Stelara struck: a case of noninfectious pneumonitis secondary to ustekinumab.

BACKGROUND: We describe a case of acute hypoxic respiratory failure due to drug induced lung disease secondary to ustekinumab, which is a monoclonal antibody used to treat psoriasis, psoriatic arthritis, and inflammatory bowel disease. CASE PRESENTATION: A 33-year-old man with a history of Crohn's disease presented with fevers, myalgias, and abdominal pain, and subsequently developed acute hypoxemic respiratory failure approximately 2 weeks after restarting ustekinumab for his Crohn's disease. Cross-sectional chest imaging showed ground glass opacities and bilateral consolidations. Due to progressive hypoxia, he ultimately required intubation and mechanical ventilation. Broad infectious and autoimmune work up was negative, making drug induced interstitial lung disease (DILD) the leading consideration. He was treated with high dose steroids with dramatic improvement in his respiratory status. At follow up, his imaging findings had largely resolved, and his pulmonary function tests were normal. CONCLUSIONS: For patients presenting with acute hypoxic respiratory failure, it is critical to identify the underlying cause. In addition to testing for common respiratory infections that can cause respiratory failure, patients should also be evaluated for risk factors for developing atypical or opportunistic infections as well as inflammatory pneumonitis. Due to receiving ustekinumab, our patient was both at risk for developing an opportunistic infection as well as DILD. Although rare, DILD is a recognized toxicity of ustekinumab. Ustekinumab can cause significant lung injury, as in our patient, but with steroids and avoidance of future doses of the medication, our patient demonstrated good recovery. Reassuring outcomes have similarly been described in the literature; however, this case provides further details about outcomes with long-term follow-up clinical, imaging, and pulmonary function testing data available. We recommend consideration of high dose steroids for these patients for whom DILD is suspected.