SIADH

Question 1

SIADH stands for…

Answer 1

Syndrome of Inappropriate Antidiuretic Hormone

Question 2

What does it result from…

Answer 2

An increase or continued release of ADH secretion even when plasma osmolarity is normal/low

Question 3

Was does the increased release of ADH cause?

Answer 3

Water retention
Water intoxication
Dilutional hyponatremia
Serum hypo-osmolality w NORMAL renal function

Question 4

The increased volume plasma does what?

Answer 4

Increases the GFR and inhibits the release of renin and aldosterone

Question 5

What does SIADH result in?

Answer 5

Increased sodium loss in urine, leading to greater hyponatremia

Question 6

Malignant causes of SIADH

Answer 6

Small cell lung cancer
Hodgkin's lymphoma
NHL
Pancreatic
Duodenal and GU carcinomas

Question 7

Pulmonary disorder causes of SIADH

Answer 7

Viral and bacterial pneumonia
Lung abscess
Mycoses
Chronic lung diseases

Question 8

CNS disorder causes of SIADH

Answer 8

Trauma
Infections
Tumors
Strokes
SLE

Question 9

Drugs that cause SIADH

Answer 9

Chlorpropamide
Carbamazepine
Opioids
Vincristine
Tricyclic antidepressants

Question 10

Clinical GI manifestations

Answer 10

anorexia
nausea
vomiting
abodminal cramps

Question 11

Clinical manifestations

Answer 11

Fluid retention
Dilutional hyponatremia
Oliguria (increased urine specific gravity, >1.025)
Signs of fluid volume overload
Low urine output and high urine osmolality (?1200 mOsm/kg)
Decreased serum osmolality (<280 mOsm/kg)

Question 12

Early manifestations of SIADH

Answer 12

related to water retention leading to oliguria

Question 13

Diagnosis is made how?

Answer 13

Immunoassay of ADH

Based on analysis of urine and serum electrolytes and osmolality

Question 14

Abnormal analysis of urine, serum electrolytes, and osmolality

Answer 14

Dilutional hypnatremia Na <134 mEq/L
Low serum osmolality <280 mOsm/kg
High urine osmolality
High urine specific gravity >1.025
Increased urine sodium levels

Question 15

Normal labs

Answer 15

Serum osmolality 285-295 mOsm/kg
Sodium 135-145 mEq/L
Urine specific gravity 1.003-1.030 (decreased: urine is diluted, increased: urine is concentrated)

Question 16

Initial goal is to restore normal fluid volume and osmolality by

Answer 16

fluid restriction to 800-1000 mL per day to prevent further dilution of plasma sodium levels
IV hypertonic saline solution (3%-5%)
Monitor urine and sodium osmolality, electrolytes

Question 17

Medications to help manage SIADH

Answer 17

Diuretics (when Na levels are near normal)
Demeclocycline
Tolivaptan (PO) and Conivapatan (IV) - SIADH with hyponatrmia - causes water excretion without sodium loss

Question 18

Surgical management of SIADH

Answer 18

Hypophysectomy

Question 19

Demeclocycline

Answer 19

antibiotic used to treat acne

blocks the effects of ADH on the renal tubules

Question 20

Hypophysectomy

Answer 20

Removal of the pituitary gland with a transphenoidal approach

Question 21

Preoperative teaching for hypophysectomy

Answer 21

Allow client to verbalize fears
Nasal packing will be present for 2-3 days
Mustache dressing - drip pad under nose
Mouth breathing
Explain measures to avoid increasing ICP that delays healing

Question 22

Postoperative care for hypophysectomy

Answer 22

Monitor vital signs
Monitor neurologic status (vision, mental, LOC, decreased extremity strength)
Instruct to avoid vigorous coughing, sneezing, valsalva, brushing teeth
HOB elevated at 30 degree angle
Monitor electrolyte values
Monitor I/O
Mouth breathing