Case Report: IgG4 related disease masquerading as Tuberculosis
A. Gorman, S, Cowley, A. Camon,I. Osman,S. Khan, A. Mohammad, K P. O`Rourke
Department of Rheumatology, Midlands Regional Hospital, Tullamore, Co Offaly
IgG4 related disease is a fibro-inflammatory condition characterised by dense phoplasmacytic infiltrations.  It has variety of clinical presentations and as a result it can be difficult to diagnosis. 
A 62 year old male present to the Emergency department with a one month history of night sweats, pyrexia and right cervical lymphadenopathy. His past medical history included hypertension and osteoarthritis. He had a similar presentation four years previously (2013) with fevers and night sweats. Magnetic resonance imaging of spine revealed multiple bilateral T1 and T2 hyper-intense lesions in the inter costal regions and soft tissue thickening adjacent to T7/T8. Computeed tomography (CT) guided biopsies in 2013 showed no evidence of malignancy and Tuberculosis (TB) culture was negative.He was reviewed by a respiratory team which specialised in TB and commenced on anti TB treatment for probable TB. He was intolerant of it at that time. Symptoms gradually improved without treatment.
On admission, his ESR was 65( nor 0-10)with a CRP 68 ( n <5). Rheumatoid factor, anti CCP, ANCA,ANA,PSA, CEA,AFO CA 19.9,CA 125, Immunoglobulins, bartonella serology, coxiella antibodies renal profile and liver function were all within normal range. Multiple blood cultures were negative. His IgG4 level was elevated at 0.900 ( nr 0.039-0.864).QuantiFeron test was positive however multiple TB cultures were negative. CT Neck, Thorax and Abdomen confirmed the presence of a 3.8cm lymph node mass in the right jugulogastric region. Numerous other enlarged lymph nodes were noted. A 4.3 cm paraspinal soft tissue density mass was present at T6-7 as well as further paraspinal mass. MRI spine confirmed lesions adjacent to T7-T8 Bone marrow biopsy showed no evidence of lymphoma.An excision lymph node biopsy was performed. Histology revealed elevated IgG4 plasma cell with probable histological features of IgG4 related diseases such as fibrosis and phlebitis.
He was commenced on prednisone 60mg tapering by 10mg a week and scheduled for rituximab infusion. He was also started on Isonazid and Pyrixodine as his QuantiFeron test was positive prior to commencing on rituximab infusion.
IgG4 related diseases clinical presentation can be non specific and as a result can lead to misdiagnosis and a delay in receiving treatment.  In this case the patients first presentation was in 2013. Glucocorticoids are considered the first line theory for IgG4 related disease .  The duration and tapering of the glucocorticoid regimen is still a matter of debate. Rituximab is emerging as the theory of choice for non responders and patients with episodes of relapse.