Which statement is true regarding rheumatoid arthritis and osteoarthritis?

• A. Both rheumatoid arthritis and osteoarthritis are caused by bacterial infections.
• B. Osteoarthritis typically affects younger individuals, while rheumatoid arthritis only affects the elderly.
• C. Rheumatoid arthritis is an autoimmune disease, while osteoarthritis is primarily caused by wear and tear of joints.
• D. Rheumatoid arthritis and osteoarthritis both involve only the cartilage and never affect the synovial membrane.

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the two conditions mentioned in the problem: rheumatoid arthritis and osteoarthritis. Rheumatoid arthritis is an autoimmune disease, meaning the immune system mistakenly attacks the body's own tissues, including the joints. Osteoarthritis, on the other hand, is primarily caused by mechanical wear and tear on the joints over time.
2. Step 2: Analyze the first statement: 'Both rheumatoid arthritis and osteoarthritis are caused by bacterial infections.' This is incorrect because rheumatoid arthritis is autoimmune in nature, and osteoarthritis is due to wear and tear, not bacterial infections.
3. Step 3: Evaluate the second statement: 'Osteoarthritis typically affects younger individuals, while rheumatoid arthritis only affects the elderly.' This is also incorrect. Osteoarthritis is more common in older individuals due to cumulative joint wear, while rheumatoid arthritis can affect individuals of various ages, including younger adults.
4. Step 4: Assess the third statement: 'Rheumatoid arthritis is an autoimmune disease, while osteoarthritis is primarily caused by wear and tear of joints.' This is correct because it accurately describes the underlying causes of both conditions.
5. Step 5: Review the fourth statement: 'Rheumatoid arthritis and osteoarthritis both involve only the cartilage and never affect the synovial membrane.' This is incorrect because rheumatoid arthritis can affect the synovial membrane, leading to inflammation, while osteoarthritis primarily involves cartilage degradation but can also affect other joint structures.