Neuroendocrine Disorders After TBI

Question 1

Which part of pituitary does ADH come from

Answer 1

Posterior pituitary

Question 2

What complication is there if hyponatremia is corrected too fast

Answer 2

Pontine myelinolysis

Question 3

Fracture of what part of the skull can result in diabetes inspidus

Answer 3

Sella turcica

Question 4

Treatment of SIADH

Answer 4

Fluid restriction to 1L/day; hypertonic saline with severe symptoms

Question 5

What does ADH do?

Answer 5

Increase water retention

Question 6

What medication can be used to treat SIADH hyponatremia

Answer 6

Demeclocycline, which inhibits ADH action in the kidney

Question 7

What can cause hypernatremia in TBI patients

Answer 7

Diabetes insipidus

Question 8

Which hormone from pituitary gland is most commonly increased in TBI patients

Answer 8

Growth Hormone

Question 9

3 main causes of hyponatremia in TBI patients

Answer 9

SIADH, CSW and psychogenic polydipsia

Question 10

Medical treatment of diabetes insipidus

Answer 10

1. Hormone replacement with desmopressin (DDAVP), which is ADH analog.
2. Chlorpropamide, which potentiates the effects of ADH and is used in mild DI with partial ADH deficiency

Question 11

How do you treat CSW

Answer 11

Replace fluids with NS and correct Na levels with salt tabs

Question 12

What medication commonly causes SIADH

Answer 12

Carbamazepine

Question 13

Pathophysiology of diabetes insipidus

Answer 13

Decrease in ADH resulting in increased urinary volume resulting in increased Na concentration in blood –> hypernatremia

Question 14

SIADH vs CSW and extracellular volume

Answer 14

SIADH = isovolemic hyponatremia
CSW = hypovolemic hyponatremia

Question 15

All TBI patients are recommended to undergo endocrine function evaluation at ________ and at ______ post-injury regardless of severity of injury

Answer 15

3 months and at 1 year

Question 16

Serum Na, serum osmolality, urine osmolality in SIADH vs DI vs CSW

Answer 16

SIADH = dec serum Na, dec serum osmolality, inc urine osmolality.
DI = inc serum NA, inc serum osmolality, dec urine osmolality
CSW = dec serum Na, dec serum osmolality, nml urine osmolality

Question 17

What happens to ADH levels in CSW and why

Answer 17

ADH levels go up because of increased Na excretion in urine resulting in decreased extracellular volume

Question 18

What is more common in TBI patients, SIADH or CSW

Answer 18

CSW

Question 19

What causes CSW in TBI patients

Answer 19

Renal Na transport abnormalities resulting in extracellular volume depletion