(SIADH) Syndrome of inappropriate antidiuretic hormone

Question 1

SIADH

Answer 1

• Excessive amounts of ADH (vasopressin) is released from posterior pituitary results in
  — Fluid retention
  — - There is an increase in water retention in kidneys. More water reabsorbed=less urine formed.
  — -Therefore decreased urine output

Question 2

SIADH causes

Answer 2

• SIADH is often nonendocrine in origin
• The causes will either directly stimulate pitiuary gland or increase sensitivity of renal tubules

Question 3

SIADH- who is at risk

Answer 3

• Malignancies
  — lung CA, pancreatic CA
• Central Nervous System disorders
  — head injury, stroke, brain tumors, encephalitis, meningitis
• Meds
  — SSRI, chemo, opioids (morphine), general anesthesia
• Pulmonary disorders
  — COPD, severe pneumonia, use of mechanical vents

Question 4

SIADH- what will the nurse observe?

Answer 4

• Decreased urine output
• Hyponatremia
  — Muscle cramps/twitching, weakness, lethargy, N/V, with severe decrease in Na seizures, coma
  — Dilutional hyponatremia- blood is dilute (less concentrated). Actual amount of serum measured is less due to increased blood volume
• GI disturbances: Loss of appetite, N/V
• Wt. gain, tachycardia

Question 5

SIADH diagnostic tests

Answer 5

• Decreased serum sodium
• Decreased plasma osmolality
  — Increased urine osmolality (not urinating)
• Increased urine specific gravity

Question 6

Serum osmolality

Answer 6

• Serum osmolality- measure of hydration status.
• Will measure concentration of blood
• Blood osmolality will increase with dehydration
• Nl value: 275-295/300 milliosmoles
  — The lower the number, the less concentrated the blood
  — The higher the number, the more concentrated the blood will be

Question 7

Specific Gravity

Answer 7

• Indicator or urine concentration
• Nl value: 1.001- 1.005
  — The lower the number, the more dilute the urine will be.
  — The higher the number, the more concentrated the urine will be.

Question 8

Syndrome of inappropriate antidiuretic hormone

Answer 8

• In SIADH, vasopressin (antidiuretic hormone [ADH]) is secreted even when plasma osmolarity is low or normal.
• In SIADH, ADH continues to be released
  — Water is retained
  — Dilutional hyponatremia
  — Fluid overload

Question 9

SIADH Assessment

Answer 9

• Vital signs frequently
• I &Os
• Urine specific gravity
• Daily wts
• Monitor electrolytes
• GI function
  — Anorexia, N/V are early signs of SIADH

Question 10

SIADH Nsg implementations

Answer 10

• Fluid restrictions
• Hypertonic IV solution
• Diuretics
  — demeclocycline (Declomycin)
  — tolvapan (Samsca)
  — conivaptan (Vaprisol)
• Safety measures & seizure precautions
  — esp with severe hyponatremia

Question 11

Compare DI vs SIADH

Answer 11

• ADH (excess or deficiency)
• Urine output (increased or decreased)
• Plasma osmolality (increased or decreased)
• Urine osmolality (increased or decreased)
• s/s (sodium levels- high or low)
  — Hypernatremia: disoriented, weakness, thirst, dry swollen tongue, sticky mucous membranes
  — Hyponatremia: nausea, muscle twitching/cramps, confusion, increased ICP, convulsions
• Which one do we monitor for dehydration and which one for fluid overload