and incontinence. There will also be a desperate polydipsia; animal will search for water.
-''Diagnosis'':
+Other clinical signs include dehydration, weight loss, anorexia and neurological signs if neoplastic in origin.
-*Urine specific gravity is low ('''1.001-1.005''')<br>Solute is absorbed in excess of water thus demonstrating a good tubular function.
+<br>
-''Psychogenic polydipsia: plasma osmolality decreased due to excess water in contrast to increased plasma osmolality with DI due to dehydration.''
+== Diagnosis<br> ==
-*'''Water deprivation test''': Aims to measure urine osmolality after 12-24 hours water deprivation to determine whether ADH is indeed deficient.
+The differential diagnosis of '''psychogenic polydipsia '''must be excluded. In this disease, patients drink excessively leading to overhydration and a functional lack of ADH (none is released as water does not need to be conserved). The kidney in this case will have decreased ability to concentrate urine due to '''medullary washout'''. The hypertonicity within the medulla is abolished by the excess water.''<br>''
-A positive test for diabetes insipidus is a failure to concentrate urine >1.010 after 12-24 hours.
+A urine sample should be taken. In Diabetes insipidus, urine specific gravity is low ('''1.001-1.005''').<br>
-''If psychogenic polydipsia is suspected then gradually restrict water for 3 days prior to test to avoid medullary washout giving a false positive test.''
+Blood tests will show dehydration so will see mildly elevated PCV and TP.
-*'''ADH response test''': Administer '''Desmopressin''' i/m.  Monitor specific gravity of urine 2 hourly.
+<br>
-''Treatment'':
+When other differentials have been excluded, it may be neccessary to perform a'''water''''''deprivation test''': This aims to measure urine osmolality after 12-24 hours water deprivation to determine whether ADH is indeed deficient.
-''Prognosis'':
+Steps: Collect initial urine and plasma samples for osmolality and weigh patient. Withhold food and fluid.&nbsp;Collect urine and plasma after 6 hours and thence 2 hourly.This test can be damagine to the animals health and must not be performed unless diagnosis is stongly presumed as it can become an animal welfare issue if not. '''STOP''' when: patient displays concentraing ability or patient loses &gt;5% bodyweight or&nbsp;24 hours have passed.
-Congenital central diabetes insipidus has a favourable prognosis and can be treated with desmopressin.  Nephrogenic diabetes insipidus has a more guarded prognosis.
+A positive test for diabetes insipidus is a failure to concentrate urine &gt;1.010 after 12-24 hours.
-Any expanding tumour, particularly if neurological signs are present, carries a poor prognosis.
+''<br>''
-Central diabtetes insipidus secondary to head trauma varies in prognosis and spontaneous recovery may occur.
+<br>
-[[Category:To Do - Clinical]][[Category:Endocrine Diseases - Dog]][[Category:Endocrine Diseases - Cat]]
+== Treatment<br> ==
-[[Category:Endocrine System - Pathology]]

← Older revision		Revision as of 15:22, 24 February 2011
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	[[Category:To Do - Clinical]][[Category:Endocrine Diseases - Dog]][[Category:Endocrine Diseases - Cat]]		[[Category:To Do - Clinical]][[Category:Endocrine Diseases - Dog]][[Category:Endocrine Diseases - Cat]]
		+	[[Category:Endocrine System - Pathology]]