Delirium accompanied by fever could be an early symptom of COVID-19. This is the main conclusion drawn by a scientific research review carried out by researchers from the Universitat Oberta de Catalunya (UOC) and published in the open access Journal of Clinical Immunology and Immunotherapy, which highlights the fact 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 UOC researcher Javier Correa, who carried out this study at the University of Bordeaux (France). He added that "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".

The novel COVID-19 is the seventh known coronavirus infecting humans . After less than a week of infection, the most characteristic symptoms of patients suffering COVID-19 include fever, cough, fatigue, or shortness of breath . Nonetheless, although SARS-CoV-2 mainly targets and infects the lungs, the damage it provokes can extend to other major organs, including the brain.

Indeed, emerging data is signalling that some COVID-19 patients also show atypical Central Nervous System (CNS) manifestations such as headache, loss of taste and smell and, interestingly, delirium. In this regard, recent studies from China, France or the United Kingdom have identified the presence of neurological symptoms in COVID-19 patients. Neurologic signs were recorded in France in 84% patients (N=58) suffering severe COVID-19 on ICU admission and before treatment, including patients presenting delirium features such asinattention, disorganized thinking and altered level of consciousness (44%) . In 3 centres in Wuhan, China, 36.4% of hospitalized patients (N=214) diagnosed with COVID-19 commonly showed neurologic manifestations, especially when they were suffering the more severe forms of the disease, including impaired consciousness (14.8%) .

In a recent UK-wide surveillance study, neurological and neuropsychiatric complications were recorded in patients that developed COVID-19, with 39 (31%) of 125 patients presenting altered mental status, comprising 10 patients with neuropsychiatric disorders presenting new-onset psychosis . As a result, is especially important to understand delirium in the specific context of COVID-19, since delirium is a frequent manifestation of infection, it may be regarded as an early infection symptom, and there is concern that long term cognitive consequences in patients suffering COVID-19 may emerge.