Although there are rare occasions when arthritis affects the heart, eyes, or lungs, it predominantly affects the joints. It is often divided into four main types:
• Degenerative Arthritis: This usually affects large joints such as the hips and knees, particularly in the elderly (e.g. osteoarthritis).
• Inflammatory Arthritis: Usually affects small joints and can affect anyone of any age (e.g. rheumatoid arthritis).
• Infectious Arthritis: Usually an infection caused by a virus, bacteria, or fungus.
• Metabolic Arthritis: Usually caused by irregularities in levels of uric acid in human cells (e.g. gout).