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Case Report
- Type 2 Fiber Predominance in Patients with Muscle Cramp and Exertional Myalgia: A Report of Three Cases.
- Na Rae Kim, Sung Hye Park, Lim Suh Yeon, Byung Joon Kim
- Korean J Pathol. 2003;37(1):58-61.
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Abstract
PDF - Type 2 fiber predominance or a decrease of the type 1/type 2 ratio was rarely reported as the only abnormal pathologic finding in patients suffering from muscle cramp and myalgia. Here, we describe the clinicopathologic findings of three cases of type 2 fiber predominance, presented with muscle cramp and myalgia in otherwise healthy patients. All of them were young men (18, 19 and 22 years). Light microscopic and neurologic examinations, and laboratory data showed mere nonspecific findings that were not concordant with their subjective symptoms. However, enzyme histochemistry performed on muscle biopsy revealed an increased fraction of type 2 fibers; 73%, 80%, and 75%, in each case. The pathogenesis of this entity remains unclear, but the recognition of this unusual clinicopathologic entity is important for both pathologists and neurologists so they can avoid misdiagnoses or unnecessarily tiresome studies. We emphasize that type 2 fiber predominance should be included in the underlying causes of unexplained muscle cramps and exertional myalgia, especially among young adults, although it remains unclear whether the fiber type predominance is a separate entity or a part of other underlying neurologic or systemic disorders.
Original Article
- Histopathologic Studies of Muscle and Peripheral Nerve Following Ingestion of L-tryptophan in Rats.
- Tae Sik Yoon, Tai Seung Kim, In Joon Choi, Jung Soon Shin
- Korean J Pathol. 1993;27(4):318-327.
- 1,630 View
- 12 Download
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Abstract
PDF
- The eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan in man is defined by the CDC(1989) as follows: 1) eosinophil count more than 1,000 cells per microliter; 2) generalized myaligia(at some point during the course of illness) of severity sufficient to affect a patient's ability to pursue his or her usual daily activities; 3) no evidence of any infection(e.g., trichinosis) or neoplasm that would explain either the eosinophila or the myalgia. The pathologic findings of the eosinophilia-myalgia syndrome varies according to the degree of severity and types of inflammatory cells in the skeletal muscle. In order to simulate this syndrome in animals and further determine its histopathogenesis, L-tryptophan was administered to rats in the laboratory at various doses(25 mg/kg, 50 mg/kg, 150 mg/kg) over a set period of time. In this study, positive histopathologic findings were designated according to the inflammatory cell infiltration of the epimysium and epineurium. Most of the pathologic findings in the positive group were that of inflammatory cell infiltration composed mainly of eosinophils in the epimysial, epineurial connective and surrounding adipose tissues. Only a few necrotic muscle fibers were seen, and there was absence of any evidence of inflammatory cell inflitration in endoneurium or axonal degenerations. Of 59 rats which were given L-tryptophan, 27 rats(45.8%) met the criteria and were designated as belongintg to the positive group. Only 2 rats ingested with L-tryptophan(150 mg/kg) for 2 months and 4 months showed an eosinophil count more than 1,000 cells/microliter. The eosinophil count in the positive group showed significantly different levels when compared to the the negative group and control group. On the other hand, there were no significant differences in the electrodiagnostic study and serum CK, SGOT, SGPT level between the positive, negative and control groups. In summary, histopathologic findings similar to the eosinophilia-myalgia syndrome were inducible in rats followign the administration of L-tryptophan.
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