Abstract
Background/Aims
Rheumatological conditions can present with a number of non-specific features like arthralgia, fever, fatigue, weight loss along with raised inflammatory markers and positive antibodies. Due to this, when similar symptoms are referred for input it is very important to consider other ‘mimics’. We report a case of Pigeon fancier’s lung presenting with these symptoms which was referred as likely connective tissue disease.
Methods
A 52-year-old lady of South Asian origin was referred by her GP with six month history of 3kg weight loss, arthralgia, fatigue, low grade fever and persistently raised inflammatory markers (ESR ranging from 50-64 mm/hr, CRP 10-14 mg/L, normal BMI). On further questioning there was history of mouth ulcers, non-specific rash, occasional cough but no Raynaud’s or joint swelling. Blood investigations showed weakly positive ANA and RF but negative ENA, DNA, antiCCP , CK, C3,C4. C-ANCA was positive but PR3 negative. CXR was clear and tests for chronic infections including TB were negative. Due to lack of objective CTD signs, plan was to take a careful monitoring approach to see if clinical features evolved. A month later due to worsening cough, a CT chest/abdomen arranged by GP showed ground-glass changes consistent with pneumonitis and hence her rheumatology appointment was expedited to see if there was an autoimmune unifying diagnosis. She was also referred by her GP to the chest clinic in view of CT report and mild shortness of breath.
Results
On further review, again there were no objective CTD signs. On direct questioning there was history of travelling before worsening chest symptoms to South Asia. Also around a year before her symptoms started she was given an African grey parrot. Based on this, serology for Avian precipitin was checked which showed strongly positive IgG antibodies to avian antigens (Budgerigar droppings and feathers, Pigeon feathers IgG Abs) confirming the diagnosis of pigeon fanciers lung. She fulfilled the diagnostic criteria and was asked to avoid the trigger. Urgent respiratory input was arranged where diagnosis was agreed with and disease was deemed sub-acute in presentation. Due to PFTs showing low transfer factor of 38%, Prednisolone was started with significant improvement within few days. Review of CT chest only showed inflammatory changes and no established fibrosis predicting excellent prognosis as delay in treatment can cause irreversible pulmonary fibrosis.
Conclusion
A number of conditions can mimic rheumatological conditions which usually turn out to be either infectious or malignant in origin. This case highlights the importance of considering other differentials and along with taking a travel history also asking for other possible triggers like pets. In similar scenarios the diagnosis may be ‘cagey’ but as rheumatologists we are expected to answers questions which others can’t.
Disclosure
M.F. Kazmi: None.
Out of Asia? Vector switches leading to the expansion of Eurasian Lyme disease bacteria
