Leprosy

1. Leprosy Dr. Meg-angela Christi Amores

2. 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

3. 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

5. 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

6. 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)

7. Tuberculoid Leprosy • symptoms confined to the skin and peripheral nerves • consist of one or a few hypopigmentedmacules 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.

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. Diagnosis • characteristic skin lesions and skin histopathology • associated with diffuse hyperglobulinemia, which may result in false-positive serologic tests (e.g., VDRL, RA, ANA)

15. 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)

16. Prevention and Control • Vaccination at birth with bacilleCalmette-Guérin (BCG) has proved variably effective in preventing leprosy