|Year : 2013 | Volume
| Issue : 1 | Page : 57-58
Multiple median nerve abscesses: A rare presentation of leprosy
Prashanth R Kamath, Sanath S Rao, Manjunath M Shenoy
Department of Dermatology, Yenepoya Medical College, Deralakatte, Mangalore, India
|Date of Web Publication||21-Jun-2013|
Manjunath M Shenoy
Department of Dermatology, Yenepoya Medical College, Deralakatte, Mangalore - 575 018
Source of Support: None, Conflict of Interest: None
A 25 year old male presented with swellings around the left elbow and forearm since 2 years. Examination showed 4 swellings along the course of median nerve over the left arm, elbow and forearm. They were circumscribed, soft to firm nodules with tenderness. There were no cutaneous lesions suggesting of leprosy. Histopathological examination of a biopsy from a swelling showed granulomas in the epineurium suggesting the diagnosis of leprosy neuritis. With these clinico-pathological features diagnosis of median nerve abscesses was confirmed. The patient was treated with multi drug therapy for leprosy and oral steroids.
|How to cite this article:|
Kamath PR, Rao SS, Shenoy MM. Multiple median nerve abscesses: A rare presentation of leprosy. Arch Med Health Sci 2013;1:57-8
| Introduction|| |
Leprosy, primarily a disease of the peripheral nerves, classically presents with neural or cutaneous signs and symptoms or both. In tuberculoid form of leprosy patient has high degree of resistance and most of the pathological changes are secondary to immune response.  This case is one of the tuberculoid leprosy with highly unusual finding of abscess of the median nerve.
| Case Report|| |
25 year old male presented with pain and swelling around the left elbow and medial aspect of left upper limb since 2 years; aggravated since 6 months. Swelling was insidious in onset, associated with tingling sensation of the hand, paraesthesia and weakness of the left hand. There was no history skin lesions suggesting leprosy or treatment taken for the same in the past. On examination 4 swellings were seen with single lesion each over the postero-medial aspect of arm, and elbow, and two lesions over the anterior aspect of forearm [Figure 1] and [Figure 2]. They were all well circumscribed, tender, soft to firm in consistency and the distribution suggests that they were along the course of the median nerve. Ulnar and median nerves at the site of palpation were thickened & tender. Motor system examination revealed that muscles of the hand had a power of grade 3. Sensory examination revealed impaired tactile sensations over the left thenar eminence involving the middle and index fingers. Slit skin smears were negative for lepra bacilli. Biopsy was taken from the swelling near the elbow and was sent for histopathological examination. It revealed fibro-fatty tissue entrapping nerve bundles. The epineurium showed confluent granulomas formed of epitheloid cells surrounded by dense infiltrates of lymphocytes [Figure 3]. Langhan's cells were seen in some granulomas. Fite - Faraco stain for the detection of lepra bacilli was negative. These findings suggest a diagnosis of tuberculoid leprosy. With the conglomeration of clinical, histological and bacteriological findings, final diagnosis of neuritic leprosy with multiple median nerve abscess was confirmed.
|Figure 3: Histopathology showing nerve bundle with granuloma in the epineurium. 400x|
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The patient was treated with multi-drug therapy (WHO MDT) with monthly supervised rifampicin 600 mg and clofazimine 300 mg, plus daily unsupervised dapsone 100 mg and clofazimine 50 mg. It was planned to continue for one year with monthly follow up. He was also given prednisolone 40 mg per day for the management of neuritis and planned for gradual tapering. Surgery was deferred since neurological deficit was minimal. At the end of one month some amount of improvement was noticeable with reduced tenderness in the swellings.
| Discussion|| |
Nerve abscesses are uncommon presentations of leprosy. Incidence of nerve abscess in India is 1.3 % of all patients with leprosy.  They are commonly found in paucibacillary spectrum of the disease, i.e if no acid-fast bacilli are found in tissue or smears.  Bacterial parasitization of peripheral nerve is a unique feature of leprosy.  The usual habitat of the bacteria in the nerve is the Schwann cells but ensheathed axon becomes involved in most instances.  Schwann cells assume a phagocytic function and evolve into macrophages or epitheloid cells, resulting in the formation of granuloma. The resulting neural lesion remains as a granuloma but in few cases the granuloma may soften and develop into an abscess.  Caseation may occur in microscopic foci within the granuloma or areas of necrosis may coalesce forming a cold abscess, particularly when the immunity is high.  The hypothesis is that they are formed due to anoxia produced by stretching and pressure on the nerve secondary to inflammation and vascular damage.  These processes also lead to release of serotonin, which further worsens the oedema. A vicious cycle results causing avascular necrosis of the nerve and the formation of cold abscess. Rarely, however, nerve abscess may also develop in other types of leprosy. Skin lesions may appear later in cases of neuritic leprosy indicating that the disease is primarily neural in inception and all other forms emerge from it. 
This case is unique due to several reasons. In leprosy the most commonly involved nerve is ulnar nerve followed by median nerve, sural nerve, radial and branches of facial nerve  indicating that involvement of median nerve is rare. Occurrence of multiple abscesses is even rarer. In spite of the multiple abscesses, neurological defects were minimal.
| References|| |
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[Figure 1], [Figure 2], [Figure 3]