ENDOCRINE ENDOCRINE SYSTEMSYSTEM

DIABETES INSIPIDUSDIABETES INSIPIDUS

NAME: NORAZREENA BT ANDUL GHANINAME: NORAZREENA BT ANDUL GHANIMATRIX NO:2011444488MATRIX NO:2011444488

GLANDSGLANDS

DIABETES DIABETES INSIPIDUSINSIPIDUS

• Diabetes insipidus is the Diabetes insipidus is the condition characterized by condition characterized by polydipsia ( excessive thirst ) polydipsia ( excessive thirst ) and polyuria ( excessive urine and polyuria ( excessive urine volume) due to decreased volume) due to decreased secretion or resistance to the secretion or resistance to the antidiuretic hormone (ADH) .antidiuretic hormone (ADH) .

WHO ARE MOST WHO ARE MOST AFFECTED?AFFECTED?

Diabetes insipidus is uncommon, with Diabetes insipidus is uncommon, with a prevalence of 1 case per 25,000 a prevalence of 1 case per 25,000 people.people.

No significant sex differences in No significant sex differences in central or nephrogenic diabetes central or nephrogenic diabetes insipidus exist. insipidus exist.

Male and female prevalence are equal.Male and female prevalence are equal.

(From (From http://www.endotext.org/neuroendo/neuroendo2/figuhttp://www.endotext.org/neuroendo/neuroendo2/figures2)res2)

PATHOPHYSIOLOPATHOPHYSIOLOGYGYHormones control the function of the kidneys in regulating the Hormones control the function of the kidneys in regulating the

water content of the body. water content of the body.

The hypothalamus, a small but very important gland located The hypothalamus, a small but very important gland located in the middle of the brain, manufactures the antidiuretic in the middle of the brain, manufactures the antidiuretic hormone, ADH (also known as arginine vasopressin) for hormone, ADH (also known as arginine vasopressin) for subsequent storage in the posterior pituitary gland that is subsequent storage in the posterior pituitary gland that is attached to the hypothalmus by a thin stalk.attached to the hypothalmus by a thin stalk.

ADH is released when the blood volume decreased , when a ADH is released when the blood volume decreased , when a large amount of salt shows up in blood, or when pain or stress large amount of salt shows up in blood, or when pain or stress are present. are present.

ADH release by the pituitary gland stimulates reabsorption of ADH release by the pituitary gland stimulates reabsorption of water into the blood. If water intake is not enough to make up water into the blood. If water intake is not enough to make up for the water lost in perspiration and in breathing, the for the water lost in perspiration and in breathing, the pituitary gland releases more ADH, thus reducing the amount pituitary gland releases more ADH, thus reducing the amount of water released in urine. of water released in urine.

If the blood is too dilute, the pituitary gland reduces the If the blood is too dilute, the pituitary gland reduces the secretion of ADH, causing a larger flow of water into urine.secretion of ADH, causing a larger flow of water into urine.

PHATOGENESISPHATOGENESIS

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MANIFESTATIONMANIFESTATIONSymptomsSymptoms

Polydipsia ( excessive thirst)Polydipsia ( excessive thirst)

Polyuria ( excessive urination , 2.5 liters Polyuria ( excessive urination , 2.5 liters to 15 liter of urination per day )to 15 liter of urination per day )

Nocturia ( urinary frequency at night )Nocturia ( urinary frequency at night )

DehydrationDehydration – headache, dizziness, fainting, – headache, dizziness, fainting, dry mouthdry mouth

MANIFESTATIONMANIFESTATIONSignsSigns

HypotensionHypotension

Dilute urineDilute urine

Reduced capillary refill timeReduced capillary refill time

Cold extremitiesCold extremities

Crying, growth retardation , irritability , weight Crying, growth retardation , irritability , weight loss in infantsloss in infants

Anorexia, Enuresis ( Bed wetting) , growth Anorexia, Enuresis ( Bed wetting) , growth defects in childrendefects in children

DISEASE DISEASE CLASSIFICATIONCLASSIFICATION

4 types of DI:4 types of DI:

Neurogenic Neurogenic

NephrogenicNephrogenic

DipsogenicDipsogenic

GestationalGestational

NEUROGENICNEUROGENIC• NDINDI more commonly known as more commonly known as centralcentral

• Central DI is due to lack of ADH Central DI is due to lack of ADH secretionsecretion

• Causes increased urine production and Causes increased urine production and dehydrationdehydration

• IdiopathicIdiopathic – 25% of cases. – 25% of cases.

http://geekymedics.comhttp://geekymedics.com

CAUSESCAUSES Because vasopressin is produced by the Because vasopressin is produced by the

hypothalamus & released by the posterior hypothalamus & released by the posterior pituitary gland, pathology impacting either of pituitary gland, pathology impacting either of these glands has the potential to cause these glands has the potential to cause diabetes insipidus.diabetes insipidus.

The lack of vasopressin production usually results The lack of vasopressin production usually results from some sort of damagefrom some sort of damage

benign tumor (20 percent of cases),

trauma (17 percent of cases),

neurosurgery (9 percent of cases)

rare causes which include hemochromatosis, sarcoidosis, and histiocytosis.

Neurogenic diabetes insipidus can be a failure of Neurogenic diabetes insipidus can be a failure of production at the hypothalamus, or a failure of production at the hypothalamus, or a failure of release at the pituitary.release at the pituitary.

NEPRHOGENICNEPRHOGENIC• Nephrogenic diabetes insipidusNephrogenic diabetes insipidus is a form of is a form of

diabetes insipidus due primarily to pathology of the kidney.

• which is caused by insufficient levels of antidiuretic hormone (ADH)/Argenine Vasopressin (AVP).

• Nephrogenic diabetes insipidus is caused by an improper response of the kidney to ADH,

• leading to a decrease in the ability of the kidney to concentrate the urine by removing free water.

NEPRHOGENICNEPRHOGENICAcquired Acquired 

MetabolicMetabolic – hypercalcaemia, hyperglycaemia, – hypercalcaemia, hyperglycaemia, hypokalaemiahypokalaemia

DrugsDrugs – lithium, demeclocycline – – lithium, demeclocycline – both interfere both interfere with the binding of ADH¹with the binding of ADH¹

Chronic renal disease – Chronic renal disease – polycystic kidney’spolycystic kidney’s

AmyloidosisAmyloidosis

Post obstructive uropathyPost obstructive uropathy¹¹

DIPSOGENICDIPSOGENIC

Dipsogenic DI is due to a defect or Dipsogenic DI is due to a defect or damage to the thirst mechanism, which damage to the thirst mechanism, which is located in the hypothalamus.is located in the hypothalamus.

This defect results in an abnormal This defect results in an abnormal increase in thirst and fluid intake that increase in thirst and fluid intake that suppresses vasopressin secretion and suppresses vasopressin secretion and increases urine output.increases urine output.

GESTATIONALGESTATIONALGestational DI only occurs during Gestational DI only occurs during pregnancy. During pregnancy, all women produce vasopressinase in the placenta, which breaks down ADH.

Gestational diabetes insipidus is Gestational diabetes insipidus is therefore thought to be caused by therefore thought to be caused by overproduction of vasopressinase by the overproduction of vasopressinase by the placenta causing a lack of functional placenta causing a lack of functional vasopressin.vasopressin.

Most cases of gestational DI can be Most cases of gestational DI can be treated with desmopressin. treated with desmopressin.

SIGNIFICANT LAB SIGNIFICANT LAB TESTTEST

clinical findings,clinical findings,

laboratory test laboratory test

radiological imagingradiological imaging

Routine urine test: urine specific gravity 1.005 Routine urine test: urine specific gravity 1.005 or less and osmolality of urine is less than 200 or less and osmolality of urine is less than 200 mOsm/kg .mOsm/kg .

fluid deprivation testfluid deprivation test

Radiological imaging includes MRI may show Radiological imaging includes MRI may show abnormality of pituitary or hypothalamus abnormality of pituitary or hypothalamus gland .gland .

SIGNIFICANT LAB SIGNIFICANT LAB TESTTEST

The fluid deprivation test is the most useful in The fluid deprivation test is the most useful in diagnosing diabetes insipidusdiagnosing diabetes insipidus

Helps determine cause of DI – Helps determine cause of DI – neurogenic, neurogenic, nephrogenic, primary polydipsianephrogenic, primary polydipsia

Patient is allowed fluids overnightPatient is allowed fluids overnight

Patient is then deprived of fluids for 8 hours Patient is then deprived of fluids for 8 hours (or until loss of 5% of body weight if earlier)(or until loss of 5% of body weight if earlier)

The patient is weighted hourlyThe patient is weighted hourly

Plasma osmolality is measured every 4 hoursPlasma osmolality is measured every 4 hours

SIGNIFICANT LAB SIGNIFICANT LAB TESTTEST

Urine volume & Osmolality is measured Urine volume & Osmolality is measured every 2 hoursevery 2 hours

At the end of the deprivation period the At the end of the deprivation period the patient is given 2mcg of IM patient is given 2mcg of IM DesmopressinDesmopressin

Urine volume & Serum osmolality are Urine volume & Serum osmolality are then measured over the next 4 hoursthen measured over the next 4 hours

IMAGING IMAGING CONSIDERATIONCONSIDERATION

Brain MRI - scan head looking for Brain MRI - scan head looking for tumourstumours

Pituitary MRI: T1-weighted images of Pituitary MRI: T1-weighted images of the healthy posterior pituitary yield a the healthy posterior pituitary yield a hyperintense signal. In patients with hyperintense signal. In patients with central diabetes insipidus, this signal is central diabetes insipidus, this signal is absent except in the rare familial form absent except in the rare familial form of central diabetes insipidus where the of central diabetes insipidus where the signal is still present.signal is still present.

RADIOLOGICAL RADIOLOGICAL APPEARANCESAPPEARANCES

http://ckj.oxfordjournals.org

Sagittal MRI of suprasellar cystic craniopharyngioma in a child presenting with hypothalamic diabetes insipidus. The child presented with a 2-month history of polyuria and polydipsia. Treatment was with cyst decompression and sub-total surgical excision.

RADIOLOGICAL RADIOLOGICAL APPEARANCESAPPEARANCES

Figure 11. Loss of the posterior pituitary 'bright spot' on T1 weighted MRI in hypothalamic diabetes insipidus. The normal posterior pituitary can be demonstrated as a 'bright spot' within the sella turcica on T1-weighted MRI (a). This increased signal intensity can be lost in HDI (b). An ectopic posterior pituitary 'bright-spot' can be seen some cases of childhood onset hypopituitarism, implying failure to complete normal developmental migration. Function can be normal despite the aberrant positionhttp://www.endotext.org/

REFERENCESREFERENCEShttp://ckj.oxfordjournals.org -retrieved on 12 May 17, 2012

http://geekymedics.com-http://geekymedics.com-retrieved on 12 May 17, 2012

http://www.google.com.my-http://www.google.com.my-retrieved on 12 May 17, 2012

http://www.endotext.org/neuroendo/neuroendo2 -http://www.endotext.org/neuroendo/neuroendo2 -retrieved on 12 May 17, 2012

http://www.mirage-samoyeds.com/diabetes2-http://www.mirage-samoyeds.com/diabetes2-retrieved on 12 May 17, 2012