The Role of Malnutrition and Psychiatric Illnesses in Olfactory Dysfunction Post-Kidney Transplantation.
Journal
Journal of the American Society of Nephrology : JASN
ISSN
1533-3450
Date Issued
2024-08-27
Author(s)
Abstract
Gupta et al. conducted an insightful study that was published in JASN, investigating changes in cognitive function and olfaction after kidney transplantation.1 They found that cognitive dysfunction significantly improved 3 months after transplantation, whereas olfactory function did not change. The authors propose that cognitive dysfunction in kidney disease might result from reversible metabolic perturbations, whereas olfactory defects, particularly those involving the central mechanisms, might be less reversible. We concur with these propositions but wish to supplement them by elaborating on the influences of malnutrition and occult psychiatric illnesses on olfactory function in patients with CKD. Existing studies suggest that in patients with ESKD undergoing chronic hemodialysis, olfactory and gustatory dysfunctions are significantly associated with malnutrition.2 A recently published systematic review summarized the impact of several nutritional aberrancies on olfactory disorders in patients with CKD.3 Electrolyte imbalances, nutritional levels (assessed via subjective global assessment scores), and greater inflammation severity have all been implicated as exacerbating factors of olfactory alteration in these patients. Olfactory disorders are frequently accompanied by gustatory dysfunction, another major contributor to poor intake and malnutrition, in patients with CKD. Given that nutritional improvement varies with the duration after kidney transplantation, graft function, and the effects of immunosuppressive therapies, it is plausible that graft recipients in this study still experience a degree of nutritional compromise, precluding early olfactory function recovery. Olfactory dysfunction has also been correlated with depressive symptoms and loneliness. Depression may lead to a decreased activation of secondary olfactory areas and alter olfactory processing, interfering with sensory integration.4 As the prevalence of depression and other psychiatric disorders is high in patients with both nondialysis and dialysis-dependent CKD and remains elevated even after kidney transplantation, it is possible that these illnesses may partly contribute to poorer olfactory function recovery shortly after transplantation. This provides another possible explanation for the olfactory assessment findings in the study by Gupta et al.
Type
letter