A patient presents with bilateral knee pain and morning stiffness. What is the likely underlying condition?

Bilateral knee pain accompanied by morning stiffness is strongly suggestive of rheumatoid arthritis. This autoimmune condition characteristically affects multiple joints symmetrically and often presents with stiffness that is most pronounced in the morning or after periods of inactivity. The duration of morning stiffness in rheumatoid arthritis typically lasts for more than 30 minutes, which can help differentiate it from other types of arthritis.

In contrast, osteoarthritis tends to cause stiffness that improves relatively quickly within 30 minutes after beginning movement, and it often affects joints asymmetrically. Gout usually presents as acute, unilateral episodes of pain and swelling, often beginning suddenly and can be associated with specific triggers, such as dietary factors. Septic arthritis typically presents with rapid onset of severe joint pain, swelling, and fever, often affecting a single joint rather than bilaterally.

Thus, the presence of bilateral knee pain paired with morning stiffness points toward rheumatoid arthritis as the most likely underlying condition.