Rheumatoid Arthritis (RA): Although RA typically presents with symmetrical joint involvement, some cases can be asymmetrical, especially in the early stages. The presence of polyarthritis, raised IgG levels, and potential extra-articular manifestations like hepatitis align with RA, especially considering the mention of MR (which could imply magnetic resonance imaging findings consistent with RA).

Systemic Lupus Erythematosus (SLE): SLE can present with a wide range of symptoms including polyarthritis, hepatitis, and elevated IgG levels. The disease is known for its variability and can affect multiple organ systems.
Psoriatic Arthritis (PsA): PsA can cause asymmetrical polyarthritis and is associated with psoriasis. Some patients may also have elevated liver enzymes suggestive of hepatitis, and raised IgG levels can be seen in the context of chronic inflammation.
Mixed Connective Tissue Disease (MCTD): MCTD overlaps with several autoimmune diseases including RA, SLE, and scleroderma. It can present with polyarthritis, elevated IgG levels, and potential liver involvement.

Adult-Onset Still's Disease (AOSD): AOSD is a rare condition that can present with high fevers, polyarthritis, and elevated liver enzymes. It's crucial not to miss this diagnosis due to its potential for severe complications if left untreated.
Hepatitis-Associated Arthropathy: Certain forms of hepatitis, especially hepatitis B and C, can be associated with arthropathy. The presence of hepatitis alongside arthritis warrants consideration of this diagnosis.

Sjögren's Syndrome: While primarily known for causing dry eyes and mouth, Sjögren's syndrome can also present with polyarthritis and elevated IgG levels. Hepatitis can be a rare manifestation.
Sarcoidosis: Sarcoidosis is a condition that can affect multiple organs, including the joints and liver. It can present with polyarthritis, hepatitis, and elevated IgG levels, although this combination is less common.