Anti-Diuretic Hormone Flashcards
Anti diuretic means
to prevent urination
What is the target organs of antidiuretic hormone?
Kidney
Secreted by the posterior pituitary gland
Anti-diuretic hormone
Promotes water re-absorption by kidneys
Anti-diuretic hormone
“Too low”
Diabetes Insipidus
“Too high”
SIADH
Described as the passage of very large amounts of dilute urine
Diabetes insipidus
2 forms of diabetes insipidus
Central (Neurogenic)
Nephrogenic
Causes of Central (Neurogenic)
-Idiopathic
- Tumor-associated
- Post-Operative
- Head Trauma
- Hereditary (10%)
Causes of Nephrogenic
-Lithium Toxicity
- Hypercalcemia
- Hypokalemia
-Hyperglycemia
Its pathophysiology with ADH synthesis, transport, or release
Central (Neurogenic)
Its pathophysiology is inadequate renal response to ADH despite presence of adequate ADH
Nephrogenic
Clinical Manifestations of Diabetes Insipidus
-Polyuria
- Polydipsia
- Dilute urine
- Hypovolemia
What is the normal specific gravity?
1.010-1.025
Diagnostic Test of Diabetes Insipidus
Fluid Deprivation Test
Assess ability of kidneys to concentrate urine under the influence of ADH
Fluid Deprivation Test
Stages of Fluid Deprivation Test
-Fluids are deprived for 8 hours
-Plasma osmolality are checked q4h and urine volume and osmolality q2h
- Desmopressin acetate is given at the end of the 8 hours
Medical Management of Central Diabetes Insipidus
Desmopressin (DDAVP)
- A synthetic vasopressin
-Given intranasally (nasal spray) q12 to 24 hours
- Caution: CAD
Chlorpropamide (Diabetes)
-Has an antidiuretic effect in vasopressin- sensitive DI
Nursing Management of Central Diabetes Insipidus
-During acute episodes
-Hypotonic IV fluids or D5 water, as ordered (to replace urine output)
-Encourage increased oral fluids as tolerated
-Monitor VS, urine output and specific gravity
-Monitor level of consciousness and for signs of dehydration
Management of Nephrogenic Diabetes Insipidus
-Thiazide diuretics
-Reduces blood flow to the ADH- sensitive distal nephrons
-Indomethacin
-Helps increase renal responsiveness to ADH
Collaborative & Nursing Management of Nephrogenic Diabetes Insipidus
-Low-sodium diet (no more than 3g/day) (helps decrease urine output)
- Encourage increased oral fluids as tolerated
- Monitor VS, urine output and specific gravity
- Monitor level of consciousness and for signs of dehydration
involves the continued secretion or action of arginine vasopressin (AVP) despite normal or increased plasma volume.
SIADH (Syndrome of Inappropriate Anti-Diuretic Hormone)
Causes of SIADH
-Malignancies
-Drugs
-CNS Disorders
Drugs that triggers the SIADH
-Vinca Alkaloids
-Opioids
-General Anesthetics
-Oxytocin
-Carbamazepine
-Antidepressants
CNS Disorders that triggers the SIADH
-Head Injury
-Infection (CNS)
- Stroke
SIADH tends to be self limiting if causes are:
Head trauma or Drugs
SIADH may become chronic if associated with:
Tumors or metabolic diseases
What is the first symptom of hyponatremia?
Headache
Excessive ADH can increased the reabsorption of water from the collecting ducts back into the circulation. What are the results or the manifestation of it?
-Decreased urine volume
- Increased urine specific gravity
Excessive ADH can also increased blood volume. What are the factors or the clinical manifestations of it?
-Hypertension
-Weight gain
3 classification of hyponatremia
-Mild hyponatremia
- Moderate hyponatremia
- Severe Hyponatremia
Serum sodium level of mild hyponatremia
130-134 mmol/L
Serum sodium level of moderate hyponatremia
125-129 mmol/L
Serum sodium level of severe hyponatremia
<120
Mostly asymptomatic but can report/present with headache, nausea, vomiting, fatigue, confusion, anorexia, muscle cramps
Mild Hyponatremia
Gait disturbances, headache, vomiting, fatigue, confusion, muscle cramps, depressed deep tendon reflexes
Moderate hyponatremia
Classification in hyponatremia where delirium, restlessness, agitation, or lethargy, seizures, brainstem herniation, respiratory arrest, coma, death
Severe hyponatremia
Emergency Management of SIADH with Severe Hyponatremia
-3% Hypertonic Saline
-Furosemide (Lasix)- increases excretion of free water thereby limiting treatment-induced volume expansion
High yield concept of Emergency Management of SIADH with Severe Hyponatremia
-Sodium correction must be made gradually
- Too rapid elevation of sodium levels causes CENTRAL PONTINE MYELINOLYSIS (CPM)
Medical Management of SIADH with Mild/Moderate Hyponatremia in Fluid Restriction
FLUID RESTRICTION
(First Line of Treatment)
Medical Management of SIADH with Mild/Moderate Hyponatremia in VAPTANS
-Classified as aquaretics (blocks ADH action and increase water excretion)
CONIVAPTAN
-Given as IV
-Used in combination with fluid restriction
-Should not be used for more than 4 days
TOLVAPTAN
- Given as PO
- Dose needs to be titrated after loading dose up to a max of 60 mg
-Fluid restriction is avoided as it may cause too rapid sodium correction
Medical Management of SIADH with Mild/Moderate Hyponatremia in Loop Diuretics
-Drug of Choice: Furosemide (Lasix)
-Reduces sodium reabsorption in the Loop of Henle
- Lost sodium is replaced by either 3% saline or PNSS
Medical Management of Asymptomatic Chronic SIADH
VAPTANS (Alternative)
-Chronic loop diuretic therapy with increased salt intake
(UREA)-Safe to consume
-Increases urine volume
- Dissolve powder in water and take during or after meals
-Antacids may be used if with GI upset
(Mannitol)- Diuretic
-Increases osmolarity of glomerular filtrate thereby preventing reabsorption of water
