Presentation on theme: "2 Disorders of the Posterior Pituitary Diabetes Insipidus Syndrome of Inappropriate Antidiuretic Hormone (SAIDH)"— Presentation transcript:
1 2 Disorders of the Posterior Pituitary Diabetes Insipidus Syndrome of Inappropriate Antidiuretic Hormone (SAIDH)
2 Posterior PituitaryPosterior pituitary hormones are actually produced in the hyopthalamus and only stored in the posterior pituitaryPosterior pituitary hormonesAntidiuretic hormone (ADH)OxytocinThe hormones secreted by the posterior pituitary areAntidiuretic hormone (ADH) (Also call vasopressin)and oxytocin.ADH contributes to fluid balance byControlling renal reabsorption of free waterIt also has potent vasoconstrictive properties.
3 Posterior PituitaryAntidiuretic hormone (ADH) (Also called vasopressin)Disorders/diseases resulting from dysfunctionExcess: Syndrome of Inappropriate ADH secretion (SIADH)Deficiency: Diabetes Insipidus
5 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 - diuresisSlowing or stopping urine production leads to fluid retention.That in turn causes a dilution of body sodium
6 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 nauseatedIf the situation is not corrected, seizures, coma, & even death can follow.
7 Syndrome of Inappropriate Antidiuretic Hormone Secretion - SIADH Results from many different conditions and drugsMay 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)SIADH occurs when there is too much vasopression (ADH) with inappropriate water retention and decreased blood Na levels
8 Syndrome of Inappropriate Antidiuretic Hormone Secretion - SIADH Results fromInability to produce & secrete dilute urineWater retentionIncreased extra cellular fluid volumeHyponatremia Diseases that affect the hypothalamus
9 Dx of SIADHThe following criteria should be fulfilled before a diagnosis of SIADH can be made:persistent excretion of concentrated urine with no reason for ADH releasenormal renal and adrenal functionno edema or hypovolaemia should be presentthe urine osmolarity should be greater than the serum osmolarity
10 Physical Assessment of SIADH Initially, S/S are R/T retention of water.Most common complaintsGI disturbances-loss of appetite, N,VNurseWeighs pt & documents any recent weight gainChecks pt extremities for presence of edemaPt with SIADH have free water, not salt, that is retained & edema is not usually present due to intracellular free water
11 Assessment-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 S/S occur when serum Na level drops below 125, and especially below 115Clinical S/SLethargy, headaches, hostility, uncooperativeness, disorientationEarly sign -Change in LOCNeurological S/S can progress from lethargy and headaches to decreased responsiveness, seizures, and coma.Nurse assess deep tendon reflexes, which are often < or sluggishV/S changes-tachycardia associated with increased fluid volume & hypothermia associated with CNS disturbance
12 Normal Lab Values serum osmolality (285-295 mOsm/kg) sodium (Na mEq/L)chloride ( mEq/L)Urine osmolality --24 hr specimenmOsm/kg H20-Random specimen: mOsm/kg/H20Osmolality is measures in milliosmoles per kilogram of water (mOsm/kg) The major determinants of plasma osmolality are Na, glucose, & ureaUrine specific gravityHigh=dehydrationLow=diabetes insipidusconcerntrated urine > than mOsm/kg with normal vascular volume and normal renal function
13 Lab Assessment in SIADH Extracellular fluid volume expansion affects electrolyte levels in the serum and the urineElevated urine sodium levels and specific gravity reflect an increased concentration of the urineSerum sodium levels are decreased, often as low as 110 mEq/L (normal serum sodium mEq/L) due to extracellular volume expansion and increased Na excretionFluid retention causes changes in both plasma and urine osmolalityPlasma osmolality is decreased, and the urine is hyperosmolar in relation to the plasma
14 Osmolality Urine osmolality -24 hr specimen 500-800 mOsm/kg H20 Random 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 the plasma 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
15 Posterior Pituitary hypersecretion - SIADH Symptoms - fluid retentionlow serum osmolality (normal mOsm/kg)dilutional low sodium (normal Na mEq/L)low chloride (normal mEq/L)Causes -Diseases effect the hypothalmuspneumoniaTBpositive pressure ventilationTraumaconcerntrated urine (> than mOsm/kg) with normal vascular volume and normal renal functionmuscle cramps & weaknesscerebral edema, lethargy, anorexia, headache, seizures, coma.AIDsdelirium tremensEctopic ADH secreting tumor
16 SIADH - Diagnostic Tests These tests indicateexcess of body water relative to the amount of body sodium.In other words, ADH is inappropriately holding onto too much water.Important to eliminate other causes of a low sodium level, such as hypothyroidism or adrenal insufficiency, before settling on a dx of SIADHRx- removing the offending drug or tumor, & treat the underlying condition.Blood & Urine testsMust havelow serum sodiumlow plasma osmolality levelInappropriated concentrated urine (increased urine osmolality level)
17 Posterior Pituitary: SIADH,DI *Affect kidney’s ability to concentrate urine*Measured by urine specific gravityMeasures number and size of particlesNormal:High = dehydrationLow = Diabetic InsipidusConcentrated urine: SIADHDilute urine: DI
18 Posterior pituitary: SIADH ADH excess = water intoxicationwater is reabsorbed, so assess forincreased blood volume, fluid retentionconcentrated urine, low urine outputdilutional hyponatremia (same Na, more H20)muscle cramps and weaknessanorexia, n/v, irritable, confused, disorient, seizure
19 SIADH and Hyponatremia Hyponatremia- a lower than normal concentration of sodium in the bloodCaused by inadequate excretion of water of by excessive water in the circulating bloodstreamIn 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.
22 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 producePt must have regular serum sodium measurements to ensure that the water restriction has been effectiveDehydration- The most concerning potential side effect from treatment is dehydration.
23 SIADH treatment Restrict fluid intake (800-1000 cc/day) Daily weight Strict I & OMonitor urine specific gravity0.9 NS infusion(to raise the serum Na level if water intoxication is severe)Monitor for hyponatremiaLasix may be admin to block circulatory overloadDrugs-demeclocyclin HCL & lithium-may be admin to block renal response to ADH, intereferes with action of ADHDrugs - Phenytoin - inhibits ADH releaseSurgery & Chemo -to remove or destroy neoplasms that may be the underlying cause of this syndrome
24 SIADH treatment Demeclocycline (Declomycin) Lithium Used for: Action: Excess secretion of ADH or SIADHAction:Inhibits ADH action in kidneyBlocks renal response to ADH, interferes with action of ADHTherapeutic outcome:Decreased urine specific gravity
25 Analysis - Nursing Diagnosis - SIADH 1. Fluid Volume Excess R/T compromised regulatory mechanism, excess ADH2. High Risk for Injury R/T an altered level of consciousness, confusion, & the possibility of seizures3. 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
26 Planning & Implementation Planning: Pt GoalsThe primary goal is that the pt’s fluid balance will be restoredInterventions to treat SIADH (Pt Care Plan) consists ofRestriction water intakeUsing diuretics to promote the excretion of waterAdministering drugs that interfere with the action of ADHReplacing lost sodiumFluid RestrictionAny excessive free water intake will further dilute the serum sodium concentrationStrict 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)
27 Planning & Implementation Hypertonic saline (3% NaCl) may be used to treat SIADHHelps correct serum sodium levelRaises Na osmolality in the bloodRemoves excess intracellular fluidCells shrink in hypertonic solutionIV 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 & ImplementationDrug TherapyDiuretics are sometimes used to treat pt with SIADH, to rid the body of excessive fluid, especially if CHF results from fluid overloadIf 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
28 Planning & Implementation High Risk for InjuryPromote safetyMonitor pt neuro statusSubtle 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
30 Nursing issues Fluid Volume Excess R/T inability to excrete water Hyponatremia with plasma hypo-osmolalityWeight gainPotential for InjuryInstitute seizure precautions and safety measuresReorient confused ptPrevent complications of immobilityRecognize decreased gastric motility due to hyponatremia, combined with fluid restriction and decreased mobility - >constipation
32 Diabetes InsipidusUncommon syndrome of posterior pituitary hypofunctionS/SIncreased thirst - polydipsiaIncreased urination - polyruiaResults fromADH (Vasopression) deficiency, which prevents the kidneys from reabsorbing waterInability to conserve water
33 Posterior pituitary : DI Diabetes insipidus: “to pass through”Decreased ADH = diuresisWater is lost, so assess for:Kidneys produce large amts of dilute urine (5L-10L in 24hrs)low urine specific gravity ( )polyuria (>urine output), polydipsia (>thirst)fluid deficitweight loss, turgor,dehydration, hypotension, constipation, shock
34 Posterior Pituitary hyposecretion Diabetes Insipidus Symptoms -Thrist & polyuria L/daySG < 1005Urine osmol < 100 mmol/LSe osmol > 295 mmol/kgNocturiaWeakness => weight loss, hypotension, tachycardia, constipation, shock.Sleep deprivation-due to interrupted by need to drink fluids & urinateUrine specific gravity low ( )Urine osmolality decreased ( mOsm.kg)Urine less concentrated than plasmaPlasma osmolality elevated (>295 mOsm/kg)Hypernatremia in blood
35 Diabetes Insipidus Etilogy Familial or idiopathicHead injuryNeuorsurgeryDamage to the hypothalamic areas that produce ADHCauseLesion of hypothalmus interferes with ADH synthesis/transport/releasebrain tumourpituitary/cranial surgeryhead traumaCNS infectionvascular disease.
37 4 Types of Diabetes Insipidus 3) Gestagenic-also known asGestestionalCaused by a deficiency of the antidiuretic hormone, vasopressin, that occurs only during pregnancy4) Dipsogenic, a form of primary polydipsisCaused byAbnormal thirst and theExcessive intake of water or other liquids1) Neurogenic -also known ascentralhypothalamicpituitaryneurohypophysealCaused by a deficiency of the Antidiuretic hormone, vasopressin2) Nephrogenic-also known asVasopressin - resistantCaused by insensitivity of the kidneys to the effect of the antidiuretic hormone, vasopressin
38 Diagnosis & Rx Diabetes Insipidus Diagnosis D.I.History and examinationWater deprivation test (see next slide)Vasopressin challenge test (see next slide)24 hours urineHigh sodium in bloodMRI of pituitary, hypothalmus and skull to see damaged areasDiagnosis & Rx Diabetes InsipidusTreatmentIntravenous fluids Hypertonic saline IV-Extracellular solution to pull fluid from outside the cell to inside the cellVasopressin SC/IM/IV, nasal prepLong term DDAVP (Desmopression) nasal prep. (analog ADH)
39 Diagnosis - Fluid Deprivation Test (To identify cause of polyuria) Baseline VS, then check hourly-allows RN to detect changes, esp postural hypotensin & tachycardiaDeprive pt of fluid-Observe for compliance with fluid restrictionHourly- urinary output, specific gravity, & osmololityUrine test results determine whether testing can proceed.Testing can proceed if urinary osmolality stabilized for 3 samples and 3% wt loss is noted
40 Dx- Vasopressin challenge Order for 5 Units of aqueous vasopressin scContinue hourly urinary measurementsVasopressin triggers and ongoing assessment detects Changes in urinary specific gravity and osmolalitySpecific gravity & osmolality decrease with primary and secondary diabetes insipidusNo response is seen with nephrogenic diabetes insipidue
41 Diabetes insipidus treatment Vasopressin (Pitressin) : is ADHClassification: Hormone (antidiuretic)Uses: Treatment of central diabetes insipidus sue to deficient antidiuretic hormone.Route/Dose: IM, sc, nasal sprayNsg Implications:replace fluid: saline and glucosemonitor I & Ocheck specific gravityobserve electrolytesMonitor adverse reactions-abdominal cramps, angina, MI
42 Diabetes insipidus treatment Desmopressin (DDAVP)Classification: Hormone (andiuretic)Indication: Management of primary nocturnal eneuresis unresponsive to other treatment modalitiespo, sc, IV, IntranasalAction: An anologue of naturally occuring vasopressin (antiuretic hormone). Primary action is enhanced reabsorption of water in the kidneysTherapeutic 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
43 Observe for Water Intoxication with all agents ADH excess = water intoxicationwater is reabsorbed, so assess forincreased blood volume, fluid retentionconcentrated urine, low urine outputdilutional hyponatremia (same Na, more H20)muscle cramps and weaknessanorexia, n/v, irritable, confused, disorient, seizure
45 Nursing Issues Fluid and electrolyte imbalance: R/T >diuresis, monitor urine and plasma osmolaritymonitor 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 normalmonitor s/s dehydrationweight pt daily & assess for edemaFluid volume deficitNurse will monitor for hypotension, constipation, shockSleeping problems: R/T nocturia & increased thirstEducation: