I have used very similar analogies in the past, but this author, Christine Miserandino, uses spoons as a metaphor for the limited amount of energy she has each day as a sufferer of lupus.
Reading this, I teared up at several points. It reminds me of something I once wrote regarding how I have to plan each step of my day and contemplate every little decision, always hyper-aware that an everyday occurrence could be the trigger for my next Migraine.
Check it out. I think anyone reading my blog will find it a good, sad, realistic read.