Diabetes Insipidus
Presentation:
J.M. is a 33 year-old female patient who recently relocated to the United
States. J.M. had no significant medical history besides complaints of
headaches which have increased in severity over the past year. Recently
J.M. had stated that these headaches had become significant enough that it
was affecting her quality of life and she came into the local ER for a
medical evaluation. At that time J.M. was found to have a pituitary tumor
which was diagnosed via a head CT scan. A craniotomy was performed and the
tumor was removed successfully. J.M. was then transferred to the Surgical
Intensive Care Unit for hourly neuro checks and strict recording of intake
and output. J.M. arrived in the unit within one hour of completion of her
surgery, and at that time was alert and oriented with urine output of 50 -
150ml per hour. However, J.M.’s urine output started to increase in the
following hours with a peak urine output of 700 -1500ml per hour. The
neurosurgeon on call was informed and orders for hourly urine sticks for
urine specific gravity were ordered along with q 6 hour serum osmolarity and
electrolytes tests. J.M. soon developed severe thirst and was consuming
around 600ml of fluid by mouth hourly in addition to 200ml of normal saline
intravenously per hour. During this time J.M.’s urine specific gravity
decreased to below normal levels while her serum osmolarity increased to
above acceptable limits.
Diagnosis & Treatment:
The diagnosis of Diabetes Insipidus was assigned to J.M.’s condition and
treatment was started to correct the fluid imbalance. Diabetes Insipidus is
a condition where the patient’s kidneys are unable to conserve water, and in
J.M’s case this was caused by the trauma inflicted on her pituitary gland
during surgery. Antidiuretic hormone (ADH) which is produced in the
hypothalamus and stored and released by the posterior pituitary gland is
responsible for controlling the amount of water that the kidneys conserve.
In J.M’s case the pituitary gland was unable to release appropriate amounts
of ADH resulting in a severe imbalance in intake and output. The treatment
of choice in this case was a regimen of vasopressin given subcutaneously
every 6 hours based on J.M.’s lab values. Neurosurgery ordered a sliding
scale of SQ vasopressin to be regulated by the lab results of J.M. J.M.
responded well to the vasopressin and within several hours her intake and
output equalized. According to the neurosurgeon this condition would be
self-limiting for J.M. and she would be able to be taken off the vasopressin
relatively soon. Since the condition was caught quickly the patient did not
suffer any effects of dehydration or any severe electrolyte imbalances, two
of the most common complications from this condition. J.M. was transferred
out of the unit within two days and was scheduled to be discharged within
the week. A follow up MRI showed the surgery to be successful in completely
removing the tumor.
Case created by Jessica Mazzone,
2010.