SARS-CoV-2 - a new challenge for laboratory medicine

Observations of nemaline bodies in muscle biopsies of critically ill patients infected with SARS-CoV-2

Patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who have been admitted to the intensive care unit (ICU) often face months of physical disability after discharge. To optimize recovery, it is important to understand the role of musculoskeletal alterations in critically ill patients infected with SARS-CoV-2. The main aim of the present study was to describe the presence and morphology of nemaline bodies found in the skeletal muscle tissue from critically ill patients infected with SARS-CoV-2. In n = 7 patients infected with SARS-CoV-2, ultrastructural characteristics of vastus lateralis muscle obtained on days 1-3 and days 5-8 following ICU admission were investigated in more detail with electron microscopy. Those muscle biopsies consistently showed variable degrees of myofiber necrosis and myofibrillar disorganization. In 4/7 (57%) patients on days 5-8, the Z-line material accumulated into nemaline bodies with a typical lattice-like appearance at higher magnification, similar to that found in nemaline myopathy. This study is the first to describe the disintegration of myofibrils and the accumulation of Z-line material into nemaline bodies in the skeletal muscle tissue obtained from critically ill coronavirus disease-19 patients following ICU admission, which should be interpreted primarily as a non-specific pathological response of extreme myofibrillar disintegration associated with myofiber necrosis.

CA 15-3 prognostic biomarker in SARS-CoV-2 pneumonia

The severity of lung involvement is the main prognostic factor in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Carbohydrate antigen 15-3 (CA 15-3), a marker of lung damage and fibrosis, could help predict the prognosis of SARS-CoV-2 pneumonia. This was a retrospective and observational study. CA 15-3 was analyzed in the blood samples of patients consecutively admitted for SARS-CoV-2 pneumonia and whose blood samples were available in the biobank. Other prognostic markers were also measured (interleukin 6 [IL6], C-reactive protein [CRP], D-dimer, troponin T, and NT-ProBNP). The occurrence of in-hospital complications was registered, including death, the need for medical intensive care, and oxygen therapy at discharge. In this study, 539 patients were recruited (54.9% men, mean age: 59.6 ± 16.4 years). At admission, the mean concentrations of CA 15-3 was 20.5 ± 15.8 U/mL, and the concentration was correlated with male sex, older age, and other severity markers of coronavirus disease of 2019 (COVID-19) (IL6, CRP, D-dimer, troponine T, and NT-ProBNP). CA 15-3 levels were higher in patients who died (n = 56, 10.4%) (35.33 ± 30.45 vs. 18.8 ± 12.11, p < 0.001), who required intensive medical support (n = 78, 14.4%; 31.17 ± 27.83 vs. 18.68 ± 11.83; p < 0.001), and who were discharged with supplemental oxygen (n = 64, 13.3%; 22.65 ± 14.41 vs. 18.2 ± 11.7; p = 0.011). Elevated CA 15-3 levels (above 34.5 U/mL) were a strong predictor of a complicated in-hospital course, in terms of a higher risk of death (adjusted odds ratio [OR] 3.74, 95% confidence interval [CI]: 1.22–11.9, p = 0.022) and need for intensive care (adjusted OR 4.56, 95% CI: 1.37–15.8) after adjusting for all other risk factors. The degree of lung damage and fibrosis evaluated in terms of CA 15-3 concentrations may allow early identification of the increased risk of complications in patients with SARS-CoV-2 pneumonia.

Laboratory medicine in pandemic of COVID-19

After the outbreak in China in the year 2019, severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) quickly spread around the world causing a protracted pandemic. Approximately one-third of infections appear to be asymptomatic. Symptomatic disease is characterized primarily by symptoms of respiratory tract infection of varying severity. But Coronavirus Disease 2019 (COVID-19) is much more than an acute respiratory disease because SARS-CoV-2 affects many organs inducing a vast number of symptoms such as cardiovascular, neurological, gastrointestinal, dermatological, with numerous complications. Short and long-term effects of infection, severe ones, and especially mild forms of the disease which affect a huge number of patients need to be further investigated. Laboratory medicine has a crucial role in early diagnosis of the disease, recognition of the patients who need hospital care, and close monitoring of hospitalized patients to timely identify associated clinical complications as well as follow-up of patients with long-term COVID-19.

Usefulness of laboratory parameters and chest CT in the early diagnosis of COVID-19

In the present study, the importance of laboratory parameters and CT findings in the early diagnosis of COVID-19 was investigated. To this end, 245 patients admitted between April 1st, and May 30th, 2020 with suspected COVID-19 were enrolled. The patients were divided into three groups according to chest CT findings and RT-PCR results. The non-COVID-19 group consisted of 71 patients with negative RT-PCR results and no chest CT findings. Ninety-five patients with positive RT-PCR results and negativechest CT findings were included in the COVID-19 group; 79 patients with positive RT-PCR results and chest CT findings consistent with COVID-19 manifestations were included in COVID-19 pneumonia group. Chest CT findings were positive in 45% of all COVID-19 patients. Patients with positive chest CT findings had mild (n=30), moderate (n=21) andor severe (n=28) lung involvement. In the COVID-19 group, CRP levels and the percentage of monocytes increased significantly. As disease progressed from mild to severe, CRP, LDH and ferritin levels gradually increased. In the ROC analysis, the area under the curve corresponding to the percentage value of monocytes (AUC=0.887) had a very good accuracy in predicting COVID-19 cases. The multinomial logistic regression analysis showed that CRP, LYM and % MONO were independent factors for COVID-19. Furthermore, the chest CT evaluation is a relevant tool in patients with clinical suspicion of COVID-19 pneumonia and negative RT-PCR results. In addition to decreased lymphocyte count, the increased percentage of monocytes may also guide the diagnosis.

Emergency surgical workflow and experience of suspected cases of COVID-19: A case report

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 has been confirmed to be a newly discovered zoonotic pathogen that causes highly contagious viral pneumonia, which the World Health Organization has named novel coronavirus pneumonia. Since its outbreak, it has become a global pandemic. During the outbreak of coronavirus disease 2019 (COVID-19), however, there is no mature experience or guidance on how to carry out emergency surgery for suspected cases requiring emergency surgical intervention and perioperative safety protection against virus.

CASE SUMMARY

A 41-year-old man was admitted to the hospital for emergency treatment due to "3-d abdominal pain aggravated with cessation of exhaust and defecation". After improving inspections and laboratory tests, the patient was assessed and diagnosed by the multiple discipline team as "strangulation obstruction, pulmonary infection”. His body temperature was 38.8 °C, and the chest computed tomography showed pulmonary infection. Given fever and pneumonia, we could not rule out COVID-19 after consultation by fever clinicians and respiratory experts. Hence, we performed emergency surgery under three-level protection for the suspected case. After surgery, his nucleic acid test for COVID-19 was negative, meaning COVID-19 was excluded, and routine postoperative treatment and nursing was followed. The patient was treated with symptomatic support after the operation. The stomach tube and urinary tube were removed on the 1^st d after the operation. The clearing diet was started on the 3^rd d after the operation, and the body temperature returned to normal. Flatus and bowel movements were noted on 5^th postoperative day. He was discharged after 8 d of hospitalization. The patient was followed up for 4 mo after discharge, no serious complications occurred. A 71-year-old woman was admitted to our emergency room due to "abdominal distention, fatigue for 6 d and fever for 13 h". After the multiple discipline team evaluation, the patient was diagnosed as "intestinal obstruction, abdominal mass, peritonitis and pulmonary infection". At that time, the patient's body temperature was 39.6 °C, and chest computed tomography indicated pulmonary infection. COVID-19 could not be completely excluded after consultation in the fever outpatient department and respiratory department. Therefore, the patient was treated as a suspected case, and an urgent operation was performed under three-level medical protection. Postoperative nucleic acid test was negative, COVID-19 was excluded, and routine postoperative treatment and nursing were followed. After the operation, the patient received symptomatic and supportive treatment. The gastric tube was removed on the 1^st d after the operation, and the urinary tube was removed on the 3^rd d after the operation. Enteral nutrition began on the 3^rd d after the operation. To date, no serious complications have been found during follow-up after discharge.

CONCLUSION

Based on the previous treatment experience, we reviewed the procedures of two cases of suspected COVID-19 emergency surgery and extracted the perioperative protection experience. By referring to the literature and following the regulations on prevention and management of infectious diseases, we have developed a relatively mature and complete emergency surgical workflow for suspected COVID-19 cases and shared perioperative protection and management experience and measures.