This molecule, expressed in the lungs, heart and vessels, is a key membrane protein in the Renin-Angiotensin System (RAS)[I]. This hormonal system plays a major role in the regulation of blood pressure[II].
Once bound, the virus enters the cell via the formation of endosomes, i.e. lipid pockets / vesicles, resulting from the fusion of its viral envelope and the plasma membrane of the host’s cells. This penetration is facilitated by specific proteins of the host[III].
Now inside the cell, the virus will synthesize RNA complementary to the one it already has as well as proteins by exploiting the machinery of the host cell. It will thus be able to multiply by creating new viruses and release them in the body.[IV].
All these mentioned stages of the virus’s life cycle constitute potential targets for therapies.[IV].
Clinical manifestations and symptoms
The duration of the‘incubation is on average 5 days, with extremes of 2 to 12 days and the onset of symptoms is usually gradual over several days[V]. During this period, the subject may be contagious[VI]. This contagiousness would be more important in symptomatic patients, especially when they cough[V].
Observational studies have shown that the infection may be asymptomatic or paucisymptomatic (no or few clinical manifestations) in 30 to 60% of infected subjects[V].
The first symptoms are not very specific: headache, muscle pain, fatigue[V]. Some patients have pain, nasal congestion, sore throat or diarrhea[VII]. The fever and the respiratory signs come secondarily, often two or three days after the first symptoms.
About 80% of people recover without needing hospital treatment[VII]. The seriousness of the clinical signs, in particular dyspnea (respiratory discomfort), requires that approximately 20% of patients be kept in hospital, 5% of whom require admission to intensive care. Older people and those with other health problems (high blood pressure, heart or lung problems, diabetes or cancer) are more likely to have severe symptoms[V].
In early descriptive studies from China, an average of one week elapsed between the onset of symptoms and admission to hospital in the state phase of the disease. At this stage, symptoms include fever, cough, chest pain and difficulty breathing. A chest CT scan almost always shows pneumonia affecting both lungs. Other clinical signs have been described since the first studies: signs of damage to the central nervous system expressed in particular in the elderly in the form of disorientation; were also found, sudden loss of taste (ageusia) or / and smell (anosmia), events which remain infrequent but which make it possible to confirm the diagnosis of Covid-19[V].
Certain dermatological manifestations of COVID-19 have also been reported. These are acrosyndromes (aspect of pseudo-engeluresPainful red patches often appearing on the extremities extremities), sudden onset of persistent redness, sometimes painful, and urticaria lesions passengers[VIII].
It is important for patients who have such skin problems to consult a dermatologist (teleconsultation or other), in order to verify if these are associated with a Covid + syndrome or not[VIII].
Finally, a possibly abnormal accumulation of maladies de Kawasaki has been observed in France and abroad. It is a rare disease (approximately 1 in 10,000), inflammatory, which develops in children, and whose causes are unclear. It affects the majority (80%) of children under 5 years old, with a peak incidence around the age of 12 months, with a boy / girl ratio of 1.5[IX].
Its onset could be favored by a nonspecific viral infection. Since COVID-19 is a viral disease, it is therefore a plausible hypothesis that children develop Kawasaki disease at term after contact with COVID-19. Possibly serious, this disease has treatments. With good management, healing is usually complete within 2 months.
Kawasaki disease should be suspected in a child with a high fever (<39.5 ° C) which exceeds the duration of 5 days, and not reduced by paracetamol, and other clinical signs (conjunctivitis, buccopharyngeal involvement, rash cutaneous, extremity damage, cervical adenopathiesIncrease in the size of the lymph nodes in the neck). If in doubt, call your doctor[X].
COVID-19 does not have the same consequences for all people. Our bodies, depending on our immunity, our age, our possible associated pathologies (comorbidities), do not all react in the same way to the virus. The most fragile people are considered “people at risk”. There are specific management recommendations in these situations.[VIII].
Author: Nada Moulla
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