Siddhartha Yadav: Diagnosing and treating the “Nepalese” microbes

A large portion of my work as a doctor in Nepal is to treat infections. Even in chronic conditions – COPD, diabetes, malignancy – I find that infectious micro-organisms take the toll more rapidly than the disease itself. It is fascinating how these minute beings have the power to bring human life to a standstill.

Fever without an obvious localising site often presents a diagnostic dilemma here. One of the reasons is that the spectrum of micro-organisms we are dealing with in Nepal is very different from that elsewhere. In a study looking at the etiology of febrile illnesses in adults presented to the Patan Hospital in Kathmandu (Am. J. Trop. Med. Hyg., 70(6), 2004, pp. 670-675), the most common organism isolated was Salmonella enterica (typhi and paratyphi) causing enteric fever. Perhaps this is why some researchers on enteric fever refer to Kathmandu as the “typhoid capital of the world.”

Kathmandu has cashed in on this title. In the past few years, there have been numerous clinical trials and research studies on typhoid in the city that have changed the understanding and management of typhoid fever. Yet, the impact of these studies on the day to day practise of clinicians in Kathmandu is debatable. Most of us prefer to practice what we have been doing for years or refer to Western books written, instead of following what local research on antibiotic effectiveness suggests.

Undertreatment of typhoid fever with less effective antibiotics, low dosage, and for a short duration is common here. Last week, at a program organised by the Mountain Medicine Society of Nepal, Dr Jeremy Farrar, an avid researcher on infectious diseases, suggested that using appropriate antibiotics at adequate doses to treat typhoid fever is necessary to prevent resistance and spread in the community. In this context, the need to keep ourselves updated on effective treatment of a common problem like typhoid fever cannot be overemphasised.

Another microbe that I like to call “Nepalese” is Mycobacterium tuberculosis. Considering the department of health services estimates that 45 per cent of the total population is infected with tuberculosis (this does not necessarily imply active disease), it is not surprising that we often suspect tuberculosis in patients who have had a fever for a long time. However, it is not always easy to confirm this suspicion. The acid fast bacilli smear test has low sensitivity (40% to 60%). Nucleic acid amplification tests are yet to be widely implemented here.

Surprisingly, I have seen Mantoux test being widely used here to diagnose tuberculosis. My bookish knowledge suggests that Mantoux is a screening test: to be used in the apparently healthy. But we use it more often in those presenting with signs and symptoms of tuberculosis or an abnormal chest radiograph, and pronounce active tuberculosis based on its result.

I am not quite sure how well this approach works. I would expect that 45 per cent of the Nepalese adult population – those infected – to have a positive Mantoux test anyway. In a country where we are not very enthusiastic about treating latent tuberculosis infection, I do not see much of a role for the Mantoux test in adults, which is in contrast to the popular belief of many clinicians here. Correct me if I am wrong on this point.

So that leaves us with treating tuberculosis empirically when the diagnosis cannot be confirmed. If only the treatment for this disease was shorter, this would not be much of an issue. But committing somebody to treatment for at least six months in the face of an uncertain diagnosis poses a huge psychological strain on the patient and family members.  I can only hope that better diagnostic tools such as the nucleic acid amplification tests will be widely available in Nepal in the near future and at an affordable price.

Besides these two microbes, there are many others which pose a diagnostic and treatment challenge. The Patan fever study showed that rickettsial disease (scrub typhus and murine typhus) and leptospirosis are much more common here than expected. Malaria, kala-azar (visceral leishmaniasis), and filariasis are other infectious diseases that are very common in the southern parts of Nepal.

Treatment of infectious diseases with appropriate antibiotics is very rewarding. The patient improves dramatically within a short time. The challenge, however, lies in making the correct diagnosis and selecting proper antibiotics. Our approach here, most of the time, is to start our fight with our heavy guns: potent antibiotics that should have been reserved for serious infections.  

Ceftriaxone happens to be our favorite drug for healing in patients these days. Even for out patients, there is a tendency to start treatment for simple respiratory infections, sinusitis, or urinary tract infections with potent broad spectrum antibiotics. In addition, I have seen fourth generation cephalosporins and imipenems being used as first line treatment for simple infections.

Using potent broad spectrum antibiotics as first line drugs for simple infections can get a patient better sooner and the chances of treatment failure are slim but this approach promotes antibiotic resistance. In the long run, we would lose the option of using antibiotics when faced with a serious life threatening infection, as injudicious use of antibiotics will have rendered our microbes resistant to most of them.

Identifying and treating infections in Nepal is not an easy task. The organisms are different, there are minimal diagnostic tools, and the treatment guidelines are sometimes not clear. Despite this the clinicians here have done a fairly good job of diagnosing and treating infections using their experience and clinical judgment. Now is the time to move a step further to inculcate better diagnostic tools, evidence based treatment protocols, and the rational use of antibiotics.
Siddhartha Yadav is a former BMJ Clegg Scholar