OMISSION OF CHEST X-RAY FROM DIAGNOSTIC ALGORITHM IN CASE OF INFECTIOUS PULMONARY (LUNG) TB.
(Excerpts from “Detailed Study on Eradication of TB and India’s DOTS Program”).
Omission of Chest X-ray: The real focus of relentless human research has perpetually been on lucrative ailments; medicine is inundated with breathtaking tools to detect illnesses of the rich and mighty like obesity, hypertension and heart disease. But for TB, Indian clinicians are desperately handicapped, constrained to rely upon the same two ancient tools – sputum smear test and chest X-ray.
No doubt, sputum test is cheap and confirmatory of the presence of TB. Sighting of causative TB germs in sputum slide of a symptomatic person is a definitive proof of diagnosis while no pattern of shadows in chest X-ray is typical (and hence diagnostic) of TB. While doctors misread & disagree over interpretation of X-ray shadows, there are no such controversies in sputum test.
So, government deleted X-ray (in infectious cases) from the menu of DOTS – a sputum-based venture. Once a patient’s sputum comes positive, he is treated for 6-8 months without an X-ray. Blindly!
This is wrong, illegal & unethical. It violates basic human rights. First, man refuses to do any R&D! Then he brazenly drops one of the mere two tools at his disposal! It is like deliberately piercing one of the two eyes, claiming that one is enough. Despite some limitations, X-ray is indispensable and complimentary to sputum test. No qualified doctor, in case he himself develops infectious TB, would submit thus to blind TB treatment without first undergoing a chest X-ray.
Further, ‘spotting an X-ray shadow’ instantly electrifies the doctor to clinch the presence or absence of TB. Without an X-ray, the treating physician is virtually blindfolded. He fails to distinguish extensive from minimal lung damage in a given case. And, once patient’s sputum dries up, his follow up becomes speculative. Besides, deliberate refusal to obtain and preserve for future reference visual records of an event so vital (at times fatal) amounts to a medico-legal crime. Even otherwise, by itself, the sputum test detects only 48% of the sick; it does not detect pediatric, extra-pulmonary or smear negative TB.
Fate of such a mammoth program has been left precariously hanging from a feeble thread – at the mercy of a solitary test and its sole performer. Are govt. labs, technicians and their reporting 100% reliable?
Therefore, X-rays must be done at diagnosis (as in China) and then every 2 months of treatment.
Omission of chest X-ray from the diagnostic algorithm in case of infectious pulmonary (lung) TB:
Ever since the invention of X-ray in 1895, doctors have exhibited a natural tendency to diagnose Pulmonary (lung) TB on the sole basis of chest X-ray. They have virtually been labeling and treating X-ray shadows. However, mounting scientific evidence has questioned the practice of such over-dependence on X-ray for the diagnosis of TB.
Studies involving numerous doctors and X-rays of known cases have exposed several Limitations of chest X-ray:
1. No chest X-ray pattern is absolutely typical of lung TB. A TB lesion can cause any and every kind of shadow in chest X-ray, as can pneumonia or cancer etc. No shadow, whatever its shape, size or location, can be termed diagnostic of TB.
2. Etiology difficult to ascertain from X-ray. Only bacteriology provides the final evidence of tubercular etiology of shadows. In other words, there is only one definite proof of lung TB and that is a sputum positive report because we see the causative TB germs in the sputum-slide of the person.
3. Interpretation purely subjective:
· Even an experienced doctor can misread X-ray; labeling pneumonia shadows as TB or vice-versa – he could dismiss spots of TB as those of pneumonia or cancer.
· Under-diagnosis: In one study* (5), 5% of sputum positive (infectious) cases were missed altogether, their chest X-rays read as normal!
· Over-diagnosis: By reading X-ray (alone), the doctor could sinfully mislabel even a perfectly healthy individual as suffering from TB.
· Displaying disturbing inconsistency, he might disagree with his own previous opinion; shown the same X-ray second time over, he might take a comic U-turn.
· In interpreting chest X-rays, doctors were found to widely disagree with one another – displaying significant inter-observer disparity. 30% of the times two experienced doctors looking on the same X-ray won’t agree on the verdict.
4. Activity within the lesion difficult to assess.
5. Operational disadvantages:
· Delay in getting result.
· Comparative non-applicability on a large scale.
· Costly equipment and consumables.
· Special training to read X-rays required.
Therefore, it has been concluded that a purely radiological criterion is unreliable in giving confirmed diagnosis of lung TB or for monitoring of treatment.
Scientists have, on the other hand, highlighted several comparative advantages of sputum smear microscopy:
· Simple, cheap and quick.
· Easy training.
· Mass scale applicability feasible.
· Fewer resources required for setting up microscopes, labs and for consumables.
· Electricity not essential.
· Subjective element absent: Inconsistencies as observed in X-ray were documented to be minimal if – instead of X-ray – the diagnosis was based upon sputum smear microscopy. Inter-observer difference here was negligible. “On the question: ‘is the smear positive for acid-fast bacilli – Yes / No?’ the frequency of agreement was 93%.”* (6)
· Besides, why do we give drugs to the patient? To cure the patient – and not to cure or clean up the shadows in his X-ray, isn’t it? Drugs are given to kill the bacilli that make him sick, and which is directly documented only through sputum test.
The basic thinking behind the new concept of this new program probably is to check the spread of infection. Targets of RNTCP are to detect at least 70% of new infectious (sputum smear-positive) cases and to cure at least 85% of them. The immediate prime aim therefore is to somehow reduce transmission through catching and curing our army of infectious cases, thus rendering the nation’s environment safer for general public, thereby hopefully lessening future caseload. Unlike a private doctor who tailors a separate prescription in his endeavors to cure every individual case, this program was originally designed purely for mass application – to cure not 100% but a vast majority of patients; especially those spreading the infection to others. It is by its very nature ‘One size fits all’; in a shrine, same food is cooked on mass scale – eat it or leave it. The design, in the first place, is not geared for individualized treatment but offers one practical option for the poor masses.
Possibly, inspired by such thinking and saddled with resource crunch (real or imaginary), the government of India, in a drastic move, omitted chest radiography nearly completely from the menu of this new TB program, RNTCP!
No chest X-ray is now done in patients who have infectious pulmonary disease i.e. confirmed sputum positivity.
Of the total 3 categories within this program in which all patients are grouped, infectious cases end up constituting bulk of two categories (Cat I & Cat II). All these cases are now diagnosed and monitored through a single test – sputum test.
Radiography stands withdrawn from this domain.
A simplified diagrammatic representation of diagnostic algorithm as practiced under RNTCP is given hereunder:
During recent decades, medical science has made tremendous progress; it has grown by leaps and bounds. It has virtually been inundated with newer tools and techniques for clinching the diagnosis of diverse ailments. However, most revolutionary advancements have come about in lucrative fields like heart disease, critical care, obesity, beautification and mood elevation etc. But when it comes to diagnosing TB – the commonest of all ailments – man continues to be miserably short of tools. Clinicians are frustratingly constrained to rely upon the same two ancient (though time-tested and still effective) tools namely:
· 124-year-old sputum smear microscopy test.
· 111-year-old chest X-ray.
First, man refuses to do any R&D on TB, failing to invent desperately needed newer tools. And then, as if that was not enough, rubbing salt in to the wounds, he, citing certain limitations, brazenly drops one of the mere two tools at his disposal from the diagnostic algorithm of DOTS!
This is absolutely wrong!
This is inhuman.
It is a suicidal renunciation, turning the clock back to pre 1895 era. It is like wrenching out the very soul out of TB management. It is like shooting in one’s foot. It is like piercing one eye with a needle, declaring that one is enough.
Because, despite all its limitations painstakingly researched and emphasized, for the diagnosis and follow up of TB, one tool (chest X-ray) inseparably compliments the other (sputum test). They are like two eyes for TB.
Besides, is it ethical? Does it not violate human rights? In the modern era of 21st century, the WHO & the govt. of India join their brute might to deliberately and arbitrarily deprive an innocent patient of a fundamental right to something so elementary and vital to his diagnosis and follow up, and that too without his consent or knowledge – all in the name of public good, scarcity of resources, economy, newer research, operational feasibility or expediency. Is it fair to indulge in such medical brinkmanship when so many lives are on the line? Shouldn’t the supreme issue of human life & health transcend all trivial considerations?
No qualified doctor could possibly agree to submit himself ever to TB treatment upon being labeled sputum positive, without first undergoing a chest X-ray. This was corroborated by a tiny survey done in Faridabad. To the question – if ever your own sputum came positive thrice, would you submit to treatment without first undergoing a chest X-ray? – All ten well-qualified and experienced physicians of Faridabad formally interviewed* (7) answered a resounding and emphatic ‘No’. Each one wanted his chest X-ray first, disagreeing with the current diagnostic algorithm of RNTCP.
Furthermore, scores of other doctors interviewed informally by the petitioner during the past 5 years have reiterated similar dissenting views.
How could something that is not considered good enough by experts for themselves or for their own beloved family members be good for the masses? How can you preach what you are unwilling to submit to yourself?
What are the main limitations of not performing a chest X-ray?
1. Crucial delay in diagnosis: A doctor is taught to leave no stone unturned when a TB-suspect first approaches him. In TB, first opportunity is the golden one. As the diagnosis (and treatment) gets delayed, it endangers the patient’s life. It also poses serious risk of transmission of infection to others. There can be no better stimulus than ‘stumbling upon an abnormal shadow in X-ray’ for the treating physician to explore with redoubled energy and resolve the key question – TB or no TB and thus clinch an early diagnosis.
2. A doctor fails to make a fundamental distinction – between extensive lung damage (or cavity formation) and a minimal lesion in a given case:
In remedying rampant non-uniformity of diagnostic criteria in the past, DOTS has swung to the other extreme – by becoming too terribly uniform, crudely fitting all grades and shades of TB patients in to mere 3 categories. Since no chest X-ray is taken, the doctor fails to differentiate a bad case (with extensive lung-destruction and cavity formation) from a good case (with minimal lesion). Once confirmed to be sputum positive, both are blindly and uniformly treated under category I, exposing the former to some risk of poor response, treatment-failure or relapse.
3. Follow up of a patient becomes virtually a blind exercise:
After 2 months of medication, symptoms disappear and the patient feels better. Sputum often turns negative (from positive). During the next 4 months, continued sputum negativity (absence of germs in sputum) is the sole indicator of the patient’s progressive recovery. It is indirect evidence and deserves to be reinforced by complimentary visual evidence – progressive shrinkage or clearance of the shadows in serial chest X-rays.
Further, after 6 months, treatment is blindly stopped. It appears presumptive. One final X-ray could at times warn of some residual activity, requiring some further remedial medication beyond the stipulated 6 months.
4. We are left solely and completely at the mercy of the sputum test. Often, once effective treatment starts, sputum simply dries up! Patient genuinely fails to cough up and bring out any phlegm as required for the testing. Sputum ‘not obtainable’ doesn’t necessarily imply ‘negativity’ and ‘recovery’. His follow up becomes presumptive.
5. A category II patient is treated initially with all 5 drugs simultaneously – practically the entire firepower that man has at his disposal today.
This is so because it is possibly the last opportunity for that patient. If this 8-month attempt fails, he is doomed; he may turn out a resistant (incurable) case – may even die. So, a category II case virtually sways right on edge, tied merely to a thread – that of hope.
If this one person doesn’t merit as elementary a scientific test as chest X-ray, no one on the earth does! To deal with such a grim situation with anything less than the very best available to man is to play with human life. Not to give him one hundred percent and right now is insanity.
Besides, TB must be respected as a lifetime sickness; it could potentially run for generations. This is the only life a patient has and the future of his entire family is virtually at stake. A slip up at this grave moment will possibly cause irreversible damage to the entire family future.
6. In the absence of a chest X-ray, a doctor may miss a coexistent lung disease that can be instantly spotted by a chest X-ray picture and which might have crucial and intimate bearing over that patient’s response to anti-TB treatment and which might need an urgent and timely intervention e.g. lung-collapse, pleural effusion, pneumothorax, hydropneumothorax, pyothorax, hylar lymphadenopathy or pneumoconiosis etc.
Further, by helping to assess the extent of damage, a chest X-ray also serves at times as a mandatory prognostic indicator.
7. Curiously, even perpetually sputum negative chest cases (PTB, category III) diagnosed on the basis of an initial chest X-ray, do not get the benefit or courtesy of repeat X-rays during the rest of their course of treatment (6 months). Is it fair to monitor even such cases’ progress through sputum tests alone? This deprivation within the module gives credence to suspicions that the real determinant behind omission of radiography is more economic than scientific.
8. What is the scientific justification of conducting follow up of extra-pulmonary cases (Category III) through periodic sputum tests, which are irrelevant? Serial chest X-rays are indispensable in several cases e.g. a case of Pleural Effusion or Primary TB with Hylar Lymphadenopathy etc. Such omissions give further credence to suspicions that corners have been cut deliberately and ruthlessly merely to economize – at any cost.
9. A medico-legal crime:
TB treatment is a long journey – in to the unknown. If and when, at a later date, the fatigued patient encounters slow response, complications, drug toxicity or treatment failure, a baseline X-ray done on day 1 would sure come in handy for comparison – to evaluate his current status.
Just as any human body-tissue once taken out by a surgeon must be sent for mandatory histo-pathological examination and the slides and records preserved for several years; similarly, it seems logical to conduct chest X-rays and preserve the precious visual records for future reference and comparison. X-ray pictures, preserved carefully, provide priceless insight into a patient’s medical history for all times to come.
Deliberate refusal to obtain and preserve visual records of an event so vital (at times even fatal) is a medico-legal crime. The patient has a right to getting it recorded radio-logically, even if it affords a limited benefit towards his future safety? After all, every penny counts when the chips are down.
We would soon have on our hands a substantial population of ex-patients from RNTCP pipeline who have no past X-ray records of their residual scarring to evaluate fresh activity with. A doctor can’t make comparisons in vacuum.
10. Disadvantage sometimes in assigning correct category:
X-ray affords a doctor an opportunity, however faint, to reconfirm a patient’s version of his past illness. Spotting old healed scars (of an earlier episode), which the patient has failed to report – knowingly or inadvertently, will empower the doctor to assign correct and tougher category (namely Cat. II). Patient’s own version would have landed him in the softer Cat.1 and all sorts of trouble. The timely shifting of category eventually proves decisive for that patient’s fate.
11. When TB occurs in an HIV positive individual, there is usually less coughing. Chances of sputum coming positive too are comparatively less. Can the current diagnostic algorithm then be termed ‘futuristic’ for a nation like India, which is fast emerging HIV capital of the world and is getting excessively bedeviled with co-infection of HIV & TB?
12. Doctor’s mind put on autopilot mode:
Anecdotal evidence suggests that an RNTCP trained doctor at times begins to function all too mechanically, putting his own brain on autopilot mode. The modular training encourages him to sit back and follow a ‘no touch technique’. Further, refusing to look at an X-ray that may be full of clues, he habitually procrastinates by conveniently hustling every patient in to sputum-testing pipeline that may take a week or two. As a result, often a glaringly X-ray positive patient walking in voluntarily is not grabbed with appropriate urgency. He may never return to collect his sputum reports.
13. RNTCP training module for doctors doesn’t seek to hone doctors’ X-ray reading skills. The doctors are not shown any X-rays and therefore remain ill equipped to do justice with the diagnosis of sputum negative TB or to handle patients with extensive lung-damage, cavities, pleural effusion etc. Similarly the brief training hardly prepares him well for the diagnosis of childhood or extra-pulmonary TB, which can often be a highly complex proposition.
Any TB patient, who is not sputum positive, tends to receive a raw deal and faces discrimination from the national program that unfairly accords priority to sputum positive segment of patients (Please also see ‘How program discriminates against half the TB patients’).
Prayer No. 2……….
· DOTS must be urgently modified by due inclusion of radiography.
· Each and every TB patient must undergo a chest X-ray at the time of diagnosis – before initiation of treatment.
· Thereafter, chest X-rays must be repeated at the end of 2, 4 and 6 (and 8) months of treatment in every case (except extra-pulmonary cases).