Endocrine Abstracts

Although TIH is a well-established complication of this drug class, the extent of this problem and the serious morbidity that can result is often not appreciated. At our centre, we became aware of three serious cases of TIH over a 2-week period during the ‘heat wave’ in July 2013. In at least one of these cases excessive water drinking was a clear precipitant. We therefore determined the incidence of TIH at our hospital and in particular whether there is a seasonal effect on admission rates.

We retrospectively reviewed records of all admissions to our hospital containing a discharge diagnosis code of hypo-osmolality/hyponatraemia over a 14-month period. The medical discharge summary of each case was reviewed to identify cases where TIH was implicated as the predominant cause. Patients with a co-morbidity of heart failure, malignancy or liver disease were excluded from the analysis. Average monthly temperature data were obtained from public records (Met Office).

443 patients were admitted with a coding diagnosis of hypo-osmolality/hyponatraemia between June 2012 and August 2013. Amongst these there were 73 cases of TIH. Cases of TIH were sorted chronologically by month of admission. The monthly average temperature was then compared with the monthly TIH admission rate. Our data demonstrate a background monthly admission rate of three to four cases of TIH but with evidence of seasonal peaks in the hotter months with nine and seven cases admitted in July and August 2012 respectively and ten cases in July 2013.

TIH is common cause for acute medical admission in the UK. Our data suggest evidence of seasonal variation in the incidence of the problem with patients being at greater risk of developing this complication during the hotter months of the year. An increase in fluid intake during hotter weather may underlie this association.