About Us
Meet Our Practitioners
Irina Frenkel, FNP
Irina Frenkel, FNP is a certified family nurse practitioner (NP) who has practiced functional medicine for the majority of her career. She obtained her nursing degree from Loyola University and her Master’s degree from DePaul University in Chicago. While teaching and working on her research in chronic disease reversal, she identified that there are drug-alternative methods to keeping the body balanced and healthy. Through a commitment to healthy lifestyle choices, she was able to improve her own pancreatic function after a diabetes diagnosis. Since then, she has made it her mission to educate her patients on how to achieve the best possible health outcomes.
Sarah Brown, DNP, CNM, WHNP
Sarah Brown, DNP, CNM, WHNP is a certified nurse midwife and women’s health nurse practitioner (NP). She has experience working in pediatrics, labor & delivery, community birth, and gynecology settings. She obtained her doctorate degree from University of Illinois at Chicago. A primary passion of Sarah’s is physiologic birth, which involves moving through labor, birth, and postpartum in a way that prioritizes a woman’s natural body processes and capabilities. Functional medicine is also an interest to Sarah as she recognized a profound intersection with her own specialty. While finishing her program at UIC, Sarah began working at retreat as a nurse and has since joined the team as a provider. She plans to integrate her knowledge in reproductive and intimate health with her functional medicine training to optimize health outcomes from puberty to menopause, and everything in between.
Savannah Catalano, PEC
Savannah Catalano is the Patient Experience Coordinator at Retreat. She brings a diverse background in personal training, gym operations management, and engineering recruiting, which allows her to approach patient care with both empathy and organization. Savannah has a strong passion for fitness and cooking, and she believes that feeling good in one’s body is foundational to overall well-being. She joined Retreat in November 2025 and is dedicated to ensuring every patient feels safe, comfortable, and supported from the moment they walk through the door. Savannah is committed to creating a welcoming environment where patients can focus on healing, restoring their bodies, and getting back to feeling their best.
Kelli Walewander, BSN, Lead RN
Kelli serves as the Lead Registered Nurse at Retreat Care, bringing a strong background in emergency and prehospital medicine to her role. She holds a Bachelor of Science in Nursing (BSN) and is a licensed Registered Nurse with over seven years of experience as an Emergency Room nurse, along with five years of prior experience as a paramedic.
Currently, Kelli is pursuing her Doctor of Nursing Practice as a Family Nurse Practitioner (DNP-FNP), with a professional interest in functional health and preventative care. Her approach to patient care emphasizes a balanced model that integrates evidence-based healthcare while prioritizing proactive, preventative strategies to support long-term health and wellness.
Known for providing experienced, compassionate nursing care, Kelli is committed to creating a comfortable, welcoming environment where patients feel supported, heard, and empowered throughout their care journey.
Patient Reviews
"I would highly recommend Retreat if you are looking for a wholistic and sustainable way to improve your health."
"I’ve experienced sustainable results beyond what I imagined was possible. Because of this place I’m excited to see what lies ahead when it comes to my health."
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