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Conventional techniques, such as plain radiography and bone-scintigraphy, were used in the past to evaluate skeletal changes in patients with leprosy. More recent publications focus on radiological imaging of affected nerves, and involve advanced modalities such as Computed Tomography (CT-scan), Ultrasonography (US), and Magnetic Resonance Imaging (MRI). US and MRI can play an especially important role in the evaluation of nerve involvement in newly diagnosed patients, and also during leprosy reactions. This is important, because when nerve involvement is diagnosed in time, it may be reversible with adequate treatment. Radiological modalities can also play an important role during the followup of patients with leprosy with nerve function impairment. Skeletal and soft-tissue abnormalities occur, even after treatment. The so-called neuropathic foot is a well known consequence. Because of nerve function impairment, there is a constant risk of developing ulcers and subsequent osteomyelitis, or neuro-osteoarthropathy (Charcot foot or tarsal disintegration), which can lead to the amputation of the affected limb. Different radiological modalities can be used during the evaluation and follow-up of patients with leprosy with a neuropathic foot. With this up-to-date review, we highlight the importance and potential role of radiological imaging techniques in leprosy.

OBJECTIVES: An MRI study done in 2000 on 10 leprosy patients with neuropathic feet, without clinical complications such as ulcerations, osteomyelitis or Charcot deformities revealed abnormalities in nine patients, with degradation, interruption of subcutaneous fat and effusion/synovitis, all located in the first metatarsophalangeal (MTP) region. Since these MRI abnormalities may precede clinical complications of the foot, a follow-up study was performed. DESIGN: A new evaluation was based on a clinical examination and an MRI of the same patients who participated in the initial study. RESULTS: Four patients were lost to follow-up. Average follow-up period was 4-6 years. MRI abnormalities in the MTP 1 region in the first study were no longer visible in three patients, but were still present in two patients. In six patients new MRI findings were found, without clinical evidence of ulceration, osteomyelitis or Charcot deformity. No relationship was found between MRI findings in the MTP 1 region at the start of the study and the development of foot ulcers, callus or skin fissures in the MTP 1 region during follow-up. CONCLUSION: MRI findings of interruption and infiltration of the subcutaneous fat in leprosy patients with uncomplicated neuropathic feet do not necessarily have any clinical implication for the development of future foot problems

Pure neural leprosy (PNL) is difficult to diagnose because skin lesions and acid-fast bacilli (AFB) in slit smears are absent. At present, the gold standard for PNL diagnosis is the histopathological examination of a peripheral nerve biopsy. Even so, detection of bacteria is difficult and histological findings may be non-specific. Furthermore, nerve biopsy is an invasive procedure that is only possible in specialized centres. Therefore, there is a need for additional diagnostic methods that may help to confirm the clinical diagnosis of PNL. In the present study, an additional laboratory test, the ELISA for anti-phenolic glycolipid I (PGL-I) IgM antibodies, was performed on 103 individuals with clinical and neurophysiological signs of peripheral neuropathy, of which 67 were diagnosed as PNL patients and 36 remained as 'not diagnosed as PNL', as well as on a control group of 34 patients with other neurological diseases. An antibody response was present in 14/67 (21%) of the patients diagnosed as PNL as compared with 3/34 (9%) of controls. Anti-PGL-I positivity was observed in 5/8 (63%) of the AFB positive cases. Patients whose diagnosis was confirmed solely by Mycobacterium leprae PCR on the nerve sample had 4/25 (16%) seropositivity. In addition, anti-PGL-I antibodies were detected in 9/40 (23%) of the PNL patients who were PCR negative for M. leprae DNA. Moreover, two patients who showed clinical and eletrophysiological manifestations suggestive of PNL were diagnosed with the help of their positive test results in the anti-PGL-I ELISA. In conclusion, detection of antibodies against PGL-I in patients with peripheral neuropathy is useful as an additional laboratory test to help PNL diagnosis.

Conventional techniques, such as plain radiography and bone-scintigraphy, were used in the past to evaluate skeletal changes in patients with leprosy. More recent publications focus on radiological imaging of affected nerves, and involve advanced modalities such as Computed Tomography (CT-scan), Ultrasonography (US), and Magnetic Resonance Imaging (MRI). US and MRI can play an especially important role in the evaluation of nerve involvement in newly diagnosed patients, and also during leprosy reactions. This is important, because when nerve involvement is diagnosed in time, it may be reversible with adequate treatment. Radiological modalities can also play an important role during the followup of patients with leprosy with nerve function impairment. Skeletal and soft-tissue abnormalities occur, even after treatment. The so-called neuropathic foot is a well known consequence. Because of nerve function impairment, there is a constant risk of developing ulcers and subsequent osteomyelitis, or neuro-osteoarthropathy (Charcot foot or tarsal disintegration), which can lead to the amputation of the affected limb. Different radiological modalities can be used during the evaluation and follow-up of patients with leprosy with a neuropathic foot. With this up-to-date review, we highlight the importance and potential role of radiological imaging techniques in leprosy.

An MRI study done in 2000 on 10 leprosy patients with neuropathic feet, without clinical complications such as ulcerations, osteomyelitis or Charcot deformities revealed abnormalities in nine patients, with degradation, interruption of subcutaneous fat and effusion/synovitis, all located in the first metatarsophalangeal (MTP) region. Since these MRI abnormalities may precede clinical complications of the foot, a follow-up study was performed.A new evaluation was based on a clinical examination and an MRI of the same patients who participated in the initial study.Four patients were lost to follow-up. Average follow-up period was 4-6 years. MRI abnormalities in the MTP 1 region in the first study were no longer visible in three patients, but were still present in two patients. In six patients new MRI findings were found, without clinical evidence of ulceration, osteomyelitis or Charcot deformity. No relationship was found between MRI findings in the MTP 1 region at the start of the study and the development of foot ulcers, callus or skin fissures in the MTP 1 region during follow-up.MRI findings of interruption and infiltration of the subcutaneous fat in leprosy patients with uncomplicated neuropathic feet do not necessarily have any clinical implication for the development of future foot problems.

We identified risk factors associated with increased yearly incidence rates of leprosy in five island populations. Age, sex, household size and Mycobacterium leprae-specific antibodies as well as contact factors were studied. Of 94 index patients (patients diagnosed in 2000), 43 (46%) were classified as multibacillary (MB), 17 (19%) were seropositive for PGL-1 [corrected] antibodies and 6 (7%) had M. leprae DNA in nasal swabs as determined by polymerase chain reaction (PCR) testing. All PCR positive patients were also seropositive. Forty-four of 4903 initially symptom free persons developed leprosy within 4 years, giving an incidence rate of 298 per 1000 person-years. Men had a 22 times higher risk [95% confidence interval (CI): 1.2-4.1] of developing leprosy than women. People living in households with more than 7 members had a 3.1 times higher risk (95% CI: 1.3-7.3) than households of 1-4 members. Persons who were seropositive in 2000 had a 3.8 times higher risk (95% CI: 1.1-12.6) than seronegative persons. Household contacts of MB patients had an adjusted hazard ratio (aHR) of 4.6 (95% CI: 1.6-12.9) and household contacts of PCR positive patients an aHR of 9.36 (95% CI: 2.5-34.9) compared with non-contacts. Patients with PCR positive nasal swabs, suggesting nasal excretion of M. leprae, are probably the patients with the highest transmission potential. Since all index patients who were PCR positive were also seropositive, serology seems an adequate tool to identify these patients. Preventing seropositive persons from becoming seropositive and infectious patients might break the chain of transmission.

Pure neural leprosy (PNL) is difficult to diagnose because skin lesions and acid-fast bacilli (AFB) in slit smears are absent. At present, the gold standard for PNL diagnosis is the histopathological examination of a peripheral nerve biopsy. Even so, detection of bacteria is difficult and histological findings may be non-specific. Furthermore, nerve biopsy is an invasive procedure that is only possible in specialized centres. Therefore, there is a need for additional diagnostic methods that may help to confirm the clinical diagnosis of PNL. In the present study, an additional laboratory test, the ELISA for anti-phenolic glycolipid I (PGL-I) IgM antibodies, was performed on 103 individuals with clinical and neurophysiological signs of peripheral neuropathy, of which 67 were diagnosed as PNL patients and 36 remained as 'not diagnosed as PNL', as well as on a control group of 34 patients with other neurological diseases. An antibody response was present in 14/67 (21%) of the patients diagnosed as PNL as compared with 3/34 (9%) of controls. Anti-PGL-I positivity was observed in 5/8 (63%) of the AFB positive cases. Patients whose diagnosis was confirmed solely by Mycobacterium leprae PCR on the nerve sample had 4/25 (16%) seropositivity. In addition, anti-PGL-I antibodies were detected in 9/40 (23%) of the PNL patients who were PCR negative for M. leprae DNA. Moreover, two patients who showed clinical and eletrophysiological manifestations suggestive of PNL were diagnosed with the help of their positive test results in the anti-PGL-I ELISA. In conclusion, detection of antibodies against PGL-I in patients with peripheral neuropathy is useful as an additional laboratory test to help PNL diagnosis.

The objective of this study was to examine the clinical signs, symptoms and course of neuropathies in patients with leprosy who after treatment developed nerve impairment, not explained by relapse or reversal reactions. We searched the case-records of leprosy patients, seen between 1985 and 2002 at the department of dermatology at our centre. Included in the study were patients who had developed nerve impairment after treatment of leprosy in the absence of relapse, erythema nodosum leprosum, or reversal reactions, and who were referred to a neurologist. In these patients, we recorded age, onset of leprosy, type of leprosy, treatment of leprosy, signs and symptoms of delayed nerve impairment, results of electrophysiological studies, responses to treatment and course. Included were 14 patients, of whom eight had a (sub)acute multiple mononeuropathy (group I); and six had a slowly progressive multiple mononeuropathy (group II). Patients in group I had limited improvement of nerve impairment after treatment with corticosteroids, and recurrence of symptoms and signs (usually of the motor nerves) when corticosteroids were tapered off. Patients in group II had slowly progressive predominantly sensory nerve impairment. Initially, they had only subjective symptoms, after at least 3 years objective signs became detectable. These patients were not treated with immunosuppressants. Two groups of patients with unexplained delayed nerve impairment could be distinguished. One group had a multiple mononeuropathy resembling reversal reactions with insufficient response to corticosteroids. In these patients, more aggressive and prolonged immunosuppressive treatment should be considered. The aetiology for the neuropathy in the other group remains unclear and further investigations are needed to understand the pathogenesis before treatment recommendations can be given.

With the introduction of reproducible serological tests it was hoped that relapses in leprosy patients, after discontinuing treatment, could be detected before damaging reactions occurred and before the patients became infectious. The possible value of an ELISA using a semisynthetic analogue of phenolic glycolipid-I to detect antibodies to this antigen in order to predict a relapse in multibacillary patients was investigated. In contrast to that reported for paucibacillary patients, this test was useful to detect early relapses in multibacillary patients. In 3 out of 4 multibacillary patients who relapsed, the ELISA-values were increased. The decreased ELISA-values in the one relapsed patient could be attributed to the corticosteroid therapy. In the multibacillary patients who did not relapse after RFT, the ELISA-values were consistently low or decreased. In only one patient did the ELISA-values increase following his release from treatment and this patient was clinically suspected of developing a relapse.