65 year male recently got bed restricted due to generalized
weakness following anorexia and vomiting.
He has been using lithium carbonate for his manic-depressive
illness for some 15 years.
On examination he is lethargic but able to communicate,
Temp: 101f, pulse 124bpm and respiratory rate 16 /min. Blood pressure 100/60
lying and 70/40 on sitting.
Investigation: Lithium 1.5 mmole/lit; Urea 20mg/dl and S. creatinine 1.3mg/dl. Na
169 , Ca 2.3mmole/l.
Glucose 4mmole; urine osmolality 240.
Give probable reason for patients hypernatremia, polyurea
and polydipsia?
This patient has developed nephrogenic diabetes inspidus due
to prolong use of lithium for his
Manic-depressive illness. Lithium block the action of ADH as
well as adenylate cyclase in collecting duct
, thereby excessive water excretion or we can say decreased
water absorption has led to increased serum osmolality and decreased urine
osmolality. In this way thrist mechnism is stimulated to compensate increased
serum osmolality.
\
Common Drugs causing nephrogenic diabetes inspidus:
Lithirm
Amphotericin B
Demeclocycline
No comments:
Post a Comment