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Hansens Disease and the role of electrodiagnostic studies in Pure Neuritic Hansens Disease.
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Hansen's Disease .pptx
- 1. Hansen’s Disease : Overview and Diagnosis Presenter : Dr. Saran A K Preceptor : Dr. Yogesh Kumar DM Seminar 2 | 18 August 2023 DEPT. OF PHYSIOLOGY, AIIMS PATNA 2
- 2. DEPT. OF PHYSIOLOGY, AIIMS PATNA 3 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 3. DEPT. OF PHYSIOLOGY, AIIMS PATNA 4 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 4. General Details • Name – XYZ • ID – 109112300599527 • Age – 51 years • Gender – Female • Occupation – Homemaker • Address – Patna • DOE – 11th August 2023 DEPT. OF PHYSIOLOGY, AIIMS PATNA 5
- 5. Chief Complaints 1. Tingling and Numbness over all four limbs x 1 year 2. Loss of sensations in all four limbs x 6 months 3. Weakness in right hand x 5 months 4. Ulcers over index finger on both hands DEPT. OF PHYSIOLOGY, AIIMS PATNA 6
- 6. History of Presenting Complaints Patient non-diabetic, right-handed individual was apparently alright one year ago when she noticed tingling and numbness of all four limbs, initially starting with the lower limb. • Insidious in onset, gradually progressive • Initially involved the soles, H/o slippage of chappals from both feet unknowingly while walking, which has increased over the duration of past one year. • Slowly progressed to currently involving up to knee • H/o recurrent multiple healing ulcers in soles and feet. • No diurnal fluctuation/falls at night • No h/o pain DEPT. OF PHYSIOLOGY, AIIMS PATNA 7
- 7. Reduced temperature sensation over bilateral lower limbs since 6 months • Insidious symmetrical in onset • Initially unable to appreciate hot or cold while washing feet, • Gradually progressed to current state, up to knee in both limbs. • No bowel and bladder involvement • No band like sensation • No h/o pain in the limbs/claudication/difficulty in walking • No swelling of limbs/color change DEPT. OF PHYSIOLOGY, AIIMS PATNA 8
- 8. Reduced sensation over both upper limbs and weakness of right upper limb since 5 months • Insidious in onset, gradually progressive • Tingling and numbness • Began with all five fingers, now progressed up to elbow in left upper limb and mid arm in right upper limb. • Unable to appreciate pain, temperature and touch in upper limb (left > right) • Difficulty in grasping objects cup, keys, mixing, eating food etc. • Associated with ulcers in the both upper limb • Not clear on loss of sweating DEPT. OF PHYSIOLOGY, AIIMS PATNA 9
- 9. • No h/o LOC, trauma • No h/o weight loss or weight gain • No h/o of difficulty in combing hair (lifting hand above head) • No h/o difficulty in walking/swaying • No h/o neck pain/shock like sensation – Lhermitte sign • No blurring of vision, diminution of vision, double vision • No h/o difficulty chewing or swallowing food • No h/o diminished sensation over face • No h/o swaying, reduced hearing • No change in voice/nasal twang, difficulty in swallowing food. DEPT. OF PHYSIOLOGY, AIIMS PATNA 10
- 10. • No h/o intake of drugs, alternative medicine • No h/o of reduced tears/increase burning in eyes • No h/o exertional dyspnoea, coloured urine, reduced urine output • No h/o polyuria, polydipsia, nocturia • No fever, rash, arthritis, oral ulcers ,photosensitivity, headache, stiffness of limb • No h/o discoloration of teeth/ nails/diarrhea • No h/o fatigue, giddiness, reduced sweating/ palpitations • No h/o of dry skin, constipation, cold intolerance • Menstrual cycles normal. DEPT. OF PHYSIOLOGY, AIIMS PATNA 11
- 11. Family History • Non consanguineous marriage • No h/o similar complaints in her family members • No h/o DM, HTN, tuberculosis, epilepsy, thyroid disease in the family • Low socioeconomic status DEPT. OF PHYSIOLOGY, AIIMS PATNA 12
- 12. Past History • H/o of recurrent incidence of healing ulcers in the upper and lower limbs. • No previous hospitalizations. • Not a known DM, HTN, epilepsy, asthma, thyroid disorder. Personal History • Vegetarian with normal appetite. • Sleep normal with no recent changes in sleep pattern or duration. • Bowel and bladder habits normal. • No h/o of smoking or alcohol consumption. DEPT. OF PHYSIOLOGY, AIIMS PATNA 13
- 13. General Examination • Conscious cooperative, well oriented to time place and person. • No pallor, icterus, cyanosis, clubbing, lymphadenopathy or edema • PR – 80/min regular, normal volume character, peripheral pulses well felt, no radio femoral delay. • RR – 18 cycles per minute, thoracoabdominal • BP – 136/80 mm Hg in the upper right arm sitting position DEPT. OF PHYSIOLOGY, AIIMS PATNA 14
- 14. Head to toe examination • No loss of hair • No neurocutaneous markers • No hypopigmented patches • Thickened nerves – B/L Ulnar Nerve (R>L), B/L CPN thickened • No macroglossia • No Mees lines – suggestive of Arsenic Poisoning DEPT. OF PHYSIOLOGY, AIIMS PATNA 15
- 15. Examination of Nervous System • Higher Mental Functions appear to be normal DEPT. OF PHYSIOLOGY, AIIMS PATNA 16
- 16. DEPT. OF PHYSIOLOGY, AIIMS PATNA 17 Cranial Nerve Right Left I Normal Normal II Visual Acuity Normal Visual Field Normal Colour Vision Normal Visual Acuity Normal Visual Field Normal Colour Vision Normal III, IV, VI Pupillary Reflexes present EOM –Full Pupil Round Reactive 4mm in size Pupillary Reflexes present EOM –Full Pupil Round Reactive 4mm in size V Sensory intact Motor intact Jaw Jerk Absent Sensory intact Motor intact Jaw Jerk Absent Examination of cranial nerves
- 17. DEPT. OF PHYSIOLOGY, AIIMS PATNA 18 Cranial Nerve Left Right VII Normal Normal VIII AC>BC Normal AC>BC Normal IX, X Palatal and Pharyngeal Reflex – present Palatal movements normal Palatal and Pharyngeal Reflex – present Palatal movements normal XI Sternocleidomastoid and trapezius – Normal power Sternocleidomastoid and trapezius – Normal power XII No deviation of tongue, No wasting, fasciculation or fibrillation No deviation of tongue, No wasting, fasciculation or fibrillation
- 18. Motor System Examination DEPT. OF PHYSIOLOGY, AIIMS PATNA 19 1. Bulk of muscle Left Right Upper Limb Hypothenar wasting All other muscles normal Hypothenar wasting (R>L) All other muscles normal Lower Limb Normal Normal 2. Tone of muscle Left Right Upper Limb Normal Normal Lower Limb Normal Normal
- 19. DEPT. OF PHYSIOLOGY, AIIMS PATNA 20 3. Power Left Right Movement at shoulder joint • Flexion • Extension • Abduction • Adduction • Internal Rotation • External Rotation 5 5 5 5 5 5 5 5 5 5 5 5 Movement at elbow • Flexion • Extension 5 5 5 5
- 20. DEPT. OF PHYSIOLOGY, AIIMS PATNA 21 Left Right Movement at wrist • Flexion • Extension • Abduction • Adduction • Handgrip 4 4 4 4 Weak 4 4 4 4 Weak R>L Movement at hip joint • Flexion • Extension • Adduction • Abduction • External Rotation • Internal Rotation 5 5 5 5 5 5 5 5 5 5 5 5
- 21. DEPT. OF PHYSIOLOGY, AIIMS PATNA 22 Left Right Movement at knee joint • Flexion • Extension 5 5 5 5 Movement at ankle joint • Plantar Flexion • Dorsiflexion 5 5 5 5 Toe Movements • Flexion • Extension 4 4 4 4
- 22. DEPT. OF PHYSIOLOGY, AIIMS PATNA 23 Left Right Superficial Reflexes Present, Flexor Plantar Present, Flexor Plantar Deep Tenson Reflexes All could be elicited except Supinator and Ankle Jerk All except Ankle Jerk Reflexes
- 23. Tests for co-ordination DEPT. OF PHYSIOLOGY, AIIMS PATNA 24 Left Right Upper Limb Normal Normal Lower Limb Normal Normal
- 24. DEPT. OF PHYSIOLOGY, AIIMS PATNA 25 Left Right Spinothalamic Sensations 1. Pain 2. Temperature 3. Pressure • Impaired up to elbow in upper limb • Up to knee in lower limb • Impaired up to mid arm in upper limb • Up to knee in lower limb Dorsal Column Sensations 1. Fine Touch 2. Vibration 3. Proprioception • Up to elbow • Lost up to knee • Up to mid arm • Lost up to knee Sensory System
- 25. Bilateral distal symmetrical sensory motor neuropathy of upper and lower limbs with palpable ulnar, common peroneal nerve. DEPT. OF PHYSIOLOGY, AIIMS PATNA 26 • Examination of Cerebellum – Normal • Gait – Normal
- 26. Differential Diagnosis • Metabolic (Diabetes, Amyloidosis) • Inflammation (Vasculitis) • Congenital (Charcot Marie Tooth Disease) • Traumatic • Tumoral (Nerve Sheath Tumor) • Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) • Hansen’s Disease (? Pure Neuritic Hansen’s) DEPT. OF PHYSIOLOGY, AIIMS PATNA 27
- 27. DEPT. OF PHYSIOLOGY, AIIMS PATNA 28 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 28. DEPT. OF PHYSIOLOGY, AIIMS PATNA 29 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 29. Hansen’s Disease • A chronic infectious disease caused by acid fast bacilli of Mycobacterium leprae complex. • M. Leprae and M. Lepromatosis • Discovered by Gerard Armauer Hansen in Norway in 1873. • Mainly affects skin and peripheral nerves. DEPT. OF PHYSIOLOGY, AIIMS PATNA 30
- 30. WHO Case Definition A case of leprosy is defined as an individual who has not completed the course of treatment and has one or more of 3 cardinal signs. DEPT. OF PHYSIOLOGY, AIIMS PATNA 31
- 31. Cardinal signs of leprosy 1. Anaesthetic hypopigmented or erythematous macules 2. Thickened or enlarged peripheral nerve with loss of sensation and/or weakness of the muscles supplied by that nerve. 3. Presence of acid-fast bacilli in slit skin smear. DEPT. OF PHYSIOLOGY, AIIMS PATNA 32
- 32. DEPT. OF PHYSIOLOGY, AIIMS PATNA 33 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 33. DEPT. OF PHYSIOLOGY, AIIMS PATNA 34 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 34. • M. Leprae is an obligate intracellular organism; it cannot be cultured in artificial media. • Grows best at 27 to 33ºC - predilection to cooler areas • Generation time - approx. 12.5 days • Incubation period - 3-5 years (Tuberculoid) and 8-12 years (Lepromatous) DEPT. OF PHYSIOLOGY, AIIMS PATNA 35
- 35. DEPT. OF PHYSIOLOGY, AIIMS PATNA 36
- 36. Transmission Not fully understood. 1. Probably spread by the respiratory route; nasal discharge from untreated patients with multibacillary disease 2. Occasionally, by organisms may enter through broken skin. 3. Contact with armadillos (handling, killing, or eating) DEPT. OF PHYSIOLOGY, AIIMS PATNA 37
- 37. DEPT. OF PHYSIOLOGY, AIIMS PATNA 38 Nine banded armadillos common in Southern United States.
- 38. • Leprosy is not highly contagious; most people do not develop disease after exposure. • Development of disease depends on a variety of factors, including immune status and genetic influences. DEPT. OF PHYSIOLOGY, AIIMS PATNA 39
- 39. Risk Factors 1. Close contact 2. Type of leprosy in index case – LL > TT 3. Age 4. Genetics – variants in genes of NOD2 dependent signaling pathways 5. Immunosuppression DEPT. OF PHYSIOLOGY, AIIMS PATNA 40
- 40. DEPT. OF PHYSIOLOGY, AIIMS PATNA 41 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 41. DEPT. OF PHYSIOLOGY, AIIMS PATNA 42 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 42. 1. WHO classification (with its modifications) is most used system in leprosy control programs. 2. Ridley Jopling classification is most widely used for research and academic purposes. DEPT. OF PHYSIOLOGY, AIIMS PATNA 43
- 43. WHO Classification of Leprosy WHO classification is a clinical classification tailored to determine the appropriate therapy for leprosy patients 1. Paucibacillary 2. Multibacillary DEPT. OF PHYSIOLOGY, AIIMS PATNA 44
- 44. • Paucibacillary - A case of leprosy with 1 to 5 skin lesions without presence of bacilli on skin smear. • Multibacillary - A case of leprosy with • >5 skin lesions; or • with nerve involvement (pure neuritic or any number of skin lesions and neural involvement) or • with demonstrated presence of bacilli in a SSS (slit skin smear) irrespective of the number of skin lesions. DEPT. OF PHYSIOLOGY, AIIMS PATNA 45
- 45. National Leprosy Eradication Program (NLEP) Classification DEPT. OF PHYSIOLOGY, AIIMS PATNA 46 Ref : Ridley Jopling Textbook of Leprosy
- 46. Ridley-Jopling Classification Most scientific, widely accepted and research- oriented classification that is based on four parameters 1. Clinical features, 2. Histological features, 3. Bacteriological features (slit-skin smears) and 4. Immunological features (lepromin testing) DEPT. OF PHYSIOLOGY, AIIMS PATNA 47
- 47. Based on all these four parameters, leprosy is divided into five groups 1. TT: Tuberculoid leprosy 2. BT: Borderline tuberculoid leprosy 3. BB: Borderline-borderline leprosy 4. BL: Borderline-lepromatous leprosy 5. LL: lepromatous leprosy DEPT. OF PHYSIOLOGY, AIIMS PATNA 48
- 48. • TT and LL are immunologically stable poles • BT, BB and BL are unstable types. • The borderline types may up or downgrade. DEPT. OF PHYSIOLOGY, AIIMS PATNA 49 Ref : Ridley Jopling Textbook of Leprosy
- 49. DEPT. OF PHYSIOLOGY, AIIMS PATNA 50 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 50. DEPT. OF PHYSIOLOGY, AIIMS PATNA 51 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 51. Key steps in immunopathogenesis 1. M. leprae enters the body via the nose and then spreads to the skin and nerves via the circulation. 2. Followed by multiplication in dermal lymphatics and vascular endothelium ; major role in the hematogenous spread. DEPT. OF PHYSIOLOGY, AIIMS PATNA 52
- 52. 3. M. leprae invades peripheral nerves via blood vessels of the perineurium. 4. The immunological response mounted by the host dictates the clinical phenotype that develops. 5. In TT, the monocytes destroy the organism completely; while in LL, micro vacuolated monocytes (phagocytes) with bacillary debris may persist. DEPT. OF PHYSIOLOGY, AIIMS PATNA 53
- 53. 6. Toll-like receptors on innate immune cells may recognize mycobacterial lipoproteins, generating cytokines. 7. This regulates inflammation and influences the course of the adaptive cell-mediated immunity into a Th1 or Th2 response. DEPT. OF PHYSIOLOGY, AIIMS PATNA 54
- 54. DEPT. OF PHYSIOLOGY, AIIMS PATNA 55
- 55. 8. Th1-type cytokines are associated with TLR1 and TLR2 activation, and Th2-type cytokines are associated with inhibition of this activation. 9. The expression of TLR1 and TLR2 has been found to be stronger on monocytes and DCs in TT lesions than in the LL counterparts. DEPT. OF PHYSIOLOGY, AIIMS PATNA 56
- 56. DEPT. OF PHYSIOLOGY, AIIMS PATNA 57 Ref : IADLV Textbook of Dermatology
- 57. 10. In tuberculoid lesions, the CD4/CD8 T-cell ratio is 2:1 • A Th1-like profile characterized by proinflammatory cytokines IL-2, IFN-γ, TNF and IL-12 • They induce strong CMI and result in intense phagocytic activity. DEPT. OF PHYSIOLOGY, AIIMS PATNA 58
- 58. 11. In lepromatous leprosy, CD4/CD8 ratio is 1:2 • A Th2-like profile characterized by anti- inflammatory cytokines IL-4 and IL-10. • Associated with weak CMI, but strong humoral response. DEPT. OF PHYSIOLOGY, AIIMS PATNA 59
- 59. 12. A polyclonal B-cell response and antibody production with no effect on M. leprae results in formation of immune complexes. DEPT. OF PHYSIOLOGY, AIIMS PATNA 60
- 60. DEPT. OF PHYSIOLOGY, AIIMS PATNA 61
- 61. DEPT. OF PHYSIOLOGY, AIIMS PATNA 62
- 62. Immune Mechanisms of Nerve Damage • The bacterial cell wall contains M. Leprae – specific phenolic glycolipid (PGL-1). • Helps M. Leprae to bind to Laminin in the basal lamina of Schwann cells thus invading peripheral nerves. DEPT. OF PHYSIOLOGY, AIIMS PATNA 63
- 63. DEPT. OF PHYSIOLOGY, AIIMS PATNA 64
- 64. DEPT. OF PHYSIOLOGY, AIIMS PATNA 65
- 65. DEPT. OF PHYSIOLOGY, AIIMS PATNA 66
- 66. DEPT. OF PHYSIOLOGY, AIIMS PATNA 67
- 67. DEPT. OF PHYSIOLOGY, AIIMS PATNA 68 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 68. DEPT. OF PHYSIOLOGY, AIIMS PATNA 69 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 69. DEPT. OF PHYSIOLOGY, AIIMS PATNA 70
- 70. DEPT. OF PHYSIOLOGY, AIIMS PATNA 71
- 71. Indeterminate Leprosy (IL) DEPT. OF PHYSIOLOGY, AIIMS PATNA 72 Lesions are normaesthetic and no enlarged nerves.
- 72. Tuberculoid Leprosy (TT) DEPT. OF PHYSIOLOGY, AIIMS PATNA 73 Ref : IAL Textbook of Leprosy
- 73. Borderline Tuberculoid (BT) DEPT. OF PHYSIOLOGY, AIIMS PATNA 74
- 74. Borderline Borderline (BB) DEPT. OF PHYSIOLOGY, AIIMS PATNA 75
- 75. Borderline Lepromatous (BL) DEPT. OF PHYSIOLOGY, AIIMS PATNA 76
- 76. Lepromatous Leprosy (LL) DEPT. OF PHYSIOLOGY, AIIMS PATNA 77
- 77. Other Manifestations of Leprosy DEPT. OF PHYSIOLOGY, AIIMS PATNA 78 Sites Manifestations Occular Madarosis Conjunctivitis Keratitis Iridocyclitis Skeletal Bone cyst Subarticular erosions Subluxation,dislocation or synostosis of joints Testicular Azoospermia Reduced levels of testosterone Epididymorchitis
- 78. Leprae Reactions • Reactions are acute inflammatory episodes superimposed on the relatively uneventful usual course of leprosy. • Acute hypersensitivity reactions to bacillary antigens. • Type 1 reactions (T1Rs) occurs in the borderline spectrum. • Erythema nodosum leprosum (ENL) or T2R occur in lepromatous spectrum. DEPT. OF PHYSIOLOGY, AIIMS PATNA 79
- 79. DEPT. OF PHYSIOLOGY, AIIMS PATNA 80
- 80. DEPT. OF PHYSIOLOGY, AIIMS PATNA 81
- 81. Middle aged lady, vegetarian with no comorbidities presented with chronic progressive, symmetric sensory motor neuropathy initially involving bilateral lower limb since 1 year with loss of temperature, pain sensation in B/l lower limb and upper limbs since 5-6 months without the presence of anesthetic skin lesions. DEPT. OF PHYSIOLOGY, AIIMS PATNA 82 Bilateral distal symmetrical sensory motor neuropathy of upper and lower limbs with palpable ulnar, common peroneal nerve.
- 82. Algorithm - Diagnostic Approach for Pure Neuritic Leprosy (PNL) 83 Ref : IADLV Textbook of Dermatology
- 83. DEPT. OF PHYSIOLOGY, AIIMS PATNA 84
- 84. Pure Neuritic Leprosy (PNL) PNL is defined as exclusive nerve involvement • in the form of nerve thickening or neural deficit • without any skin lesions, a negative slit skin smear • in the absence of other causes of nerve involvement DEPT. OF PHYSIOLOGY, AIIMS PATNA 85
- 85. The prevalence of PNL in India ranges from 4.7 to 17% , with higher prevalence in Southern part of India. DEPT. OF PHYSIOLOGY, AIIMS PATNA 86
- 86. Features • Area of sensory loss • Weakness of a limb (with or without deformities) • Ulcers and other secondary changes over skin • Thickened nerve trunks • Nerve tenderness, neuropathic pain and occasionally nerve abscesses. DEPT. OF PHYSIOLOGY, AIIMS PATNA 87
- 87. Features Area of sensory loss Weakness of a limb (with or without deformities) Ulcers and other secondary changes over skin Thickened nerve trunks • Nerve tenderness, neuropathic pain and occasionally nerve abscesses. DEPT. OF PHYSIOLOGY, AIIMS PATNA 88
- 88. Pattern of nerve involvement • Nerves of upper extremities, especially ulnar nerve, is the most affected in PNL followed by lower limbs (common peroneal nerve and posterior tibial nerve). • Other nerve trunks are less commonly affected. DEPT. OF PHYSIOLOGY, AIIMS PATNA 89
- 89. • Nerve involvement is mostly in the form of mononeuritis (approximately 60%). • However, mononeuritis multiplex and polyneuritic form, also called ‘mononeuritis multiplex summation’, are also not uncommon. DEPT. OF PHYSIOLOGY, AIIMS PATNA 90
- 90. DEPT. OF PHYSIOLOGY, AIIMS PATNA 91 Ref : Ridley Jopling Textbook of Leprosy
- 91. DEPT. OF PHYSIOLOGY, AIIMS PATNA 92 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 92. DEPT. OF PHYSIOLOGY, AIIMS PATNA 93 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 93. 1. History and clinical Examination 2. Slit Skin Smear 3. Skin Biopsy 4. Nerve Biopsy 5. Serologic Tests 6. Electrophysiological Tests DEPT. OF PHYSIOLOGY, AIIMS PATNA 94
- 94. Slit Skin Smear • The most simple and valuable test for leprosy • Minimum of 4 sites • The suspected lesion may also be included DEPT. OF PHYSIOLOGY, AIIMS PATNA 95
- 95. DEPT. OF PHYSIOLOGY, AIIMS PATNA 96
- 96. • Morphologic Index – It is the measure of no. of Acid-fast bacilli (AFB) in skin scrapings that stain uniformly bright (viable). • Bacteriological Index – A log scale measure of the density of M. Leprae in the dermis. DEPT. OF PHYSIOLOGY, AIIMS PATNA 97
- 97. DEPT. OF PHYSIOLOGY, AIIMS PATNA 98 A diagnosis of Pure Neuritic Hansen’s requires a negative SSS result. Ref : Ridley Jopling Textbook of Leprosy
- 98. Skin Biopsy • The biopsy should be taken from the middle of the lesion where the disease is active. • Histopathological examination DEPT. OF PHYSIOLOGY, AIIMS PATNA 99
- 99. Nerve Biopsy • Gold standard for diagnosis of PNL. • Nerve biopsy will not be required if a skin lesion is present. • A thickened sensory nerve is suitable such as • supraorbital branch of the 5th cranial nerve • sural nerve at the back of the leg • There is no risk of motor damage. DEPT. OF PHYSIOLOGY, AIIMS PATNA 100
- 100. Fluorescent Leprosy Antibody Absorption Test (FLA - ABS) • To identify subclinical cases • Detects IgM antibodies to PGL-1 (Phenolic Glycolipid 1 ) antigen of M Leprae. • 92% sensitive and 100% specific DEPT. OF PHYSIOLOGY, AIIMS PATNA 101
- 101. Electrophysiological Studies in Hansen’s Disease • Peripheral nerve trunk involvement manifests as sensory, motor or autonomic deficit. • However, by the time it becomes clinically manifest, the damage to the nerve fascicles present within the nerve is quite advanced. DEPT. OF PHYSIOLOGY, AIIMS PATNA 102
- 102. • A stage of functional blockade always precedes visible pathological changes in the nerve. • If the preclinical nerve damage can be detected early, the deformities and disabilities can be prevented to a large extent. • Electrophysiological studies can be used both for diagnostic and monitoring purposes. DEPT. OF PHYSIOLOGY, AIIMS PATNA 103
- 103. Nerve Conduction Studies (NCS) • Nerve conduction studies (NCS) detected changes in 40% of the patients who had silent neuropathy. • Precede nerve function impairment and are more sensitive than monofilament test and voluntary muscle testing. DEPT. OF PHYSIOLOGY, AIIMS PATNA 104 Ref: Kumar B. Pure or Primary neuritic Leprosy (PNL). Lepr Rev. 2016 Dec;87(4):450-55. PMID: 30226349.
- 104. Common findings 1. Dampening of sensory nerve action potentials (SNAP) and Compound motor action potential (CAMP) indicating axonal damage and 2. Decreased sensory conduction velocity, increased latency and temporal dispersion indicate demyelination. DEPT. OF PHYSIOLOGY, AIIMS PATNA 105
- 105. Electromyography (EMG) The muscles usually examined in leprosy are, • Abductor pollicis brevis for testing the function of the median nerve, • Abductor digiti minimi for testing the ulnar nerve and • Extensor digitorum brevis for testing the lateral popliteal nerve. DEPT. OF PHYSIOLOGY, AIIMS PATNA 106
- 106. • On needle EMG, the normal brief injury potentials are greatly prolonged (increased insertional activity) • Occasionally continue in a burst of decreasing frequency and amplitude (Pseudo myotonic run) • Fibrillation, fasciculation, giant motor unit potentials and incomplete interference or reduced recruitment pattern. DEPT. OF PHYSIOLOGY, AIIMS PATNA 107
- 107. DEPT. OF PHYSIOLOGY, AIIMS PATNA 108
- 108. DEPT. OF PHYSIOLOGY, AIIMS PATNA 109 Bilateral distal symmetrical sensory motor neuropathy of upper and lower limbs with palpable ulnar, common peroneal nerve.
- 109. Other investigations • Blood glucose, ANA, ANCA, HIV, HBsAG and Anti HCV • A Skin Slit Smear result of the patient is awaited, a negative result is mandatory to rule the case as a Pure Neuritic Hansen’s (PNL). • However, MDT therapy was advised due to a strong clinical picture of PNL. DEPT. OF PHYSIOLOGY, AIIMS PATNA 110
- 110. DEPT. OF PHYSIOLOGY, AIIMS PATNA 111 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 111. DEPT. OF PHYSIOLOGY, AIIMS PATNA 112 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 112. Treatment of Leprosy (Multi Drug Therapy : MDT) DEPT. OF PHYSIOLOGY, AIIMS PATNA 113
- 113. DEPT. OF PHYSIOLOGY, AIIMS PATNA 114
- 114. DEPT. OF PHYSIOLOGY, AIIMS PATNA 115 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 115. DEPT. OF PHYSIOLOGY, AIIMS PATNA 116 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 116. Summary – Hansen’s Disease • A chronic inflammatory condition caused by AFB M. Leprae. • WHO and Ridley Jopling Classification • PNL is a form of Hansen’s with exclusive nerve involvement. • In addition to the routine tests, NCS and EMG are useful in early detection in suspects - preventing deformities and disability. • Treatment – Multi Drug Therapy DEPT. OF PHYSIOLOGY, AIIMS PATNA 117
- 117. References 1. Jopling WH, McDougall AC. Handbook of leprosy 6 E. Heinemann Professional; 2020 2. IADVL concise textbook of dermatology. Jaypee Brothers Medical Publishers Pvt. Limited; 2019 3. Kumar B, Kar HK. IAL textbook of leprosy. Jaypee Brothers Medical Publishers Pvt. Limited; 2015. 4. Preston DC, Shapiro BE. Electromyography and neuromuscular disorders. Elsevier Health Sciences; 2020. 5. Kumar B. Pure or Primary neuritic Leprosy (PNL). Lepr Rev. 2016 Dec;87(4):450-55. PMID: 30226349. DEPT. OF PHYSIOLOGY, AIIMS PATNA 118
- 118. THANK YOU ! saran.adhoc@gmail.com DEPT. OF PHYSIOLOGY, AIIMS PATNA 119
- 119. DEPT. OF PHYSIOLOGY, AIIMS PATNA 120 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
- 120. DEPT. OF PHYSIOLOGY, AIIMS PATNA 121 Overview • Clinical Case • Defintion • Microbiology • Classification of Leprosy • Pathophysiology of Leprosy • Clinical Features • Diagnosis • Treatment • Summary DEPT. OF PHYSIOLOGY, AIIMS PATNA
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- This is the broad outline of the seminar. First we will see a case, its history and clinical examination. After that to have a proper insight, we will have a look at Hansen’s disease, its definition, microbiology, going deep into the classification and pathophysiology. Then we will see the clinical features and try to corelate it with the case at hand while also mentioning the diagnostic measures. Before finishing, we will also have a look at the accepted treatment regimes followed.
- So here is the case. Presenting the case of a 51 year old female, a homemaker. The date of examination was on 11th August. The chief complaints of the patient were tingling and numbness over all four limbs for the past one year and loss of sensations in all four limbs since 6 months. She also complained of weakness in the right hand since the past 5 months and gave the history of recurrent healing ulcers over fingers on both hand. She upon presentation had a ulcer on the index finger of the right hand.
- The history of presenting complaints. Patient non diabetic, right handed individual was apparently normal one year ago when she noticed tingling and numbness of upper and lower limbs, initially starting with the lower limb. These negative sensations were insidious in onset and gradually progressive. It initially involved the soles with patient giving history of slippage of chappals from both feet unknowingly while walking which was increased over the duration of past one year. Now it is upto the level of the knee. She also gives h/o recurrent healing ulcers in soles and feet. There is no history of diurnal variations or pain.
- The history of reduced temperature sensation over bilateral lower limbs dates back to 6 months. It was insidious in onset and patient gives the history of being unable to appreciate hot or cold while washing feet. It was also progressive in nature currently upto the level of the knee. There was no bowel and bladder involvement or band like sensation ruling out the possiblity of a spinal cord lesion. No h/o pain, claudication, swelling or colour change ruling out vascular causes.
- The patient also gave the history of reduced sensation over both upper limbs and weakness of right upper limb since 5 months. The loss of pain temperature and touch sensation was insidious intially started as tingling and numbness in all the five fingers, now progressed up to the level of elbow in left upper limb and mid arm in right upper limb. The loss was more on the left compared to right. The patient gives recurrent history of difficulty in grasping objects like cup, keys etc and painless healing ulcers in both hands, having one on the right hand at the the time of examination. She was not clear on the loss of hair in the limbs or sweating.
- Now for the negative history. There was no h/o of LOC or trauma, No h/o weight loss or weight gain. No h/o of lifting hand above the head or difficulty in walking or swaying ruling out the involvement of proximal muscles. No h/o neck pain or shock like sensation, a sign called Lhermitte sign asoociated with Vit B12 deficiency. No blurring or dimunition of vision. No h/o double vision, difficulty in chewing or swallowing food, no h/o of dimnished sensation over face. There was also no history suggestive of any cranial nerve involvement.
- There was no h/o of intake of drugs or alternative medicine, No h/o reduced tears. There are no history suggestive of any other systemic involvement. Nothing suggestive of diabetes, vasculitis or thyroid disease that can all present with peripheral neruropathy.
- No relevant family history..
- Nothing in past history except for the history of recurrent incidences of healing ulcers in upper and lower limb. She is vegetarian with normal sleep, bowel and bladder habits with no history of any smoking or alcohol
- Hansen’s Disease or leprosy is an age-old disease and is described in the literature of ancient civilizations. It is a chronic infectious disease caused by acid fast bacilli of the mycobacterium leprae complex which includes mycobacterium leprae and m lepramatosis. Mycobacteria was discovered by Gerard Armauer Hansen in 1873 and hence the name and it affects mainly skin and peripheral nerves.
- The WHO defines a case of a Hansen’s disease as an individual who has not completed the course of treatment and has one or more of the 3 cardinal signs
- These are one, anesthetic patches that are either hypopigmented or erythematous. Thickened or enlarged peripheral nerve with loss of sensation and or weakness of the muscle supplied by that nerve. And thirdly, the presence of acid-fast bacilli in slit skin smear.
- Coming to a bit more about Mycobacterium
- Mycobacterium lepare is an obligate intracellular organism, meaning it cannot be cultured in artificial media. It grows best at 27 – 33 degree Celsius thus explaining the predilection of the microbe to cooler areas of the body like the skin, nerve segments close to the skin, and the mucous membranes of the upper respiratory tract. The generation time is approx. 12.5days and this can explain the rather long incubation period. 3 to 5 years in Tuberculoid and 8 to 12 years in lepromatous leprosy.
- This is skin smear showing Mycobacterium leprae demonstrated by the Ziehl Neelsen staining. I hope we can appreciate the solid bacilli seen on the right and the left compared to the non solid fragmented granular bacteria on the right.
- About the transmission, this part is not yet fully understood. Earlier it was believed to transmitted through skin by touch, thus actually causing much of the stigma related to the disease. However, the spread by the respiratory route, that is through the nasal discharge from untreated patients with MB disease is gaining importance recently. Literature also has evidence of transmission in which organisms may enter through broken skin. In parts of South America, where Armadillos act as reservoirs of the bacteria, handling, killing and eating of the animal is known to cause the disease.
- With all that said, leprosy is not that highly contagious as it was once believed to be. That is most people do not develop the disease after the exposure. The development of the diseae depends on a variety of factors including immune status and genetic influences.
- We will see what are the risk factors that predispose the individual to contract a disease of leprosy. Close contact with patients of Hansen’s disease can be a risk factor. Also, the type of leprosy in the index case is to be noted, a case of lepromatous leprosy has more risk than a case of Tuberculoid leprosy. Age is also a risk factor since people with ages more than 30 years have been known to contract the disease more than their younger counterparts. Genetics play a role too, like in the people possessing the variants in genes of NOD2 dependent signaling pathways are more susceptible to the disease. Immunosuppression f following solid organ transplantation, chemotherapy, HIV infection, or use of biologic agents for management of rheumatologic conditions can pose as a risk.
- Let's now see the classification of leprosy. Although there are many types of classification of leprosy, I will mention the most used two here.
- The first one is the WHO classification which is the most used system in leprosy control programmes around the world. There are many modifications that are followed like the National Leprosy Eradication Progammme classification followed in India. The second one is the Ridley Jopling Classification which is extensively used for research and academic purposes.
- The WHO classification is a clinical classification with the main aim of determining the appropriate therapy for leprosy patients. It classifies leprosy into paucibacillary leprosy and multibacillary leprosy.
- Paucibacillary is defined as a case of leprosy with 1-5 skin lesions without the presence of bacilli on skin smear. Multibacillary is a case of leprosy with more than 5 skin lesions, or with nerve involvement or with demonstrated presence of bacilli in a SSS. The nerve involvement can be isolated like in a pure neuritic case or one associated with skin lesions.
- NLEP Classification or National Leprosy Eradication Program classification is a modification of the WHO Classification of leprosy with slight modification. It was introduced in 2009 and is still followed without change. The only difference between the NLEP Classification and WHO Classification is in the nerve involvement part. NLEP classifies leprosy with one nerve involvement also in paucibacillary type.
- The other classification which is widely accepted is Ridley Jopling Classification. It is more research oriented taking into account the many nuances of the disease such as clinical features, histological features, bacteriological features as shown in slit skin smears and immunological features as in tests such as lepromin tests.
- Based on this leprosy is divided into five groups. These classification in in fact represent a spectrum of disease conditions from the milder TT or the tuberculoid type to the severe LL lepromatous type of leprosy. In between these poles like the rest, like the BT or the borderline tuberculoid leprosy, BL or the borderline lepromatous type and BB which is the borderline borderline leprosy.
- The ends of this spectrum, TT and LL represents the immunologically stable forms. While the BT BB and BL represent the unstable types and hence can upgrade or downgrade. Here in this representation, you can see the middle portion is the unstable one, the ends represent the stable variant. Here you can notice, both in TT and LL, there are subgroups labelled as TTp and TTs. TTp represent the polar form which doesn’t change, while the TTs is the downgraded form. Similarly with LL.
- We will see much more on the different types of leprosy later in this presentation. Now, lets go on to the pathophysiology of leprosy. Here we see the key steps in the immunopathogenesis of leprosy as well as the immune mechanisms that lead to nerve damage, which can be corelated to the case at hand.
- We will see the key steps in immunopathogenesis first. It all begins when the M. Leprae enters the body possibly through the nose and then spreads to the skin and nerves via circulation. Multiplication takes place in the dermal lymphatics as well as in the vascular endothelium which plays a major role in the hematogenous spread.
- M.Leprae invades the peripheral nerves via the blood vessels of the perineurium. The important aspect in the pathogenesis of leprosy is that the immunological response mounted by the host dictates the clinical phenotype that develops. For example, in TT type of leprosy monocytes destroy the organism completely while in LL, microvacuolated monocytes with bacillary debri may persist suggesting a graver form of disease.
- The Toll like receptors on innate immune cells recognize the mycobacterial PAMPs, generating cytokines and this in turn regulates inflammation and influences the course of adaptive cell mediated immunity into a Th1 or Th2 response.
- In our body normally, the sentinel cells in the innate immune system, the APCs present the pathogen to the naïve T cell and depending on the type of pathogen and a host of various factors like the interleukins have two characteristic responses, the Th1 response which kick start the cell mediated immunity or the Th2 response mainly involving the humoral immunity.
- The Th1 cytokines are associated with TLR1 and TL2 activation and Th2 cytokines are associated with the inhibition of this activation. In leprosy, the expression of TLR1 and TL2 have been found to be stronger on monocytes and dendritic cells in tuberculoid lesions compared to their lepromatous counterparts.
- In leprosy, Th1 response is initiated by cytokines IL12, IL2, TNF and IFN and leads to a tuberculoid type phenotype, while if Th2 type is initiated by IL4 and IL 10 leads to a lepromatous type of phenotype.
- In tuberculoid lesions, the CD4/CD8 ratio is 2:1 showing a Th1 like profile courtesy of cytokines like IL-2 IFN TNF and IL12. It shows a strong cell mediated immune response and result in intense phagocytic activity.
- In lepromatous leprosy, CD4/CD8 ratio is 1:2 giving a Th2 like response mediated by IL4 and IL10. It is associated with a weak Cell mediated immune response but a strong humoral response.
- But here the polyclonal B cell response and antibody production is of no effect on M Leprae as it a intracellular pathogen and it results in the formation of immune complexes.
- This diagram summarises the pathophysiology and the different responses of the immune system. If the TLR 1 or 2 is activated the phagocytosis and antimicrobial activity is enhanced instructing a adaptive cellular response. Otherwise there would be a adaptive humoral immune response. Why this is important is because, if the Th1 pathway if triggered you can see that it strengthens the antimicrobial activity leading to a better immune response contrary to what happens when the Th2 is triggered.
- This sums up the Hansens disease phenotypic spectrum, as we move from tuberculoid to lepromatous skin lesions increases along with the bacterial load. The cell mediated immunity is more in the Tubeculoid end compared to the Humoral Response at the Lepromatous end. Nerve damage is a common feature throughout the spectrum.
- Now lets see the immune mechanisms leading to nerve damage. M Leprae is unique structurally in a way that its cell wall contains M Leprae specific phenolic glycolipid that binds to the Laminin in the cytoskeleton of Schwan cells thus enabling them to invade peripheral nerves.
- This binding alone causes rapid demyelination. It also induces cytotoxic immunity and inflammatory response leading to acute manifestation of inflammatory nerve damage. Second way is it can induce the Schwann cells to express self antigen which causes the cell to becomes self reactive thus amplifying the damage.
- The possible mechanisms of peripheral nerve damage is through processes such as ischemia, apoptosis or demyelination through the activity of inflammatory mediators or t cell mediated cytolysis.
- Lets now see the various clinical features of different types of leprosy.
- When a healthy person gets infected by the M.Leprae, the subclincal stage is called as the indeterminate leprosy. However 80 percent of the Indeterminate form undergoes self healing and only 20 % manifests as one of many types of leprosy.
- The different types of leprosy can be understood along these few lines. When we look the no and size of patches TT types has very few but big patches. As we go to the other side the size decreases and number increases so that in the LL its small multiple patches. The loss of sensations are predominant in the tuberculous end of the spectrum. When we look at the morphology of skin lesions, the border becomes more inconspicuous as we go to the lepromatous pole and the symmetry of lesions changes from asymmetrical to symmetrical.
- The indeterminate form of leprosy is characterized by a large lesion that is normaesthetic with no involvement of the nerves.
- This is the characteristic turgid looking inverter saucer shaped lesion of TT Leprosy. Sensation and hair growth is absent in the lesion. AFB il nil and lepromin reactivity is strongly positive.
- The lesion of the border line tuberculoid has a distinct margin in one end and an indistinct at the other side. Sensation and hair growth is diminished. AFB nil or scanty, and lepromin weakly positive.
- The skin lesions of the borderline borderline form is known for its Swiss cheese kind of appearance.
- In Borderline lepromatous, the center of the small multiple skin lesions begin to show characteristic induration. Sensations and hair growth are only slightly diminished. AFB are many, however lepromin activity is negative.
- Lepromatous Leprosy show the characteristic Leonine or the lion like facies. No of lesions are small and innumerable. Sensations are minimally lost and hair growth not affected initially. Lepromin reactivity is negative.
- There are other manifestations of leprosy as well such as ocular, skeletal or testicular. There can be madarosis, conjunctivitis, keratitis or iridocyclitis in the eye. Subarticular erosions in bone or subluxations of joints. Azoospermia, reduced levels of testosterone and epididymoorchitis.
- Leprae reactions are acute inflammatory episodes superimposed on the relative uneventful courses of leprosy. They are acute hypersensitivity reactions to bacillary antigens and are mainly of two types. Type 1 reactions occur in Borderline spectrum and Type 2 reactions or erythema nodosum leprosum ENL occur in lepromatous spectrum.
- Type 1 reaction or reversal reaction happens during downgrading of lesions, usually during the course of treatment. The existing lesion turns edematous and reddish associated with features such as edema and neuritis even causing sudden loss of motor function. Type 2 reaction on the other hand refers to the newly formed painful erythematous dermal or subcutaneous nodules, It is associated with widespread inflammatory responses and both reaction may require steroids in addition of MDT.
- So that completes our understanding of the classification, clinical features and pathophysiology of Hansen’s Disease. Now coming back to the case summary. Middle aged lady, vegetarian with no comorbidities presented with chronic progressive, symmetric sensory motor neuropathy initially involving bilateral lower limb since 1 year with loss of temperature, pain sensation in B/l lower limb and upper limbs since 5-6 months without the presence of anesthetic skin lesions. On detailed clinical examination, the clinical diagnosis was Bilateral distal symmetrical sensory motor neuropathy of upper and lower limbs with palpable ulnar, common peroneal nerve.
- Lets now see the alogirithm depicting the diagnostic approach to PNL. The diagnosis of PNL is more like a diagnosis of exclusion. In a case suggestive of neuropathy like we have here, complete history and clinical examination should be conducted and any nerve thickening or skin lesions suggestive of leprosy should be picked up. Sensory testing should be done by SW filament for touch and temperature and pain testing should be done along with motor examination. Then other causes of peripheral neuropathy like metabolic causes, infections, inflammation etc should be ruled out. In a high endemic zone PNL should always be considered as a differential and SSS should be done which should be negative for a diagnosis of PNL. Other investigations that need to be done will be discussed in the following slides.
- Pure Neurtic form of Hansens disease is defined as disease exclusively affecting nerve in the form of a nerve thickening or neural deficit without any skin lesions substantiated by a negative SSS while also ruling out other causes of nerve involvement.
- The prevalence of PNL in India ranges from 4.7 to 17%. Therefore PNL need to be considered as a differential in cases of peripheral neuropathy.
- Features are area of sensory loss, weakness of limb with or without deformities, ulcers and other secondary changes over skin in the presence of thickened nerve trunks. All of which was found during the history and clinical examination of the case. It can also be associated with nerve tenderness, neuropathic pain and occasional nerve abscesses.
- Features are area of sensory loss, weakness of limb with or without deformities, ulcers and other secondary changes over skin in the presence of thickened nerve trunks. All of which was found during the history and clinical examination of the case. It can also be associated with nerve tenderness, neuropathic pain and occasional nerve abscesses.
- Next coming to pattern of nerve involvement, nerves of upper extremities especially the ulnar nerve is most affected. This is followed by common peroneal nerve and posterior tibial nerve in the lower limbs.
- 60 percent of Nerve involvement is mostly in form of mononeuritis. However PNL can also present as mononeuritis multiplex or polyneuritic form called as mononeuritis multiplex summation.
- Essential Diagnostic criteria of PNL includes epidemiological features like an endemic area or history of contact with leprosy patients, clinical features such as thickened peripheral nerve with sensory impairment with or without motor impairment, laboratory features like a negative SSS, or a negative skin biopsy. The auxiliary diagnostic criteria involves nerve biopsy or FNAC findings suggestive of leprosy and NCS showing decline in amplitude and velocity and increase in latency.
- Coming to the diagnosis, history and clinical examination forms the primary most important part. Others are slit skin smear, skin biopsy, nerve biopsy, serological tests and electrophysiological tests.
- Slit skin smear is the most popular simple and valuable test for leprosy. Minimum of 4 sites is biopsied including the site of suspected lesion.
- Zeil Nehlsen stating is used to demonstrate the bacteria. Live bacteria appear as solid staining and dead non viable bacteria appear as granular.
- Depending on this two parameters are calculated. Morphologic Index is the measure if no of acid fast bacilli in skin scrapings that stain uniformly bright that are viable. Bacteriological index is the log scale measure of the density of M Leprae in the dermis.
- Here as you see in the table, as the number of bacilli in the given field increases, the BI increases giving us a measure of the bacterial load. In a case of PNL, the SSS should be negative. In the given case, SSS was taken from the Dermatology department and the results are awaited.
- Skin biopsy is another diagnostic test for leprosy and should be taken from the middle of the hypopigmented patched and looked for characteristic histological changes.
- Nerve biopsy is the gold standard for diagnosing PNL and is one only if there are no skin lesions. A thickened sensory nerve such as the supraorbital branch of the 5th cranial nerve or the sural nerve is biopsied and therefore there is no risk of motor damage.
- Serological tests like the fluorescent leprosy antibody absorption test is done to identify subclinical cases and it detects IGM antibodies to PGL-1 antigen with 92 percent sensitivity and 100 percent specificity.
- Electrophysiological studies though not routinely done in Hansen’s disease, can prove to be beneficial because most peripheral nerve trunk involvement manifests as sensory, motor or autonomic deficit. However by the time they clinically manifest, the nerve damage would be quite advanced.
- It is said that the stage of functional blockade always preceeds visible pathological changes in the nerve. And if the preclinical nerve damage can be detected early, the deformities and disabilities can be prevented. Electrophysiological studies can hence be used both for the diagnostic as well as for the monitoring purposes.
- The advantage of NCS is that it can detect patients in silent neuropathy and that it is more sensitive than the traditional monofilament test and the voluntary muscle testing.
- The common finding seen in NCS are 1. Dampening of the sensory nerve action potentials and CMAP indicating axonal damage and 2. Decreased sensory conduction velocity, increased latency and temporal dispersion indicating demyelination.
- The muscles that are usually examined in leprosy are abductor policis brevis for testing the function of the median nerve, abductor digiti minimi for testing the ulnar nerve and extensor digitorum breivis for testing the lateral popliteal nerve.
- In leprosy, EMG shows increased insertional activity, pseudomyotonic run, fibrillations, fasciculations, giant motor unit potentials and a reduced recruitment pattern all suggestive of neuropathy.