Evaluation of neuromuscular symptoms in UK Gulf War veterans: a controlled study.

OBJECTIVES To determine whether Gulf War veterans with neuromuscular symptoms that included weakness and fatigue had either 1) objective correlates for muscle weakness or fatigue; or 2) any etiologic explanation for such symptoms; and if so, 3) whether such objective measures or etiologic mechanisms were specific to Gulf War service. METHODS Forty-nine ill Gulf War veterans with more than four neuromuscular symptoms (Gulf-ill) were compared with 26 Gulf-well veterans, 13 symptomatic Bosnian veterans (Bosnia-ill), and 22 symptomatic troops who were not deployed to the Gulf (Era-ill). Quantitative myometry was used to objectively measure weakness and fatigue. Subjects had an ischemic forearm exercise test, a subanaerobic bicycle exercise test, and a muscle biopsy. RESULTS Quantitative strength and fatigue measures did not correlate with self-perception of weakness or fatigue for any of our groups. No specific muscle biopsy abnormalities were found. There was no defect of adenylate deaminase or glycogenolysis found. Gulf-ill subjects did find the subanaerobic bicycle exercise more effortful and generated significantly higher plasma lactate concentrations compared with Gulf-well subjects. CONCLUSION Because complaints of weakness and fatigue in unwell servicemen do not correlate with actual weakness or fatigue, explanations for these symptoms must lie outside of the neuromuscular system. Increased lactate production during subanaerobic bicycle exercise reflects mitochondrial inefficiency, but it is unclear whether this reflects mitochondrial damage sustained during Gulf War service or inactivity secondary to ill health.