Leprosy Management and Clinical Features

Clinical Manifestations and Management of Leprosy

• Leprosy, also known as Hansen's disease, is an old infectious disease.
• It's caused by the intracellular bacterium Mycobacterium leprae.
• The bacterium was discovered by Dr. Armauer Hansen in 1874.
• The disease primarily affects skin, peripheral nerves, eyes, extremities, and respiratory mucosa.
• It's a chronic infectious disease.
• The bacterium is an acid-fast bacillus.
• The bacterium is difficult to cultivate outside a host.
• Hosts include humans and armadillos.
• The bacterium multiplies slowly.

Etiologic Agent

• Mycobacterium leprae, discovered in 1873 by G.A. Hansen, is an acid-fast, alcohol-fast, and gram-positive bacillus.
• It prefers cooler regions of the body (below 37°C).
• It's an obligatory intracellular parasite.
• It has not been cultured extracellularly, but can replicate in mouse footpad and armadillos.
• Viable bacilli appear as solid rods with rounded ends under carbol-fuchsin staining.
• Dead bacilli are fragmented and granular.

Epidemiology

• The primary host is human.
• Infection is also seen in armadillos and African chimpanzees.
• Males are more often affected than females (M/F ratio 1.5-2 to 1).
• The ratio varies in different geographic regions.
• All ages can be affected, but 20% of cases occur in children under 10 years.
• This is an extremely rare case for infants.

Geographic Range

• New case detection rates in 2005 varied by area, ranging from less than 10 to 22-26.9 people per 100,000.

Case Definition (Cardinal Signs)

• Definite loss of sensation in a skin lesion consistent with leprosy.
• Skin smears positive for acid-fast bacilli.
• Thickening of one or more peripheral nerves.

Lab Diagnosis

• Microscopy is useful in diagnosis.
• Culture.
• Serology (detecting antibodies).
• Molecular methods.
• Demonstration of cell-mediated immunity (CMI).
• Samples can be collected from nasal mucosa, skin lesions, earlobes, forehead, cheek, chin and buttocks.

Classification of Leprosy (Ridley-Jopling)

• This system categorizes leprosy based on skin lesions, bacterial load, and histology.
• Includes Tuberculoid, Borderline Tuberculoid, Borderline Borderline, Borderline Lepromatous, Lepromatous, Indeterminate, Single Lesion Paucibacillary, Paucibacillary, Multibacillary categories, as well as their characteristics.

Leprosy Spectrum

• A graphical representation of leprosy types as a function of cell-mediated immunity and antibodies.

Pathogenesis

• Clinical forms depend on the ability of the host to mount a cell-mediated immune response.
• One type, with strong CMI response, is characterized by well-demarcated granulomas with low numbers of mycobacteria within the skin and nerve lesions.
• Another, with weak response, involves lesions limited to skin patches and nerve trunks.

Treatment of Leprosy

• Chemotherapy is the standard treatment.
• First-line drugs include rifampicin, dapsone, and clofazimine.
• Treatment duration varies based on the type of leprosy and the patient's bacterial load, ranging from 6 to 24 months.
• Second-line drugs, like ofloxacin and minocycline, may be used in cases of resistance or specific scenarios.
• Multidrug therapy (MDT) is commonly used, aiming to prevent resistance to any single drug.
• Different treatment regimes are recommended for paucibacillary (PB) and multibacillary (MB) forms.

Lepra Reactions

• Acute inflammation due to immunological reactions against bacilli.
• Medical emergency.
• Two main reaction types:
  • Type 1 (reversal reaction): Seen in certain types, due to immune system response.
    • Characterized by pain, tenderness, swelling, and erythema.
  • Type 2 (Erythema Nodosum Leprosum – ENL): Occurs sometime after treatment, is due to vasculitis/inflammation from immune response.
    • Characterized by tender, inflamed subcutaneous nodules, fever, lymphadenopathy, and arthralgia.

Complications

• Systemic involvement, including nasal mucosa cartilage damage.
• Bone destruction, osteomyelitis, and testicular atrophy (testosterone loss).
• Renal involvement and amyloidosis.
• Complications of peripheral nerve involvement include sensory loss, muscle weakness, hypoaesthesia or anaesthesia, ulcers, and nerve clawing.

Other Considerations

• The presentation of leprosy, including the development of lesions/ skin characteristics and nerve damage, can affect the patient's daily life and wellbeing
• Grading is used to define the number of bacilli found in specimens of affected areas.
• Bacteriological index, morphological index, and serological tests are utilized in diagnosis.
• Importance of education, psychosocial support, and reduction of stigma in management is also noted.

This quiz explores the clinical manifestations and management of leprosy, a chronic infectious disease caused by Mycobacterium leprae. It covers the disease's etiology, the characteristics of the causative agent, and its impact on various body systems. Test your knowledge on this historical yet relevant disease.