Tracheal enlargement or Mounier-Kuhn syndrome in giant cell arteritis: a possible causal association with therapeutic implications.

Giant cell arteritis (GCA) is a large-vessel vasculitis with rarely described respiratory initial manifestations. We report such a case presenting with hoarseness, stridor, cough and dyspnea, in which a tracheomegaly with tracheomalacia was found. No signs of relapsing polychondritis were present. The respiratory symptoms rapidly improved after glucocorticoids and Azathioprine. Tracheomegaly or Mounier-Kuhn syndrome is characterized by marked dilatation of trachea and central bronchi. The differential diagnosis and the possible relationship between tracheomegaly and GCA involving metalloproteinase-induced elastolysis are discussed. This is the first case, to our knowledge, of Mounier-Kuhn syndrome in vasculitis. The association of tracheomegaly with GCA may be underestimated, as the diagnosis is not always obvious on conventional radiographs. A tracheal enlargement finding in GCA requires monitoring to ensure early detection and prevention of spontaneous tracheal rupture. Adding a metalloproteinase inhibitor like Doxycycline to GCA therapy would be rational for the prophylaxis of complications.