Central diabetes insipidus following immunization with anti-COVID19 BNT162b2 Comirnaty vaccine

ABSTRACT

Introduction: The coronavirus disease 19 (COVID19) pandemic urged to develop new vaccines to reduce the morbidity and mortality associated with this disease. Recognition and report of potential adverse effects of these novel vaccines (especially the urgent and life-threatening ones) is therefore essential. Case Presentation A 16-year-old boy presented to the Paediatric Emergency Department with polyuria (9 liters per day), polydipsia and concomitant weight loss (- 6 Kg) over the last four months. His past medical history was unremarkable. Onset of symptoms was referred to be few days after second dose of anti- COVID19 BNT162b2 Comirnaty vaccine. The patient was admitted to the Paediatric Department. The physical exam was normal, without neurological abnormalities. Auxological parameters were within normal limits (height -0.12 SDS, weight +0.35 SDS). Daily fluid balance monitoring confirmed polyuria and polydipsia (IN 6,250 L / OUT 7,100 L). Biochemistry laboratory analysis and urine culture were normal (Sodium levels 141 mEq/L). Serum osmolality was 297 mOsm/Kg H2O (normal values 285-305), whereas urine osmolality was 80 mOsm/Kg H2O (normal values 100-1100), suggesting diabetes insipidus. Hormonal tests showed no significant impairment of anterior pituitary function. Test with Desmopressin was performed and confirmed the diagnosis of central diabetes insipidus. Brain MRI revealed pituitary stalk enlargement (4 mm) with contrast enhancement, and loss of posterior pituitary bright spot on T1 weighted imaging. Even in absence of pituitary enlargement, those signs were consistent with neuroinfundibulohypophysitis. Immunoglobulin levels were normal. Low doses of oral Desmopressin were sufficient to control patient's symptoms, normalizing serum and urinary osmolality values and daily fluid balance at discharge. Brain MRI after 2 months showed stable thicken pituitary stalk and detectable small posterior pituitary. Due to persistence of polyuria and polydipsia, therapy with Desmopressin was adjusted by increasing dosage and number of daily administrations. Clinical and neuroradiological follow-up is still ongoing. Conclusion(s) Hypophysitis is a rare disorder characterized by lymphocytic, granulomatous, plasmacytic, or xanthomatous infiltration of the pituitary gland and stalk. Common manifestations are headache, hypopituitarism, and diabetes insipidus. To date, only time correlation between SARS-CoV-2 infection and development of hypophysitis and subsequent hypopituitarism has been reported. Further studies will be needed to deepen a possible causal link between anti-COVID19 vaccine and diabetes insipidus.