Throes refers to a condition of agonizing struggle or difficulty. It is the word used in the phrase in the throes of, which means to be in the midst of (something difficult). Because throes are by definition violent, painful, or otherwise agonizing, it doesn’t make much sense to use in the throes of as a neutral synonym of in the midst of. For example, it would be odd to say, “We are in the throes of an economic recovery”—this phrase comes from a recent news story—because an economic recovery is certainly not violent or painful.
Examples
But the country is in the throes of civil war, and the hotel is struggling. [NOW Toronto]
The officers found a passenger in the vehicle in the throes of a drug overdose. [Victoria Times Colonist]
As cities are in the throes of dealing with tight budgets, many look at charging “user fees” instead of raising property taxes or cutting services. [Pioneer Press (article now offline)]