Abstract | IMPORTANCE: OBSERVATIONS: We report a male patient in his mid-20s with progressive episodes of flaccid muscle weakness, associated low serum potassium levels, and a pathologic decrement in the long exercise test. Because the familial inheritance in the family was initially unknown, thorough diagnostic tests were performed including contrast-enhanced computed tomography scan, which displayed a mass in the anterior mediastinum. The test results for autoantibodies against myasthenia gravis ( acetylcholine receptor, muscle-specific tyrosine kinase, and low-density lipoprotein receptor-related protein 4) and other end plate channelopathies were negative, and test results for hypokalemia-inducing hormones (thyroid, corticotropin, and cortisol) were negative. Surgery identified a thymus of 13 × 8 × 3 cm(3). Histologic analysis was consistent with thymic hyperplasia of the follicular subtype and immunohistologic analysis showed cytokeratin 5/6 in hyperplastic epithelial cells. A 2-year follow-up revealed the postoperative absence of weakness episodes. As in 30% of familial cases, molecular genetics testing failed to identify a mutation in periodic paralysis genes. CONCLUSIONS AND RELEVANCE:
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Authors | Renrong Yang, Karin Jurkat-Rott, Jinlin Cao, Guofeng Wang, Hans-Peter Seelig, Changping Yang, Guibao Liu, Lin Pan, Haiyan Zheng, Frank Lehmann-Horn |
Journal | JAMA neurology
(JAMA Neurol)
Vol. 70
Issue 11
Pg. 1436-9
(Nov 2013)
ISSN: 2168-6157 [Electronic] United States |
PMID | 24061198
(Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Antigens, CD
- Adrenocorticotropic Hormone
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Topics |
- Adrenocorticotropic Hormone
(metabolism)
- Adult
- Antigens, CD
- Exercise Test
- Follow-Up Studies
- Humans
- Hypokalemic Periodic Paralysis
(diagnosis, etiology, surgery)
- Magnetic Resonance Imaging
- Male
- Thymectomy
(methods)
- Thymus Gland
(pathology)
- Thymus Hyperplasia
(complications)
- Tomography, X-Ray Computed
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