ABSTRACT
Background: Coronavirus Disease-19 (COVID-19) has an important impact on the kidney, however, the involvement of the last part of the nephron has not been previously documented. Methods: We present the case of a 71 years old man with respiratory failure in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pneumonia who, after about 20 days of hospitalization, presented the typical symptoms of diabetes insipidus. The water deprivation test led to the diagnosis of nephrogenic diabetes insipidus. The analysis of the underlying cause was complex because of the patient's pharmacological and medical history. In particular, potential alternative causes for nephrogenic diabetes insipidus including urinary tract infection and previous lithium therapy had to be ruled out. Results: The sequence of pathognomonic events typical of diabetes insipidus associated with anamnestic, clinical and laboratory evidences strongly supported the diagnosis of nephrogenic diabetes insipidus due to SARS-CoV-2, rather than to other etiologies. Conclusions: The collecting duct could represent a target for SARS-CoV-2 infection, directly or indirectly as a result of lesions of upstream portions of the nephron which would cascade into the distal segment. Other molecules, besides angiotensin 2 converting enzyme, might be involved in facilitating the viral aggression. The complexity of the geriatric patient shows the importance of a comprehensive approach which integrates a careful monitoring of clinical signs and symptoms, laboratory and instrumental tests. This is especially important in the context of SARS-CoV-2 infection and in the management of its unexpected complications.