1 / 45

Posterior Pituitary - PowerPoint PPT Presentation

  • Uploaded on

2 Disorders of the Posterior Pituitary Diabetes Insipidus Syndrome of Inappropriate Antidiuretic Hormone (SAIDH). Posterior pituitary hormones are actually produced in the hyopthalamus and only stored in the posterior pituitary Posterior pituitary hormones Antidiuretic hormone (ADH)

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Posterior Pituitary' - frayne

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
2Disorders of the Posterior PituitaryDiabetes InsipidusSyndrome of Inappropriate Antidiuretic Hormone (SAIDH)

Posterior pituitary

Posterior pituitary hormones are actually produced in the hyopthalamus and only stored in the posterior pituitary

Posterior pituitary hormones

Antidiuretic hormone (ADH)


The hormones secreted by the posterior pituitary are

Antidiuretic hormone (ADH) (Also call vasopressin)

and oxytocin.

ADH contributes to fluid balance by

Controlling renal reabsorption of free water

It also has potent vasoconstrictive properties.

Posterior Pituitary

Posterior pituitary1

Antidiuretic hormone (ADH) (Also called vasopressin)

Disorders/diseases resulting from dysfunction

Excess: Syndrome of Inappropriate ADH secretion (SIADH)

Deficiency: Diabetes Insipidus

Posterior Pituitary



Posterior Pituitary Hypersecretion

Siadh syndrome of inappropriate hormone secretion
SIADH - Syndrome of Inappropriate Hormone Secretion

  • ADH (anti-diuretic hormone) is a hormone made in the pituitary gland.

  • ADH does what the name says - it stops urination - diuresis

  • Slowing or stopping urine production leads to fluid retention.

  • That in turn causes a dilution of body sodium

Siadh syndrome of inappropriate hormone secretion1
SIADH - Syndrome of Inappropriate Hormone Secretion

  • Depending on the rapidity & the extent of the sodium drop, a battery of S/S appear.

  • Lethargy, weakness, & foggy thinking are common. Personality changes can happen.

  • Low sodium levels often make pt nauseated

  • If the situation is not corrected, seizures, coma, & even death can follow.

Syndrome of inappropriate antidiuretic hormone secretion siadh

SIADH occurs when there is too much vasopression (ADH) with inappropriate water retention and decreased blood Na levels

Results frommany different conditions and drugs

May be produced by certain tumors such as lung cancer or may result from chronic lung diseases. Medicines associated with SIADH include common meds as antidepressants, antianxiety agents, antipsychotic agents, seizure meds, and desmopressin (DDAVP)

Syndrome of Inappropriate Antidiuretic Hormone Secretion - SIADH

Syndrome of inappropriate antidiuretic hormone secretion siadh1
Syndrome of Inappropriate Antidiuretic Hormone Secretion - SIADH

  • Results from

    • Inability to produce & secrete dilute urine

    • Water retention

    • Increased extra cellular fluid volume

    • Hyponatremia Diseases that affect the hypothalamus

Dx of siadh

  • The following criteria should be fulfilled before a diagnosis of SIADH can be made:

  • persistent excretion of concentrated urine with no reason for ADH release

  • normal renal and adrenal function

  • no edema or hypovolaemia should be present

  • the urine osmolarity should be greater than the serum osmolarity

Physical assessment of siadh
Physical SIADHAssessment of SIADH

  • Initially, S/S are R/T retention of water.

  • Most common complaints

    • GI disturbances-loss of appetite, N,V

  • Nurse

    • Weighs pt & documents any recent weight gain

    • Checks pt extremities for presence of edema

  • Pt with SIADH have free water, not salt, that is retained & edema is not usually present due to intracellular free water

Assessment clinical manifestations of siadh
Assessment SIADH-Clinical Manifestations of SIADH

  • Water retention, hyponatremia, & resulting fluid shifts have an effect on CNS function, especially when serum sodium level drops. Normal serum Na 135-145. S/S occur when serum Na level drops below 125, and especially below 115

  • Clinical S/S

  • Lethargy, headaches, hostility, uncooperativeness, disorientation

  • Early sign -Change in LOC

  • Neurological S/S can progress from lethargy and headaches to decreased responsiveness, seizures, and coma.

  • Nurse assess deep tendon reflexes, which are often < or sluggish

  • V/S changes-tachycardia associated with increased fluid volume & hypothermia associated with CNS disturbance

Lab assessment in siadh
Lab SIADHAssessment in SIADH

  • Extracellular fluid volume expansion affects electrolyte levels in the serum and the urine

  • Elevatedurine sodium levels and specific gravity reflect an increased concentration of the urine

  • Serum sodium levels are decreased, often as low as 110 mEq/L (normal serum sodium 135-145 mEq/L) due to extracellular volume expansionand increased Na excretion

  • Fluid retention causes changes in both plasma and urine osmolality

  • Plasma osmolality is decreased, and the urine is hyperosmolar in relation to the plasma

Osmolality urine osmolality 24 hr specimen 500 800 mosm kg h20 random specimen 50 1200 mosm kg h20
Osmolality SIADHUrine osmolality -24 hr specimen 500-800 mOsm/kg H20Random specimen: 50-1200 mOsm/kg/H20

  • Osmolality is measures in milliosmoles per kilogram of water (mOsm/kg). The major determinants of plasma osmolality are Na, glucose, & urea.

  • The Kidneys are mainly responsible for maintaining the concentration of body fluids within this range of osmolality.

  • When theplasma osmolality becomes abnormal, changes in the level of antidiuretic hormones (ADH) cause the kidneys to conserve or increase the excretion of water to return the osmolality to normal

Siadh diagnostic tests

Blood & Urine tests SIADH

Must have

low serum sodium

low plasma osmolality level

Inappropriated concentrated urine (increased urine osmolality level)

These tests indicate

excess of body water relative to the amount of body sodium.

In other words, ADH is inappropriately holding onto too much water.

Important to eliminateother causes of a low sodium level, such as hypothyroidism or adrenal insufficiency, before settling on a dx of SIADH

Rx- removing the offending drug or tumor, & treat the underlying condition.

SIADH - Diagnostic Tests

Posterior pituitary siadh di
Posterior Pituitary: SIADH,DI SIADH

  • *Affect kidney’s ability to concentrate urine*

  • Measured by urine specific gravity

    • Measures number and size of particles

    • Normal: 1.003 - 1.030

    • High = dehydration

    • Low = Diabetic Insipidus 1.001-1.005

    • Concentrated urine: SIADH

    • Dilute urine: DI

Posterior pituitary siadh
Posterior pituitary: SIADH SIADH

  • ADH excess = water intoxication

  • water is reabsorbed, so assess for

    • increased blood volume, fluid retention

    • concentrated urine, low urine output

    • dilutional hyponatremia (same Na, more H20)

      • muscle cramps and weakness

      • anorexia, n/v, irritable, confused, disorient, seizure

Siadh and hyponatremia
SIADH and Hyponatremia SIADH

  • Hyponatremia- a lower than normal concentration of sodium in the blood

  • Caused by inadequate excretion of water of by excessive water in the circulating bloodstream

  • In a severe case the pt may experience water intoxication, with confusion and lethargy, leading to muscle excitability, convulsions, and coma.

  • Treatment: Fluid and electrolyte balance may be restored by IV infusion of a balanced solution or a fluid restricted diet.

Siadh diagnosis treatment
SIADH SIADHDiagnosis & Treatment


Diagnostic SIADH Study


Decreased plasma osmolality

Urine sodium and urine osmolality elevated

Elevated ADH levels++++++

Normal renal, adrenal, & thyroid functions

Nursing Assessment

Headache,Personality change, Confusion,Irrritability, Dysarthria(difficult, poorly articulated speech), Lethargy,Impaired memory

Restless, weakness, fatigue, gait disturbances

Weight gain+++++


Siadh treatment

  • Water Restriction is the cornerstone of treatment

  • Decreased water intake allows serum sodium level to rise normally.

  • The maximum amount of water that pt with SIADH are allowed to drink is just slightly more that the amount of urine they produce

  • Pt must have regular serum sodium measurements to ensure that the water restriction has been effective

  • Dehydration-The most concerning potential side effect from treatment is dehydration.

Siadh treatment1
SIADH SIADHtreatment

  • Restrict fluid intake (800-1000 cc/day)

  • Daily weight Strict I & O

  • Monitor urine specific gravity

  • 0.9 NS infusion(to raise the serum Na level if water intoxication is severe)

  • Monitor for hyponatremia

  • Lasix may be admin to block circulatory overload

  • Drugs-demeclocyclin HCL & lithium-may be admin to block renal response to ADH, intereferes with action of ADH

  • Drugs - Phenytoin - inhibits ADH release

  • Surgery & Chemo -to remove or destroy neoplasms that may be the underlying cause of this syndrome

Siadh treatment2
SIADH SIADHtreatment

  • Demeclocycline (Declomycin)

  • Lithium

  • Used for:

    • Excess secretion of ADH or SIADH

  • Action:

    • Inhibits ADH action in kidney

    • Blocks renal response to ADH, interferes with action of ADH

  • Therapeutic outcome:

    • Decreased urine specific gravity

Analysis nursing diagnosis siadh
Analysis - SIADHNursing Diagnosis - SIADH

  • 1. Fluid Volume Excess R/T compromised regulatory mechanism, excess ADH

  • 2. High Risk for Injury R/T an altered level of consciousness, confusion, & the possibility of seizures

  • 3. Altered Nutrition: Less than Body Requirements R/T an inability to ingest or digest food or absorb nutrients because of biologic factors (ex-anorexia, N/V)

  • 4. Altered Thought Processes R/T physiologic changes within the central nervous system

Planning implementation

Planning: Pt Goals SIADH

The primary goal is that the pt’s fluid balance will be restored

Interventions to treat SIADH (Pt Care Plan) consists of

Restriction water intake

Using diuretics to promote the excretion of water

Administering drugs that interfere with the action of ADH

Replacing lost sodium

Fluid Restriction

Any excessive free water intake will further dilute the serum sodium concentration

Strict I&O, daily weights, guides the determination of the degree of fluid restriction necessary. A wt gain of 2 pounds (or 1 Kg) or more per day or a gradual increase during several days is cause for concern.

A 1 Kg weight increase is equivalent to 1000ml fluid retention (1Kg = 1 L)

Planning & Implementation

Planning implementation1

Drug Therapy SIADH

Diuretics are sometimes used to treat pt with SIADH, to rid the body of excessive fluid, especially if CHF results from fluid overload

If diuretics are used, be aware of potential effect of electrolyte losses; sodium loss can be potentiated, which further contributes to the clinical picture of SIADH

Hypertonic saline (3% NaCl) may be used to treat SIADH

Helps correct serum sodium level

Raises Na osmolality in the blood

Removes excess intracellular fluid

Cells shrink in hypertonic solution

IV saline is given cautiously because it may contribute to the fluid overload already present & precipitate an episode of CHF.

If the pt needs routine IV fluids, the MD orders a solution in saline (5% dextrose in saline) rather than a solution in water.

Planning & Implementation

Planning implementation2

High Risk for Injury SIADH

Promote safety

Monitor pt neuro status

Subtle Changes, such as muscle twitching before neuro S/S progress to seizures or coma. Check LOC to time, place, & person because disorientation may be present.

Confusion is another neuro sign. Nurse reduces environmental stimuli & explain interventions in simple terms.

Flow sheets contain ongoing info about LOC, motor & sensory neuro assessment, & pertinent lab data helpful in detecting trends.

Decreased LOC and seizures are complications of the low serum sodium level R/T SIADH

Planning & Implementation

Nursing issues
Nursing issues SIADH

  • Monitoring fluid balance(s/s fluid retention):

  • Cardiac problems (water reabsorbed so >bld volume):

  • Neurological problems (headache seizures,cerebral edema, coma,):

  • Energy limitations (muscle cramps, weakness):

  • Allied health problems (anorexia):

  • Risk for injury: (confusion, muscle tremors, etc.)

Nursing issues1
Nursing issues SIADH

  • Fluid Volume Excess R/T inability to excrete water

  • Hyponatremia with plasma hypo-osmolality

  • Weight gain

  • Potential for Injury

    • Institute seizure precautions and safety measures

    • Reorient confused pt

  • Prevent complications of immobility

  • Recognize decreased gastric motility due to hyponatremia, combined with fluid restriction and decreased mobility - >constipation

Diabetes insipidus

Diabetes Insipidus SIADH

Posterior Pituitary

Diabetes insipidus1
Diabetes Insipidus SIADH

  • Uncommon syndrome of posterior pituitary hypofunction

  • S/S

    • Increased thirst - polydipsia

    • Increased urination - polyruia

  • Results from

    • ADH (Vasopression) deficiency, which prevents the kidneys from reabsorbing water

    • Inability to conserve water

Posterior pituitary di
Posterior pituitary : DI SIADH

  • Diabetes insipidus: “to pass through”

  • Decreased ADH = diuresis

  • Water is lost, so assess for:

    • Kidneys produce large amts of diluteurine (5L-10L in 24hrs)

    • low urine specific gravity (1.001-1.005)

    • polyuria (>urine output), polydipsia (>thirst)

    • fluid deficit

      • weight loss, turgor,dehydration, hypotension, constipation, shock

Posterior pituitary hyposecretion diabetes insipidus

Symptoms SIADH -

Thrist & polyuria 5 - 20L/day

SG < 1005

Urine osmol < 100 mmol/L

Se osmol > 295 mmol/kg


Weakness => weight loss, hypotension, tachycardia, constipation, shock.

Sleep deprivation-due to interrupted by need to drink fluids & urinate

Urine specific gravity low (1.001-1.005)

Urine osmolality decreased (50-200

Urine less concentrated than plasma

Plasma osmolality elevated (>295 mOsm/kg)

Hypernatremia in blood

Posterior Pituitary hyposecretion Diabetes Insipidus

Diabetes insipidus etilogy

Familial or idiopathic SIADH

Head injury


Damage to the hypothalamic areas that produce ADH


Lesion of hypothalmus interferes with ADH synthesis/transport/release

brain tumour

pituitary/cranial surgery

head trauma

CNS infection

vascular disease.

Diabetes InsipidusEtilogy

Diabetes insipidus etilogy1
Diabetes Insipidus SIADHEtilogy

  • Drug Related

  • Ethanol & Phenytoin (Classification: Antiarrhythmic, Anticonvulsant):

    • Inhibit ADH secretion

  • Lithium (Classification: Antimanic) & Demeclocycline(Classification:anti-infective-Tetracycline):

    • Inhibit ADH action in kidney

4 types of diabetes insipidus

1) Neurogenic SIADH -also known as





Causedby a deficiency of the Antidiuretic hormone, vasopressin

2) Nephrogenic-also known as

Vasopressin - resistant

Caused by insensitivity of the kidneys to the effect of the antidiuretic hormone, vasopressin

3) Gestagenic-also known as


Caused by a deficiency of the antidiuretic hormone, vasopressin, that occurs only during pregnancy

4) Dipsogenic, a form of primary polydipsis

Caused by

Abnormal thirst and the

Excessive intake of water or other liquids

4 Types of Diabetes Insipidus

Diagnosis rx diabetes insipidus

Diagnosis D.I. SIADH

History and examination

Water deprivation test (see next slide)

Vasopressin challenge test (see next slide)

24 hours urine

Highsodium in blood

MRI of pituitary, hypothalmus and skull to see damaged areas


Intravenous fluids Hypertonic saline IV-Extracellular solution to pull fluid from outside the cell to inside the cell

Vasopressin SC/IM/IV, nasal prep

Long term DDAVP (Desmopression) nasal prep. (analog ADH)

Diagnosis & RxDiabetes Insipidus

Diagnosis fluid deprivation test to identify cause of polyuria
Diagnosis - Fluid Deprivation Test SIADH(To identify cause of polyuria)

  • Baseline VS, then check hourly-allows RN to detect changes, esp postural hypotensin & tachycardia

  • Deprive pt of fluid-Observe for compliance with fluid restriction

  • Hourly- urinary output, specific gravity, & osmololity

  • Urine test results determine whether testing can proceed.

    • Testing can proceed if urinary osmolality stabilized for 3 samples and 3% wt loss is noted

Dx vasopressin challenge
Dx- Vasopressin challenge SIADH

  • Order for 5 Units of aqueous vasopressin sc

  • Continue hourly urinary measurements

  • Vasopressin triggers and ongoing assessment detects Changes in urinary specific gravity and osmolality

    • Specific gravity & osmolality decrease with primary and secondary diabetes insipidus

    • No response is seen with nephrogenic diabetes insipidue

Diabetes insipidus treatment
Diabetes insipidus treatment SIADH

  • Vasopressin (Pitressin) : is ADH

  • Classification: Hormone (antidiuretic)

  • Uses: Treatment of central diabetes insipidus sue to deficient antidiuretic hormone.

  • Route/Dose: IM, sc, nasal spray

  • Nsg Implications:

  • replace fluid: saline and glucose

  • monitor I & O

  • check specific gravity

  • observe electrolytes

  • Monitor adverse reactions-abdominal cramps, angina, MI

Diabetes insipidus treatment1
Diabetes insipidus treatment SIADH

  • Desmopressin (DDAVP)

  • Classification: Hormone (andiuretic)

  • Indication: Management of primary nocturnal eneuresis unresponsive to other treatment modalities

  • po, sc, IV, Intranasal

  • Action: An anologue of naturally occuring vasopressin (antiuretic hormone). Primary action is enhanced reabsorption of water in the kidneys

  • Therapeutic Effects: Prevention of nocturnal enuresis. Maintenace of appropriate body water content in diabetes insipidus.

  • Nsg Implication: Monitor urine & plasma osmolality & urine volume frequently. Assess pt for symptoms of dehydration (excessive thirst, dry skin & mucous membranes, tachycardia, poor skin turgor) Weigh pt daily & assess for edema

Observe for water intoxication with all agents
Observe for Water Intoxication SIADH with all agents

  • ADH excess = water intoxication

  • water is reabsorbed, so assess for

    • increased blood volume, fluid retention

    • concentrated urine, low urine output

    • dilutional hyponatremia (same Na, more H20)

      • muscle cramps and weakness

      • anorexia, n/v, irritable, confused, disorient, seizure

Diabetes insipidus2
Diabetes Insipidus SIADH

  • Fluid Volume Deficit R/T inability to conserve water

    • Thirst, dry mucous membranes

    • Decreased skin turgor

    • Hypotension, tachycardia

    • Hemoconcentration, plasma hyperosmolality, hypernatremia

    • Increased urine output

    • Dilute urine-monitor specific gravity

Nursing issues2
Nursing Issues SIADH

  • Fluid and electrolyte imbalance: R/T >diuresis,

  • monitor urine and plasma osmolarity

  • monitor specific gravity (usually will be low with >diuresis)

  • monitor urine volume (usually will be high 5-10L in 24 hr)

  • Therapy successful when urine output and specific gravity begin to return to normal

  • monitor s/s dehydration

  • weight pt daily & assess for edema

  • Fluid volume deficit

  • Nurse will monitor for hypotension, constipation, shock

  • Sleeping problems: R/T nocturia & increased thirst

  • Education: