Leprosy Flashcards
What is leprosy?
Leprosy, also called Hansen disease, is a chronic bacterial infection primarily affecting the skin and peripheral nerves, usually caused by Mycobacterium leprae. The form the disease takes depends on the person’s immune response to the infection.
What causes leprosy?
Leprosy is nearly always caused by Mycobacterium leprae, an intracellular acid-fast bacillus related to Mycobacterium tuberculosis and Mycobacterium ulcerans. M. leprae grows best at cool temperatures, explaining its predilection for affecting skin and peripheral superficial nerves. It divides very slowly and can take years to reach a number sufficient to show signs of infection.
What are the clinical manifestations of leprosy?
The clinical manifestations of leprosy depend on the immune response to Mycobacterium leprae/lepromatosis and range over a spectrum:
Multibacillary Lepromatous Leprosy (LL): Shows limited or low immunity to M. leprae/lepromatosis.
Paucibacillary Tuberculoid Leprosy (TT): Shows a strong immune response to M. leprae/lepromatosi
What are the clinical features of Tuberculoid (TT) leprosy?
Tuberculoid (TT) leprosy is the paucibacillary form characterized by:
A few (1–2) sharply defined red patches with raised borders or a single larger hypopigmented patch less than 10 cm in diameter.
Loss of sweating with rough, dry, hairless skin in the patches.
Loss of sensation in the lesions.
Affected nerves are thickened and tender on palpation.
What are the clinical features of Borderline Tuberculoid (BT) leprosy?
Borderline Tuberculoid (BT) leprosy presents with:
Similar lesions to Tuberculoid (TT) leprosy but larger, more numerous (5-20), and can be less well-defined.
Asymmetrical distribution of lesions.
Presence of satellite lesions.
Anaesthesia over the lesions is less pronounced compared to TT.
Peripheral nerves are affected in an asymmetrical pattern, which can lead to deformity and disability.
What are the clinical features of Borderline Borderline (BB) leprosy?
Borderline Borderline (BB) leprosy is a rarely seen, transient, and unstable form of leprosy characterized by:
Multiple lesions of varying size, shape, and distribution.
Skin-colored or erythematous lesions.
Rare but characteristic inverted saucer-shaped lesions with sloping edges and a punched-out center, also known as “Swiss cheese lesions.”
What are the clinical features of Borderline Lepromatous (BL) leprosy?
Borderline Lepromatous (BL) leprosy is characterized by:
Widespread, bilaterally symmetrical lesions.
Presence of macules, papules, and nodules of variable size and shape.
Normal sensation and hair growth within the lesions.
Characteristic “glove and stocking” numbness.
Widespread peripheral nerve involvement.
What are the early symptoms and skin manifestations of Lepromatous (LL) leprosy?
Early Symptoms: Nasal stuffiness, discharge, and bleeding.
Skin Lesions: Widespread, poorly defined hypopigmented and erythematous macules with a shiny surface and normal sensation.
Progression: Widespread infiltration of skin forming nodules and plaques.
What are the characteristic facial features of Lepromatous (LL) leprosy?
Lepromatous (LL) leprosy can cause leonine facies, which includes:
Thickening of the forehead.
Loss of eyebrows and eyelashes (madarosis).
Distortion of the nose.
Thickening of the earlobes.
How does Lepromatous (LL) leprosy affect the eyes, testes, and liver?
Eyes: Corneal anaesthesia, keratitis, corneal ulceration, uveitis, glaucoma, and potential irreversible blindness.
Testes: Orchitis, testicular atrophy, sterility.
Liver: Hepatitis, hepatic amyloidosis
How does Lepromatous (LL) leprosy affect the kidneys and bones?
Kidneys: Glomerulonephritis, renal amyloidosis.
Bones: Osteoporosis, resorption of digits.
How is a Skin Slit Smear used in diagnosing leprosy?
A Skin Slit Smear involves making a small slit over the skin (earlobe, forehead, or lesional skin), scraping the exposed dermis onto a glass slide, and examining it under a microscope for acid-fast bacilli. This method is useful for diagnosing multibacillary leprosy.
What is the Lepromin test and how is it used in diagnosing leprosy?
The Lepromin test is an intradermal test for delayed-type hypersensitivity to Mycobacterium leprae antigens. Although it is not specific, it helps in classifying the type of leprosy.
How is a Skin Biopsy used in the diagnosis of leprosy?
A Skin Biopsy can show typical features depending on the type of leprosy. Special stains may be required to demonstrate the bacilli in the tissue.
How is M. leprae DNA PCR used in diagnosing leprosy?
M. leprae DNA PCR is a highly specific method for detecting leprosy organisms, confirming the presence of the bacteria in a sample.
What is the differential diagnosis for hypopigmented patches and macules in leprosy?
Hypopigmented patches and macules in leprosy may need to be distinguished from:
Pityriasis alba
Pityriasis versicolor
Leishmaniasis
Yaws
What is the differential diagnosis for pigmented and raised lesions in leprosy?
Pigmented and raised lesions in leprosy may resemble other cutaneous infections, such as:
Cutaneous leishmaniasis
Lupus vulgaris
What is the treatment regimen for PB-leprosy (Paucibacillary leprosy)?
Medications: Rifampicine 600 mg once a month under supervision plus Dapsone (DDS) 100 mg daily for 6 months unsupervised.
Compliance: If compliance is a problem, completing the 6-month dose within 9 months is acceptable.
Note: Always check for complications
What is the treatment regimen for MB-leprosy (Multibacillary leprosy)?
Medications: Rifampicine 600 mg and Clofazimine (Lampren) 300 mg once a month under supervision, plus Dapsone (DDS) 100 mg daily and Clofazimine 50 mg daily unsupervised for 12 or 24 months, depending on local policy.
Compliance: If compliance is a problem, completing the 12-month program within 18 months or the 24-month program within 36 months is acceptable.
Note: Always check for complications!
What are the primary complications of leprosy?
The primary complications of leprosy are reactions that cause nerve damage, leading to:
Loss of sensation
Loss of muscle strength
Ulceration and deformity as consequences of nerve damage
What are the two types of leprosy reactions?
- Reversal Reaction (RR):
Increased swelling with erythema of existing lesions
Appearance of new lesions
Enlargement and tenderness of nerves with potential function loss
Sometimes acral edema - Erythema Nodosum Leprosum (ENL):
Sudden appearance of tender erythematous nodules
The patient may feel ill, with tender nerves
Possible arthritis, lymphadenitis, orchitis, iridocyclitis, and glaucoma
Can lead to blindness and organ involvement
How does leprosy lead to ulceration and deformity?
Ulceration: Secondary to loss of protective sensation. Patients do not feel heat, pressure, or pain, leading to neglected skin trauma.
Deformity: Results from loss of muscle strength (e.g., claw hand, drop foot) and complications such as cellulitis, deep infections, and osteomyelitis, which may lead to the loss of digits.
Lagophthalmos: Involves eye anaesthesia and lack of blink reflex, leading to drying out and ulceration of the eye, potentially resulting in blindness.
What is the impact of nerve damage on muscle strength and deformity in leprosy?
Nerve damage in leprosy leads to:
Loss of muscle strength, causing deformities like claw hand and drop foot.
Increased risk of ulceration due to lack of sensation and muscle weakness.
Consequences may include osteomyelitis, shortening of digits, stiffness, and contractures.
How is a Reversal Reaction (RR) in leprosy managed?
Steroid Treatment: Start with prednisolone 30-40 mg daily, taper down to 20 mg daily over 2 months. Maintain this dose for PB (1-2 months) or MB (2-4 months or longer).
Tapering: Gradually taper the dose to zero over the following 2 months.
Monitor: Ensure treatment duration is sufficient and check for intercurrent infections such as TB and strongyloide
How is mild Erythema Nodosum Leprosum (ENL) managed?
Mild ENL Treatment: Use acetyl salicylic acid (aspirin) 1000 mg three times daily for 1-2 weeks.
Check for Infections: Monitor for intercurrent infections, particularly TB
How is severe Erythema Nodosum Leprosum (ENL) managed?
Severe ENL Treatment: Start prednisolone 80-100 mg daily for 2 days, then taper off over 2 weeks. This may need to be repeated.
Thalidomide (if available): Use 100-400 mg once daily for 1-2 weeks, but never in pregnant women or women without 100% safe contraception due to the risk of severe birth defects.
Check for Infections: Monitor for complications like TB.
How should ulceration in leprosy be managed?
Wound Care: Clean and cover wounds; use zinc adhesive sticking plaster for superficial wounds, renewing every 1-2 weeks. Trim hyperkeratotic rims.
Avoid Bulky Bandages: Especially on feet, as they can cause local pressure and delay healing.
Antibiotics: Only use when cellulitis is present.
How can further deformity in leprosy be prevented?
Daily Care: Encourage daily inspection, soaking, oiling, trimming cracks, and softening skin with 15% salicylic acid in vaseline.
Exercise: Stretch digits actively and passively to prevent contractures.
Eye Care: For unblinking eyes, use protective glasses during the day and a soft cover with vaseline at night. Train patients to consciously blink regularly to moisten the eye.
