By Dr. Sanjay Mehta & Dr. Jeetendra Sharma
The second wave of coronavirus mutant has stretched the medical infrastructure to a point which is beyond imagination. The rise in cases is so alarming that the nation is battling the oxygen crisis and uncontrolled numbers of deaths. The challenges ahead are tremendous with responsibility on the shoulders of the medical fraternity facing a new challenge daily. The rapid surge gave a very small time window to doctors and healthcare workers to re-strategise using their collective wisdom.
It is important to be aware that this disease differs from the usual flu in one important form that is the hyper immune response of the affected person which appears after 5 to 6 days of the disease in a symptomatic patient. Unfortunately in a few cases this leads to complications especially in those with co morbidities. Hence day 6 is the critical day to watch out for, as early pick of such cases going into immunity overdrive if caught early and treated promptly will ensure very few people will actually require hospitals or Oxygen bed. This early pick is possible on day 6 in patients with continuing symptoms through rigorous monitoring of communities falling sick through tele-consultation with appropriately informed clinicians supported by volunteers. They can use various tools including clinical judgement, blood tests, X-rays o Ultra low dose CT scans depending on availability and individual case presentation, to initiate the critical and timely use of corticosteroids in aborting the hyper immune response to limit the damage to internal organs . It is important to avoid giving steroids before day 5/6 , as during this stage when the virus is multiplying and body is fighting against it the steroids will support the virus . Similarly delaying the steroids allows damage to lungs from hyper immune response hence both early and late institution of steroid therapy pushes the patients towards lung damage and eventual need for oxygen support. Also it’s indiscriminate and prolonged use specially in diabetics and immunosuppressive patients may predispose for fungal infections like mucormycosis, aspergillosis , candida etc. Noteworthy here is that steroids are like double edged swords to be carefully used till the time some safer substitute gets approved.
Ultra low dose CT scan proved to be a good option to timely assess severity and damage to lungs early. In this context it is necessary to emphasise that Ultra low dose HRCT, earlier used for screening lung cancers , is an important tool where using multiple detectors and tweaking the scanning parameters,radiation exposure can be brought down to sub-mSv dose , what you get exposed to in your air flights from the sun equivalent to a couple of X-rays and not hundreds, that is practically harmless compared to the risk of morbidity associated with COVID complications . Hence it is important to know for all having access to such a tool, the recent warning though well meaning by Dr. Randeep Guleria of AIIMS is to avoid whimsical scans on friends and relatives advice but not for scans advised by your clinicians.
Today, radiologists in the country are well-equipped with state-of-the-art facilities, knowledge and expertise and with technology up gradation this field has seen such rapid advancements in recent times . Ultra low dose CT scan has been found as an effective tool in the diagnosis of moderate to severe cases of Covid. In addition, it is useful to monitor changes during treatment and assess for complications such as lung rupture , superadded lung infections and occasionally identify clots in lung arteries using contrast . In the early phase of pandemic with poor turn around times for RTPCR , hospitals have used it effectively in triaging cases in emergency alongside RAT( Rapid Antigen Test ) .
Generally speaking RTPCR / RAT test diagnose Covid within couple of days from onset of symptoms . While around 6thday in patients with persistent high grade fever, a particular pattern of cough , falling saturation below 93 or appearance of breathing problem the Ultra low dose CT scan will help to find the severity of the disease. The clinicians get a CT score of Covid patients to determine, decide and initiate the treatment. While in the end of second week or the third week of infection chest CT can be useful in evaluating patients with moderate or severe disease to identify disease progress and complications. It is for this reason; several state governments have asked the radiology departments to notify patients with a CORADS score of 4 or 5.
It must be known that radiologists across the globe in accredited centres follow the ALARA principle (As Low As Reasonably Achievable) and give the minimal radiation possible during the scan. The medical investigations and treatment are also analysed based on the ‘risk vs benefit’ ratio and only used when benefits outweigh the risks which are almost non-existent.
Today when there is a need to utilise all resources to defeat Coronavirus, it is imperative to spread awareness among doctors, public and the concerned stakeholders on the safe use of Ultra low dose CT scan and also highlight the low risk associated through correct information.
(The authors, Dr. Sanjay Mehta is Chairperson Imaging, Artemis Hospitals and Dr. Jeetendra Sharma is Chief – Critical Care (Unit II) & Chief- Medical Quality, Artemis Hospitals. Views expressed are personal and do not reflect the official position or policy of the Financial Express Online.)