Understanding Leprosy: Causes, Treatment, and Prevention
1. Dr. D. K. Brahma
Associate Professor
Department of Pharmacology
NEIGRIHMS, Shillong
2. Leprosy is caused by a slow-growing type of
bacteria called Mycobacterium leprae (M. leprae)
Also known as Hansen's disease, after the scientist
who discovered M. leprae in 1873 - Dr. Gerhard
Henrik Armauer Hansen of Norway
Bears social stigma
It primarily affects the skin, mucous membrane
and the peripheral nerves
Long Incubation period (3 – 5 years)
Curable now – deformities/defects – may not
reverse
4. The simplest, oldest, cheapest, most active and most commonly
used
Diamino diphenyl sulfone (DDS)
MOA:
Leprostatic even at low concentration – higher conc. Arrests growth of
may other bacteria
Chemically related to Sulfonamides – same mechanism – inhibition of
incorporation of PABA into folic acid (folic acid synthase)
Specificity to M leprae – affinity for folate synthase
Doses for acute infection – too toxic
Activity:
Used alone – resistance – MDT needed
Resistance – Primary and Secondary (mutation of folate synthase – lower
affinity)
2.5% to 40% Vs 20% Resistance
However, 100 mg/day – high MIC -500 times and continued to be effective
to low and moderately resistant Bacilli (low % of resistant patient)
Persisters. Also has antiprotozoal action (Falciparum and T. gondii)
5. Pharmacokinetics:
Complete oral absorption and high distribution (less CNS
penetration)
70% bound to plasma protein – concentrated in Skin, liver,
muscle and kidney
Acetylated and glucoronidae and sulfate conjugated –
enterohepatic circulation
Half life 24-36 Hrs, but cumulative (1 – 2 weeks)
ADRs: Generally Well tolerated drug (100 mg /day)
Haemolytic anaemia (oxidizing property) - G-6-PD are more
susceptible
Gastric - intolerance, nausea, gastritis
Methaemoglobinaemia, paresthesia, headache, mental
symptoms and drug fever
Allergic rashes, FDE, phototoxicity, exfoliative dermatitis and
hepatotoxicity etc.
6. Sulfone syndrome: Starts after 4- 6 weeks of
therapy, more common with MDT
Symptoms: Fever, malaise, lymph node enlargement,
desquamation of skin, jaundice and anemia –
malnourished patients
Management: stopping of Dapsone in severe
cases, corticosteroid therapy
Corticosteroids (prednisolone 40 – 60 mg/day) –
severe cases – till reaction controlled – tapered over
8-12 weeks
Dapsone contraindications: Severe anaemia
and G-6-PD deficiency and hypersensitivity
7. A dye - Leprostatic and anti-inflammatory
MOA: Interferes with template function of DNA in M.
leparae
Activity: Used alone resistance (1 -3 years) – but Dapsone
resistance cases responds in 2 months (lag period)
Kinetics: orally effective – accumulates in fat in crystalline
form – entry to CSF poor – half life 70 days
Used as component of MDT
ADRs: - well tolerated
Reddish-black discolouration of skin – exposed parts
Discolouration of hair and body secretions, dryness of skin and
itching, acneform eruptions and phototoxicity – conjunctival
pigmentation
GI symptoms: Enteritis with intermittent loose stool, abdominal
pain, anorexia and weight loss – early and late symptoms
Should be avoided in pregnancy and liver & kidney disease
8. Rifampicin: Cidal. 99.99% killed in 3-7 days, skin
symptoms regress within 2 months
Not satisfactory if used alone – persisters even prolonged
treatment
Included in MDT to shorten the duration of treatment
and also to prevent resistance
Not toxic and no induction of hepatic enzyme - dose as
single dose only
Should not be used in ENL and Reversal phenomenon
Ofloxacin: all fluoroquinolones except
ciprofloxacin are active. Used as alternative to
Rifampicin – 22 daily doses
Minocycline: Lipophillic - enters M leprae. Less
marked effect than Rifampicin
9. Granulomatous infection – skin,, mucous membrane
and nerves
Systems of Classification:
1st (Based on immune system of the patient): Mainly two types:
lepromatous (sore on skin, nerves, and other organs) and
tuberculoid (sore on skin)
2nd (Ridley-Jopling system – based on symptoms): Borderline
tuberculoid leprosy (BL), Borderline lepromatous (BL),
Borderline leprosy (BB) and Intermediate leprosy (I)
For operational purposes: WHO
Paucibacillary (>5 lesions): few bacilli and noninfectious – TT
and BT and I
Multibacillary (<5 lesions): large bacilli load and infectious –
LL, BL and BB types
Single lesion Paucibacillary: single lesion
10. Paucibacillary (PB) - TT and BT
and I
Multibacillary (MB) - LL, BL and
BB
• 1- 5 skin lesions
• No nerve/only one nerve
involvement +/- 1-5 skin lesions
• Skin smear negative at all sites
• 6 or more skin lesions
• More than one nerve involved
irrespective of skin lesions
• Skin smear positive at any one of
the sites
11. Initially (1982) – PBL Dapsone + Rifampicin for
6 Months and MBL – Dapsone + Rifampicin +
Clofazimine – 2 years or till disease
inactivity/smear negative – with added 5 years
surveillance for MBL cases
However, 12 years study (in 1994) – fixed
duration for 6 months and 2 years was
recommended – 12 million to 2.7 million and
no resistance
In 1999 – 6 months and 1 year recommended
12. Drug Paucibacillary (PB) Multibacillary (MB)
Rifampicin 600 mg once a month
Supervised
600 mg once a month
Supervised
Dapsone 100 mg daily self
administered
100 mg daily self
administered
Clofazimine - 300 mg once a month
Supervised
50 mg daily self administered
Duration 6 Months 12 Months
13. Photo Courtesy: Dr. Anju R. Marak,
SM&HO cum DLO and DMO-MCH,
Ri-Bhoi District, Meghalaya
14. 1. Lepra Reaction Occurs in LL type (Type – III HSR) – coincides
with institution of chemotherapy or intercurrent infection
Arthus type of reaction – release of antigens from killed bacilli - may be
mild, moderate and severe (ENL)
Symptoms: enlarged lesions, become red (inflamed nodules and papules)
and painful, new lesions – fever and other constitutional symptoms
Treatment:
Mild analgesics
Mild: Clofazimine - 200 mg daily
Moderate to severe-Steroids: 60 mg/day-Prednisolone - taper off in 2-3 months
2. Reversal reaction Occurs in TT and BL cases (Type II HSR) –
delayed hypersensitivity to M. leprae antigens
• Symptoms: Cutaneous ulceration, multiple nerve involvement with
swollen and tender nerves – occurs suddenly even after completion of
therapy …… Treatment: same as above
17. “The biggest disease today is not leprosy
or tuberculosis, but rather the feeling of
being unwanted, uncared for, and
deserted by everybody.” – Mother Teresa
Thank you