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Leprosy
OVERVIEW: A chronic granulomatous infection caused by Mycobacterium leprae, an organism which has a high predilection for cooler regions - skin, mucous membrane and peripheral nerves. Leprosy is classified on a spectrum reflecting degrees of lost immunity (Ridley-Jopling classification).
• Indeterminate leprosy
Early cutaneous lesions; Findings are very subtle most commonly diagnosed in contacts of known leprosy cases. The lesions tend to heal spontaneously, but may progress to any of the other leprosy types.
• Tuberculoid leprosy (TT)
Characterized by early localized skin lesions and/or nerve lesions. Bacilli are few and difficult to find. Resistance to infection is high, and spontaneous recovery may occur; however peripheral nerves can be destroyed.
• Lepromatous leprosy (LL)
A generalized infection involving skin, oral, nasal, and upper respiratory mucous membrane, the anterior eye, cutaneous and peripheral nerve trunks, the RE system, adrenals, and testes. Numerous bacilli are easily found in tissue specimens. Patient's resistance to infection is low, and untreated disease is progressive
• Borderline (dimorphous) leprosy
This has features of both TT and LL poles in various combinations. Usually sub-divided into borderline tuberculoid (BT), mid-borderline (BB) and borderline lepromatous (BL). Borderline forms are unstable and may regress (reversal reaction) toward TT form or progress (Downgrading reaction) toward the LL form, depending on the effects of treatment and shifts in immune status
System(s) affected: Skin/Exocrine, Musculoskeletal, Nervous, Endocrine/Metabolic, Reproductive, Pulmonary, Hemic/Lymphatic/Immunologic
Genetics: Specific HLA-associated genes may be linked to different classes of disease, HLA-DR2 with TT and HLA-MT1 with LL
Incidence/Prevalence in USA: Extremely low; about 140 cases in 1992, mostly in immigrants from leprosy-endemic areas
Predominant age: Leprosy can present at any age, although cases in infants under 1 year are extremely rare
Predominant sex:
• Childhood: Male = Female
• Adults: Male > Female (2:1)
SIGNS AND SYMPTOMS: • Indeterminate leprosy
• One or more hypopigmented or hyperpigmented macules or plaques
• Anesthetic patches, though sensation is preserved in early stages
• TT
• Initial hypopigmented, hypesthetic macules with sharp demarcations
• Fully developed lesions are asymmetric and densely anesthetic with depressed atrophic central areas and elevated margins; loss of sweat glands and hair follicles near the lesion
• Nerve involvement occurs early
• Ulnar, peroneal, and greater auricular nerves may be palpably and visibly enlarged
• Neuritic pain
• Muscle atrophy - small muscles of the hand
• Facial nerve involvement leads to lagophthalmos, keratitis and corneal ulceration
• Hand and foot contracture
• Hand infection and plantar ulcers secondary to trauma
• Resorption and loss of phalanges may supervene
• LL
• Extensive cutaneous involvement, usually bilaterally symmetrical
• Highly variable cutaneous lesions macules, nodules, papules or plaques
• Sites of predilection are face, ears, wrists, elbows, buttocks and knees
• Loss of lateral eye brows
• Leonine facies
• Nasal stuffiness, epistaxis, septal perforation
• Nasal obstruction, laryngitis, hoarseness
• Saddle nose
• Keratitis, iridocyclitis
• Painless inguinal and axillary lymphadenopathy
• Testicular infiltrate and scarring - sterility
• Gynecomastia
• Borderline leprosy
Increasing variability in the appearance of skin lesions
• Papules and plaques may co-exist with macular lesions
• Anesthesia is less prominent than in TT
• Ear lobes slightly thickened, but eye brows and nasal region spared
• Skin lesions become even more numerous in BL type but without the symmetry typical of polar LL
• Skin lesions of BT generally resemble those of TT but are greater in number and have less well defined margins
CAUSES: Mycobacterium leprae: an acid fast rod is the causal agent. Incubation period is frequently 3-5 yrs although a range of 6 months to several decades has been seen
RISK FACTORS: • Close family contacts of untreated leprosy patients have 8 fold increased risk
• Compromised immunological status
• Poor socioeconomic status
DIAGNOSIS DIFFERENTIAL DIAGNOSIS: • Lupus erythematosus
• Lupus vulgaris
• Sarcoidosis
• Yaws
• Dermal leishmaniasis
• Other skin conditions
• Peripheral neuropathy
• Syringomyelia
LABORATORY: • Demonstration of acid-fast bacilli in skin smears made by scraped-incision method is strong evidence of leprosy
• Skin biopsy
• Histologic involvement of peripheral nerves pathognomonic
• Mild anemia, elevated ESR and hyperglobulinemia
• Lepromin test: Usually positive in TT and negative in LL poles. It has no diagnostic value since it gives false positives in nearly all normal adults
• Serodiagnostic assay: Based on the detection of antibody to phenolic glycolipid 1, this assay has a sensitivity of over 95% in LL and about 30% in TT
Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A
PATHOLOGICAL FINDINGS: • TT: Noncaseating granulomas containing lymphocytes, epithelioid cells, and perhaps giant cells; bacilli are difficult to demonstrate
• LL: granulomas comprising macrophages, large foam (Virchow or lepra) cells, and many intracellular bacilli, frequently in spheroidal masses
• Borderline leprosy: granulomas change from an epithelioid cell predominance in BT to a macrophage predominance as the lepromatous pole is approached
SPECIAL TESTS: • Sero diagnostic assay
• Detection of M. Leprae in tissue by polymerase chain reaction
IMAGING: N/A
DIAGNOSTIC PROCEDURES: N/A
TREATMENT APPROPRIATE HEALTH CARE: Outpatient usually, except in reactional states where inpatient care is called for
GENERAL MEASURES: • Manage with multidisciplinary approach, including orthopedic surgery, ophthalmology and physical therapy in addition to specific drugs
• Rigid soled foot wear or walking plaster casts may prevent plantar ulcers
• Physical therapy and casts prevent hand contractures
• Utilize vocational retraining and rehabilitation along with psychological support
• Immediate recognition and treatment of eye problems essential
• Manage mild reactional states such as reversal reaction and erythema nodosum leprosum (ENL) with bed rest, analgesics and sedatives. Severe reactions require corticosteroids, thalidomide or clofazimine. Specific therapy must be continued without interruption.
SURGICAL MEASURES: Reconstructive surgery - nerve and tendon transplants, release of contractures and other cosmetic procedures can give more functional mobility and social acceptance
ACTIVITY: Dependent on severity of disease
DIET: Nutritious balanced diet
PATIENT EDUCATION: • Educate about the indolent course of the disease; importance of therapeutic completion
• Information pamphlets and awareness to ease psychological trauma and stigma
• Encourage case reporting
MEDICATIONS DRUG(S) OF CHOICE: • Drugs and treatment duration are based on bacterial load (in skin smear) and clinical types. Multibacillary cases: bacterial load of 10 to the 11th power and clinical types BB, BL or LL. Paucibacillary cases: bacterial load of about 10 to the 6th power and clinical types TT, BT and indeterminate.
• Multibacillary standard regimen includes rifampin, clofazimine and dapsone:
• Adult outside USA >35 kg
• Rifampin 600 mg once a month
• Clofazimine 300 mg once a mo+ 50 mg/d
• Dapsone 100 mg/d
• Adult outside USA < 35 kg
• Rifampin 450 mg once a month
• Clofazimine 300 mg once a mo+ 50 mg/d
• Dapsone 50 mg/d
• Children ages 10-14
• Rifampin 450 mg once a month
• Clofazimine 200 mg once a mo+ 50 mg qod
• Dapsone 50 mg/d
• Children underweight
• Rifampin 12-15 mg/kg once a mo
• Clofazimine 150 mg once a mo+ 50 mg qod
• Dapsone 1-2 mg/kg/d
• Adults in the USA (recommended regimen)
• Rifampin 600 mg/d for 3 years
• Dapsone 100 mg/d for life
• Clofazimine is given in dapsone-resistant cases: 50-100 mg/d for life
• Paucibacillary standard regimen
• Outside USA
• Rifampin same doses as above
• Dapsone 50-100 mg/d
• In USA
• Rifampin 600 mg a day for 6 mos
• Dapsone 100 mg/d for 3-7 years
Contraindications:
• Clofazimine and minocycline: pregnancy
• Ofloxacin: relative contraindication in children and adolescents
Precautions:
• Hemolysis and methemoglobinemia are common untoward reactions to dapsone
• Screen for G6-PD deficiency to prevent drug-induced hemolysis
• Reactionary states should be anticipated and treated aggressively
• Dapsone: Gl upset, headaches, pruritus, agranulocytosis, fever, rash
• Clofazimine: Gl upset and skin pigmentation
• Minocycline: reduce dose in renal damage
Significant possible interactions: Refer to manufacturer's literature for each drug
ALTERNATIVE DRUGS: • WHO recommended and widely used in countries where leprosy is endemic:
• Rifampin 600 mg monthly + ofloxacin 400 mg/d + minocycline 100 mg/d for up to 2 years
• Shorter duration of therapy in multi- and paucibacillary cases with rifampin 400 mg/d + ofloxacin 600 mg/d
FOLLOW UP PATIENT MONITORING: • Frequent follow-up visits until therapy course is stabilized, then monthly supervision
• Periodic CBC, renal and hepatic function
PREVENTION/AVOIDANCE: • Early case finding and chemotherapy to suppress infectiousness and control spread
• Examine family and other close contacts regularly for leprosy
• Vaccination with BCG; 2 doses give good protection
POSSIBLE COMPLICATIONS: • Crippling of the hand and foot
• Trauma and secondary infection leading to loss of digits and extremities
• Blindness
• Lucio phenomenon - arteritis
• Secondary amyloidosis
• ENL: Rx with thalidomide 200 mg bid tapering to 50-100 mg/d in chronic patients
• Severe reversal reaction: prednisolone 40-60 mg/day, tapering slowly
EXPECTED COURSE AND PROGNOSIS: Generally indolent, but may be interrupted by ENL and type l lepra reaction. Prognosis is good with early detection and therapy.
MISCELLANEOUS ASSOCIATED CONDITIONS: HIV-positive patients with early or subclinical leprosy are more likely to develop overt disease. Concurrent leprosy may accelerate HIV-disease course.
AGE-RELATED FACTORS:
Pediatric: Rare in infants under one year
Geriatric: N/A
Others: N/A
PREGNANCY: Clofazimine and minocycline contraindicated during pregnancy; dapsone may be used
SYNONYMS: • Hansen's disease
ICD-9-CM: 030.9 Leprosy
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