IgG4 related disease

Background

• IgG4-related disease (IgG4-RD) is a systemic fibroinflammatory illness of unknown etiology
• It's a multi organ disease that most commonly affects the pancreas, kidneys, retroperitoneum, salivary glands and orbits

Clinical Features

• No specific symptoms as it is dependent on which organs are affected
• Autoimmune pancreatitis is the most common presentation of IgG4-RD and can be mistaken for malignancy
• Patients do not typically experience generalized symptoms such as fevers or night sweats

Differential Diagnosis

• Pancreatic cancer
• Sjogren's syndrome
• Primary sclerosing cholangitis
• Retroperitoneal fibrosis
• Castleman disease

Evaluation

• Typically, diagnosis not made in the ED

Outpatient Workup

• Tissue biopsy with IgG stain is required for diagnosis
• Serum IgG4 levels are usually elevated and helpful for diagnosis and also helpful for serial monitoring
• C3 and C4 complement levels may be decreased
• Total serum IgG levels may also be elevated

Management

• Prednisone at higher doses is the current standard treatment
• Further immunosuppression may be warranted based on response to prednisone
• Consultation with a rheumatologist is usually necessary