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The neuromuscular pathology of the Eosinophilia-Myalgia syndrome
R J Seidman1, L D Kaufman, L Sokoloff
1Department of Pathology, State University of New York, Stony Brook 11794-8691.
Abstract:
The Eosinophilia-Myalgia Syndrome (EMS) is a recently reorganized disorder in patients ingesting pharmacologic doses of L-tryptophan. We studied the lesions of skeletal muscle, peripheral nerve and skin in 12 cases of EMS. Perimyositis was severe in four, moderate in two, mild in three and absent in three cases. The lesions contained many eosinophils, T-helper cells, mast cells and activated macrophages. Type 2 myofiber atrophy was present in five cases and in one, this was the only pathologic finding. Severe epineurial inflammation was seen in the three sural nerve biopsies. Indirect evidence for peripheral neurologic involvement in three other cases consisted of inflammation surrounding intramuscular nerve twigs (two cases) and neurogenic atrophy (one case). Phlebitis accompanied the connective tissue inflammation in five cases and endarteritis in one. Fasciitis was present in three of four skin biopsies and dermal fibrosis in one.
Insights
Eosinophilia-Myalgia Syndrome (EMS) involves inflammation in muscles, nerves, and skin. Histological examination revealed eosinophils, T-helper cells, and macrophages in affected tissues.
Area of Science:
- Neurology
- Pathology
- Immunology
Background:
- Eosinophilia-Myalgia Syndrome (EMS) is a disorder linked to L-tryptophan supplementation.
- Understanding the pathological basis of EMS is crucial for diagnosis and treatment.
Purpose of the Study:
- To investigate the histological findings in skeletal muscle, peripheral nerve, and skin of patients with EMS.
- To characterize the cellular infiltrate and tissue damage associated with EMS.
Main Methods:
- Histopathological examination of skeletal muscle, sural nerve biopsies, and skin biopsies from 12 EMS patients.
- Analysis of cellular composition including eosinophils, T-helper cells, mast cells, and macrophages.
- Assessment of muscle fiber atrophy and nerve inflammation.
Main Results:
- Perimyositis was observed in 9 out of 12 cases, with varying severity.
- Significant epineurial inflammation was noted in sural nerve biopsies.
- Muscle lesions showed eosinophils, T-helper cells, mast cells, and activated macrophages.
- Type 2 myofiber atrophy was present in 5 cases.
- Skin biopsies revealed fasciitis and dermal fibrosis in most cases.
- Evidence of peripheral neuropathy included epineurial inflammation and neurogenic atrophy.
Conclusions:
- EMS is characterized by significant inflammatory infiltrates in muscle, nerve, and skin.
- The findings support a T-helper cell-mediated inflammatory process in EMS.
- Histopathological analysis is essential for diagnosing and understanding the pathology of EMS.