Endocrine Abstracts

Background

Fluid balance in patients with diabetes insipidus and COVID-19 is very fragile. The prevalence of hyponatraemia in patients with pneumonia due to COVID-19 seems to be low, but in patients admitted to intensive care units (ICU) is high (up to 20.5%). In contrast, hypernatraemia may also develop in COVID-19 patients in ICU (up to 3.7% of cases), due to insensible water losses from pyrexia, increased respiration rate and use of diuretics. Both hypo and hypernatremia were associated with increased mortality and sepsis.

Case report

A 35 years old, non-smoker women with diabetes insipidus and pituitary insufficiency due to a pituitary stalk tumor (12/8/12 mm diameter) developed COVID-19 in august 2020. She also had obesity (BMI= 38.7 kg/m2), vitamin D insufficiency (25 OH vitamin D= 22.7 ng/mL) and dyslipidemia. Blood pressure, renal function were normal and she had no diabetes mellitus. Endocrine assessment 6 months prior to COVID-19 infection showed gonadotroph insufficiency (FSH=4.1 mUI/ml, LH=1.37 mUI/ml, estradiol<10 pg/ml), central hypothyroidism on levothyroxine treatment (TSH= 1.6 mUI/l, FT4= 9.2 pmol/l) and low normal basal 8 a.m. cortisol levels (4.77 µg/dl) with stimulation to low dose (1 µg, iv) short Synacthen test up to 19.6 µg/dl (ie 540 nmol/l) at 30 minutes and 16.2 µg/dl (ie 446.4 nmoll) at 60 minutes. 8 a.m. ACTH level was normal (16.4 pg/ml). Serum prolactin level was suppressed (0.4 ng/ml) on small dose dopamine agonist therapy (Cabergoline 0.5 mg/week). At COVID-19 diagnosis she was on Desmopressin 240 µg/day, Levothyroxine 50 µg/day, Cabergoline 0.5 mg/week, Cholecalciferol 500 IU/day and Rosuvastatin 5 mg/day. She presented a mild disease with fever, cough, but not pneumonia and did not required hospitalization’. Plasma sodium monitoring was not possible, but the patient did not experienced abnormal variations in fluid balance and body weight was stable. Due to suboptimal adrenal reserve, she was advised (by virtual counselling) taking oral glucocorticoids and to progressively decrease the dose after full recovery. She also received supportive treatment. She fully recovered and 2 months after infection she displayed normal serum natremia (Na=145 mmol/l), high-normal serum osmolality, similar pituitary function and high titer of anti SARS Cov-2 IgG (95.1 IU/ml, normal range < 12 IU/ml).

Conclusion

Patient education, virtual patient counselling, careful monitoring of fluids intake and excretion, daily body weight monitoring and glucocorticoid dose adjustments are mandatory in patients with diabetes insipidus and pituitary insufficiency during Covid-19 infection.