Answer
- Diagnosis : Diabetes Insipidus.
- his previous operation is for cerebral tumour & this
tumour is the cause of deficiency of ADH leading to
Diabetes Insipidus as it destroys the supraoptic &
supra ventricular nuclei, hypothalamo - hypophyseal
tract or posterior Pituitary gland.
Work Step by Step
Diabetes Insipidus
Causes
1- Deficiency of ADH :
due to alesion ( tumour ) destroying the Supraoptic
& paraventricular nuclei, Hypothalamo-hypophyseal
tract or posterior pituitary gland.
2- inability of kidney to respond to ADH ( nephrogenic
diabetes ): ADH fails to increase renal cAMP.
Manifestations
1- Polyuria :
- excretion of large volume of urine (= diabetes )
which may reach 20 liters / day, due to lack of
tubular reabsorption of water.
- urine is colourless, tasteless ( Insipidus ) & watery
with a low specific gravity ( 1001 - 1003 ).
2- Polydipsia :
- drinking large amounts of water secondary to
polyuria.
- fatal dehydration develops if the sense of thirst is
absent.
3- Vitamin Deficiency :
loss of water soluble vitamins especially vitamin B
in urine.
4- B.M.R. :
-is increased to maintain body temperature constant
- increased B.M.R. is due to drinking large volume of
fluids with low temperature.
5- Signs of increased intracranial tension & pressure
manifestations as Anterior Pituitary Insufficiency:
may occur in presence of atumour.
