COVID-19 Connect Chancellor entry by Riddhi Bhalla

The pandemic through the lens of a first year medical student

I had participated in the Connect Chancellor Telangana competition sharing my views and understanding of the pandemic as a first year medical student. The following is my article

Do give it a read and share your opinions. 

Thank you. Happy reading:) 

Declaration: The following article is my own work based on personal study and research. I have not plagiarized the work of any other persons. 

Following are the resources that have been used to gather information and data:

1. https://mmrjournal.biomedcentral.com/articles/10.1186/s40779-020-00240-0

https://www.who.int/health-topics/coronavirus#tab=tab_1

2. https://coronavirus.jhu.edu/us-map

3. https://www.youtube.com/watch?v=PWzbArPgo-o&list=WL&index=2&t=0s

Abstract:  The novel Corona virus has taken over the world in one sweeping motion. The first pandemic of the millennial generation has been the most talked about subject over social media for months now. Everyone seems to have a lot to say about the virus, many conspiracy theories have surfaced pertaining to its spread, origin, treatment and vaccine development. Never has healthcare and drug research taken such a centre stage in world politics and bilateralism. The pandemic has left the markets at an all time low, unemployment rates are sky rocketing and there seems to be no silver lining to this dark and gloomy cloud. In this article I aim to consolidate all the factual data available on the origin, spread and treatment of the SARS-COV-2 Virus. It is believed to have originated in the wet markets of Wuhan in the province Hubei of China. Its genomic data has been analyzed by several labs all over the world and the virus was found to have structural similarities to the virus causing the SARS outbreak back in 2002-2003. The symptoms shown by the Covid-19 patients are very similar to those shown by patients suffering from common place diseases like pneumonia, flu and upper respiratory diseases. This makes it incredibly hard for doctors to identify possibly infected subjects. Added to this is the shortage of Covid-19 test kits and PPE gear for healthcare workers. To avoid wastage of test kits it is essential that other tests readily available to us in a clinical setting are used judiciously to rule out any other possible ailment. The disease has a high rate of reproducibility and a very less series interval which contributes to its high rate of spread. No cure is currently available for the disease but treatment is being given by treating the symptoms which are dry cough, difficulty in breathing, low blood volume and pressure and high fever. Since the virus can survive on formite surfaces from anywhere between 3 hours to 5 days the only viable option left to contain its spread is self quarantining and social distancing. The norms given by various government institutions must be followed like our life depends on it because at this point it quite literally does.

 

The origin, spread and treatment of SARS-COV 2

                                                                                                                                         -Riddhi Bhalla

The story of the origin of the virus begins in the country of China with the onset of the SARS (Severe Acute Respiratory Distress Syndrome) epidemic which terrorized the country in 2002 and 2003. It originated from bats, transmitted to civets and underwent mutation such that it became capable of infecting humans. Another virus has been traced back to the same notorious source of bats which is MERS (Middle Eastern Respiratory Distress Syndrome). This virus underwent zoonosis too. It transmitted from bats to camels and then finally human beings. The case fatality rate of SARS was 10% while that of MERS was a whopping 34%. The Corona virus fatality rate was 3.4% in the beginning of March 2020 and is unfortunately on the rise as we speak. It has been postulated that the virus could have been spread worldwide due to another vector- Pangolins. These animals are trafficked for their scales which are believed to have healing properties.

The virus has 96.2% similarity to the Corona virus of bats RaTG13. It consists of a positive single stranded RNA (+ve ssRNA) surrounded by a nucleocapsid protein which is further surrounded by a proteinaceous envelope. It has a variety of surface proteins which are the Spike protein and Hemaglutinin esterase protein which helps in its attachment to type-II pneumocytes in the lungs.It also has an M protein and an E protein. The virus can enter the body through two routes: 1. Oro-fecal and 2. Respiratory droplets.

After entering the body the virus attaches to the ACE-II receptors on the surface of the type-II alveoli with the help of Spike protein and Hemaglutinin esterase protein. The single stranded RNA is now released and multiplies by using the enzyme RNA dependent RNA polymerase in the host to create multiple copies. The single stranded RNA also undergoes translation to produce polyproteins by using the host cell’s ribosomes. These polyproteins are now acted upon by proteases to form the structural proteins of the virus. By combining the newly produced RNA strands and synthesized proteins millions of virus particles are released in the body. Ultimately the cell dies and releases inflammatory mediators. In response to this, macrophages within the alveoli release cytokines in heavy amounts causing a characteristic cytokine storm, the cytokines released include IL-4, IL-6(Interleukins) TNF-α(Tumor necrotic factor). This immune response causes pulmonary capillaries to undergo vasodilatation and the surrounding endothelial cells to undergo  contraction which increases membrane permeability and causes the plasma to flow into interstitial spaces and alveolar cavities. This leads to a severe complication called pulmonary edema, this, coupled with the death of surfactant producing pneumocyte type-II and damage to type-I cells responsible for gas exchange wrecks havoc over the respiratory system causing hypoxemia and respiratory acidosis and alveolar collapse. The body also employs its natural immune responses to fight off the attack which involves Neutrophils.

 These neutrophils release reactive oxygen species like proteases which in this case isn’t helpful as it further catalyses the production of more virus particles in the body. 

The end result of this whole ordeal is formation of consolidation of cell debris in alveoli. The interleukins (IL-4 and IL-6) released as a part of cytokines, when present in large amounts travel to the Central Nervous System, to the hypothalamus and cause release of PGE-2. This causes the high fever seen in COVID-19 patients. The lack of oxygen is sensed by chemo receptors which lead to increase in respiratory rate and heart rate giving the classic symptom of “Shortness of breath”. As the disease progresses it triggers SIRS (Systemic Inflammatory Response System) this increases the membrane permeability of systemic blood vessels causing the blood volume to lower as well as decrease the peripheral resistance leading to “Septic shock”. Less perfusion to organs leads to “Multisysytem organ failure” 

The diagnosis of SARS-COV-2 is difficult due to its similarity to common diseases like flu and pneumonia, added to this is the shortage of test kits. A variety of tests can be used to detect it if close attention is paid to specific markers. Firstly a nasopharyngeal swab is taken which is then studied using RT-PCR (Reverse Transcriptase PCR). Nucleic acid amplification test (NAAT) may also be used but it is expensive and time consuming. It is important to rule out bacterial or viral pneumonia as well as influenza type A and B. Another test CBC (Complete Blood Count) can be run to check for lymphopenia as it has been observed that 80% of the patients show this symptom. CMP (Complete Metabolic Panel) includes BMP (Basic Metabolic Panel) and LFT (Liver Function Test). The BMP helps in analysis of glucose level, electrolyte balance as well as renal function. The LFT will report levels of AST and ALT as well as bilirubin, all of these are elevated in case of liver damage which is seen in COVID-19 patients. Another complication pertaining to the virus is in relation to procalcitonin levels. It is seen that procalcitonin levels are increased in case of bacterial infections and not viral infections but the level spikes up in case of SARS-COV-2 infection. A number of other non specific inflammatory markers are observed and can be useful for diagnosis, these are: CRP (C-Reactive proteins), ESR (Erythrocyte Sedimentation Rate), D-dimer, IL-6, LDH (Lactate dehydrogenase), CK-MB (Creatinine Kinase MB), Troponins and Ferritin.

X-rays, CT-scans as well as sonography imaging techniques are being used. The CT scan seems to have the best result and sensitivity. The CT scans of COVID-19 patients were seen to have special characteristics like: Ground glass opacities, consolidations and “Crazy paving pattern”. The sonography is also helpful and shows increased B-lines and pleural line thickening in case of COVID-19.

The virus has two forms- S form and L-form. The S-form constitutes 30% of the current infections and is less aggressive and shows less severe symptoms. The L-form constitutes 70% of the cases and is more virulent. It seems to be a mutated version of S-form of the virus. Treatment of the virus is purely symptomatic as no vaccine has been developed till now. IVF fluids have to be given sparingly in order to avoid overwhelming of the lungs and patient has to be put on mechanical ventilator. The tidal volume has to be lower than normal so as to oxygenate damaged lung tissue. To compensate respiratory rate must be increased. PEEp- Positive end expiratory pressure has to be maintained in order to prevent collapse of lungs. It has been observed that oxygenation is better in prone position. HFNC (High Flow Nasal Cannula) and NIPPV (Non invasive positive pressure ventilation) cannot be used as it will cause aerosol formation of virus which will put everyone in the surroundings at risk. 

The medicines currently  used are “Remdesivir” which was used to treat Ebola. This drug is in its third phase of clinical trials. It inhibits RNA-dependent RNA polymerase which can stop multiplication of the virus within the host. Antimalarial drug- “Hydroxychloroquine” is being used as it possibly inhibits entry of the virus into pneumocyte type-II cells. Antipyretics are being used to bring down fever. Proteases inhibitor-“Ritonavir” and IL-6 inhibitor “Tocilimuzab” are also being used. Immunosuppressants have to be used sparingly but are also helpful e.g.: Corticosteroids.

Certain diseases put a subject more at risk than the normal population. Cardiovascular diseases increase risk of infection by 10.6% while pulmonary diseases increase risk by 7.3% and diabetes by 6.3%. Cancer and other immunosuppressive diseases increase chances of infection by 5.6%. Mortality rate in individuals above the age of 80 is 14. While younger population has lower fatality rate, they can act as carriers of the virus. 

The virus has an RO of 3 days and a series interval of approximately 4 to 5 days. This makes the rate of transmission difficult to control. As of May 9th, 2020 there have been 3.97 Million confirmed cases and 276 Thousand deaths.

 The virus is spreading rapidly despite strict measures taken by all countries. This impresses upon us the importance of staying at home and following guidelines issued by the government. This new age product of mutation can only be defeated through aggressive implementation of rules and strict adherence to good hygiene practices like washing of hands, keeping surroundings clean and wearing a mask if you step outside. I hope and pray that these difficult times will soon pass and we as a country will emerge victorious.

My certificate:

Thank you for reading:)