Clinical utility of serial systemic immune inflammation indices (SSIIi) in the context of post covid-19 neurological syndrome (PCNS).

Dear Editor

We present the data of serial systemic immune inflammation indices (SSIIi) over four months in the setting of PCNS. The clinical details of this case were published previously [1]. The patient showed evidence of PCNS on discharge with persistent fatigue, brain fog, tiredness with a modified Rankin score of 3 at three months post-discharge [2]. His SSIIi over four months are shown in Fig. 1 (note the first SII (normal at 252)on 12/02/2020 was three weeks before the COVID-19 infection.).

Fig. 1

Serial systemic immune inflmmatory indices (SSIIi) over a four months period in a case of Post Covid-19 Neurological Syndrome (PCNS).

Systemic immune inflammation index (SII) includes neutrophil, platelet and lymphocyte counts which comprehensively summarizes the interplay between the innate and adaptive immune system in COVID-19, cancer, stroke, venous sinus thrombosis and many other disorders. Each SSIIi peak was clinically correlated with an additional neurological or thromboembolic event in this case [1]. Shared pathobiology between stroke and COVID-19 associated neurological disorders are well described and likely to benefit from SSIIi in diagnosis, progress and prognosis of these global health problems [[3], [4], [5], [6], [7]]. We suggest SSIIi to be an excellent, easily available, universal biomarker for many neurological diosrders, in particular, stroke.

The emerging reports suggest that admission SII's clinical utility is a significant prognostic biomarker for survival in COVID-19 [8]. We believe the value of SSIIi is far higher than a single SII as demonstrated here. Given the pandemic's enormity, the routine reporting of SII in simple blood tests might provide extra, useful information universally.