SECONDARY ADRENAL INSUFFICIENCY IN PATIENT WITH COVID-19 AND HEAD AND NECK CANCER: PITFALLS IN DIAGNOSIS AND TREATMENT

Abstract

SIADH or Syndrome of Inappropriate Antidiuretic Hormone (ADH) secretion is an endocrinological disorder which occurs when there is an evidence of continued ADH secretion in the absence of an appropriate osmotic volume stimulus. Secondary adrenal insufficiency is caused by the insufficient adrenocorticotropic hormone (ACTH) production and imitates SIADH. Both conditions lead to euvolemic hyponatremia, can be misdiagnosed resulting in inadequate treatment and potentially fatal outcome. Our case is about fifty-seven-year-old male patient who was treated with chemoradiotherapy for hematological malignancy of oropharynx and presented with severe hyponatremia several times which almost ended fatally. Taking into account his malignant disease, patient was diagnosed with SIADH as a cause of hyponatremia, however after having suffered Covid-19 infection and started on glucocorticoid therapy, the sodium levels finally corrected and secondary adrenal insufficiency has been declared the cause of hyponatremia. SIADH is often thought to be the cause of hyponatremia in patients with malignant disease. However, SIADH represents a diagnosis of exclusion. Before making a final diagnosis, thyroid and adrenal insufficiency must be ruled out. Moreover, adrenal insufficiency itself imitates SIADH and results in hyponatremia but the management and potential outcomes of these two conditions differ significantly. In patients with Covid–19 infection, notably in patients previously treated for malignancies (chemoradiotherapy, check-point inhibitor therapy), glucocorticoid therapy should be carefully deescalated because of the risk of unrecognized secondary adrenal insufficiency. Glucocorticoids given to the patients with malignant disease and Covid–19 pneumonia shouldn't be discontinued abruptly.