Mental confusion could be an early sign of Covid-19, study finds

Delirium or mental confusion accompanied by fever could be an early symptom of COVID-19, particularly in elderly patients, according to a review of studies.

The research, published in the Journal of Clinical Immunology and Immunotherapy, suggests that together with the loss of the senses of taste and smell, and headaches that occur in the days prior to the manifestation of coughing and breathing difficulties, some patients also develop delirium.

As such, the manifestation of this state of confusion, when accompanied by high fever, should be considered an early marker of the disease, particularly in the case of elderly patients.

"Delirium is a state of confusion in which the person feels out of touch with reality, as if they are dreaming," explained Javier Correa from the Universitat Oberta de Catalunya (UOC) in Spain.

"We need to be on the alert, particularly in an epidemiological situation like this, because an individual presenting certain signs of confusion may be an indication of infection," said Correa, who carried out this study at the University of Bordeaux in France.

Correa, together with UOC researcher Diego Redolar Ripoll, reviewed scientific work published on the effects of COVID-19 in relation to the central nervous system, i.e. the brain.

The review found that there are growing indications that the novel coronavirus also affects the central nervous system, and produces neurocognitive alterations, such as headaches and delirium, as well as psychotic episodes.

"The main hypotheses which explain how the coronavirus SARS-CoV-2 affects the brain point to three possible causes: hypoxia or neuronal oxygen deficiency, inflammation of brain tissue due to cytokine storm and the fact that the virus has the ability to cross the blood-brain barrier to directly invade the brain," said Correa.

He noted that any one of these three factors has the potential to result in delirium.

The evidence of hypoxia-related brain damage has been observed in autopsies carried out on patients who have died from the infection, and it has been possible to isolate the virus from the cerebral tissue, Correa said.

According to the researchers, delirium, cognitive deficits and behavioural anomalies are most likely to be the result of systemic inflammation of the organ and a state of hypoxia, which also causes the neuronal tissue to become inflamed and cause damage in areas such as the hippocampus.

This is associated with the cognitive dysfunctions and behavioural alterations presented by patients suffering delirium, they said.