ADH Associated diseases Flashcards
Name 2 ADH associated diseases
SIADH - Syndrome of inappropriate ADH
DI - Diabetic Insipidus
What are the functions of ADH VasoPressin
Water level regulation via water resorption mechanisms and vasoconstriction
What may trigger SIADH? Aka Excess ADH secretion
SCLC - Neuroendocrine ectopic release
Infection - pneumonia / TB
A
Drugs - Thiazide like diuretics / SSRI/ TCA
Head trauma - meningitis / haemorrhage
What is the pathological factor in SIADH
HYPONATREMIA ~ Severity
Excess ADH = Excess water retention
To maintain euvolemic volume - Compensatory increased Na+ Secretion
= Hyponatremia
How would SIADH present?
Altered mental state - reduced GCS
Ataxia
N/V
Weakness and cramps
headache
How would someone serum/urine U/E
Serum osmolality - LOW Serum Na+ - Low
Urine Osmolality - HIGH Urine Na+ - High
Clinical euvolemic
SIADH tX
Acute - Hypertonic saline 3% + fluid restriction
+
ADH-Ri - Tolvaptan
What neurological complication may present in SIADH
If untreated excess loss of Na+ can lead to hyponatraemic encephalopathy due to reduced serum osmolality
What is diabetic insipidus?
Excess diuresis consequence of either reduce ADH release (cranial) or reduced ADH response (nephrogenic)
Which results in impaired water reabsorption
What are the cranial causes of DI?
ADH gene mutation, Pituitary adenoma, iatrogenic
What are nephrogenic causes of DI?
ADHR gene mutation,
Renal tubular acidosis
How may DI present?
Polydipsia
Polyuria
Postural Hypotension
Dehydration and lethargy
Hypernatremia (compensatory Sodium resorption to maintain euvolemic)
DI - DX
If patient presents with >3l urine daily then suspect
1st line - water deprivation test - no fluid >6hrs
Normally - Serum Osmolality would go down, Urine osmolality go up (Due to water resorbtion)
W/DI - Serum Osmolality UP, Urine osmolality - DOWN
2nd line Desmopressin test
If Cranial associated DI - increases urine osmolality / With nephrogenic - no effect
DI- TX
Cranial- Desmopressin
Nephrogenic - Thiazide - Bendroflume thiazide
