When the Centers for Disease Control and Prevention updated their list of coronavirus symptoms to 12 in total, the reasons behind other symptoms such as inflammation and confusion still couldn't be fully explained by medical experts. International researchers came together to determine of coronavirus is attacking the central nervous system alongside the respiratory system.
Recently published in The Laryngoscope, an international team was headed by Dr. Ahmad Sedaghat from the University of Cincinnati College of Medicine. As head of the Department of Otolaryngology-Head and Neck Surgery, his team discovered that psychological symptoms were closely associated with the loss of taste and smell.
'If you had asked me why would I be depressed or anxious when I am COVID positive, I would say it is because my symptoms are severe and I have shortness of breath or I can't breathe or I have symptoms such as cough or high fever," said Sedaghat. Meanwhile, the other symptoms such as fever, cough, and shortness of breath appeared as severe indicators of the virus.
'None of these symptoms that portended morbidity or mortality was associated with how depressed or anxious these patients were,' explained Sedaghat. 'The only element of COVID-19 that was associated with depressed mood and anxiety was the severity of patients' loss of smell and taste.' This discovering was both shocking and unexpected, he said
An 'Unexpected Finding'
For their research, 114 patients at Kantonsspital Aarau in Switzerland answered a cross-sectional telephone questionnaire. Their recent diagnosis of coronavirus were accompanied by symptoms of excessive mucus, cough, fever, and shortness of breath.
In addition to the typical respiratory symptoms, almost 50% of the patients had a depressed mood recently while 21% were moody every day. Furthermore, 45% of the patients had mild anxiety and 10% had severe anxiety.
"The unexpected finding that the potentially least worrisome symptoms of COVID-19 may be causing the greatest degree of psychological distress could potentially tell us something about the disease," said Sedaghat. He believes that their findings suggest that psychological distress is a reflection of the virus infecting the central nervous system.
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The Olfactory Tract
When the loss of smell became a symptom of infection, experts had thought that the olfactory tract is most likely how the virus enters the central nervous system. Previous studies have shown through mouse models that the nasal tract allows infection to reach the brain, infecting the central nervous system and causing inflammation and psychological symptoms.
Sedaghat explained that these central nervous system symptoms may be determining how diminished a patient's sense of smell is. This may indicate that the virus is infecting olfactory neurons, decreasing the sense of smell, and then using the olfactory tract to enter the central nervous symptom.
There had also been rare reported cases of Covid-19 patients experiencing confusion, imitating drunkenness, having an altered mental state, and having seizures. The more common CNS symptoms are anxiety and depressed mood.
Scientists still have much to discover with how the virus is able to penetrate the central nervous system. Sedaghat said, this really opens up doors for future investigations to look at how the virus may interact with the central nervous system.
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