Introduction: Acute interstitial pneumonia (AIP), also known as Hamman-Rich syndrome, is a rare idiopathic lung disease that has a high in-hospital mortality. Unfortunately, no clear treatment guidelines exist to guide immunosuppressive therapy in this condition. Case: A 76-year-old male with a past medical history significant for polymyalgia rheumatica on 7.5mg of prednisone and a recent hip replacement 2 month prior was initially admitted for 1 week to an outside hospital, where he was diagnosed and treated for a small right hilar pulmonary embolism. Although he had multiple negative SARS-COV2 PCR, he was empirically treated with remdesivir and decadron given patchy ground glass opacities noted on CT scan. He was then discharged to home with oxygen and prior regimen of 7.5 mg prednisone. Unfortunately, his symptoms acutely worsened and he presented to our institution with severe hypoxia. Interval CT scan showed worsened bilateral ground glass infiltrates, basilar predominance. Bronchoscopy with (BAL) showed neutrophil predominance. Comprehensive infectious disease work up from BAL was unrevealing. Transbronchial biopsy was aborted given the patient's worsening hypoxemia. He required high flow nasal cannula despite receiving 1mg/kg dosing of the methylprednisolone. His comprehensive autoimmune work up including ANCA, Scl-70, CCP, RNP, Jo-1, smith, C3, C4, HIV, SARS-COV-2 antibody were all unrevealing. Patient denied any environmental exposures or inhalants. Patient was started on pulse-dose steroids with 1000mg x 3 days. He was also empirically treated for pneumocystis pneumonia (PJP) given chronic steroid use. Despite these interventions, his oxygenation was slow to improve. Decision was made to start him 500mg BID dosing of mycophenolate. Over the course of the next 4 weeks in the hospital, he was eventually able to be weaned to 5 L nasal cannula and was then discharged home. Follow up HRCT 1 month later in the clinic showed major improvement in bilateral infiltrates. Discussion: AIP is often characterized by rapidly progressive hypoxemic respiratory failure that is refractory to standard treatment. This case presented with clinical course and imaging findings that were consistent with diagnosis of AIP. Surgical biopsy was deemed unsafe given respiratory failure. Based on literature review, there was one other case that described success with mycophenolate use. We describe a case of rapidly progressive interstitial lung disease in a patient without lung parenchymal disease. He was successfully treated with pulse dose steroids and mycophenolate and was able to avoid invasive mechanical ventilation.
Covid-19 mimicker: Treatment of acute interstitial pneumonia during the pandemic