Patient Portal. Sheila Shung, MD, Internal Medicine. Austin, Texas . Your Wellness Is Our Business. We take care of people from 16 to 102 years old. Same day urgent appointments are available for established patients. Call us today: 512-833-0140. Fax: 512-833-0142 . 12319 N. Mopac Expressway. Suite C-240. Austin, Texas 78758 . 12319 N. Mopac ....