Contact us at 509-838-6500 or visit us at 105 W 8th Ave, Suite 6080, Spokane, WA 99204: Arthritis Northwest PLLC. 509-838-6500 Patient Portal. Who We Are. Our Mission; Meet Our Providers; Directions; What We Do. About Practice; Services. Rheumatoid Arthritis; Psoriatic Arthritis; Ankylosing Spondylitis; Gout; Pseudogout;.