Leprosy

Leprosy is an Contagious disease. It has been known for a very long time. Today, it is mostly called Hansen's disease, named after the person who discovered the bacterium, Gerhard Armauer Hansen. It is caused by a bacterium, Mycobacterium leprae. A person with leprosy is called a leper.

Geography

Multibacillary leprosy lesion

In the U.S., Hansen’s disease is rare. Around the world, as many as 2 million people are permanently disabled as a result of Hansen’s disease.

Overall, the risk of getting Hansen’s disease for any adult around the world is very low. That’s because more than 95% of all people have natural immunity to the disease.

Countries that reported more than 1,000 new cases of Hansen’s disease to WHO between 2011 and 2015 are:

• Africa: Democratic Republic of Congo, Ethiopia, Madagascar, Mozambique, Nigeria, United Republic of Tanzania
• Asia: Bangladesh, India, Indonesia, Myanmar, Nepal, Philippines, Sri Lanka
• Americas: Brazil

Multibacillary Leprosy

History

In former times, leprosy was seen as a divine punishment for sins committed.

Signs and symptoms

The symptoms of leprosy are irregular spots and patches on the skin. These are either lighter colored than the surrounding skin, or reddish in color. On those patches, hair will fall out, and they will feel numb to the patient. Nerves will form knots there. With the illness progressing the sense of touch will become less and less (until the patient feels completely numb). So called leptomes and ulcers will eat away the skin, the flesh and the organs on the patches.

Leprosy hand affected fourth digit

The disease can cause skin symptoms such as:

• A large, discolored lesion on the chest of a person with Hansen’s disease.
• Discolored patches of skin, usually flat, that may be numb and look faded (lighter than the skin around)
• Growths (nodules) on the skin
• Thick, stiff or dry skin
• Painless ulcers on the soles of feet called chancre
• Painless swelling or lumps on the face or earlobes
• Loss of eyebrows or eyelashes

Symptoms caused by damage to the nerves are:

• Numbness of affected areas of the skin
• Muscle weakness or paralysis (especially in the hands and feet)
• Enlarged nerves (especially those around the elbow and knee and in the sides of the neck)
• Eye problems that may lead to blindness (when facial nerves are affected)

Enlarged nerves below the skin and dark reddish skin patch overlying the nerves affected by the bacteria on the chest of a patient with Hansen’s disease. This skin patch was numb when touched.

Leprosy map

Symptoms caused by the disease in the mucous membranes are:

• A stuffy nose
• Nosebleeds

Since Hansen’s disease affects the nerves, loss of feeling or sensation can occur. When loss of sensation occurs, injuries such as burns may go unnoticed. Because you may not feel the pain that can warn you of harm to your body, take extra caution to ensure the affected parts of your body are not injured.

Histopathology of leprosy

If left untreated, the signs of advanced leprosy can include:

• Paralysis and crippling of hands and feet
• Shortening of toes and fingers due to reabsorption
• Chronic non-healing ulcers on the bottoms of the feet
• Blindness
• Loss of eyebrows
• Nose disfigurement

Other complications that may sometimes occur are:

• Painful or tender nerves
• Redness and pain around the affected area
• Burning sensation in the skin

Etiology

Hansen’s disease is a chronic infectious disease caused by Mycobacterium leprae and usually affects the skin and peripheral nerves, but can have a wide range of possible clinical manifestations.

Mycobacterium leprae

Classification

Patients can be classified into three groups, each with slightly different signs and symptoms:

Paucibacillary (PB), or tuberculoid, Hansen’s disease is characterized by one or a few hypopigmented or hyperpigmented skin macules that exhibit loss of sensation (anesthesia) due to infection of the peripheral nerves supplying the region. The body’s immune response may also result in swelling of the peripheral nerves; these enlarged nerves may be palpated under the skin, and may or may not be tender to the touch. The nerves most often found to have swelling are:

• Great auricular nerve
• Ulnar nerve above the elbow and dorsal cutaneous branches at the wrist
• Median nerve at the wrist (in the carpal tunnel)
• Radial nerve (superficial at wrist)
• Common peroneal nerve (also femoral cutaneous and lateral popliteal nerves where they wind around the neck of the fibula)
• Posterior tibial nerve, posterior to the medial malleolus
• Sural nerve
• patient presented to a clinical setting with an inflammatory cutaneous lesion on the thorax

Multibacillary (MB), or lepromatous, Hansen’s disease is characterized by generalized or diffuse involvement of the skin, a thickening of the peripheral nerves under microscopic examination, and has the potential to involve other organs, the eyes, nose, testes, and bone. The nodular form of this condition is the most advanced form of the disease. Ulcerated nodules contain large numbers of M. leprae acid-fast bacilli packed in macrophages that appear as large foamy cells. MB form of Hansen’s disease is associated with: multiple, symmetrically-distributed skin lesions that might not exhibit loss of sensation

• nodules
• plaques
• thickened dermis
• frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis

Diagnosis - labs

Hansen’s disease is diagnosed based on clinical presentation and the diagnosis is confirmed by skin or nerve biopsy and acid fast staining. In the United States, the National Hansen’s Disease Program provides diagnostic services.

Some serological tests have been developed and promoted by some investigators, but they lack sufficient sensitivity and specificity to be used as diagnostic tests. For this reason they are not used to diagnose Hansen’s disease.

Specimens and Tests

Depending on the form of leprosy suspected by the treating physician, the following specimens may be collected:

• Skin smears from the earlobes, elbows, and knees
• Skin biopsy from edges of active patches
• Nerve biopsy from thickened nerves
• Skin and nerve biopsy
• Biopsies are needed to definitively confirm a diagnosis of Hansen’s disease and to classify the disease, and slit skin smear may also be helpful in diagnosing those with mutlibacillary disease.

• In the multibacillary form of Hansen’s disease, tissue biopsy of various affected sites may reveal typical histopathologic changes that show large numbers of foam cells. Foam cells are macrophages that have ingested, or phagocytized, M. leprae bacteria, but are unable to digest the organisms, who in turn multiply and use the macrophage as a method of transport throughout the body. This is how the bacteria cause the multiple lesions that may appear in all parts of the body in MB leprosy patients.

Acid fast staining

The Ziehl-Neelson method using 5% sulphuric acid as decolorizing agent is used. The presence of acid-fast bacilli confirms the diagnosis of Hansen’s disease.

Treatment

Hansen’s disease is treated with multidrug therapy (MDT) using a combination of antibiotics depending on the form of the disease:

Paucibacillary form – 2 antibiotics are used at the same time, daily dapsone and rifampicin once per month Multibacillary form – daily clofazimine is added to rifampicin and dapsone. Treatment usually lasts between one to two years. The illness can be cured if treatment is completed as prescribed.

Reactive Episodes

At least one in four patients with Hansen’s disease experience reactive episodes – or “reactions” – during their treatment, although reactions may occur before treatment begins or after it is completed. Reactions are not due to medications used to treat the disease, although people treated with clofazimine tend to have slightly fewer episodes. There are two main groups of reactions:

Type 1 reactions, also called reversal reactions, are typical in PB or tuberculoid Hansen’s disease, and also in its borderline presentations, and show up as edema and erythema of pre-existing lesions. In some cases, neuritis and rarely new lesions or fever may also occur. Type 2 reactions or Erythema nodosum leprosum (ENL) are most frequently seen in patients with MB or lepromatous Hansen’s disease. Patients usually present with painful erythematous nodules, often distributed between existing lesions, and moderate to high fever. Inflammation of other tissues may be present, including peripheral neuritis, orchitis, lymphadenitis, iridocyclitis, nephritis, periostitis and arthralgias.

Lucio’s phenomenon, a rare reaction characterized by multiple hard-to-heal ulcers of varying size, is usually seen in patients with diffuse lepromatous leprosy who are of Mexican ancestry.

Complications and clinical course

Usually people do not die of leprosy, but of secondary infections and diseases they get.

• For many years there was a leprosy colony on the Hawaiian Island of Molokai called Kalaupapa.
• Tens of thousands of people from the United States that had the disease were sent there.

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  New cases of leprosy, in 2003. The darker the color, the more cases.

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  Skull deformed by leprosy

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  Feet deformed by leprosy

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  24-year-old man from Norway, suffering from leprosy, 19th century.

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