[Peripheral nerve damage in patients with leprosy]. / Neuropathies au cours de la lèpre.

Leprosy is one of the six diseases that the WHO considers as the major threat in developing countries. Damage to nerves can occur before, during, and after treatment and can result in disabilities and long-term disfigurement, which is associated with stigma. Considered exotic and rare in European countries, it is important for neurologists to be able to make the diagnosis of leprosy early in order to rapidly alleviate patient suffering and prevent and reverse nerve damage. Leprosy must be considered in the differential diagnosis of peripheral neuropathy, even in the absence of skin lesions and especially when present in a patient from an endemic country. Immune response and mechanisms involved in nerve damage are not clearly understood. There is no predictive test for the extent of nerve damage and no good evidence on the best treatment.

[Neurological manifestations of leprosy]. / Manifestations neurologiques de la lèpre.

Leprosy, also known as Hansen's disease, is a chronic, infectious disease caused by Mycobacterium leprae. Bacilli localize preferentially in the skin and peripheral nerves and have a propensity to cause nerve damage. The resulting disability has caused great suffering for victims in many countries. Despite recent advances in the immunopathogenesis, epidemiology and prognostic factors of leprosy nerve damage, many aspects of the disease have remained enigmatic. The spectrum of clinical and pathological manifestations of the disease ranges from lepromatous to tuberculoid, depending on the host's T-cell-mediated immune response. Diagnosis is based on three criteria: characteristic skin lesions in association with thickened nerves, demonstration of acid fast bacilli in slit skin smears, and histopathology of skin biopsies. Nerve biopsy is necessary to establish the diagnosis of pure "neural leprosy". In developed countries, the diagnosis is suspected when a patient who has stayed in an endemic area suffers from a peripheral neuropathy of unknown etiology. To facilitate determination of the appropriate antibiotic regimen, patients are classified as either paucibacillary or multibacillary. Some patients may have multibacillary leprosy in nerves and paucibacillary leprosy in skin, which emphasizes the usefulness of nerve biopsy. The course of the disease is often complicated by immune mediated "reactions", which can rapidly lead to further nerve damage, namely reversal reaction and erythema nodosum leprosy. However, nerves are often functionally impaired before developing obvious symptoms such as skin reactions or nevralgia (silent neuropathy). Early recognition and prompt treatment with corticosteroids of leprous reactions and "silent neuropathies" is very important to prevent disability with all its attendant problems. Research progress from clinical trials may improve current methods of prevention and treatment of nerve damage in leprosy.

[How to detect neuropathy in leprosy]. / Comment dépister la neuropathie hansenienne?

In leprosy, the early detection of peripheral nerve damage is essential for the prevention of disability. To date, there is no consensus on what is the best clinical test to reveal such abnormalities. In this prospective study we examined the effectiveness of five clinical tests to assess radial cutaneous nerve (RCN) damage (the most frequently involved). Light touch was assessed by two nylon threads (based on the Semmes-Weinstein monofilaments testing technique) bent on the skin at a pressure of 0.5 (N. 4 nylon) and 0.2 gram (N. 5 nylon). Pinprick and cooling sensations were examined by a needle and a drop of ether. The nerve thickness was assessed by palpation. Sensory findings were then compared to sensory nerve conduction values of the RCN and a sensitivity analysis was performed. The patient group consisted of 108 consecutive new leprosy sufferers (138 RCN) who attended the Institut de Léprologie Appliquée de Dakar during one year. Diagnosis and classification were based on Ridley and Jopling's criteria (clinical examination, skin smears and biopsy). Normal values were determined among 22 healthy subjects (44 RCN). The best tests in term of sensitivity were palpation (.60), N. 5 nylon (.65) and N. 5 + palpation (.79). Their positive predictive values were .84 (palpation), .94 (N. 5 nylon) and .83 (N. 5 + palpation). The best tests in term of area under the curve were palpation (.66), N. 5 nylon (.71) and N. 5 + palpation (.78). The results remain the same for the lepromatous or tuberculoid leprosy patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Segmental ulnar nerve conduction in Hansen's disease]. / Les vitesses de conduction motrices cubitales étagées dans la maladie de Hansen.

In leprosy, ulnar neuritis is considered to be selectively localised at the elbow and is often treated by surgical decompression when pain and/or neurological deficit occurs. The aim of this prospective study is to assess the prevalence, localisation and severity of ulnar nerve damage in leprosy. Motor nerve conduction velocity (MNC) was measured at 3 different segments: arm, elbow and forearm, and was expressed both in meters/second and percentage of the mean normal values found in our laboratory or as reported in other studies. The patient group consisted of 123 consecutive new leprosy sufferers (228 ulnar nerves only) who attended the Institut de Léprologie Appliquée de Dakar over the period of one year. Diagnosis and classification were based on Ridley & Jopling's criteria, including skin and nerve biopsy. Mean MNC was reduced by 13.5 m/s at the arm, 19.8 m/s at the elbow and 7.8 m/s at the forearm as compared to the mean normal values. Increased distal latency as an isolated finding was rare (0.9%). Mean MNC was more reduced in the BL, LL (lepromatous) than in the TT, BT (tuberculoid) subgroups, despite similar disease durations (22.3 +/- 18.7 months and 24.2 +/- 26.4 months respectively (n.s.). Using different normal MNC values did not affect the conclusion: we did not see any selective slowing of ulnar MNC at the elbow suggesting that nerve damage is not primarily related to mechanical factors.

[Detecting and monitoring leprosy neuropathy: which test to chose?]. / Dépister et surveiller une neuropathie hansénienne: quel test choisir?

The purpose of the study is to propose a simple and reproducible test for assessing nerve damage in leprosy. It is applied to the sensory branch of the radial nerve of leprosy patients, prior to any treatment. Skin sensitivity is measured by means of a needle, a drop of ether and some calibrated filaments. These three tests are collated and compared with the results of electromyographic examination of the nerve. The filament calibrated to 0.2 grams gives optimum sensitivity (0.79) and excellent specificity (0.95) in relation to the electromyographic test. Its routine use in the field is simple and reproducible and should result in a greater number of patients receiving the treatment they need.

[Epidemiological study of HIV seroprevalence in a leprosy patient population in Senegal]. / Etude épidémiologique de la séroprévalence de l'infection par le VIH dans une population hansénienne au Sénégal.

We report the findings of an epidemiological study conducted between June 1989 and February 1990 on a population of leprosy patients in southern Senegal (Bignona major endemic disease sector). Two types of population were studied: patients living in urban areas and inmates of leprosaria. The global HIV seroprevalence (HIV 2 in all cases) of the leprosy-patient population was 1.15% (3/257): 0.8% (1/130) for the urban group and 1.5% (2/127) for the leprosaria. The seroprevalence rate does not differ significantly from that for the control group studied and for blood donors (1/221). The diagnosis of leprosy in the seropositive subjects had been established before 1980. None of them showed any sign of relapse. The immunodepression associated with the presence of HIV was only moderate: it was reflected in a lowering of the CD4 count and of the CD4/CD8 ratio, but with no clinical sign of AIDS.

T cell response to purified filtrate antigen 85 from Mycobacterium bovis Bacilli Calmette-Guérin (BCG) in leprosy patients.

T cell proliferation and IFN-gamma production of peripheral blood mononuclear cells from 25 healthy controls and 39 leprosy patients were tested against BCG-bacilli and culture filtrate. Mycobacterium leprae and purified antigen 85 (the major secreted 30-32 kD protein antigen) from M. bovis strain BCG. In lepromin negative healthy controls, blastogenesis was low to M. leprae and completely negative to antigen 85. IFN-gamma levels were very low, close to detection limits. In all lepromin positive controls, significant proliferation and IFN-gamma secretion was found in response to M. leprae and antigen 85. In the group of lepromatous leprosy (LL) patients, 25/29 of patients (with either positive (13) or negative (12) lymphoproliferative response to BCG) were unreactive to M. leprae or to antigen 85. Four LL patients with positive T cell response to BCG responded with detectable lymphoproliferative response and IFN-gamma secretion to antigen 85. All tuberculoid (TT) leprosy patients responded to BCG, M. leprae and antigen 85. Hence, T cells from leprosy patients and controls demonstrate a marked parallelism of responsiveness towards whole M. leprae and purified antigen 85 from M. bovis BCG, suggesting strong cross-reactivity between the two species and underlining the biological importance of such secreted antigens.