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Leprosy

Overview

Leprosy, also known as Hansen’s disease, is a chronic bacterial infection. It is a granulomatous disease of the peripheral nerves and mucosa of the upper respiratory tract. If left untreated, the disease can cause nerve damage, leading to muscle weakness and atrophy, and permanent disabilities. Leprosy is curable and treatment provided in the early stages averts disability. The disease has been around since ancient times, often surrounded by terrifying, negative stigmas and tales of leprosy patients being shunned as outcasts. Outbreaks of leprosy have affected, and panicked, people on every continent.

Leprosy is an uncommon disease in the UK, yet it remains an important disease globally with 250,000 cases diagnosed annually. Its importance lies in the need for early diagnosis and expert treatment and support, both for those with active disease and for those who are physically, psychologically, or socially affected by it. The majority of cases are reported in Africa and Asia. Leprosy occurs throughout the tropics and sub-tropics and is still present in some parts of southern Europe, the Middle East and North Africa. Countries with the greatest numbers of new cases detected in 2010 included India, Indonesia and Brazil. So far, leprosy has been eliminated from 119 out of the 122 endemic countries.

 

Signs and symptoms

Initial infection is asymptomatic. The disease progresses slowly and has an incubation period ranging from 2 to 12 years. Most people infected with the organism are thought not to develop clinical disease but the exact proportion is not known. Once symptoms appear the disease progresses, usually insidiously, but sometimes rapidly. In females, pregnancy may precipitate clinical leprosy.

 

Symptoms mainly affect the skin, nerves, and mucous membranes and include:

  • Skin lesions that may be faded/discoloured

  • Growths on the skin

  • Thick, stiff or dry skin

  • Severe pain

  • Numbness on affected areas of the skin

  • Muscle weakness or paralysis (especially in the hands and feet)

  • Eye problems that may lead to blindness

  • Enlarged nerves (especially those around the elbow and knee)

  • Stuffy nose

  • Nosebleeds

  • Ulcers on the soles of feet 

 

The type of disease which develops reflects the degree to which the host is able to mount a cell mediated immune response. Types of disease may be classified according to the Ridley-Jopling classification, which is based on skin lesion type and bacterial load:

  1. Tuberculoid leprosy (TT): Patients have a vigorous cell-mediated immune response. This results in well-demarcated lesions containing few bacilli and surrounded by lymphocytes.

  2. Lepromatous leprosy (LL): Patients do not develop effective cell-mediated immunity. Lesions are diffusely infiltrated with macrophages in which bacteria multiply in large numbers. Antibodies are produced, often in large quantities, but are ineffective in killing the bacilli.

  3. Borderline leprosy: This category covers the spectrum between the two extremes described above. Patients have some cell-mediated immune response, multiple lesions and unstable immunity. Borderline leprosy can be further classified according to the category it most resembles:

  • Borderline tuberculoid (BT)

  • Borderline (mid-borderline) (BB)

  • Borderline lepromatous (BL)

 

Complications of leprosy can include:

  • Blindness or glaucoma

  • Disfiguration of the face (including permanent swelling, bumps,                                                                                                         and lumps)

  • Erectile dysfunction and infertility in men

  • Kidney failure

  • Muscle weakness that leads to claw-like hands or an inability to                                                                                               flex the feet

  • Permanent damage to the inside of the nose, which can lead to                                                                               nosebleeds and a chronic, stuffy nose.

  • Permanent damage to the nerves outside the brain and spinal cord, including those in the arms, legs, and feet. Nerve damage can lead to a dangerous loss of feeling. A person with leprosy-related nerve damage may not feel pain when the hands, legs, or feet are cut, burned, or otherwise injured

 

Causes

Leprosy is caused by the acid-fast and slow-growing bacillus, Mycobacterium leprae. It is transmitted via droplets from the nose and mouth of untreated patients with severe disease, but is not highly infectious.

 

Risk factors / at risk groups

Children more likely than adults

 

Diagnosis / microbiological testing

Skin biopsy gives definite result.A skin smear test may also be done.

With paucibacillary leprosy, no bacteria will be detected.

In contrast, bacteria are expected to be found on a skin smear test from a person with multibacillary leprosy.

 

Treatment / preventative measures

Leprosy can be easily treated with a 6–12-month course of combination therapy. The treatment is highly effective, and has few side-effects and low relapse rates. There is currently no known drug resistance for combination therapy.

 

The World Health Organisation now recommends one of two standard multidrug regimens:

For paucibacillary patients: (presence of a few bacilli)

  • Rifampicin 600mg once monthly, supervised using directly observed therapy (DOT),

  • Dapsone 100mg once daily (or 1-2 mg/kg per day for adults weighing less than 35kg)

Treatment course: 6 months

 

For multibacillary patients: (presence of many bacilli)

  • Rifampicin 600 mg monthly, supervised using DOT (450mg for adults under 35kg)

  • Clofazimine 300 mg monthly, supervised using DOT AND 50mg daily on alternate days unsupervised

  • Dapsone 100 mg daily, unsupervised (50mg for adults under 35kg)

Treatment course: 12 months

 

Precautions:

  • Close contacts of all leprosy patients should be traced and examined

  • Health education – remove irrational fears and misunderstandings common in rural endemic areas

  • Chemoprophylaxis in cases with contact of multibacillary leprosy

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