Untreated infections, cancer, physical injuries, diseases like Chlamydia going untreated for a long time.
Yes, in the case of chlamydia or gonorrhea
Gonorrhea is the sexually transmitted disease that causes painful urination. It is treatable with modern antibiotics but left untreated can lead to pelvic inflammatory disease and can even affect joints and heart valves.
Gonorrhea is a sexually transmitted infection caused by bacteria that can infect the genital tract, as well as the throat and rectum. Symptoms may include pain or burning during urination, abnormal discharge, and in some cases, no symptoms at all. If left untreated, gonorrhea can lead to serious health complications, such as pelvic inflammatory disease and infertility.
Cats and dogs can die it heart worm is left untreated. Call your vet.
Bacterial vaginosis will not cause blood poisoning, even if left untreated.
If you do anything about it, then by definition you aren't leaving it untreated.
If left untreated, a UTI (urinary tract infection) can potentially turn into a more serious kidney infection.
I believe you are referring to gonorrhea. If so, here is the description:Gonorrhea (also gonorrhoea) is a common Sexually_transmitted_infectioncaused by the bacterium Neisseria_gonorrhoeae(also called Gonococcus, which is often abbreviated as "GC" by clinicians). In the US, its incidence is secondAnswers.comonly to Chlamydia_infectionamong bacterial STDs.Answers.comIn both men and women if gonorrhea is left untreated, it may spread throughout the body, affecting joints and even heart valves.Gonorrhea cannot be spread by sharing toilets and bathrooms.For more information, visithttp://en.wikipedia.org/wiki/Gonorrhea
You can die
If hyperglycemia is left untreated, it can lead to ketoacidosis.
Diseases are "degenerative" in natuture and when left untreated, they damage the body. In the extreme even simple diseases left untreated can cause death.