Question

Describe the musculoskeletal involvement in sarcoidosis.

Hint:

Arthritis is the most common musculoskeletal involvement in sarcoidosis, typically presenting as a non-deforming and non-erosive arthritis in the large joints.

Answer 1

Step 1: Overview of Musculoskeletal Involvement.
Musculoskeletal involvement occurs in about 25-50% of sarcoidosis cases, and it can present in various forms such as arthritis, bone involvement, and muscle pain.
Step 2: Arthritis in Sarcoidosis.
The most common musculoskeletal manifestation of sarcoidosis is arthritis, which typically affects large joints, such as the knees, wrists, and ankles. The arthritis is usually non-deforming and non-erosive, resembling a form of inflammatory arthritis. It is often associated with erythema nodosum (a skin manifestation) and is sometimes accompanied by joint swelling and pain.
Step 3: Muscle Involvement.
Myopathy or muscle weakness can also be seen in sarcoidosis. This muscle involvement is less common but can lead to significant disability. It is typically due to granulomas in the muscles themselves or a systemic inflammatory response.
Step 4: Bone Involvement.
Bone involvement is less common but can present with osteopenia or osteolysis, often due to granuloma formation within the bone or the result of systemic inflammation.