Which condition is NOT a known cause of weight loss?

High blood pressure, or hypertension, is not typically associated with weight loss as one of its known causes. While some conditions can lead to weight loss due to underlying metabolic changes that alter appetite or energy expenditure, hypertension itself does not have a direct effect that would result in significant weight loss.

Chronic infections, malignancies, and hyperthyroidism are all conditions that can increase metabolic demands or alter body function in ways that can lead to unintentional weight loss. Chronic infections, for example, can cause systemic inflammation, which may decrease appetite and lead to weight loss. Malignancies often cause weight loss due to increased energy expenditure and changes in metabolism. Hyperthyroidism accelerates metabolism significantly, frequently resulting in noticeable weight loss despite an increased appetite.

Therefore, while high blood pressure is a serious health issue that requires management, it does not typically lead to weight changes in the same way that the other listed conditions do.