Introduction:
Leprosy is a chronic infectious illness caused by Mycobacterium leprae. It is one of the most prevalent treated peripheral neuropathies worldwide. This infection preferentially affects the skin, peripheral nerves, eyes, nasal mucosa, and reticulum-endothelial system. The host's innate resistance to M. Leprae invasion determines the clinical and pathological symptoms. Multidrug Therapy (MDT) is an effective way to treat leprosy before impairment manifests. Early leprosy diagnosis frequently results in fewer disabilities.
How Leprosy Is Classified?
Ridley and Jopling's 1966 categorization is the most widely acknowledged one for leprosy. It was founded on clinical, histological, and immunological criteria. It classified leprosy into five categories: Borderline Tuberculoid (BT), borderline (BB), borderline lepromatous (BL), lepromatous (L), and tuberculoid (T). Later on, the minor form indeterminate (I) was added. Pure Neuritic Form (PNL) is another clinical manifestation of leprosy that does not involve any skin lesions. Another ailment is called "silent neuropathy" (SN). It is typified by decreased sensory and motor abilities without the usual indicators of neuritis, such as skin irritation, discomfort, paraesthesia, or numbness. Another name for it is "quiet nerve paralysis."
What Are the Clinical Signs Seen in Leprosy Neuropathy?
Considered to be the quintessential example of inflammatory neuropathy, leprosy is a neuropathy by itself. Damage to both the cutaneous nerve endings and the nerve trunks is considered neural involvement. Inflammation or the result of the reactive regeneration process can cause sensory, autonomic, and motor complaints. The most prevalent type of clinical presentation typically begins with sensory information. Most neuropathies are small-fiber neuropathies, especially in the early stages. Large fibers become engaged later or may even become predominant in certain situations. Presentations of leprosy comprise mononeuritis, polyneuritis, and mononeuritis multiplex.
Leprosy most commonly manifests as mononeuritis, with upper limb nerves afflicted more frequently than lower limb nerves. The ulnar, median, posterior auricular, superficial radial, common, superficial, and posterior tibial nerves are the most often affected.
The thickening and enlargement of nerves occur as a result of inflammation. Upon palpation, they typically expand and become painful. Subsequently, motor and sensory indications and symptoms are noted. In leprosy, involvement of the posterior tibial nerve results in anesthesia of the sole, which may be followed by an ulcer, a deformity, severe breakdown of the foot bones, or neuropathic foot.
The relationship between the ulnar and median nerves is frequently seen when two nerves in the same limb are involved. Bilateral involvement of the ulnar nerve occurs typically at varying phases of the disease's course. The median nerve is rarely compromised.
Leprosy-related involvement of the cranial nerve is not uncommon. The most impacted cranial nerves are the fifth (trigeminal) and seventh (facial).
Leprosy frequently presents with rheumatological symptoms in addition to cutaneous and
neurological involvement, albeit they are frequently underestimated.
The following are signs of leprosy reactions:
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Type 1 response, a reversal reaction, is characterized by the sudden development of fresh skin lesions and redness.
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Type 2 reaction, also known as Erythema Nodosum Leprosum (ENL); symptoms include numerous skin nodules, fever, joint and muscle pains, and redness of the eyes; also, there is intense neuritic pain and a rapid progression of peripheral nerve injury, which can develop into claw hand or foot drop.
What Are the Methods of Diagnosing Leprosy Neuropathy?
A person with one of the following fundamental indications of leprosy is considered to be a case of leprosy, according to the eighth report of the WHO Expert Committee on leprosy:
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A noticeable lack of feeling in a pale (hypopigmented) or reddish skin region.
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A peripheral nerve that has grown or expanded, causing weakness or loss of feeling in the muscles it supplies.
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When acid-fast bacilli are present in a Slit-Skin Smear (SSS).
The following techniques can be used to test the aforementioned basic signs:
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Intraepidermal Nerve Fiber (IENF) quantification in skin biopsies has become an accurate clinical diagnostic technique for tiny fiber sensory neuropathy.
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The hands, feet, and eyes are routinely examined to determine the degree of nerve function damage associated with leprosy neuropathy. However, evaluation of the cutaneous feeling on the face is only done occasionally.
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Neural Conduction Studies (NCS), Quantitative Sensory Testing (QST), ballpoint or Semmes-Weinstein MFT tests for assessing the tactile sensitivity of skin lesions, and voluntary muscle tests for assessing motor function are among the nerve function evaluation procedures tested in leprosy neuropathy.
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High-frequency ultrasonography with color Doppler (HFUS with CD) This method has been utilized recently to further aid in diagnosis and treatment by describing distinctive alterations in leprosy neuropathy.
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Other methods for examining autonomic fiber involvement in leprosy include laser Doppler and infrared thermography.
What Are the Treatment Options for Leprosy Neuropathy?
In every kind of leprosy, M. leprae is present in microscopic form within the nerves. Therefore, treating leprosy with MDT, treating type 1 and type 2 reactions, treating inflammation, performing reconstructive surgery, physiotherapy, and resting are the methods used to control leprosy neuropathy. Amitriptyline or Gabapentin can be used to treat neuropathic pain.
Multi-Drug Therapy (MDT):
Anti-leprosy medications target different parts of the leprosy bacillus. Combined therapy with Multiple Drug Therapy (MDT) is an efficient way to treat infection with bacteria and reduce the chance of drug resistance. Dapsone, Rifampin, and Clofazimine are included in MDT.
Other Treatment Protocols:
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Fluoroquinolones - Moxifloxacin has proven to be one of the fluoroquinolones' most effective bactericidal agents.
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Macrolides - The only macrolide that exhibits notable bactericidal activity towards M. leprae is Clarithromycin.
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Tetracycline - The only tetracycline that works against M. leprae is Minocycline, which has bactericidal properties.
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Anti-inflammatory Medication - Corticosteroids are the most important anti-inflammatory medication for the treatment of neuritis, even while MDT kills bacteria and lowers the antigenic burden that causes responses and neuritis. Prednisolone is widely regarded as a significant medication for treating nerve function impairment (NFI).
What Are the Considerations for Non-Pharmacological Treatment of Neuritis?
According to WHO guidelines, treatment for neuritis, whether it is treated independently or in conjunction with leprosy responses, should also involve the following measures:
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Allowing the injured limb to rest, perhaps even with a nighttime brace
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During the post-acute phase, active muscular strengthening activities and passive stretching for weakening muscles are recommended.
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Dry skin should be moisturized and oiled to prevent cracking and surface sores.
Conclusion:
Over the years, the overall incidence of leprosy has decreased with the introduction of MDT, and patients who have finished their treatment are regarded as having been cured of their M. leprae infection. However, many M. leprae patients live with decreased sensation and physical deformities as a result of the nerve damage they induce. The development of novel therapeutic drugs to address neuropathy in leprosy is highly necessary.
