Start with this link: There are several types. This is a good starting resource. http://www.nlm.nih.gov/medlineplus/ency/article/000587.htm
Answered 4/10/2015
3.9k views
4 doctors weighed in across 3 answers
6 doctors weighed in across 2 answers
4 doctors weighed in across 3 answers
90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.
Ask your question