Endocrine Abstracts

Background: Central diabetes insipidus (DI) has now been described in a handful of case reports as a symptom of Covid-19 infection - associated with acute respiratory distress syndrome (ARDS)1 - and as a possible late onset sequela secondary to Covid-19 infection. It has also once been reported following immunization with mRNA Covid-19 vaccination. Our Trust serves a population of 612,000 and we have recently observed two cases of central DI, one post Covid-19 infection and one post vaccination.

Case presentations: The first case is a 44 year old woman, normally fit and well, who presented with acute symptoms of excessive thirst (14 litres per day) and polyuria four weeks after symptomatic Covid-19 infection. The second case is a 69 year old woman, also normally well, who developed symptoms of DI three weeks following Covid-19 mRNA (Pfizer) booster vaccination.

Investigation: Both individuals were confirmed to have normal anterior pituitary function prior to undergoing modified water deprivation testing, which confirmed the diagnosis of central DI. Morning urine osmolalities were 111 and 145mOsm/kgH20, serum osmolalities 309 and 301mOsm/kgH20 respectively; urine output falling and osmolality correcting to 534 and 487 mOsm/kgH20 three hours post Desmopressin administration.

Treatment and Outcome: Desmopressin was commenced with good symptomatic benefit in both cases. MRI pituitaries are awaited. It is currently unclear whether the DI will be permanent or resolve spontaneously with time.

Discussion: Previous case reports have described DI as a rare association with Covid-19, likely secondary to pituitary hypophysitis. Our recent experience suggests this may be a more common association than previously thought. In fact, we have a third case currently under investigation for possible partial DI post Covid-19 vaccination. DI has a low population prevalence (1/25,000) and it may therefore require collaboration between centres to assess how frequently this association is being observed.