Nitrocathexis and Nitrokathexis

Dear Editor,

The word ‘cathexis’ refers to the concentration of mental energy on one particular person, idea, or object. Used in psychoanalysis to describe unhealthy degrees of attraction, we find this phenomenon in medical care as well.¹

The term nitro cathexis can be used to describe situations where people living with kidney disease, their caregivers, and renal care professionals focus exclusively on levels of nitrogenous wastes, such as urea nitrogen or creatinine. While these values are integral to renovigilance, other, equally important parameters should not be ignored. These include urinary albumin, serum electrolytes, hematologic indices, and bone mineral metabolism markers. The Renal Pentad provides a comprehensive overview of renal health indicators.²

While nitrocathexis is similar to glucocathexis (an excessive preoccupation with glucose control, also termed as a glucocentric approach),³ it may overlap with nephrocathexis, i.e, focus on renal biochemistry, while ignoring systemic determinants of renal health.

We take the opportunity to propose another novel term, nitrokathexis. Though it sounds similar to nitrocathexis, it has different relevance [Table 1]. The word ‘kathexis’ means retention, and has been used in terms such as myelokathexis, lipokathexis, and glucokathexis.^3-5 Nitrokathexis may be defined as a state where circulating levels of creatinine are low, despite poor renal function. Such a situation is most encountered in malnutrition, where low protein intake leads to reduced conversion of nitrogenous precursors to creatinine.⁶ This may lead to fallacies in diagnosis and severity stratification of CKD. Blood urea nitrogen:creatinine and creatinine:cystatin C ratios can be used to overcome these shortcomings, and predict sarcopenia and long-term outcomes in various renal and extra-renal conditions.^7,8 The various reasons have been depicted in Table 2.

The terms nitrocathexis and nitrokathexis are relevant to both renal physicians and pathologists. As we navigate the increasingly complex nephroverse, we must be mindful not to be overtly nitrocathexic, while ensuring that we identify and manage nitrokathexis.