Leprosy Mailing List – August 23, 2021
Ref.: (LML) Smear positivity after one year course of MB MDT
From: Joel Almeida, London and Mumbai
Dear Pieter & colleagues,
Dr. Suryanarayan Rao, a colleague from India, has asked for advice about a patient
with LL HD - lepromatous leprosy (ref LML - 20 Aug 2021) Esteemed colleagues will be well placed to advise further, but the following approach is likely to be in the patient's best interests.
Presuming this patient is an adult with LL HD and lives in an area that is still endemic, the main threats to them following 1 year of MDT come from ENL episodes and reinfection. How can an independent private practitioner best protect this patient?
A dose of MIP vaccine (also known as Mycobacterium w) can be given. It is likely to evoke a favourable immune response if the patient downgraded from BL to LL. This can be gauged from a positive lepromin test. If the response to MIP vaccine is disappointing, the patient might be considered to have LLp (polar lepromatous) HD with genomically related anergy to HD bacilli. Then, further precautions seem wise for such patients living in endemic areas.
A combination of 3 bactericidal drugs given monthly under supervision will significantly reduce the risk of ENL as well as reinfection in endemic areas. It will also help ensure regular drug ingestion and allow regular monitoring of nerve function for sensory or motor deterioration. There will also be a regular opportunity to counsel, reassure and encourage the patient and, when helpful, the family too (if the patient permits). Periodic tests of hepatic and renal function, blood counts, as well as clinical examination will help rule out serious adverse effects. Monthly examination can help rule out any physical signs of inflammation or deterioration.
ROM (rifampicin + ofloxacin + minocycline) is the combination first promoted and used by WHO in the 1990s, with good outcomes. Moxifloxacin, however, is more bactericidal than ofloxacin. Therefore, moxifloxacin is better able than ofloxacin to balance the anti-microbial efficacy of rifampicin. Antimicrobial imbalance otherwise allows the selection of mutant bacilli resistant to the most potent drug in a combination.
Rifampicin 600mg +
Minocycline 100mg +
Moxifloxacin 400 mg
taken faithfully at least once a month offers robust anti-microbial prophylaxis. Clarithromycin, favoured by Brazil in some circumstances, is also included for exceptional use in the US national HD program guide.
Many colleagues would prefer to include daily administration of potent antimicrobials to LL patients for at least 2 years after the start of treatment. This may be because of the report that patients treated with 1 year of MDT yielded bacilli that grew in mouse footpads. In the USA the national HD program guide encourages 2 years of MDT including daily rifampicin, for (multibacillary) MB HD patients.
Once LL patients in an area are skilfully diagnosed, treated and consistently protected against reinfection, transmission in that area tends to decline fairly rapidly. Prophylaxis against reinfection in polar LL patients becomes steadily less necessary as transmission declines. Prolonged anti-microbial protection not only maintains the polar LL patient in a non-infectious state, but it also greatly reduces their risk of developing ENL neuritis with painful, swollen nerves.
If the LL patient in an endemic area cannot afford to pay for monthly doses of 3 bactericidal drugs after a year of MDT, then MDT (free of charge) can be continued. Reliable supplies of MDT are the backbone of HD treatment and control.
At the first sign of sensory loss, the patient needs to be offered prednisolone to avert further deterioration in nerve function. Such vigilance against nerve function impairment needs to be maintained for at least two years after the start of MDT. Similar treatment is indicated for signs of inflammation in lesions, nerves or organs. Anti-microbial protection greatly reduces the risk of ENL but if ENL still occurs then it requires robust treatment. Advice on self-care and prevention of permanent damage is important especially if anaesthesia has set in. If deformity has already developed, then specialist rehabilitation is indicated. If common mental disorders develop then referral to a clinical psychologist is indicated. If ostracism, job loss and social exclusion are inflicted on the patient (this is less likely for patients bearing the relatively non-emotive and easily transliterated label "HD") then counselling of the family/employer as well as referral to NGOs and patient support groups are indicated. It is important to let relevant people know that such a patient is non-infectious because MDT killed nearly all the HD bacilli and subsequently prophylaxis is preventing reinfection.
Smear positivity is not the reason for offering polar LL patients prophylaxis after one year of MDT. The risks of reinfection and ENL are the reason. The rate of bacillary clearance from skin smears merely correlates with the specific immune response to HD bacilli, and is therefore a helpful (if only inexact) way to gauge the immune response. Polar LL patients tend to show the slowest rate of bacillary clearance from skin smears, making them the slowest of "slow responders". However, an overwhelming majority of bacilli in the skin smears of treated patients are non-viable. Prophylaxis after MDT, for polar LL patients in endemic areas, is mainly for protection against reinfection and ENL.
Best wishes to Dr. Suryanarayan Rao as he seeks to act in the best interests of his patient. By protecting his patient against ENL and reinfection, using anti-microbials, he is also striking a blow against transmission in his area.
Joel Almeida
LML - S Deepak, B Naafs, S Noto and P Schreuder
LML blog link: http://leprosymailinglist.blogspot.it/
Contact: Dr Pieter Schreuder << editorlml@gmail.com
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