An unusual cause of stridor

A 12-month-old infant was referred with a 6-week history of recurrent admissions with worsening stridor. On each previous admission, the stridor responded well, but transiently, to oral dexamethasone. At this presentation, he required high-dependency unit care with high flow oxygen due to marked increased work of breathing. He was born at term, previously well, and up to date with immunisations. There was no significant family history. There were no smokers and two cats at home. He was afebrile with moderate subcostal recession and tracheal tug. On auscultation, breath sounds were normal with transmitted sounds of inspiratory and expiratory stridor. The rest of his examination was normal. He commenced dexamethasone 0.15 μg/kg three times a day, which was weaned as his clinical status improved. Blood tests showed total white cell count 9 x 10ˆ9/L, CRP Question 1 Please list four differentials for this child9s mediastinal mass. Question 2 Which of these approaches would be suitable at this stage? CT-guided biopsy Bronchoscopic biopsy Excision biopsy Watch and wait and monitor response to steroids Question 3 What is first line treatment for Mycobacterium avium complex lymphadenitis? Complete excision Clarithromycin and complete excision Clarithromycin, rifampicin, ethambutol and complete excision Isoniazid, rifampicin, pyrazinamide and ethambutol and complete excision Answers can be found on page 2.