SIADH Flashcards
What is SIADH
Inappropriate ADH release
- Euvolemia (a lot of water)
- Hyponatremia
How does Euvolemia occur due to hyponatremia and too much ADH
Excess ADH
Raised water retention
Compensated Na excretion
= Euvolemia
What are the main causes of SIADH
Tumours - SCLC, Prostate and Pancreatic
Head trauma
Infection - TB, Pneumonia and meningitis
What drugs can cause SIADH
Carbamazepine
SSRI
Sulfonylurea
What is the pathology of SIADH
RAAS = Increased ADH
Vessel constriction = Increase BP
APO 2 expression = Increase BV (Water retention)
-water retained and sodium excreted
What are the symptoms of SIADH/Hyponatremia
Vomiting
Headache
Low GCS
Muscle weakness
What are the complications w/ severe hyponatremia
seizures Brainstem herniation (Raised ICP)
How can low sodium cause brainstem herniation
low sodium = more water retention
Water enters skull = increase ICP
-Hyponatremic encephalopathy
-Tentorial herniation
How can a brainstem herniation cause tentorial herniation
If the brainstem herniates into the foramen magnum
How is SIADH diagnosed
Low sodium w/ normal potassium in serum
High urine osmolality (Concentrated)
What is the differential for SIADH and how is it treated
0.9% saline
How is SIADH treated
Fluid restriction w/ hypertonic saline
Treat the cause (Tumour resection)
What can be given to treat chronic SIADH
Furosemide
Vaso Antagonist
