Steroid Therapy and Steroid Response in Autoimmune Pancreatitis

Abstract

Autoimmune pancreatitis (AIP), a unique subtype of pancreatitis, is often accompanied by systemic inflammatory disorders. AIP is classified into two distinct subtypes on the basis of the histological subtype: immunoglobulin G4 (IgG4)-related lymphoplasmacytic sclerosing pancreatitis (type 1) and idiopathic duct-centric pancreatitis (type 2). Type 1 AIP is often accompanied by systemic lesions, biliary strictures, hepatic inflammatory pseudotumors, interstitial pneumonia and nephritis, dacryoadenitis, and sialadenitis. Type 2 AIP is associated with inflammatory bowel diseases in approximately 30% of cases. Standard therapy for AIP is oral corticosteroid administration. Steroid treatment is generally indicated for symptomatic cases and is exceptionally applied for cases with diagnostic difficulty (diagnostic steroid trial) after a negative workup for malignancy. More than 90% of patients respond to steroid treatment within 1 month, and most within 2 weeks. The steroid response can be confirmed on clinical images (computed tomography, ultrasonography, endoscopic ultrasonography, magnetic resonance imaging, and ¹⁸F-fluorodeoxyglucose-positron emission tomography). Hence, the steroid response is included as an optional diagnostic item of AIP. Steroid treatment results in normalization of serological markers, including IgG4. Short- and long-term corticosteroid treatment may induce adverse events, including chronic glycometabolism, obesity, an immunocompromised status against infection, cataracts, glaucoma, osteoporosis, and myopathy. AIP is common in old age and is often associated with diabetes mellitus (33-78%). Thus, there is an argument for corticosteroid therapy in diabetes patients with no symptoms. With low-dose steroid treatment or treatment withdrawal, there is a high incidence of AIP recurrence (24-52%). Therefore, there is a need for long-term steroid maintenance therapy and/or steroid-sparing agents (immunomodulators and rituximab). Corticosteroids play a critical role in the diagnosis and treatment of AIP.

Keywords: IgG4; autoimmune pancreatitis; corticosteroid; treatment.

Figure 1

A timetable of standard oral corticosteroid therapy.

Figure 2

A case of Mikulicz disease with autoimmune pancreatitis (AIP) accompanied by multiple immunoglobulin G4 (IgG4)-related systemic lesions in a 70 year-old female patient. (a) Visualization by 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) of systemic inflammatory lesions with abnormal FDG uptake (the arrow heads indicate from the top to the bottom: dacryoadenitis, sialadenitis, mediastinum lymphadenopathy, hepatic pseudotumor, autoimmune pancreatitis, and choledocho-chlecystitis. (b) Disappearance of the lesions 3 months after steroid initiation. (c) Computed tomography before steroid treatment demonstrated an enlarged pancreas with a capsule-like rim (thin arrow) and markedly thickened hilar bile duct (thick arrow). (d) Computed tomography 1 year after steroid initiation revealed pancreatic parenchymal shrinkage and improved bile duct thickness. (e) Abdominal ultrasonography before (f,h,j) and 2 months after (g,i,k) steroid therapy showed a dramatic improvement in the size of the pancreas, as well as wall thicknesses of the gallbladder up to the hilar bile duct (white arrows).

Figure 2

A case of Mikulicz disease with autoimmune pancreatitis (AIP) accompanied by multiple immunoglobulin G4 (IgG4)-related systemic lesions in a 70 year-old female patient. (a) Visualization by 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) of systemic inflammatory lesions with abnormal FDG uptake (the arrow heads indicate from the top to the bottom: dacryoadenitis, sialadenitis, mediastinum lymphadenopathy, hepatic pseudotumor, autoimmune pancreatitis, and choledocho-chlecystitis. (b) Disappearance of the lesions 3 months after steroid initiation. (c) Computed tomography before steroid treatment demonstrated an enlarged pancreas with a capsule-like rim (thin arrow) and markedly thickened hilar bile duct (thick arrow). (d) Computed tomography 1 year after steroid initiation revealed pancreatic parenchymal shrinkage and improved bile duct thickness. (e) Abdominal ultrasonography before (f,h,j) and 2 months after (g,i,k) steroid therapy showed a dramatic improvement in the size of the pancreas, as well as wall thicknesses of the gallbladder up to the hilar bile duct (white arrows).

Figure 3

A case of focal-type AIP with sclerosing cholangitis at the hilar and intrahepatic bile ducts in a male 70 year-old patient. Magnetic resonance cholangiopancreatography before steroid treatment showed (a) multiple biliary stenosis at the hepatic hilum (arrow heads) and intrahepatic bile ducts, with improvements 3 months after steroid therapy (b).

Figure 4

A steroid response in a pancreatic cyst of an AIP patient. Computed tomography demonstrated a unilocular cyst (arrow) at the pancreas tail, 15 mm in size, at the initial diagnosis of AIP (a). The cyst disappeared after steroid initiation (b).