Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was identified in Wuhan, China, in December 2019. The disease has since spread worldwide, leading to the ongoing COVID-19 pandemic. Symptoms of COVID‑19 are variable, but often include fever, cough, headache, fatigue, breathing difficulties, loss of smell, and loss of taste. Symptoms may begin one to fourteen days after exposure to the virus. At least a third of people who are infected do not develop noticeable symptoms. Of those people who develop symptoms noticeable enough to be classed as patients, most (81%) develop mild to moderate symptoms (up to mild pneumonia), while 14% develop severe symptoms (dyspnea, hypoxia, or more than 50% lung involvement on imaging), and 5% suffer critical symptoms (respiratory failure, shock, or multiorgan dysfunction). Older people are at a higher risk of developing severe symptoms. Some people continue to experience a range of effects (long COVID) for months after recovery, and damage to organs has been observed. Multi-year studies are underway to further investigate the long-term effects of the disease.

COVID‑19 transmits when people breathe in air contaminated by droplets and small airborne particles containing the virus. The risk of breathing these in is highest when people are in close proximity, but they can be inhaled over longer distances, particularly indoors. Transmission can also occur if splashed or sprayed with contaminated fluids in the eyes, nose or mouth, and, rarely, via contaminated surfaces. People remain contagious for up to 20 days, and can spread the virus even if they do not develop symptoms. Several COVID-19 testing methods have been developed to diagnose the disease. The standard diagnostic method is by detection of the virus’s nucleic acid by real-time reverse transcription polymerase chain reaction (rRT-PCR), transcription-mediated amplification (TMA), or by reverse transcription loop-mediated isothermal amplification (RT-LAMP) from a nasopharyngeal swab. Several COVID-19 vaccines have been approved and distributed in various countries, which have initiated mass vaccination campaigns. Other preventive measures include physical or social distancing, quarantining, ventilation of indoor spaces, covering coughs and sneezes, hand washing, and keeping unwashed hands away from the face. The use of face masks or coverings has been recommended in public settings to minimize the risk of transmission. While work is underway to develop drugs that inhibit the virus, the primary treatment is symptomatic. Management involves the treatment of symptoms, supportive care, isolation, and experimental measures.

Kidney function refers to the function of the kidney to excrete metabolic waste in the body and maintain the stability and acid-base balance of electrolytes such as sodium, potassium and calcium. The examination of renal function includes blood creatinine, blood urea nitrogen, blood and urine β 2-microglobulin, urinary albumin, urinary immunoglobulin G, urinary secretory immunoglobulin A, etc. Kidney is one of the indispensable organs in human body. It forms the urinary system together with ureter, bladder and urethra. The kidney is a pair of parenchymal organs, one on the left and one on the right. They are located on both sides of the spine and close to the posterior abdominal wall. Because this part is located at the waist, people commonly call the kidney “waist”. The kidney looks like a broad bean with a smooth surface. Each kidney is 10 ~ 12cm long, 5 ~ 6cm wide, 3 ~ 4cm thick and weighs 120 ~ 150g.

The kidney has three basic functions: (1) Produce urine and excrete metabolites. The body produces a variety of wastes in the process of metabolism. Most of the wastes are discharged with urine through glomerular blood filtration and secretion of renal tubules; (2) Maintain fluid balance and acid-base balance in the body. Through the filtration of glomerulus and the reabsorption and secretion of renal tubules, the kidney discharges excess water in the body, regulates acid-base balance and maintains the stability of internal environment; (3) Endocrine function.① Secrete renin, prostaglandin and kinin. Blood pressure is regulated by renin angiotensin aldosterone system and kallikrein bradykinin prostaglandin system; ② Erythropoietin stimulates bone marrow hematopoiesis; ③ Active VitD3. Regulate calcium and phosphorus metabolism; ④ Many endocrine hormone degradation sites – such as insulin, gastrointestinal hormones, etc. When renal function is not complete, these hormones T1 / 2 are significantly prolonged, resulting in metabolic disorders; ⑤ Target organ of extrarenal hormone. Such as parathyroid hormone, calcitonin, etc. It can affect and regulate renal function.

Thyroid gland is a very important gland in vertebrates and belongs to endocrine organ. In mammals, it is located below the thyroid cartilage of the neck and on both sides of the trachea. The human thyroid gland is shaped like a butterfly, like a shield, so it is named after it. Thyroid gland is the largest endocrine gland in adults, located in the front of the neck, brownish red, in “H” shape, weighing about 25g; It is composed of left and right leaves, isthmus and conical leaves. The left and right lobes of the thyroid gland are conical (the right lobe is slightly larger) and close to the side of the throat and trachea. The upper end reaches the middle of the thyroid cartilage and the lower end reaches the fourth tracheal ring. It is about 5cm long and 2.4cm wide. Its inner side is attached to the cricoid cartilage through the lateral ligament. Therefore, during swallowing, the thyroid gland can move up and down with the throat. The thyroid isthmus connects the left and right lobes and is located in front of the second to fourth tracheal cartilage ring. The thyroid isthmus of a few people can be absent. More than 60% of people extend a conical leaf upward from the isthmus. Conical leaves vary in length, and some can reach hyoid bone. It is a remnant of thyroid development. Near the left and right lobes of the thyroid gland, an independent mass of thyroid tissue can be seen, which is called parathyroid. The thyroid gland has two layers of capsule, the outer layer is thyroid capsule, which is composed of deep cervical fascia (anterior tracheal fascia), which is closely connected with the cervical vascular sheath to the outside; The inner layer is called fibrous capsule, which is the capsule of the gland itself. It directly adheres to the surface of the gland tissue and goes deep into the essence of the gland, dividing the gland tissue into several leaflets. The connection between thyroid capsule and fibrous capsule is loose and easy to separate, so intracapsular thyroidectomy can be performed clinically. From hyoid bone to thyroid isthmus or conical lobe, sometimes there is a small muscle bundle, called thyroid levator muscle, which can lift the thyroid gland. Therefore, thyroid function plays a great role in the human body.

A substance produced and released by tumor cells often exists in tumor cells or host body fluids in the form of metabolites such as antigens, enzymes and hormones. Tumors can be identified or diagnosed according to their biochemical or immune characteristics. What are tumor markers? The biochemical properties and metabolic abnormalities of tumor cells, so there are substances with qualitative or quantitative changes in the body fluids, excretions and tissues of tumor patients. These are tumor markers. Clinically, tumor markers are mainly used for the discovery of primary tumors, the screening of high-risk groups, the differential diagnosis of benign and malignant tumors, the judgment of tumor development, the observation and evaluation of tumor treatment effect, and the prediction of tumor recurrence and prognosis.

Cardiac markers, also known as myocardial markers, are indicators of cardiomyocyte necrosis. Generally, specific values are obtained through laboratory examination. The main cardiac markers include creatine kinase, creatine kinase isozyme, troponin, myoglobin and so on. In case of myocardial cell necrosis, such as viral myocarditis or acute myocardial infarction, the above enzymes in the cells can be released into the blood. The rise of corresponding indicators can be seen during laboratory examination, suggesting the occurrence of myocardial necrosis. At the same time, according to the rising range of cardiac markers, we can indirectly understand the area of cardiomyocyte necrosis and the severity of the disease.

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