Demystifying COVID-19: Understanding the Disease, Its Diagnosis and Treatment

There are nearly 30 million confirmed cases of COVID-19 in almost all countries and regions worldwide, and more than 900,000 deaths as of September 2020. Almost all of the cases are over 30 years old, and deaths are mostly over 50 years old. The rate of fatality varies greatly by population and geography. Males are represented slightly more than females in confirmed patients in many series, but male predominance is more remarkable in deaths. While there is an increasing trend in deaths since the beginning of March, there is a plateau and a slight downslope after mid-April. Provided with the progress of the disease in the world, it is seen that the number of cases continues to rise and break records, but deaths do not increase in the same way. Although many countries have a drive for a premature ‘normalization’, an immature decision of normalization has caused a surge of newly diagnosed cases and deaths in many countries.

Eradication of a disease is a very difficult and multi-factorial, multi-faceted question. The prevalence of COVID-19 in the regions around the country, the intensity of the population’s relationship with other countries, age distribution, and other demographic factors affect the magnitude of the impact of the disease on a population. In addition, the virulence of the virus, the immunity level of the population, measures taken for immunization, availability of necessary drugs, the capacity of the health sector to mitigate the pandemic will affect the damage on the society as a whole. The tests applied to identify the cases, filing, and surveillance are effective factors in the response of the state's health organization to this disease.

COVID-19 can cause disease in almost all ages and all groups. However, those with comorbid diseases are at high risk in terms of the progression of the disease, deterioration such as hospitalization in an intensive care unit (ICU), mechanical ventilation requirement, and the risk of death. Smoking, COPD, coronary artery disease, heart failure, cancer, kidney and liver failure, and obesity have been directly associated with death rates other than advanced age and male gender. Patients with comorbid diseases are older people (mean age 60 y vs. 45 y), presented with shortness of breath more commonly , have more severe COVID-19 (30% vs. 10%), which directly impacts the clinical course, morbidity, and mortality.

The rapid spread of the disease has strained the health system and increased the risk of infection on healthcare workers (HCW). HCW is the group with the highest risk of transmission among all professions. Within COVID-19 deaths, HCW is overrepresented when compared to all other groups. The prevalence of the disease in the general population maintains a certain correlation with the prevalence in HCW. Resuscitative interventions and airway procedures that trigger aerosolization pose the greatest risk for disease transmission to HCW. Therefore, the use of PPE is vital. Proper training and education of HCW are invaluable in this pandemic era. Since the viral load taken in these procedures is higher than the contamination outdoors, it can be thought that the disease progresses more severe ly in the HCW than the others. In case of all viral outbreaks, hospitals should prepare and follow strict guidelines regarding ventilation of the workplaces and contact precautions.

COVID-19 affects almost every organ and system in the body, depending on the severity of the disease, viral load, and host factors. In definition, the complex (ACE2) receptors – protein S of the virus leads to the involvement of various tissues and organs. ACE2 receptors are present on most cells, inducing cardiovascular symptoms, kidney disease, and neurological involvement. Complaints and findings such as fever, dry cough, and weakness are predominant in many large series . However, shortness of breath almost invariably predicts a more severe disease course in most patients. More rarely, neurological, gastrointestinal, or dermatological complaints and findings are also noted, mostly in conjunction with other signs. Laboratory and radiological adjuncts are mostly the keys for an expedient diagnosis and management, especially in institutions with a high number of admissions in a time unit. The clinician should be alert on how to interpret hallmarks of the disease, which can predict a grave outcome and severe course in any given patient.

As the organism is afflicted by COVID-19 as a whole, recognition of the disease can sometimes pose difficulties for healthcare workers. Laboratory and radiological workup are necessary for expedient diagnosis in most cases. Although considered as a gold standard, the need for certified laboratories, expensive equipment, and trained staff are drawbacks of RT-PCR tests to be applied to large numbers of people as screening tests . Chest radiography is recommended as an initial test for any patient with suspicion of the disease, while chest tomography is more sensitive to demonstrate specific lesions and the extent of the disease inflicting lungs.

In the last centuries, cardiovascular diseases (CVD) have been the prominent cause of health impairment worldwide. Starting with the COVID-19 outbreak, which has become the predominant health issue all over the world since December 2019, this phenomenon has to be reassessed in many aspects. In a given patient, CVD results in a more serious clinical course of COVID-19 and a boosted risk of death. Additionally, both CVD and COVID-19 cause myocardial damage, which increases morbidity and mortality with a synergistic effect. It is also clear that cardiac patients (i.e., CVD and others) are deprived of the usual healthcare services they receive due to the overcrowdedness and shift of hospital and pre-hospital medical services in the COVID19 era. As we can contemplate that pandemics will not disappear quickly anytime soon, the health system will have to be reorganized completely. The purpose of this article is to reveal and seek solutions to the relationship between pandemics and heart disease and their impact on ordinary healthcare, along with CVD, myocardial damage, and other diseases caused by COVID-19.

Nausea/vomiting, diarrhea, abdominal pain, and ageusia are gastrointestinal (GI) symptoms commonly recorded in the pandemic. The gastrointestinal system (GIS) is important in diagnostic procedures screening for COVID-19. This chapter aims to highlight this important aspect of the course of COVID-19, with a special emphasis on diagnostic opportunities. Many articles cited that GIS is closely related to COVID-19 in certain aspects. First of all, GI complaints and their severity show a strong correlation with the severity of the disease. Second, GI signs and symptoms are associated with higher AST and ALT and coagulation deficiencies. Patients with GI signs tend to have fever more frequently; however, they have a less severe course disease. Liver injury is seen more commonly in males and associated with lymphocytopenia, neutropenia. It has been observed that AST is associated with mortality in COVID-19. Inflammatory bowel diseases are not a high risk for COVID-19. The objective of this chapter is to highlight the value of GI signs and symptoms in the evaluation of the patient suspected to have COVID-19 and to focus on the need to assess specific clues ruling in and out the disease.

We are facing a de novo global crisis that we have never faced after World War II. During the pandemic period, there is an increased and uncontrollable level of ‘information pollution’ compared to the past, especially in social media and other mass media. This increases the stress load on people. Developing adverse emotional, physical, or cognitive responses that arise in response to the effects of the COVID-19 pandemic is viewed as a normal reaction to one’s environment. Anxiety, depression, and delirium can ensue as a pathological and extreme persistent response to these stimuli. During the pandemic period, it is normal to feel down as you get information about it. In fact, worrying during this process is a necessary reaction to protect ourselves and is a normal emotional response. Self-awareness and recognition of the psychological and physical responses getting out of control to decide to get help from professionals are crucial.

We all recognize the typical signs and symptoms of COVID-19 (fever, shortness of breath, persistent non-productive cough). Less common symptoms are headaches, confusion (talking nonsense), numbness/hypoesthesia, seizure (convulsions), vomiting, loss of smell (anosmia), and sense of taste (ageusia). It can be noted that this group of symptoms consisted mostly of neurological complaints. COVID-19 causes CNS damage with various mechanisms. For example, anosmia or hyposmia is seen quite frequently among individuals even with mild COVID-19. Therefore, physicians should be alert in noting nervous system-related symptoms and findings that can be seen in the course of COVID-19.

Pneumonia and its major complication, acute respiratory distress syndrome (ARDS), are the outstanding causes of morbidity and mortality attributed to the SARSCoV-2. Angiotensin-converting enzyme 2 (ACE2) receptor is commonly found in the alveolar cells of the lung, causing common respiratory symptoms in COVID-19. In addition, the development of respiratory failure, ARDS, and the need for a mechanical ventilator is precipitated by an undertreated pneumonia. ARDS is a condition associated with many disease processes, which causes reduced lung compliance and severe hypoxemia. For early diagnosis and treatment, attention should be paid to the risk of developing ARDS in patients whose disease duration lasts for longer than one week.

It has not been proven that the infection is transmitted to the baby in the uterus. It is currently known that pregnant women with COVID-19 are mostly infected in the last period of pregnancy. In general, the clinical course of the disease is similar to non-pregnant ones. Most drugs can be given to these women in the treatment of COVID-19 and its complications, while some are dangerous. In addition, women with COVID-19 can and should breastfeed their babies with adherence to universal precautions and hygiene. Tomography can be elicited in pregnant women due to this vital requirement. When pregnant women are suspected of having COVID-19, they have priority for treatment and hospitalization. Compared to adults, children have less tendency to be infected with the disease, and they recover from the disease with milder symptoms. Stronger immunity in children fed with breast milk and other vaccines is also a supportive assumption. Fever and respiratory complaints are common in children. Increased inflammatory markers and low lymphocyte count (and percentage) in complete blood count (lymphopenia) are less common in children.

There are some differences in the way the symptoms are perceived and expressed by the elderly. Senses and perception can be blunted due to difficulties and impairments in the structure and function of the nerves. For example, the perception of pain, which is sharper and more severe in young people, can be felt milder, more uncertain, or ill-defined in the elderly. In the elderly, too, the main complaints can be listed as fever, dry cough, and shortness of breath. There may be mild to severe sore throat, loss of sense of smell, weakness, muscle and joint pain, headache, diarrhea, rarely runny nose, and cough with phlegm. They are more prone to have a more severe disease course. Researchers reported that the fatality rate in all cases in China was 1.4%, while it was 22% in cases over 80 years old. This chapter aims to delineate specific difficulties the elderly face when they were infected with COVID-19 and to discuss possible solutions for this vulnerable group in the pandemic period.

It is well established that there is no ‘standard’ protocol for the treatment of COVID-19. The use of certain antiviral agents and antibiotics such as azithromycin has been concluded to be beneficial, and therefore, their use has been recommended. Namely, remdesivir and favipiravir may be the best potential antiviral drugs for the treatment of COVID-19. However, treatments should be tailored for every given patient in regard to the signs and symptoms, the severity of the disease, age and comorbid diseases, organ failures, phase of the disease, pregnancy status, and possible drug interactions. The use of NSAIDs as an antipyretic, analgesic, and anti-inflammatory agents appears to be indicated in viral infections such as COVID-19, also during pandemic periods. There is no evidence to support NSAIDs not to be used in COVID-19 infections due to their side effects. NSAIDs are used after paracetamol, if necessary, to manage the symptoms of COVID-19. Although it has been postulated that deficiencies of certain vitamins and minerals (e.g., vitamins C and D), multi-center, community-based, well-designed studies are necessary to clarify their relationship with COVID-19, especially before recommending them for treatment. In brief, treatments should be individualized, and evidence-based principles must be followed.

There are currently no recommended specific treatments for the group with severe COVID-19. Therefore , supportive treatment is essential. Expedient recognition and decisions for aggressive measures such as permanent control of the airway and positive-pressure ventilation, along with CST and t-PA administration, should be evaluated using certain selection criteria. Prone position is mostly associated with more favorable outcomes than supine position in the resuscitation of selected cases. Shock is also a catastrophic event that should be recognized and managed as early as possible for favorable outcomes. If the mean arterial pressure (MAP) cannot be kept above 65 mmHg with intravenous (IV) hydration and lactate cannot be maintained below 2 mmol/L, vasopressor support should definitely be initiated. Extracorporeal membrane oxygenation (ECMO) therapy is used in ARDS to temporarily maintain adequate O2 supply and CO2 elimination and / or provide perfusion in patients with respiratory and / or heart failure who do not respond to conventional interventions and whose physiological variables are abnormal despite maximal support. The development of coagulopathy is associated with high mortality in patients with COVID-19. Therefore, low molecular weight heparin (LMWH) should be used for prophylactic purposes. In order to reduce the incidence of VTE, it should be administered to patients with severe conditions and who are dependent on mechanical ventilation. Prophylactic LMWH will also benefit patients at high risk of VTE. The use of LMWH and anticoagulant therapy has been shown to reduce mortality in COVID19. The FDA has also recently approved the use of convalescent (immune) plasma therapy (CPT) in the COVID-19 era. Sera of the persons recovering from COVID-19 infection can be used in the prophylaxis or treatment of COVID-19 infection. CPT is one of the most important treatment options that can be used in pandemic COVID-19 infection. Antibody replacement by plasma infusion may be beneficial in the first 7-10 days of the disease. CPT is an important option for the prevention and treatment of COVID-19 disease in the presence of a sufficient number of people who can donate Ig-containing plasma. Patients treated with CP have a shorter hospital stay and lower mortality rates than other patients.

Vaccination immunity is vital to prevent widespread viral infection and reduce morbidity and mortality. Patients with COVID-19 infection develop a polyclonal active immune response to viral antigens. Antibodies that develop as a result of this polyclonal immunity can neutralize the virus and prevent further infection in the recovered host. The magnitude and duration of protection of a vaccine administered to humans in society cannot be the same for every individual. The acquisition of immunity depends on the functioning of the person's own immune system. Therefore, a vaccine in the population is never 100 % protective. There are expectations that the COVID-19 vaccine should have at least a 50% protection rate. Vaccine development stages also require a process that can take years; therefore, the public will probably hardly reach a vaccine that is safe and economical for public use in the near future. The global medical community should search for effective ways to provide vaccination be easily reached by vulnerable groups all over the world in order to secure healthy new generations.