Explained | Why have doctors cautioned against misuse of CT scans and steroids to diagnose and treat COVID-19?

The story to date: As doctors check out completely different protocols to handle sufferers with COVID-19, Dr. Randeep Guleria, director of the All India Institute of Medical Sciences (AIIMS) and member of the National Taskforce on COVID-19, has cautioned against the use of CT scans indiscriminately to diagnose the illness, particularly within the early levels. This exposes people to pointless radiation, which might be dangerous in the long term, he mentioned. A single CT scan is equal to 300 X-rays, Dr. Guleria warned, which can enhance the chance of most cancers later in life for younger folks. Doctors and the World Health Organization (WHO) are additionally cautioning against the use of corticosteroids like dexamethasone, a potent anti-inflammatory drug, for sufferers who have non-severe COVID-19. Corticosteroids have been confirmed to profit sufferers with average and extreme an infection.

When is a CT scan suggested for a COVID-19 affected person?

An RT-PCR take a look at is the usual for analysis or affirmation of COVID-19. Use of CT for the analysis of COVID-19 ought to be restricted to that subgroup of sufferers who could have classical signs of the sickness however have a unfavorable RT-PCR take a look at consequence. However, a chest CT could be helpful in evaluating sufferers with average or extreme illness, to establish problems like thromboembolism or pneumomediastinum.

There are sure conditions involving COVID-19 sufferers through which a clinician may depend upon a CT scan to arrive at remedy selections. These embody eventualities the place a affected person could have classical signs of COVID-19 however his RT-PCR take a look at is unfavorable, or conditions when a CT pulmonary angiogram could be so as to rule out pulmonary embolism in a affected person who’s on anti-coagulants and steroids and is just not exhibiting any indicators of restoration. Also, in instances the place a affected person within the ICU with extreme COVID-19 is just not exhibiting any enchancment and a chest X-ray exhibits new lesions, a CT look may give a clue in direction of a analysis of harmful COVID-19-associated fungal super-infections like aspergillosis or mucormycosis. In a fourth situation, a clinician may order a CT chest to rule out spontaneous pneumomediastinum, a life-threatening complication.

“However, these four scenarios together constitute less than 2% of situations where a CT chest is ordered in COVID-19 cases. Rather than CT findings, it is oxygen saturation that is the key to treatment decisions. Yet, in 95% of the cases, CT scan is a misused tool, often prescribed to rule out pneumonia even in mild cases of COVID-19. There is no point in ordering CT early in the course of COVID-19 because even patients with mild severity may have some ground-glass opacities in the lungs, which do not merit treatment and will resolve on their own,” says R. Aravind, Head of Infectious Diseases, Government Medical College, Thiruvananthapuram.

The consensus assertion from Fleischner Society, a global, multidisciplinary affiliation for thoracic radiology, states that “imaging is not indicated” in suspected COVID-19 an infection with gentle scientific options. The assertion helps the use of imaging in sufferers with worsening respiratory standing in addition to in these with average to extreme scientific options which might be indicative of COVID-19 pneumonia.

Also learn | CT scan machines could be spreaders if protocols not adopted

To sum up, though CT has been utilized in assessing the severity of COVID-19 pneumonia, its routine use is just not really useful.

Are a number of CT scans dangerous?

When indicated, a chest CT ought to be carried out with a low-dose, single-phase protocol utilizing quick scanning strategies to minimise movement artifacts (affected person motion main to delicate errors).

There is not any proof to help the use of routine multi-phase chest CT in sufferers with COVID-19 pneumonia. Dr. Guleria mentioned in accordance to knowledge from the International Atomic Energy Agency, one CT scan was equal to virtually 300 to 400 chest X-rays, which put children at substantial threat of most cancers in the long run. A research revealed within the New England Journal of Medicine in 2007 mentioned primarily based on knowledge from 1991 to 1996, 0.4% of all cancers within the U.S. could also be attributable to radiation from CT research and that the present estimate might be within the vary of 1.5% to 2%.

Apart from all this, the dangers of transmission and contamination confronted by radiology technicians and workers each time a COVID-19 affected person undergoes diagnostic imaging, particularly in an air-conditioned, closed area, can’t be dismissed.

Why are steroids being prescribed for COVID-19 sufferers?

Even although many doctors in India had began treating severely unwell COVID-19 sufferers with corticosteroids like dexamethasone a lot earlier in the course of the pandemic, advice on their use from worldwide businesses just like the WHO got here solely in September 2020, following the U.K.’s RECOVERY Trial, which discovered mortality profit for sufferers who obtained steroids.

In many sufferers, loss of life happens following a hyper-immune response (cytokine storm) to the SARS-CoV-2 virus, which damages the lungs and different organs, main to multi-organ dysfunction syndrome. Corticosteroids like dexamethasone, as anti-inflammatory brokers, work by calming down the immune system and stopping the development of organ harm.

“Steroids are the most potent weapon we have to combat COVID-19. But the therapeutic window for starting steroids has to be spot-on. Determining the timing, dosage and duration is an art which has to be mastered,” says Dr. Aravind.

One of the primary considerations is that we don’t want to begin steroids too early within the sickness when viral replication is going on as it’d intrude with the immune system’s pure potential to combat again. We additionally don’t want to miss that vital level when steroids can forestall the immune system from unleashing the cytokine storm, he says.

The WHO pointers say that steroids could also be administered to sufferers whose resting saturation ranges are under 94% and whose respiration price at relaxation is over 24 per minute. However, steroids can profit some sufferers who aren’t on supplementary oxygen but however are exhibiting early indications that they may worsen.

Kerala’s pointers thus speak about recognising exertional desaturation — the autumn or depletion in oxygen saturation studying by over 3% from the baseline oxygen ranges, post-exercise or after the six-minute stroll take a look at — and addressing it on the proper time in order that interstitial irritation could be arrested. The stroll take a look at requires people to stroll for six straight minutes, and not using a pause, on a good floor with an oximeter on the finger. After six minutes, if the oxygen stage doesn’t go down, the person will probably be thought-about wholesome. But if the oxygen stage drops under 93%, or by 3%, or if the person suffers from breathlessness, then they’re suggested to search medical consideration.

“We want to pick up patients who are at risk of progressing to hypoxemia at rest. The earliest feature of COVID-19 pneumonia will be interstitial involvement, which leads to a demand-supply mismatch of oxygen. So, patients with normal oxygen saturation (> 94%) at rest in room air and who are clinically stable are put through the six-minutes/40-step walk test. If the oxygen levels drop after the walk test, these patients may be started on low-dose steroids after consulting the pulmonary specialist or a physician to prevent the cytokine storm syndrome,” says Dr. Aravind.

When do steroids turn into a double-edged sword?

That mentioned, steroids can end up to be a double-edged sword if the dosage, timing or length of the drug goes unsuitable. Steroids aren’t mandated for all sufferers and actually not for gentle sufferers within the early levels of the sickness. The set off for beginning steroids has to be exertional desaturation and not the day of sickness.

Dr. Guleria had identified lately that he was seeing many gentle COVID-19 instances the place steroids had stimulated viral replication, inflicting oxygen ranges to drop. There is potential hurt related to the long-term use of steroids in a severe COVID-19 affected person. This features a rise in blood glucose ranges, which is able to want to be rigorously managed with insulin to forestall secondary bacterial or fungal infections.