Hyponatremia Case Studies

A 73 year old Caucasian American male was brought to our hospital with an acute presentation of generalized weakness and altered mental status. Nine days before his admission to the hospital, he developed sudden onset of weakness and had extremely poor mobility that he required help to utilize the bathroom. He also required increasing assistance in ambulation. He stated that he quickly recovered and was well 2 days later. However, at a follow-up outpatient appointment with his primary care physician, his laboratory blood work showed that he had a serum sodium of 122 mEq/L. He was advised to go to the emergency room, but he declined. He was given 1 liter of normal saline instead. He returned to his primary care physician for blood work

Patient had had poor oral intake prior to this admission and was euvolemic. In consideration of his euvolemic status, SIADH was determined to be the most likely cause for his hyponatremia. Hypothyroidism and adrenal insufficient were less likely based on the lab values of his thyroid function test and cortisol values. Cerebral salt wasting syndrome was also less likely after the urine osmolality was found to be high (FeNa, Urine Osmolality, Serum Osmolality). He was initially put on free water restriction, gentle normal saline drip and high protein diet while his BMP was monitored closely. The serum sodium improved from 120 mEq/L to 127 mEq/L after his first day of admission. Our nephrology team later started him on fludrocortisone (how much?) and salt tablet. His serum sodium was monitored every 6 hours during the first 48 hours of admission. Initially, his altered mental status and hyponatremia slowly improved. A CT of his head was ordered which showed no acute abnormality. However, an MRI of his brain showed prominent pontine T2 hyperintensity. His neurological examination also revealed deficit in bilateral eye adduction. Based on the findings of his MRI and neurological examination, our neurology team concluded the patient had a diagnosis of Central Pontine