Absolutely!
Pyometra
http://www.peteducation.com/article....2+2109&aid=918
http://petsmd.com/Health/Dogs/Pyometra
http://omalmalamutes.com/omal/pyometra.htm
My dog, Luma, is a Siberian Husky (IOW, hyperactive!) and loves to jump up and give me kisses every morning. She never leaves a bit of her home-cooked food in her bowl.
But last Tuesday, something changed. One morning, she didn't get out of her bed. I tried to say "good morning" to her, but she wouldn't even lift her head. I asked her if she was hungry, but no response. I forced myself to stay calm and tried to feed her… but she wouldn't eat. I knew something was wrong before I even touched her skin, which was extremely hot. Then I noticed that she had some cloudy white/yellow vaginal discharge.
My husband and I got her to the vet, where we found out she had a temperature of 103.5 (high fever in a dog) and a very high white blood cell count, indicating a possible infection. They wanted to keep her overnight. They told us they would need to do an emergency spay the next morning.
We prayed and prayed, and were able to bring her home the next afternoon (Wednesday). We carefully kept her away from her sister (litter-mate) for an entire week.
Then this morning… my husband took her and her sister outside, and when he brought them back in, he told me she was bleeding from her vagina. I immediately knew that was wrong. Within the 10 minutes it took us to quickly get dressed, Luma passed several huge blood clots. I got her into the car while my husband locked up. Then blood started, quite literally, pouring from her vagina. On the way to the vet, she laid her head down, and I was terrified she had passed.
Thankfully we made it to the vet within 30 minutes of the start of the bleeding. They got her into emergency surgery (again). According to the vet, they were able to stabilize her and within a few hours, she was waking up from her surgery and starting to walk around. The vet told me that the leftover uterine stump had rotted away and exposed a blood vessel. She had lost a large amount of blood. But she's okay… praise the Lord! God-willing, we will be picking her up tomorrow afternoon.
Please, please spay your pets.
Pyometra is always fatal if left untreated! And it is more common than you would think.