Unit 2: Syndrome of Inappropriate Antidiuretic hormone (SIADH) Flashcards
Causes of SIADH
there is an increase in ADH
- lung cancer
- CNS disorders (tumor in brain or neck)
- Side effects of medications (NSAIDs, psychotropic meds)
Syndrome of Inappropriate Antidiuretic Hormone (SIADH)
- increased ADH
- water overload
- hyponatremia d/t hemodilution
- reabsorption of water in the kidneys; decreased urinary output
Pathophysiology of SIADH
the excess secretion of ADH leads to reabsorption of water in the kidneys
- hyponatremia secondary to hemodilution; there is no decrease in total body sodium
- excess ADH results in decreased urine output w/ an increase in concentration (increased specific gravity) and osmolality of urine
Clinical manifestations of SIADH associated with resultant hyponatremia
- anorexia
- nausea
- malaise followed by
- headache, irritability, confusion and weakness
- when serum sodium levels continue to decrease (below 120 mEq/L) may have seizures or become comatose
- neurological signs associated with hyponatremia are r/t osmotic fluid shifts in the brain that lead to cerebral edema and increased ICP
Signs and Symptoms of SIADH
- fluid overload (wt. gain, edema)
- decreased sodium (Na+)
- increased HR
- Hypertension
- Confusion, seizures, coma
- decreased urine output
- increased urine specific gravity (1.005-1.030)
Diagnostic evaluation for SIADH
- monitoring and trending urine-specific gravity
- serum urine and osmolality
- electrolytes
- present w/ scant urine output, elevated urine-specific gravity, and a decrease in serum sodium and osmolality
Medical Management
focused on treating the hyponatremia
Fluid Management
- fluid restriction; less than 1000 mL/day
- w/ severe hyponatremia, IV administration of 3% saline but this fluid requires close monitoring b/c of hyperosmolarity of the solution and typically infused via central venous access device
- Diuretics to increase urine output
- Demeclocycline (Declomycin), a tetracycline derivative, may be given b/c it increases water excretion by the kidneys
Demeclocycline (Declomycin)
tetracycline derivative
-can be used b/c it increases water excretion by the kidneys
Complications of SIADH
r/t decreasing sodium levels
- while sodium concentration drops below 120 mEq/L, life-threatening complications are likely to occur (seizures and coma)
- b/c of fluid shifts in the cerebral cortex, cerebral edema and increased ICP may develop, further exacerbating neurological complications
Connection Check: The nurse correlates which finding to a diagnosis of SIADH? A. Polyuria B. Polyphagia C. Decreased Urine Output D. Glucosuria
C. Decreased urine output
Connection Check: The nurse monitors the patient with SIADH for which complication secondary to serum sodium level of 120 mEq/L? A. hypotension B. hyperglycemia C. seizures D. bradycardia
C. seizures
Nursing Management: Assessment and Analysis
with SIADH, the increased reabsorption of water is directly a result of excessive secretion of ADH
- oliguria
- increased specific-gravity
- increased urine osmolarity
- resulting hemodilution secondary to water retention leads to a decreased serum sodium and osmolality
- while water retention increases, may complain of anorexia and nausea, weakness, and headache
- while serum sodium levels continue to decrease, nurse monitors for confusion and irritability
- if serum sodium drops below 120 mm Hg, patient at risk for seizures
Nursing Diagnoses
- Fluid volume excess r/t increased water reabsorption secondary to increased ADH secretion
- High risk for injury r/t cerebral edema and CNS dysfunction
- Knowledge deficit r/t required fluid restriction
Nursing Assessments
- Neurological status
- Intake and output
- Serum sodium and osmolality
- Urine-specific gravity and urine osmolality
- Skin integrity
