What is Covid – 19

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What is Covid-19?

Covid-19 (SARS-Cov 2) is a virus that is genetically related to the coronavirus responsible for the SARS outbreak in 2003. The coronavirus only contains RNA, which means that it relies on infiltrating healthy cells to multiply and survive. Once inside the cell, the virus uses its own RNA genetic code to take control and reprogramme the cells so that they produce more of the virus.

The virus causes Acute Respiratory Distress Syndrome, which is a type of pulmonary odema which can quickly lead to acute respiratory failure.

Respiratory System

Breath enters the body through the nose and mouth. The oxygen-rich air travels down the trachea which then divides into the left or right bronchus (tubes) of the two lungs. The right lung has three lobes, or sections and the left lung has two lobes.

The bronchial tubes are lined with cilia (like very small hairs) that have a wave-like motion. This motion carries mucus (sticky phlegm or liquid) upward and out into the throat, where it is either coughed up or swallowed. The mucus catches and holds much of the unwanted particles, such as germs and dust that enter the lungs and are expelled by coughing.

The air from the bronchi is then directed through smaller passages called bronchioles, past the alveoli duct and into individual alveolus.

The alveoli are part of the respiratory system where the exchange of oxygen and carbon dioxide molecules takes place to and from the capillaries in the bloodstream. These tiny, balloon-shaped air sacs are one cell thick and lie at end of the respiratory tree and are arranged in clusters throughout the lungs.

There are two types of alveoli cells – type 1 pneumocytes, which are responsible for the exchange of oxygen and carbon dioxide and type 2 pneumocytes that repair damage to the alveoli lining and secrete surfactants – which is composed of lipids and proteins.

The surfactant is a fluid that lines the alveoli cell which maintains the shape and surface tension of the air sac. By maintaining the surface tension there is more area in which the oxygen and carbon dioxide molecules can pass.

How Covid-19 affects the lungs

When a person is severely affected by the coronavirus the alveoli collapse and the smaller surface areas fill with fluid affecting the ability to take enough oxygen into these cells, thereby quickly causing damage and inflammation.

The body’s natural response causes the problem as the immune system goes into overdrive – called a cytokine storm. Normally the cytokines, which are small proteins that the immune system uses to attack a virus results in localised inflammation. Within some patients with Covid-19, uncontrolled levels of cytokines are released which then activates more immune cells resulting in hyperinflammation, which can seriously harm or kill a patient.

Symptoms of Covid-19

Some people can be asymptomatic, but for those that have symptoms, these can vary enormously and can include: continuous dry cough, high temperature, fever, loss of taste and smell, gastrointestinal problems (approx. 10%), sore throat, short of breath, muscle or joint pain, runny nose and exhaustion.

Nursing observations are important in order to check for silent hypoxia (low oxygen sats of 92% or 88% in COPD patients), respiratory rate of over 20 breaths per minute, increased heart rate (over 100 beats per minute), low blood pressure, high temperature of over 38°, low urine output (as can result in renal impairment), new episode of confusion or sepsis.

People can feel well for 7-10 days then there may be a deterioration.

People in high-risk groups

Figures up to 3/4/20 in the UK evidenced there were 4122 deaths of which 2523 were men and 1599 were woman. 3588 were in the over 65 age group and 39% (1396) were over 85.

Of the first 3883 people who became critically ill with Covid-19, over 33% were of a non-white background, whilst only being 18% of the UK population.

People with hypertension and existing lung conditions are likely to have a worse prognosis. People with existing cardiac conditions are also a high-risk group.

Testing

The use of a nasal or throat swab is tested using real time RT-PCR (Reverse transcription polymerase chain reaction) which allows for the amplification and detection of RNA and DNA sequences. Fluorescent dyes are used to detect the presence of specific genetic material from the Covid-19 virus.

Blood test results of people infected with Covid-19 include low levels of platelets, low lymphocytes, high levels of cytokines and chemokines and an increase of C-reactive protein. White blood cell levels tend to be normal.

Treatment

As Covid-19 is a virus, antibiotics are ineffective as a treatment intervention.

Continuous positive Airway Pressure (CPAP) machines are used to support patients with breathing difficulties as a result of Covid-19. They work by pushing an air-oxygen mix into the mouth and nose at a continuous rate, keeping airways open and increasing the amount of oxygen entering the lungs. Approximately 50% of patients given CPAP in Italy have avoided the need for invasive mechanical ventilation.

Invasive ventilators deliver breaths directly into the lungs, whilst being sedated, whilst being connected to a tube placed into the patient’s trachea and is carried out in intensive care units. For those on full ventilation, it is recommended that people are placed in the prone position for 12-16 hours.

Current opinion, such as Cameron Kyle-Sidell, an ICU doctor, suggests that ventilators are not an effective treatment for Covid-19. Whilst intubation is effective in treating pneumonia due to the weakness of the respiratory muscles and the ventilators assist with this, people with Covid-19 do not have pneumonia and are experiencing oxygen failure, not respiratory failure.

Reports on patients with Covid-19 who do not recover and who have received mechanical ventilation treatment vary but is estimated to be around 50%.

Reduction and Prevention of the virus

The standard recommendations, such as regular thorough handwashing, social distancing and use of PPE need to apply, but the key to helping with the reduction in severity of symptoms is to improve the immune system.

Vitamin D assists with enhancing cellular immunity, in part by reducing the cytokine storm which can be caused by the immune system in patients who have contracted the virus. The natural immune system response has been found to generate both pro-inflammatory and anti-inflammatory cytokines in patients with COVID-19, and vitamin D has been found to reduce the production of pro-inflammatory cytokines.

10 micrograms is the recommended dose of vitamin D and whilst in the summer months those with healthy diets and reasonable skin exposure to the sun, generally achieve that; there are people who may not reach these levels and therefore supplements are recommended all year round. These can include people who cover their skin when outside, such as when adhering to religious protocols, or those who use high factor skin creams. Others at risk are people who have darker skin because the pigment (melanin) in the skin does not absorb as much UV radiation, breast fed babies fed from vitamin D deficient mothers or those who have minimal exposure to the sun, such as people in care homes.

Vitamin C deficiency results in impaired immunity and higher susceptibility to infections. Additionally, infections significantly impact on vitamin C levels due to the inflammation and metabolic requirements and therefore an increase in vitamin C to help with the inflammation that occurs during an acute response to Covid-19. Vitamin C is also thought to be able to both prevent and treat respiratory and systemic infections and is therefore an important supplement to take. 100-200mg a day will help optimize cell and tissue levels as a preventative measure, however significantly higher doses are required to treat Covid-19 to compensate for the increased inflammatory response and metabolic demand.

Glossary

Cytokines are small proteins released by many different cells in the body, including those of the immune system where they coordinate the body’s response against infection and trigger inflammation. The name ‘cytokine’ is derived from the Greek words for cell (cyto) and movement (kinos).

DNA is a two-strand molecule that is found in all organisms, such as animals, plants, and viruses, and it holds the genetic code, or blueprint, for how these organisms are made and develop.

Pulmonary Surfactant is mixture of lipids and proteins which is secreted into the alveolar space by epithelial cells. Its purpose is to lower surface tension between gas (air) and liquid in the alveoli of the lungs.

RNA is generally a one-strand molecule that copies, transcribes and transmits parts of the genetic code to proteins so they can synthetize and carry out functions that keep organisms alive and developing. There are different variations of RNA that do the copying, transcribing and transmitting.

Virus is a microscopic infectious agent of genetic material that can only replicate inside the cell of a living organism. The genetic material can be either DNA or RNA. 

References

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Jarwerth, N. (2020) How is the COVID-19 Virus Detected using Real Time RT-PCR? Available at: https://www.iaea.org/newscenter/news/how-is-the-covid-19-virus-detected-using-real-time-rt-pcr (Accessed on 17 April 2020).

Kyle-Sidell, C. (2020) From NYC ICU Does Covid-19 really cause ARDS? Available at: https://www.youtube.com/watch?v=k9GYTc53r2o (Accessed on 18 April 2020).

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