Version 2: Nephrogenic diabetes insipidus in a geriatric patient affected by SARS-CoV-2: complexity of a diagnosis, complexity of a virus

Background. We describe the alteration of the last part of the nephron induced by Sars-CoV-2. Most previous studies have highlighted lesions caused by this virus in the early segments of the nephron. Starting from the pharmacological complexity and comorbidities of the geriatric patient and tracing a pathophysiological and molecular path, we demonstrate a new etiology of nephrogenic diabetes insipidus compared to those most commonly possible.

Methods. A 71 years old man with a respiratory failure in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pneumonia presented the typical symptoms of diabetes insipidus after about 20 days of hospitalization. The water deprivation test led to the diagnosis of nephrogenic diabetes insipidus. The etiological study was complex particularly because due to the patient’s previous lithium therapy.

Results. The sequence of pathognomonic events typical of diabetes insipidus associated with anamnestic, clinical and laboratory evidences supported strongly 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.