Internist Staff

Meet our Practice of University-trained and Board-certified Internists and Allergist

Internal Medicine


Allergy, Asthma, and Immunology


 Sheila D. Ballintine, MD 

Sheila D. Ballintine, MD received a bachelor of science in Biology from Boston College. She returned to her home state of New Jersey to complete her medical degree at Rutgers- Robert Wood Johnson Medical School. She then came to Chicago where she completed her training in Internal Medicine at Northwestern University, where she also completed the Women’s Health Track. Her clinical interests include   preventive medicine, diet and exercise counseling, and patient education.


 Amy C. Chen, MD 

Dr. Amy C. Chen is an internal medicine doctor. She received both her bachelor's degree and her medical degree from Northwestern University. She stayed with Northwestern to complete her residency training in internal medicine. She held faculty appointments at UCLA David Geffen School of Medicine and Oregon Health & Sciences University before returning to Chicago to join MAI. She enjoys partnering with her patients to achieve mutual health goals so that they can live better and be more fulfilled. Her clinical interests include chronic disease management, cancer survivorship, and well-woman care.


 Angelo A. Costas, MD, SC

Angelo A. Costas, MD graduated from Loyola University Chicago, prior to attending Loyola University - Stritch School of Medicine. He went on to complete his residency training in Internal Medicine at Northwestern University where he had the distinction of spending an additional year as Chief Resident of the Internal Medicine program. He currently holds a faculty appointment at Northwestern University – Feinberg School of Medicine as an Assistant Professor of Medicine. His special interests include preventive medicine and hypertension. His practice is a concierge practice which significantly limits the number of patients in his practice. Please contact the office for specific information.  


 Ami P. Desai, MD, SC

Ami P. Desai, MD completed her undergraduate training at Northwestern University where she received degrees in Psychology and Biology. She received her medical degree from the University of Illinois-Chicago. She completed her residency training in Internal Medicine at Northwestern University where she also had the distinction of spending an additional year as Chief Resident of the Internal Medicine program. She currently holds a faculty appointment at Northwestern University – Feinberg School of Medicine as a Clinical Instructor of Medicine. Her clinical interests include preventive medicine and patient education.  Dr Desai's  practice is a concierge practice which significantly limits the number of patients in her practice Please 312-922-3842 for specific information.  


 Greg D. Ewert, MD, SC

Greg D. Ewert, MD received a bachelors of science in Biology from the University of Illinois. He stayed with the University of Illinois for his medical school training. He completed his training in Internal Medicine at Northwestern University where he spent an additional year completing a fellowship in Sports Medicine. He currently holds a faculty appointment at Northwestern University – Feinberg School of Medicine as an Assistant Professor of Clinical Medicine. Dr. Ewert believes in comprehensive medical care of patients with a focus on optimizing health through diet, exercise, and other preventive measures. His practice is a concierge or retainer practice which significantly limits the number of patients in his practice. Please contact the office for specific information.  


 Vivien H. Goh, MD 

Vivien H. Goh, MD completed her undergraduate training at Washington University in St. Louis where she received her bachelor’s degree in Psychology and Public Health. She then came to Chicago where she received her medical degree from the University of Illinois College of Medicine at Chicago. She completed her residency training in Internal Medicine at Northwestern University. Her clinical interests include preventative medicine, patient education and wellness counseling, women’s health, and cardiovascular disease.


 Louis Hiotis, MD, SC

Louis Hiotis, MD completed his undergraduate degree in Biochemistry from Benedictine University. He received his medical degree from Loyola University-Stritch School of Medicine. He then completed a four-year residency in the Combined Internal Medicine and Pediatrics program from the University of Illinois Hospital in Chicago, serving as chief resident during his final year. Board certified in both Internal Medicine and Pediatrics, Dr. Hiotis can see patients of all ages. Currently, however, he limits his practice to those age 14 and older. He currently holds a faculty appointment at Northwestern University – Feinberg School of Medicine as an Assistant Professor of Medicine. His special interests include sports medicine, preventive medicine, hypertension, and cardiovascular disease.  Dr Hiotis'  practice is a concierge practice which significantly limits the number of patients in his practice Please visit his website  www.louishiotismd.com  or call 312-786-5990 for specific information.  


 Evan Ng, MD 

Evan Ng, MD, received both his undergraduate and medical degrees through the Northwestern University Honors Program in Medical Education. He completed his residency training in Internal Medicine at the Northwestern University Feinberg School of Medicine, where he now holds a faculty appointment as a Clinical Instructor. Dr. Ng believes in preventive care and emphasizes a healthy lifestyle through good nutrition and exercise. His clinical interests also include LGBTQ health, men's health, sexually transmitted infections, pre-exposure prophylaxis (PrEP), and travel medicine.  



 Steven N. Paterakos, DO 

Steven N. Paterakos, DO completed his undergraduate degree in Biology at Loyola University Chicago. He received his medical degree from Touro University Nevada Medical School. He completed Internal Medicine residency training at NorthShore University Healthsystem. His special interests include preventive medicine, hypertension, hyperlipidemia, and patient education.



 Shirley Lee TerMolen, MD, SC

Shirley Lee TerMolen, MD received her bachelor’s degree in English Literature from Dartmouth College. She completed her medical training at Ohio State University – College of Medicine. She then came to Chicago where she completed her Internal Medicine training at Northwestern University. Her special interests include well-woman care and preventive medicine.   Dr. TerMolen's practice is a concierge practice that significantly limits the number of patients in her practice  .  Please contact the office at 312-922-1290 or visit  www.shirleytermolenmd.com  for specific information on her practice.



 David A. Vermylen, MD, SC

David A. Vermylen, MD graduated from Princeton University prior to attending Northwestern University's Feinberg School of Medicine. He completed his medical residency at Northwestern, where he had the distinction of serving as Chief Resident for the Internal Medicine program. His clinical interests include preventive care and wellness counseling for men and women of all ages, as well as providing primary care for adults with common and uncommon chronic conditions.     Dr Vermylen's practice is a concierge practice which significantly limits the number of patients in his practice. Please visit his website www.davidvermylenmd.com  or call 312-922-1307 for specific information.   .

 Bradley R. Sabin, MD 

 

Bradley R. Sabin, MD completed his undergraduate degree at the University of Illinois prior to attending the Northwestern University-Feinberg School of Medicine. He completed his residency training in Internal Medicine at Northwestern University where he had the distinction of spending an additional year as Chief Resident of the Internal Medicine program. Dr. Sabin then completed a two-year fellowship in Allergy & Immunology at Northwestern University and Children’s Memorial Hospital.   He currently holds a faculty appointment at Northwestern University – Feinberg School of Medicine as a Clinical Instructor of Medicine. He is board certified in both adult and pediatric allergy & immunology and internal medicine. Dr. Sabin sees both adults and children in allergy & immunology in addition to adults in internal medicine. His special interests include asthma, nasal allergies, sinus disease, chronic cough, hives, and drug and food allergies.