The Relationship Between Diabetes Insipidus and Renal Function in Brain Dead Patients
Panayiotis Varelas1, Mohammed Kananeh2, Paul Brady3, Devin Holden4, Ashar Ata4, Chandan Mehta3, David Greer5, Mohammed Rehman6
1Albany Med-Department of Neurology, 2Thomas Jefferson Hospital, 3Henry Ford Hospital, 4Albany Med Center, 5Boston University School of Medicine, 6Neurology, Henry Ford Health
Objective:
Examine if different degrees of renal dysfunction may impact the manifestation of Diabetes Insipidus (DI) in Brain Dead (BD) patients.
Background:
It has been reported that up to 50% of BD patients do not have signs of clinical DI, which suggests remaining hypothalamic/pituitary activity. However these studies have never accounted for presence or absence of renal dysfunction in those patients
Design/Methods:
All adult patients declared BD over 12 years at a tertiary center were evaluated. DI was diagnosed by polyuria (>300 ml urine output for ≥2 consecutive hours), low urine specific gravity (< 1.005) and increasing serum sodium. Renal function was assessed by the estimated glomerular filtration rate (eGFR), calculated using the simplified Modification of Diet in Renal Disease (sMDRD) equation (validated for ages > 18)
Results:
192/266 BD patients were included in the analysis after excluding those with missing data, < 18-years-old or on vasopressin infusions (for hypotension). 122 (63.5%) developed DI. The proportion with DI decreased significantly with decreasing eGFR: for eGFR > 60ml/min, DI was present in 77.2%; for eGFR 15-60ml/min in 54.5%, and for eGFR < 15ml/min in 32% (p < 0.001). There were 14 patients with eGFR < 9.7 ml/min (all with serum creatinine > 7.1 mg/dL); none experienced DI. Using logistic regression, for every 10 ml/min increase in eGFR the odds of DI increased by 1.2 times (95% CI: 1.10 to 1.32, p < 0.001)
Conclusions:
Presence of hypothalamic/pituitary activity (based on the absence of DI) may be less common than previously thought in BD patients, as kidney dysfunction significantly impacts DI manifestation. DI is observed less frequently in BD patients who have renal injury, and some patients with severe renal dysfunction never develop clinical DI. Renal dysfunction should be accounted for when considering the presence or absence of DI in brain death.