It’s been a year now since the novel coronavirus has emerged in China’s Wuhan city. Although most Covid-19 patients have mild to moderate symptoms but the disease can cause severe medical complications in some people.
There are many questions which are still unanswered about Covid-19. Common complications of Covid-19 continue to be pneumonia, acute respiratory distress syndrome, acute cardiac injury, acute liver injury, arrhythmia, septic shock, secondary infection, and acute kidney injury.
Some COVID-19 patients are also experiencing unusual difficulties, like Guillain barre syndrome, lacy purple rashes and “silent hypoxemia” or “happy hypoxia”.
Happy hypoxia is one of those physiopathological characteristics of Covid-19 that has puzzled most of the scientific and medical community.
Why Is It Called Happy Hypoxia?
The blood oxygen saturation level (the amount of hemoglobin carrying oxygen) is around 95 per cent or more for a normal person while in hypoxemia condition the blood saturation levels drop below 94 percent.
Some patients may experience symptoms like shortness of breath and chest pain whose blood oxygen level is below 90 percent. Hence, they may also need oxygen therapy as well. And if the blood oxygen levels continue to fall, their organs may shut down, which could be life threatening.
However, despite of low blood oxygen levels, some Covid-19 patients do not feel any symptoms and feel fine, eventually until, they collapse. This unusual phenomenon gave rise to the term called “silent hypoxemia” or “happy hypoxia.”
Patients with this condition often suffer a sudden unevenness, reaching a critical state that can be fatal.
Causes Of Happy Hypoxia Found
Researchers and doctors have been trying to understand the causes of happy hypoxia in Covid-19 patients. Recently, the researchers from the University of Seville in Spain have come up with an explanation for the condition.
They say that infection in carotid bodies by SARS-CoV-2, may be the cause of the decreased blood oxygen levels in many Covid-19 cases.
Carotid bodies are sensory organs located on either side of the neck or next to the carotid artery. They detect the drop in blood oxygen and send signals to the brain to rouse the respiratory centre.
In their study, published in the journal Function, the researchers suggest that infection of this carotid body by SARS-CoV-2 in the early stages of the disease could alter its ability to detect blood oxygen levels, resulting in the silent fall in oxygen in the arteries.
They have also found a high presence of the enzyme ECA2 which is the protein the coronavirus uses to infect human cells, in the carotid body.
The hypothesis support the use of activators of the carotid body independent of the oxygen sensing mechanism as respiratory stimulants in patients with Covid-19.