Endocrine Salt Flashcards
Rx acute, severe, symptomatic hyponatraemia (< 120 mmol/L)
Hypertonic saline
High urine osmolality after fluid deprivation &
High urine osmolality after desmopressin
primary polydipsia
Fx of ADH
Works on the collecting duct of the Kidneys to retain H2O
DI is an inability to
Concentrate urine
Causes of nephrogenic DI
- genetic: Mutations in the AVPR2 gene on X chromosome=affects the vasopression (ADH) receptor, less common form = mutation in the gene that encodes the aquaporin 2 channel
- electrolytes: hypERcalcaemia, hypokalaemia
- Drugs
- lithium & demeclocycline
Causes of Cranial DI - it can be caused by (5)
hypothalamus doesn’t produce ADH for the pituitary gland to secrete
* Brain tumours
* Head injury
* Brain malformations
* Brain infections (meningitis, encephalitis and tuberculosis)
* Brain surgery or radiotherapy
What do Labs normally show (serum & urine) in DI
Salty person dilute urine
Function of the collecting duct
- fine-tunes salt and water reabsorption via ADH
and plays a major role in acid–base balance.
Explain the Ix for DI
- Water deprivation - no h20 for 8 hour; Measure urine osmolality
- Desmopressin & Measure urine osmolality after 8 hour
Sodium urine osmolality in H20 deprivation for :
Cranial DI
Nephrogenic DI
Primary polydipsia
Cranial DI -Low
Nephrogenic DI - Low
Primary polydipsia- High
After synthetic ADH desmopressin in DI
Cranial DI
Nephrogenic DI
Cranial High
Nephrogenic Low
Urine osmolality After h20 deprivation - HIGH
Urine osmolality After desmopressin - HIGH
Primary polydipsia
Urine osmolality After h20 deprivation LOW
Urine osmolality After desmopressin LOW
Nephrogenic
Urine osmolality After h20 deprivation LOW
Urine osmolality After desmopressin HIGH
Cranial DI
