Leprosy

Dr. Meg-angela Christi Amores

Leprosy

• A.k.a. Hansen’s Disease• nonfatal, chronic infectious disease caused by

Mycobacterium leprae• clinical manifestations are largely confined to

the skin, peripheral nervous system, upper respiratory tract, eyes, and testes

Etiology

• Mycobacterium leprae– obligate intracellular bacillus– confined to humans, armadillos in certain locales,

and sphagnum moss– Acid fast; ideally detected in tissue sections by a

modified Fite stain– almost exclusively a disease of the developing

world– associated with poverty and rural residence

Transmission

• Remains uncertain• Nasal droplet infection, contact with infected

soil, and even insect vectors have been considered the prime candidates

• bedbugs and mosquitoes • ~50% of leprosy patients have a history of

intimate contact with an infected person

Disease Spectrum

• Incubation period: between 2 and 40 years, although it is generally 5–7 years

• polar tuberculoid (TT) • borderline tuberculoid (BT) • mid-borderline (BB, which is rarely

encountered) • borderline lepromatous (BL) • polar lepromatous (LL)

• Tuberculoid Leprosy• symptoms confined to the

skin and peripheral nerves• consist of one or a few

hypopigmented macules or plaques • sharply demarcated and

hypesthetic, often have erythematous or raised borders, • devoid of the normal skin

organs (sweat glands and hair follicles) • dry, scaly, and anhidrotic.

• Tuberculoid Leprosy• asymmetric enlargement of

one or a few peripheral nerves• most commonly affected are

the ulnar, posterior auricular, peroneal, and posterior tibial nerves, with associated hypesthesia and myopathy

• Lepromatous Leprosy• symmetrically distributed skin

nodules , raised plaques, or diffuse dermal infiltration, which, when on the face, results in leonine facies• loss of eyebrows and

eyelashes, pendulous earlobes, and dry scaling skin, particularly on the feet• acral, distal, symmetric

peripheral neuropathy and a tendency toward symmetric nerve-trunk enlargement

• Lepromatous Leprosy• bacilli are numerous in the

skin (as many as 109/g), where they are often found in large clumps (globi), and in peripheral nerves• bacilli are plentiful in

circulating blood and in all organ systems except the lungs and the central nervous system• nerve enlargement and

damage tend to be symmetric

Complications

• Extremities– primarily a consequence of neuropathy leading to

insensitivity and myopathy– affects fine touch, pain, and heat receptors but

generally spares position and vibration appreciation

– ulnar nerve• clawing of the fourth and fifth fingers• loss of sensation

– loss of distal digits in leprosy is a consequence of insensitivity, trauma, secondary infection

Complications

• Nose– chronic nasal congestion and epistaxis– destruction of the nasal cartilage,

with consequent saddle-nose deformity or anosmia

• Eye– lagophthalmos and corneal

insensitivity– uveitis, with consequent cataracts

and glaucoma

Complications

• Testes– mild to severe testicular dysfunction– decreased testosterone, and aspermia or

hypospermia – impotent and infertile

• Amyloidosis• Nerve Abscesses– cellulitic appearance of the skin– affected nerve is swollen and exquisitely tender

Diagnosis

– characteristic skin lesions and skin histopathology– associated with diffuse hyperglobulinemia, which

may result in false-positive serologic tests (e.g., VDRL, RA, ANA)

Treatment

• dapsone (50–100 mg/d), clofazimine (50–100 mg/d, 100 mg three times weekly, or 300 mg monthly), and rifampin (600 mg daily or monthly)

Prevention and Control

• Vaccination at birth with bacille Calmette-Guérin (BCG) has proved variably effective in preventing leprosy