Etiology of polyuria in patients undergoing aneurysmal clipping for subarachnoid hemorrhage and its relationship with serum ADH levels -an observational study.

Shazia Anjum, Zulfiqar Ali, Imtiaz Naqash, Bashir Ahmad Laway

Abstract

Background: Polyuria is a common finding in patients with subarachnoid hemorrhage (SAH). It is multifactorial in origin mainly due to diabetes insipidus, cerebral salt wasting syndrome, increased fluid administration, the use of diuretics and triple H therapy. The aims of our study were to study the (i) incidence of polyuria in patients undergoing clipping of aneurysm for SAH, (ii) To investigate the aetiology of polyuria (whether diabetes insipidus or cerebral salt wasting syndrome) (iii) and to find association of polyuria with serum ADH levels in patients undergoing clipping for SAH.
Methods: All patients being operated for aneurysmal SAH (surgical clipping) from September 2017 to August 2019 were included in our study. Patients presenting with clinical features suggestive of SAH were evaluated using a predefined proforma. A detailed clinical history was taken from attendants. The baseline Glasgow coma score, baseline investigations (complete blood count, renal and liver function tests), computerized tomography scan and cerebral angiography (to determine the source of aneurysmal bleeding) were done in the preoperative period and the findings noted.. Serum and urine osmolality, serum and urine sodium, urine specific gravity of the patient, serum ADH levels were sent after induction. Polyuria was defined as the urine output of more than 3 litres over 24hours in patients not receiving mannitol and more than 6 litres/24 hours in patients receiving mannitol. All the patients having polyuria were evaluated for the cause of polyuria. Their serum osmolality, urine osmolality, serum sodium, urinary sodium, urine specific gravity and serum ADH levels were done on a daily basis till their polyuria settled. Patients were followed till they were discharged from the hospital and their outcome was seen in terms of Glasgow outcome scale (GOS).
Results: A total of 93 patients were studied. 17 patients developed polyuria with an incidence of 18.27 percent. It was seen that there were 19 episodes of polyuria in 17 patients of polyuria. The etiology of polyuria in our study was not found to be due to diabetes insipidus. However two patients had features suggestive of CSW syndrome.
The mean baseline ADH levels in 17 patients who had polyuria were similar to the baseline ADH values of control patient population. There was a decrease (statistically insignificant) in ADH levels during episodes of polyuria when compared to the baseline ADH levels.
Conclusion: Most of the patients in our study did not have polyuria due to diabetes insipidus while as two patients had features suggestive of CSW. There was a non significant decrease in ADH levels during episodes of polyuria when compared to the baseline ADH levels.