A 69-year-old woman was admitted for the treatment of marked
pleural effusions and peripheral
edema. Analytical studies of the
pleural effusion revealed exudates. Culture for bacterial organisms and
tuberculosis were negative, and cytology was normal. She had a mediastinal
tumor at the age of 61 and regular follow-up showed no evidence of
malignancy. She underwent the mediastinal
tumor resection, because we thought this was the cause of her symptoms. However, her clinical symptoms persisted after surgery. Next, we noticed subclinical
hypothyroidism, in which serum TSH level was elevated with concomitant normal
thyroid hormone levels. In addition, serum
vascular endothelial growth factor (
VEGF) levels, which have been reported to be related to the pathophysiology of the extravascular volume overload, were elevated. Although her TSH level was slightly elevated (15.4 microU/ml), we started
thyroid hormone replacement
therapy. This
therapy gradually ameliorated her clinical manifestation and abnormal laboratory data, including elevated
VEGF levels. These observations indicate that even subclinical
hypothyroidism may cause severe clinical manifestations. Furthermore, elevated
VEGF may be a contributing factor in the pathogenesis of extravascular volume overload in hypothyroid patients.