DISCUSSION
The COVID-19 disease is spreading rapidly worldwide, and no vaccine or very effective drug has been found yet. However, the transmission rate of the disease can be reduced by precautions to be taken. Therefore, it is essential to detect the patients early to prevent the spread of the disease 11,12. In addition to supportive treatments, medical treatments (antivirals, antibiotics, corticosteroids, hydroxychloroquine etc.) are applied. Unfortunately, a standard treatment protocol applied worldwide has unfortunately not yet been developed. Many treatment options have been tried in China and other countries and their effects on the virus have been published. In another study had identified 4 small molecular drugs (prulifloxacin, nelfinavir, bictegravir, tegobuvir) with high binding capacity with SARS-CoV-2 main protease 13. It has been shown that agents such as remdesivir, chloroquine and baricitinib can be used in the treatment of covid-19 14,15. Although the most common symptom of COVID-19 disease is fever, cough, and shortness of breath are also considered among other common symptoms 16,17. Uncommon symptoms such as abdominal pain, diarrhea, and olfactory disorders have also been reported in the literature as a first-line symptom18-20. However, flank pain is not as joint as a first-line symptom. According to the literature review, there are no studies examining the abdominal CT images of patients presenting with flank pain in terms of COVID-19 disease.
The sensitivity of ultrasonography in detecting urinary stones varies from 3% to 98% in various studies 21,22. Ultrasonography can be challenging in obese patients and generally offers limited or poor visualization of the mid ureter. In addition, Ultrasonography has a limited ability to depict renal or ureteral calculi which are smaller than 5 mm. However, detection of calculi smaller than 5 mm is of questionable clinical significance, as such patients are unlikely to require urological intervention23. Many studies have shown that non-contrast abdominal CT is unlikely to miss stones that require intervention compared to Ultrasound 24,25. Recent data suggest that less than 7% of patients diagnosed with kidney stones are using Ultrasonography and the use of CT continues to increase26. The American College of Radiology Appropriateness Criteria states that a low-dose non-enhanced CT of the abdomen and pelvis is the imaging examination of choice for evaluating patients with suspected urolithiasis (sensitivity 97% and specificity 95%)27. Non-contrast Abdomen CT can sometimes be the first imaging method used in patients with severe renal colic28.
The prevalence of the stone disease is very high in our region. For this reason in our clinic patients with a history of urolithiasis in the family or themselves and who have the findings to support the stone in laboratory examinations, generally, to detect suspected kidney and ureteral stones that cannot be detected on the Ultrasonography, non-contrast Abdomen CT is performed.
In one of the current publications on COVID-19 and CT imaging, the sensitivity of Thorax CT (98%) in the early diagnosis of COVID-19 was reported to be higher than that of the RT-PCR test (71%)29. This information increases the importance of Thorax CT in the diagnosis of the disease. During pandemic period in our country regardless of the branch, all physicians began to take care of COVID-19 patients. During this period, our experience with the Thorax CT imaging method, which we usually do not use as a urology specialist, has increased. We had the opportunity to see and evaluate many Thorax CTs. In this way, we learned to assess the basal lung parts of the abdominal CTs, which we pulled for urological reasons, in the lung parenchyma window. For COVID-19 disease the most common findings of Thorax CTs are round pulmonary parenchymal ground-glass opacities. Abdominal and back pain has long been described as a symptom in pneumonia in both adults and children secondary to pleural irritation 30,31. When the patients who applied to the urology outpatient clinic during the pandemic period were screened backward, we found that ten patients (3.6 %) presented with flank pain and that there were COVID-19 compatible pneumonic infiltrations in the lung bases in the abdominal CT. Irritation-related flank pain caused by inflammation in the lung basal may be the first symptom of COVID-19 disease in some patients. The first diagnosis that comes to mind in a patient admitted to the urology outpatient clinic with flank pain is stone disease. However, In this period when the COVID-19 pandemic continues, It should be kept in mind that if the pain score according to the visual analog scale pain scoring system is not very high in patients presenting with flank pain and there is no urological pathology in Abdomen CT, this pain may be a Covid-19 symptom. At the same time, radiologists should not overlook Covid-19 when evaluating images in Abdomen CTs taken in normal clinics other than the pandemic outpatient clinic. Unfortunately, there is no more effective option to struggle the Covid-19 pandemic than to reduce contagion.
The limitation of our study is that it was performed retrospectively in a single center and with a limited number of patients. Multicenter and comprehensive studies are needed to strongly advocate this outcome.