Critical neurological features of COVID-19: Role of imaging methods and biosensors for effective diagnosis

Abstract

COVID-19 is a respiratory infection that has been declared as a global health crisis by the WHO. It mainly affects the respiratory system. Apart from respiratory system, it also affects other organs as well including the brain. Numerous emerging reports have demonstrated that the COVID-19 has detrimental effects on neurological functions, and can lead to severe impairment of the central nervous system (CNS). The neurological manifestations linked with COVID-19 include headache, anosmia, encephalitis, epileptic seizures, Guillain-Barre syndrome, stroke and intracerebral hemorrhage alongwith multiple others complications. The CNS related complications may be severe and are linked with poor diagnosis which may worsen the condition. Therefore, there is a need to precisely understand the neurological sequelae along with upcoming clinical outcomes. Here, we present a brief review of the neurological complications and symptoms associated with COVID-19 along with brain imaging findings. Further, we have discussed about the emerging biosensing approaches which may aid in rapid, precise and mass diagnosis of COVID-19.

Keywords: Biosensors; COVID-19; Diagnostic imaging; Neurological complications; SARS-CoV-2.

Fig. 1

Mechanism of COVID-19 entry inside the host cell: The spike protein of SARS-CoV-2 attaches to the cellular receptor angiotensin-converting enzyme 2 (ACE2) of the host cell. The spike protein has two subunits namely the S1 subunit that regulates ACE2 attachment while other is the S2 subunit that contains the fusion peptide and transmembrane domains that allows the fusion between virus and the target cell membranes. For activation spike protein must be cleaved by the transmembrane protease serine 2 (TMPRSS2) at S1/S2 cleavage site. This mediates entry of the virus and fusion with the surface of the host plasma membrane. The figure was created with BioRender.com.

Fig. 2

The process of infections and nervous system damage by COVID-19. The COVID-19 can damage the nerve via direct infection pathways, hypoxia, angiotensin converting enzyme 2 (ACE2), immune injury, and other mechanisms. Moreover, it can penetrate into the nervous system via the olfactory nerve, and also invade by neuronal pathways and blood circulation leading to neurological disorders. The figure has been reproduced with the permission from reference number [26].

Fig. 3

Neurological manifestations of COVID-19: The SARS-CoV-2 enters through the olfactory epithelium by utilizing the angiotensin converting enzyme 2 (ACE2) receptor. After cell entry, the virus replicates and reaches to the central nervous system (CNS) leading to various neurological manifestations such as encephalopathy, epileptic seizures, anosmia/ageusia, meningitis, Gullian-Barre syndrome etc. The figure was created with BioRender.com.