SALT WON’T BREAK THIS BRAIN: A CASE OF SEVERE HYPERNATREMIA AND OVERCORRECTION WITHOUT NOTICEABLE CHANGES IN MENTAL STATUS

Introduction:

This is a 29-year-old female with a history of Smith-Lemli-Opitz syndrome (SLOS), intellectual disability, absent genu of the corpus callosum, and adipsia, who presented to our Emergency Room (ER) with hypernatremia. She has had an absent thirst sensation since childhood and chronic hypernatremia with a baseline sodium (Na+) of 150-155 mmol/L. Despite her intellectual disability, she is high functioning; she participates in the Special Olympics and works part-time. Her primary care provider ( PCP) prescribed 64 oz (1.9 L) of fluid daily to manage her hypernatremia. However, while at a summer camp, for two weeks, she was given less than 32 ounces (~945 ml) of fluids a day. Her concerned mother brought her to her PCP’s office, and her Na+ level was >180 mmol/L, so she was referred to the ER. In the ER, her Na+ was 182 mmol/L. She reported occasional dizziness. Her blood pressure was 127/91 mm Hg, heart rate 78 bpm, and she was saturating >95% on room air. She was verbal, alert, and oriented without overt motor or cranial nerve deficits except for her baseline hearing loss, and had dry oral mucosa. Her cardiovascular and pulmonary exams did not show any overt abnormalities, and she did not have any pedal edema. No neuropsychiatric testing was carried out at this time to assess for subtle cranial nerve or motor abnormalities. She was admitted and given IV dextrose. Her serum Na+ progression is shown in the table:

Nephrology was consulted due to the rapid correction of Na+, and an emergent CT scan of the brain showed no edema or hemorrhage. However, by that time, her Na+ levels had already corrected by approximately 18 mmol in 25 hours. She did not have polyuria, and urine osmolality was 1110 mOsm/kg on admission, with concurrent urine Na+ of 123 mmol/L. Her creatinine was 1.22 mg/dL on admission and decreased to 0.86 mg/dL within 24 hours. She was discharged home on the third day and continues to follow up with her PCP, with her repeat Na+ two weeks later being 150 mmol/L.

Methods:

Results:

SLOS is a genetic disorder caused by DHCR7 gene mutations, leading to impaired cholesterol synthesis, congenital anomalies, and intellectual disability. Over 90% of children with SLOS have low cholesterol and elevated 7-DHC levels at diagnosis. Our patient had compound heterozygous DHCR7 mutations and elevated 7-DHC. She attended school, participated in various sports, and could manage her own schedule. However, she needed reminders to maintain adequate water intake due to her adipsia. She has presented to the ER with acute on chronic hypernatremia on two occasions in the past 20 years: once at age 18 with a Na+ level of 162 mmol/L, and once at age 13 with a Na+ level of 178 mmol/L. Both times, she exhibited minimal symptoms of lethargy and dizziness.

Conclusions:

This is the first reported case of SLOS with adipsia and hypernatremia. We postulate that despite her baseline Na+ levels typically being around 150 mmol/L, she likely has undocumented fluctuations due to difficulty adhering to her prescribed fluid intake. This physiological acclimation may explain her lack of mental status changes on presentation despite such high Na+ levels and their rapid correction.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.