e67 Adrenal insufficiency in granulomatosis polyangitis

Abstract

Background: Granulomatosis with polyangiitis (GPA) is a multisystem small vessel vasculitis which can result in multi-organ damage if left untreated. Glucocorticosteroids are a cornerstone in the management of GPA, of which the side effects are well documented. Adrenal insufficiency is a potentially life-threatening side effect which can occur despite a slow steroid weaning regimen. We present a case of ANCA negative GPA complicated by adrenal failure secondary to oral prednisolone. Methods: A 43-year-old athletic male presented to rheumatology with elevated inflammatory markers and constitutional symptoms of weight loss, diaphoresis and fatigue. Over the preceding five years he had numerous separate encounters in the private healthcare sector concerning colitis, idiopathic thrombocytopenic purpura, sinusitis, orbital myositis and a recurrent rash. Previous imaging revealed abdominal lymphadenopathy and splenomegaly and severe sino-nasal inflammation. Immunology was unremarkable including a negative ANCA. A chest x-ray requested by Rheumatology revealed a large lung mass. CT PET detailed a 7cm mass with necrosis in the right upper lobe with multiple lung, hilar and mediastinal nodules. Video assisted thoracoscopic biopsy revealed necrotising granulomas and diagnosis of GPA was confirmed. He was successfully treated with oral methotrexate 15mg weekly and a 18 month weaning regime of oral prednisolone commencing at 60mg daily. Four days after stopping prednisolone he developed diarrhoea and vomiting. He had a tonic clonic seizure and was intubated and admitted to ITU. Initial plasma sodium concentration was 105 mmol/ litre with a normal potassium. Notably his plasma cortisol and ACTH was undetectable. He was treated with intravenous hydrocortisone and made a full recovery. A short synacthen test performed following discharge confirmed adrenal failure. Results: The absolute risk of adrenal crisis after cessation of glucocorticoids is considered rare, but it is likely to be substantially underreported in clinical practice. Secondary adrenal insufficiency can result from a rapid discontinuation of long term glucocorticoid therapy due to hypothalamic-pituitary-axis (HPA) suppression and adrenal atrophy and may persist for up to 18 months after withdrawal. Glucocorticoids administered via the nasal, topical and intra-articular route have been implicated indicating there is no route, dose, treatment duration, or underlying disease for which adrenal insufficiency can be excluded with certainty. In our case, adrenal failure was exacerbated with the development of gastroenteritis. Our patient continues on hydrocortisone therapy with no recovery of adrenal function six months following his intensive care admission. Conclusion: This case depicts the need for continued diligence for adrenal failure in patients with GPA even when glucocorticoids are withdrawn gradually. We suggest a low threshold for testing the HPA axis to identify patients who are safe to discontinue glucocorticoids.