Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Obstruction, threatened vision or major-vessel disease
Cholangitis with jaundice, bilateral ureteric obstruction, rapidly declining kidney function, orbital apex or optic-nerve compression, hypertrophic pachymeningitis, aortitis or impending aneurysmal complication requires organ rescue before prolonged diagnostic sequencing.
Action: Admit under the relevant surgical or medical team, drain infected biliary or urinary obstruction and protect vision, neural function or vascular integrity, obtain cancer and infection tissue where safely possible, then begin specialist glucocorticoid or rituximab treatment once diagnostic probability is adequate.
Synopsis
Recognise the organ patterns of IgG4-related disease, distinguish inflammatory enlargement from cancer and infection, obtain architecture-preserving tissue with expert pathology, and prevent irreversible pancreatic, biliary, renal, orbital, neural and retroperitoneal fibrosis.
IgG4-related disease is a relapsing fibroinflammatory condition that forms tumefactive lesions in pancreas, bile ducts, salivary and lacrimal glands, orbit, kidneys, retroperitoneum, aorta, lung, meninges and pituitary.
Serum IgG4 supports but does not diagnose disease: mild elevation occurs in allergy, infection and malignancy, and a meaningful minority of biopsy-proven patients have a normal concentration.
First diagnostic priority is to exclude cancer and infection before corticosteroid, especially with a focal pancreatic or biliary mass, destructive lesion, atypical nodes or constitutional decline.
Key red flags
Fever, rigors, jaundice, hypotension or a dilated obstructed biliary tree suggests ascending cholangitis and requires antibiotics and urgent drainage before immune suppression.
Retroperitoneal and vascular pattern
A periaortic soft-tissue mantle, ureteric encasement, hydronephrosis, inflammatory aneurysm or periarteritis indicates urgent structural mapping.
Investigation priorities
01
First-line organ and biochemical mapFirst stepFirst line
Identify active sites, obstruction and a safe biopsy target before treatment.
Management branches
First diagnostic sequenceExclude cancer, map organs and preserve tissue
A pancreatic, glandular, orbital, renal or retroperitoneal lesion raises IgG4-related disease.
Stabilise cholangitis, renal obstruction, visual, neurological and vascular threats and obtain cross-sectional imaging of the presenting and common associated organs.
Measure serum and organ baselines, then select an architecture-preserving core from the safest representative site before glucocorticoid where possible.
First-line inductionUse glucocorticoid with an objective early checkpoint
Active symptomatic or organ-threatening disease is secure enough for treatment and untreated infection is excluded.
Key medicines
PrednisoloneStart approximately 0.6 mg/kg orally once daily for two to four weeks in active disease, then reduce every one to two weeks toward cessation over about three to six months according to organ response and relapse risk.
RituximabGive 1000 mg intravenously on days 1 and 15 under an off-label IgG4-related disease protocol; retreatment is based on organ relapse and immune recovery rather than a fixed automatic cycle.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.